In Vitro Release Testing (IVRT) of Topical Hydrocortisone Acetate Creams: a novel approach using positive and negative controls
- Mudyahoto, Nyengeterai Amanda, Rath, Seeprarani, Ramanah, Ashmita, Kanfer, Isadore
- Authors: Mudyahoto, Nyengeterai Amanda , Rath, Seeprarani , Ramanah, Ashmita , Kanfer, Isadore
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149849 , vital:38888 , dx.doi.org/10.14227/DT270120P6
- Description: The objective was to develop and validate an in vitro release testing (IVRT) method to assess the release of hydrocortisone acetate (HCA) from five topical formulations. A marketed generic cream containing 1% HCA was used as the reference product. Vertical diffusion cells (VDCs) were used to assess and compare the release rates of HCA from cream formulations containing 0.5%, 1%, and 1.5% HCA. The study describes a novel approach to test the discriminatory power by including both positive and negative controls to declare pharmaceutical equivalence or inequivalence. The validated method was found to be sensitive, linear, precise, reproducible, robust, and selective for the analysis of HCA from topical cream products. Equivalence or inequivalence was established based on SUPAC-SS acceptance criteria using a 90% CI with limits of 75–133.33%. The IVRT method was shown to have discriminatory ability to appropriately measure significant differences in drug release from various cream formulations. This approach also provides useful information for the future development of acceptable IVRT methods to assess topical dosage forms for local action containing different drugs.
- Full Text:
- Date Issued: 2020
- Authors: Mudyahoto, Nyengeterai Amanda , Rath, Seeprarani , Ramanah, Ashmita , Kanfer, Isadore
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149849 , vital:38888 , dx.doi.org/10.14227/DT270120P6
- Description: The objective was to develop and validate an in vitro release testing (IVRT) method to assess the release of hydrocortisone acetate (HCA) from five topical formulations. A marketed generic cream containing 1% HCA was used as the reference product. Vertical diffusion cells (VDCs) were used to assess and compare the release rates of HCA from cream formulations containing 0.5%, 1%, and 1.5% HCA. The study describes a novel approach to test the discriminatory power by including both positive and negative controls to declare pharmaceutical equivalence or inequivalence. The validated method was found to be sensitive, linear, precise, reproducible, robust, and selective for the analysis of HCA from topical cream products. Equivalence or inequivalence was established based on SUPAC-SS acceptance criteria using a 90% CI with limits of 75–133.33%. The IVRT method was shown to have discriminatory ability to appropriately measure significant differences in drug release from various cream formulations. This approach also provides useful information for the future development of acceptable IVRT methods to assess topical dosage forms for local action containing different drugs.
- Full Text:
- Date Issued: 2020
Rapid method for the quantitative determination of efavirenz in human plasma
- Kanfer, Isadore, Mogatle, Seloi
- Authors: Kanfer, Isadore , Mogatle, Seloi
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6388 , http://hdl.handle.net/10962/d1006309
- Description: A pharmacokinetic interaction study between efavirenz (EFV), a non-nucleoside reverse transcriptase inhibitor used in the treatment of HIV-1 infection, and an African traditional medicine, African potato in human subjects was undertaken. This necessitated the development and validation of a quantitative method for the analysis of EFV in plasma. A simple mobile phase consisting of 0.1 M formic acid, acetonitrile and methanol (43:52:5) was pumped at a low flow rate of 0.3 ml/min through a reverse phase Phenomenex® Luna C18 (2) (5 μm, 150 mm × 2.0 mm i.d.) column maintained at 40 °C. Diclofenac sodium was used as an internal standard (IS) and EFV and IS were monitored at 247 nm and 275 nm, respectively. A simple and rapid sample preparation involved the addition of mobile phase to 100 μl of plasma to precipitate plasma proteins followed by direct injection of 10 μl of supernatant onto the column. The procedures were validated according to international standards with good reproducibility and linear response (r = 0.9990). The intra- and inter-day accuracies were between 12.3 and 17.7% at the LLOQ and between −5.8 and 9.1% for the QC samples. The intra- and inter-day precision of EFV determinations were 5.1 or less and 7.2% RSD or less, respectively across the entire QC concentration range. Mean recovery based on high, medium and low quality control standards ranged between 92.7 and 94.1% with %RSD values better than 3%. Plasma samples were evaluated for short-term (ambient temperature for 6 h) and long-term (−10 ± 2 °C for 60 days) storage conditions and were found to be stable. The method described is cost-effective and has the necessary accuracy and precision for the rapid quantitative determination of EFV in human plasma.
- Full Text:
- Date Issued: 2009
- Authors: Kanfer, Isadore , Mogatle, Seloi
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6388 , http://hdl.handle.net/10962/d1006309
- Description: A pharmacokinetic interaction study between efavirenz (EFV), a non-nucleoside reverse transcriptase inhibitor used in the treatment of HIV-1 infection, and an African traditional medicine, African potato in human subjects was undertaken. This necessitated the development and validation of a quantitative method for the analysis of EFV in plasma. A simple mobile phase consisting of 0.1 M formic acid, acetonitrile and methanol (43:52:5) was pumped at a low flow rate of 0.3 ml/min through a reverse phase Phenomenex® Luna C18 (2) (5 μm, 150 mm × 2.0 mm i.d.) column maintained at 40 °C. Diclofenac sodium was used as an internal standard (IS) and EFV and IS were monitored at 247 nm and 275 nm, respectively. A simple and rapid sample preparation involved the addition of mobile phase to 100 μl of plasma to precipitate plasma proteins followed by direct injection of 10 μl of supernatant onto the column. The procedures were validated according to international standards with good reproducibility and linear response (r = 0.9990). The intra- and inter-day accuracies were between 12.3 and 17.7% at the LLOQ and between −5.8 and 9.1% for the QC samples. The intra- and inter-day precision of EFV determinations were 5.1 or less and 7.2% RSD or less, respectively across the entire QC concentration range. Mean recovery based on high, medium and low quality control standards ranged between 92.7 and 94.1% with %RSD values better than 3%. Plasma samples were evaluated for short-term (ambient temperature for 6 h) and long-term (−10 ± 2 °C for 60 days) storage conditions and were found to be stable. The method described is cost-effective and has the necessary accuracy and precision for the rapid quantitative determination of EFV in human plasma.
- Full Text:
- Date Issued: 2009
Rapid UPLC - MS/MS method for the determination of ketoprofen in human dermal microdialysis samples
- Tettey-Amlalo, Ralph N O, Kanfer, Isadore
- Authors: Tettey-Amlalo, Ralph N O , Kanfer, Isadore
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6444 , http://hdl.handle.net/10962/d1006631
- Description: Dermal microdialysis (DMD) is a technique capable of determining the percutaneous penetration of drugs from topical formulations intended for local and/or regional activity. Typically, the concentrations of drug collected in dialysates are very low, generally in the ng/ml or even pg/ml range. An additional challenge is the very low volume of sample collected at each collection time and which can range from 1 to 30 μl only. Hence the objective was to develop and validate a rapid, accurate, precise, reproducible and highly sensitive LC–MS/MS method for the quantitative analysis of ketoprofen (KET) in dialystes following application of a topical gel product to the skin of human subjects. UPLC–MS/MS was used and KET was separated on an Acquity™ UPLC BEH C18 column (100 mm × 2.1 mm i.d., 1.7 μm) and analysed in negative-ion (NI) electrospray ionisation (ESI) mode. The mobile phase (MP) consisted of acetonitrile:methanol:water (60:20:20, v/v/v) under isocratic conditions at a flow rate of 0.3 ml/min. Samples were extracted using ethyl acetate with ibuprofen (IBU) as internal standard (IS) and the organic solvent was then evaporated to dryness and the residue re-constituted in methanol. 5 μl samples were injected and analysis was performed at ambient temperature 22 ± 0.5 °C. KET and IBU eluted at 1.07 and 1.49 min, respectively. KET and IBU responses were optimised at the transitions 253.00 > 209.00 and 205.00 > 161.00, respectively. Calibration curves were linear over the range 0.5–500 ng/ml with correlation coefficients > 0.999. The accuracy and precision of the method were found to be between 99.97% and 104.67% (R.S.D. < 2%) and the mean recovery of KET from normal saline was 88.03 ± 0.3% (R.S.D. < 2.20%). The LLOQ and LOD values were found to be 0.5 and 0.1 ng/ml respectively whereas the ULOD was set at 500 ng/ml. The method was successfully applied to determine the bioavailability of KET following application of topical KET gel, Fastum® gel, to the skin of human volunteers.
- Full Text:
- Date Issued: 2009
- Authors: Tettey-Amlalo, Ralph N O , Kanfer, Isadore
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6444 , http://hdl.handle.net/10962/d1006631
- Description: Dermal microdialysis (DMD) is a technique capable of determining the percutaneous penetration of drugs from topical formulations intended for local and/or regional activity. Typically, the concentrations of drug collected in dialysates are very low, generally in the ng/ml or even pg/ml range. An additional challenge is the very low volume of sample collected at each collection time and which can range from 1 to 30 μl only. Hence the objective was to develop and validate a rapid, accurate, precise, reproducible and highly sensitive LC–MS/MS method for the quantitative analysis of ketoprofen (KET) in dialystes following application of a topical gel product to the skin of human subjects. UPLC–MS/MS was used and KET was separated on an Acquity™ UPLC BEH C18 column (100 mm × 2.1 mm i.d., 1.7 μm) and analysed in negative-ion (NI) electrospray ionisation (ESI) mode. The mobile phase (MP) consisted of acetonitrile:methanol:water (60:20:20, v/v/v) under isocratic conditions at a flow rate of 0.3 ml/min. Samples were extracted using ethyl acetate with ibuprofen (IBU) as internal standard (IS) and the organic solvent was then evaporated to dryness and the residue re-constituted in methanol. 5 μl samples were injected and analysis was performed at ambient temperature 22 ± 0.5 °C. KET and IBU eluted at 1.07 and 1.49 min, respectively. KET and IBU responses were optimised at the transitions 253.00 > 209.00 and 205.00 > 161.00, respectively. Calibration curves were linear over the range 0.5–500 ng/ml with correlation coefficients > 0.999. The accuracy and precision of the method were found to be between 99.97% and 104.67% (R.S.D. < 2%) and the mean recovery of KET from normal saline was 88.03 ± 0.3% (R.S.D. < 2.20%). The LLOQ and LOD values were found to be 0.5 and 0.1 ng/ml respectively whereas the ULOD was set at 500 ng/ml. The method was successfully applied to determine the bioavailability of KET following application of topical KET gel, Fastum® gel, to the skin of human volunteers.
- Full Text:
- Date Issued: 2009
Sterols and sterolins in Hypoxis hemerocallidea (African potato)
- Nair, V D P, Kanfer, Isadore
- Authors: Nair, V D P , Kanfer, Isadore
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6417 , http://hdl.handle.net/10962/d1006535
- Description: Commercially available health supplements and herbal remedies containing sterols and sterolins, either from African potato (Hypoxis hemerocallidea) alone, or whether enriched with sterols and sterolins, are claimed to be efficacious in the treatment of a variety of ailments. Sterols and sterolins in African potato are purported to be the relevant constituents that are required for the therapeutic claims of such products. A patent describing the extraction of sterolins from African potato plant material has claimed that approximately 9 mg sterolins can be isolated from 100 g of an enriched aqueous African potato extract. Our analysis of African potato plant material and its sterol and sterolin content, when similarly prepared, shows that the measureable content of sterols and sterolins in African potato is far less than the amounts of these compounds that have been claimed to be necessary for therapeutic benefit. We conclude that therapeutic claims relating to sterol and sterolin content in African potato are unsubstantiated, in view of the extremely low content of such compounds that we have isolated from our plant material, and in products containing African potato, or extracts thereof.
- Full Text:
- Date Issued: 2008
- Authors: Nair, V D P , Kanfer, Isadore
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6417 , http://hdl.handle.net/10962/d1006535
- Description: Commercially available health supplements and herbal remedies containing sterols and sterolins, either from African potato (Hypoxis hemerocallidea) alone, or whether enriched with sterols and sterolins, are claimed to be efficacious in the treatment of a variety of ailments. Sterols and sterolins in African potato are purported to be the relevant constituents that are required for the therapeutic claims of such products. A patent describing the extraction of sterolins from African potato plant material has claimed that approximately 9 mg sterolins can be isolated from 100 g of an enriched aqueous African potato extract. Our analysis of African potato plant material and its sterol and sterolin content, when similarly prepared, shows that the measureable content of sterols and sterolins in African potato is far less than the amounts of these compounds that have been claimed to be necessary for therapeutic benefit. We conclude that therapeutic claims relating to sterol and sterolin content in African potato are unsubstantiated, in view of the extremely low content of such compounds that we have isolated from our plant material, and in products containing African potato, or extracts thereof.
- Full Text:
- Date Issued: 2008
Application of reverse-flow micellar electrokinetic chromatography for the simultaneous determination of flavonols and terpene trilactones in Ginkgo biloba dosage forms
- Dubber, Mary-Jean, Kanfer, Isadore
- Authors: Dubber, Mary-Jean , Kanfer, Isadore
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6357 , http://hdl.handle.net/10962/d1006049
- Description:
A reverse-flow micellar electrokinetic chromatographic (RF-MEKC) method was developed for the simultaneous qualitative determination of 10 components consisting of the flavonol glycosides, rutin and quercitrin, the flavonol aglycones, isorhamnetin, kaempferol and quercetin, the terpene trilactones, ginkgolides A, B, C and J and the sesquiterpene, bilobalide. This method was used to fingerprint Ginkgo biloba solid oral dosage forms and validated for the quantitation of the marker compounds, rutin and quercetin in some commercial products. In addition to the usual variables, the influence of some essential background electrolyte (BGE) components such as sodium dodecyl sulphate (SDS) and
-cyclodextrin concentrations were investigated. A polyimide fused-silica square capillary column (75 μm I.D. × 360 μm O.D.) with a total length of 60.0 cm and effective length of 45.0 cm was used for the separation. The final BGE consisted of 20 mM phosphoric acid, 40 mM SDS and 12 mM -cyclodextrin (pH 2.2) using reverse polarity with a voltage of −17.5 kV. Samples were injected electrokinetically at −5 kV for 3 s for the qualitative analysis and hydrodynamically at 20 mbar for 0.6 s for the quantitative assay. The total run time was 22 min and the limits of detection were 3.13 μg/ml and 1.88 μg/ml for rutin and quercetin, respectively. Fingerprint profiles of the solid oral dosage forms and the results of the quantitative analysis indicated that there were major discrepancies in the marker content between products and illustrates the value of this method for use as a procedure to assess product quality of commercially available Ginkgo biloba products. - Full Text:
- Date Issued: 2006
- Authors: Dubber, Mary-Jean , Kanfer, Isadore
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6357 , http://hdl.handle.net/10962/d1006049
- Description:
A reverse-flow micellar electrokinetic chromatographic (RF-MEKC) method was developed for the simultaneous qualitative determination of 10 components consisting of the flavonol glycosides, rutin and quercitrin, the flavonol aglycones, isorhamnetin, kaempferol and quercetin, the terpene trilactones, ginkgolides A, B, C and J and the sesquiterpene, bilobalide. This method was used to fingerprint Ginkgo biloba solid oral dosage forms and validated for the quantitation of the marker compounds, rutin and quercetin in some commercial products. In addition to the usual variables, the influence of some essential background electrolyte (BGE) components such as sodium dodecyl sulphate (SDS) and
-cyclodextrin concentrations were investigated. A polyimide fused-silica square capillary column (75 μm I.D. × 360 μm O.D.) with a total length of 60.0 cm and effective length of 45.0 cm was used for the separation. The final BGE consisted of 20 mM phosphoric acid, 40 mM SDS and 12 mM -cyclodextrin (pH 2.2) using reverse polarity with a voltage of −17.5 kV. Samples were injected electrokinetically at −5 kV for 3 s for the qualitative analysis and hydrodynamically at 20 mbar for 0.6 s for the quantitative assay. The total run time was 22 min and the limits of detection were 3.13 μg/ml and 1.88 μg/ml for rutin and quercetin, respectively. Fingerprint profiles of the solid oral dosage forms and the results of the quantitative analysis indicated that there were major discrepancies in the marker content between products and illustrates the value of this method for use as a procedure to assess product quality of commercially available Ginkgo biloba products. - Full Text:
- Date Issued: 2006
Bioequivalence assessment of generic products an innovative South African approach
- Walker, Roderick B, Kanfer, Isadore, Skinner, Michael F
- Authors: Walker, Roderick B , Kanfer, Isadore , Skinner, Michael F
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184256 , vital:44194 , xlink:href="https://doi.org/10.1080/10601330500534014"
- Description: Concurrent with the implementation of new legislation mandating Generic Substitution in South Africa, a new set of guidelines for bioavailability and bioequivalence have been published. Since one of the main objectives of the new legislation in South Africa relating to Generic Substitution is to ensure that medicines of high quality, safety, and efficacy are made more accessible and more affordable to the wider public, the need to speed up approval of such multi-source products has become a regulatory priority. In order to facilitate this process, various bioequivalence issues have been addressed including important issues such as the acceptance criteria and associated bioequivalence intervals, use of a foreign reference product and the issue of assessing highly variable drugs (HVDs). In addition, dispensations have been made with respect to food effect assessment and variability relating to genetic polymorphism in drug metabolism (genotyping/phenotyping). Furthermore, the use of “old” biostudies submitted in support of an application is subject to expiry date. Acceptance of appropriate data requires that specific criteria such as Cmax and AUC, in addition to the usual considerations, also meet the limits specified by the particular registration authority of the country where such products are intended to be marketed. Generally, these limits require that the 90% confidence interval (CI) for AUC and Cmax test/reference ratios lies within the acceptance interval of 0.80–1.25 calculated using log-transformed data. While such acceptance criteria are, in general, ubiquitous, some differences in acceptance criteria do exist between various countries. The new guidelines for bioavailability/bioequivalence studies developed by the South African regulatory authority, the Medicines Control Council (MCC), makes provision for highly variable drugs and the use of a non-South African reference product. The MCC requires that the acceptance criterion for Cmax ratios be set at 0.75–1.33 while maintaining AUC ratios at 0.80–1.25 using a 90% CI. Furthermore, provision is made to apply scaling based on average bioequivalence assessment and, as an interim measure, consideration has also been given to the use of a foreign reference product provided that equivalence between that product and the innovator product currently available on the South African market can be shown using in vitro testing.
- Full Text:
- Date Issued: 2006
- Authors: Walker, Roderick B , Kanfer, Isadore , Skinner, Michael F
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184256 , vital:44194 , xlink:href="https://doi.org/10.1080/10601330500534014"
- Description: Concurrent with the implementation of new legislation mandating Generic Substitution in South Africa, a new set of guidelines for bioavailability and bioequivalence have been published. Since one of the main objectives of the new legislation in South Africa relating to Generic Substitution is to ensure that medicines of high quality, safety, and efficacy are made more accessible and more affordable to the wider public, the need to speed up approval of such multi-source products has become a regulatory priority. In order to facilitate this process, various bioequivalence issues have been addressed including important issues such as the acceptance criteria and associated bioequivalence intervals, use of a foreign reference product and the issue of assessing highly variable drugs (HVDs). In addition, dispensations have been made with respect to food effect assessment and variability relating to genetic polymorphism in drug metabolism (genotyping/phenotyping). Furthermore, the use of “old” biostudies submitted in support of an application is subject to expiry date. Acceptance of appropriate data requires that specific criteria such as Cmax and AUC, in addition to the usual considerations, also meet the limits specified by the particular registration authority of the country where such products are intended to be marketed. Generally, these limits require that the 90% confidence interval (CI) for AUC and Cmax test/reference ratios lies within the acceptance interval of 0.80–1.25 calculated using log-transformed data. While such acceptance criteria are, in general, ubiquitous, some differences in acceptance criteria do exist between various countries. The new guidelines for bioavailability/bioequivalence studies developed by the South African regulatory authority, the Medicines Control Council (MCC), makes provision for highly variable drugs and the use of a non-South African reference product. The MCC requires that the acceptance criterion for Cmax ratios be set at 0.75–1.33 while maintaining AUC ratios at 0.80–1.25 using a 90% CI. Furthermore, provision is made to apply scaling based on average bioequivalence assessment and, as an interim measure, consideration has also been given to the use of a foreign reference product provided that equivalence between that product and the innovator product currently available on the South African market can be shown using in vitro testing.
- Full Text:
- Date Issued: 2006
Generic substitution: the use of medicinal products containing different salts and implications for safety and efficacy
- Verbeeck, R K, Kanfer, Isadore, Walker, Roderick B
- Authors: Verbeeck, R K , Kanfer, Isadore , Walker, Roderick B
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6445 , http://hdl.handle.net/10962/d1006632
- Description: In their quest to gain early entry of new generic products into the market prior to patent expiration, one of the strategies pursued by generic drug product manufacturers is to incorporate different salts of an approved active pharmaceutical ingredient (API) in a brand company's marketed dosage form and subject such dosage forms to bioequivalence assessment. These initiatives present challenges to regulatory authorities where the decision to approve bioequivalent products containing such pharmaceutical alternatives must be considered in the light of safety and efficacy, and more particularly, with respect to their substitutability. This article describes the various issues and contentions associated with the concept of pharmaceutical alternatives, specifically with respect to the uses of different salts and the implications for safety, efficacy and generic substitution.
- Full Text:
- Date Issued: 2006
- Authors: Verbeeck, R K , Kanfer, Isadore , Walker, Roderick B
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6445 , http://hdl.handle.net/10962/d1006632
- Description: In their quest to gain early entry of new generic products into the market prior to patent expiration, one of the strategies pursued by generic drug product manufacturers is to incorporate different salts of an approved active pharmaceutical ingredient (API) in a brand company's marketed dosage form and subject such dosage forms to bioequivalence assessment. These initiatives present challenges to regulatory authorities where the decision to approve bioequivalent products containing such pharmaceutical alternatives must be considered in the light of safety and efficacy, and more particularly, with respect to their substitutability. This article describes the various issues and contentions associated with the concept of pharmaceutical alternatives, specifically with respect to the uses of different salts and the implications for safety, efficacy and generic substitution.
- Full Text:
- Date Issued: 2006
African herbal medicines in the treatment of HIV: Hypoxis and Sutherlandia: an overview of evidence and pharmacology
- Mills, Edward, Cooper, Curtis, Seely, Dugald, Kanfer, Isadore
- Authors: Mills, Edward , Cooper, Curtis , Seely, Dugald , Kanfer, Isadore
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6401 , http://hdl.handle.net/10962/d1006337
- Description: In Africa, herbal medicines are often used as primary treatment for HIV/AIDS and for HIV-related problems. In general, traditional medicines are not well researched, and are poorly regulated. We review the evidence and safety concerns related to the use of two specific African herbals, which are currently recommended by the Ministry of Health in South Africa and member states for use in HIV: African Potato and Sutherlandia. We review the pharmacology, toxicology and pharmacokinetics of these herbal medicines. Despite the popularity of their use and the support of Ministries of Health and NGOs in some African countries, no clinical trials of efficacy exist, and low-level evidence of harm identifies the potential for drug interactions with antiretroviral drugs. Efforts should be made by mainstream health professionals to provide validated information to traditional healers and patients on the judicious use of herbal remedies. This may reduce harm through failed expectations, pharmacologic adverse events including possible drug/herb interactions and unnecessary added therapeutic costs. Efforts should also be directed at evaluating the possible benefits of natural products in HIV/AIDS treatment.
- Full Text:
- Date Issued: 2005
- Authors: Mills, Edward , Cooper, Curtis , Seely, Dugald , Kanfer, Isadore
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6401 , http://hdl.handle.net/10962/d1006337
- Description: In Africa, herbal medicines are often used as primary treatment for HIV/AIDS and for HIV-related problems. In general, traditional medicines are not well researched, and are poorly regulated. We review the evidence and safety concerns related to the use of two specific African herbals, which are currently recommended by the Ministry of Health in South Africa and member states for use in HIV: African Potato and Sutherlandia. We review the pharmacology, toxicology and pharmacokinetics of these herbal medicines. Despite the popularity of their use and the support of Ministries of Health and NGOs in some African countries, no clinical trials of efficacy exist, and low-level evidence of harm identifies the potential for drug interactions with antiretroviral drugs. Efforts should be made by mainstream health professionals to provide validated information to traditional healers and patients on the judicious use of herbal remedies. This may reduce harm through failed expectations, pharmacologic adverse events including possible drug/herb interactions and unnecessary added therapeutic costs. Efforts should also be directed at evaluating the possible benefits of natural products in HIV/AIDS treatment.
- Full Text:
- Date Issued: 2005
An LC-MS-MS method for the determination of cyclizine in human serum
- Mohammadi, Ali, Kanfer, Isadore, Sewram, V, Walker, Roderick B
- Authors: Mohammadi, Ali , Kanfer, Isadore , Sewram, V , Walker, Roderick B
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6408 , http://hdl.handle.net/10962/d1006481
- Description: Cyclizine is a piperazine derivative with anti-emetic activity that is useful in the prevention and treatment of nausea and vomiting associated with motion sickness. A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method is presented for the quantitation of cyclizine in serum. Sample pretreatment involved liquid-liquid extraction of 200 μl of serum with dichloromethane after the addition of 100 μl each of ammonium hydroxide and internal standard solutions. The extracts were analyzed by HPLC on a Luna ® C18 reversed-phase column and an ion-trap mass spectrometer with an electrospray interface. A limit of detection of 1 ng/ml was determined which allowed for the reliable measurement of cyclizine in the serum of human subjects. The method was found to be linear over the calibration range of 2.5-100 ng/ml. The applicability of this method was demonstrated by the analysis of serum obtained from a human volunteer following administration of a single 50 mg cyclizine hydrochloride tablet. The reported method was observed to have the necessary sensitivity, selectivity, precision and accuracy for monitoring cyclizine concentrations in human subjects following oral administration.
- Full Text:
- Date Issued: 2005
- Authors: Mohammadi, Ali , Kanfer, Isadore , Sewram, V , Walker, Roderick B
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6408 , http://hdl.handle.net/10962/d1006481
- Description: Cyclizine is a piperazine derivative with anti-emetic activity that is useful in the prevention and treatment of nausea and vomiting associated with motion sickness. A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method is presented for the quantitation of cyclizine in serum. Sample pretreatment involved liquid-liquid extraction of 200 μl of serum with dichloromethane after the addition of 100 μl each of ammonium hydroxide and internal standard solutions. The extracts were analyzed by HPLC on a Luna ® C18 reversed-phase column and an ion-trap mass spectrometer with an electrospray interface. A limit of detection of 1 ng/ml was determined which allowed for the reliable measurement of cyclizine in the serum of human subjects. The method was found to be linear over the calibration range of 2.5-100 ng/ml. The applicability of this method was demonstrated by the analysis of serum obtained from a human volunteer following administration of a single 50 mg cyclizine hydrochloride tablet. The reported method was observed to have the necessary sensitivity, selectivity, precision and accuracy for monitoring cyclizine concentrations in human subjects following oral administration.
- Full Text:
- Date Issued: 2005
A capillary zone electrophoresis (CZE) method for the determination of cyclizine hydrochloride in tablets and suppositories
- Mohammadi, I, Kanfer, Isadore, Walker, Roderick B
- Authors: Mohammadi, I , Kanfer, Isadore , Walker, Roderick B
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6406 , http://hdl.handle.net/10962/d1006479
- Description: Current compendial methods of assay for the analysis of cyclizine tablets involve the use of UV spectrophotometry. Since this is a non-selective technique its application to more complex dosage forms, such as suppositories, is unlikely to be appropriate. There is therefore a need for the development of a highly specific quantitative analytical method, such as high performance liquid chromatography (HPLC) or capillary electrophoresis (CE). The latter technique was chosen in view of some specific advantages over HPLC, such as the use of relatively non-toxic aqueous buffers, as opposed to organic solvents, which obviates the use of expensive HPLC grade solvents making CE more cost effective. Cyclizine was analyzed in 50 mM phosphate buffer (pH 2.3) and run at an applied voltage 25 kV. Detection sensitivity was enhanced by using a wavelength of 200 nm and samples were loaded hydrodynamically onto an uncoated fused-silica capillary (60 cm×50 mm i.d.). Chlorcyclizine was used as the internal standard and resolution of both compounds was achieved in less than 7 min. Stress testing was undertaken in order to investigate the appearance of breakdown products. The method has the requisite accuracy, selectivity, sensitivity and precision to assay cyclizine in tablets and suppositories. Degradation products resulting from the stress studies did not interfere with the detection of cyclizine and the assay is thus stability-indicating.
- Full Text:
- Date Issued: 2004
- Authors: Mohammadi, I , Kanfer, Isadore , Walker, Roderick B
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6406 , http://hdl.handle.net/10962/d1006479
- Description: Current compendial methods of assay for the analysis of cyclizine tablets involve the use of UV spectrophotometry. Since this is a non-selective technique its application to more complex dosage forms, such as suppositories, is unlikely to be appropriate. There is therefore a need for the development of a highly specific quantitative analytical method, such as high performance liquid chromatography (HPLC) or capillary electrophoresis (CE). The latter technique was chosen in view of some specific advantages over HPLC, such as the use of relatively non-toxic aqueous buffers, as opposed to organic solvents, which obviates the use of expensive HPLC grade solvents making CE more cost effective. Cyclizine was analyzed in 50 mM phosphate buffer (pH 2.3) and run at an applied voltage 25 kV. Detection sensitivity was enhanced by using a wavelength of 200 nm and samples were loaded hydrodynamically onto an uncoated fused-silica capillary (60 cm×50 mm i.d.). Chlorcyclizine was used as the internal standard and resolution of both compounds was achieved in less than 7 min. Stress testing was undertaken in order to investigate the appearance of breakdown products. The method has the requisite accuracy, selectivity, sensitivity and precision to assay cyclizine in tablets and suppositories. Degradation products resulting from the stress studies did not interfere with the detection of cyclizine and the assay is thus stability-indicating.
- Full Text:
- Date Issued: 2004
Analysis of macrolide antibiotics
- Kanfer, Isadore, Skinner, Michael F, Walker, Roderick B
- Authors: Kanfer, Isadore , Skinner, Michael F , Walker, Roderick B
- Date: 1998
- Language: English
- Type: Article , text
- Identifier: vital:7011 , http://hdl.handle.net/10962/d1008394 , http://www.sciencedirect.com/science/article/pii/S0021967398002763
- Description: The following macrolide antibiotics have been covered in this review: erythromycin and its related substances, azithromycin, clarithromycin, dirithromycin, roxithromycin, flurithromycin, josamycin, rokitamycin, kitasamycin, mycinamycin, mirosamycin, oleandomycin, rosaramicin, spiramycin and tylosin. The application of various thin-layer chromatography, paper chromatography, gas chromatography, high-performance liquid chromatography and capillary zone electrophoresis procedures for their analysis are described. These techniques have been applied to the separation and quantitative analysis of the macrolides in fermentation media, purity assessment of raw materials, assay of pharmaceutical dosage forms and the measurement of clinically useful macrolide antibiotics in biological samples such as blood, plasma, serum, urine and tissues. Data relating to the chromatographic behaviour of some macrolide antibiotics as well as the various detection methods used, such as bioautography, UV spectrophotometry, fluorometry, electrochemical detection, chemiluminescence and mass spectrometry techniques are also included.
- Full Text:
- Date Issued: 1998
- Authors: Kanfer, Isadore , Skinner, Michael F , Walker, Roderick B
- Date: 1998
- Language: English
- Type: Article , text
- Identifier: vital:7011 , http://hdl.handle.net/10962/d1008394 , http://www.sciencedirect.com/science/article/pii/S0021967398002763
- Description: The following macrolide antibiotics have been covered in this review: erythromycin and its related substances, azithromycin, clarithromycin, dirithromycin, roxithromycin, flurithromycin, josamycin, rokitamycin, kitasamycin, mycinamycin, mirosamycin, oleandomycin, rosaramicin, spiramycin and tylosin. The application of various thin-layer chromatography, paper chromatography, gas chromatography, high-performance liquid chromatography and capillary zone electrophoresis procedures for their analysis are described. These techniques have been applied to the separation and quantitative analysis of the macrolides in fermentation media, purity assessment of raw materials, assay of pharmaceutical dosage forms and the measurement of clinically useful macrolide antibiotics in biological samples such as blood, plasma, serum, urine and tissues. Data relating to the chromatographic behaviour of some macrolide antibiotics as well as the various detection methods used, such as bioautography, UV spectrophotometry, fluorometry, electrochemical detection, chemiluminescence and mass spectrometry techniques are also included.
- Full Text:
- Date Issued: 1998
Evaluation of the proposed FDA pilot-dose response methodology for topical corticosteroid bioeqivalence testing [authors' reply in Letters to the Editor]
- Smith, Eric W, Walker, Roderick B, Haigh, John M, Kanfer, Isadore
- Authors: Smith, Eric W , Walker, Roderick B , Haigh, John M , Kanfer, Isadore
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6423 , http://hdl.handle.net/10962/d1006558
- Description: Reply to: Letter to the Editor by Singh GJ; Fleischer N; Lesko L; Williams R - relating to original article in Pharmaceutical Research (USA), Mar 1997, vol. 14, pp. 303-308.
- Full Text: false
- Date Issued: 1998
- Authors: Smith, Eric W , Walker, Roderick B , Haigh, John M , Kanfer, Isadore
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6423 , http://hdl.handle.net/10962/d1006558
- Description: Reply to: Letter to the Editor by Singh GJ; Fleischer N; Lesko L; Williams R - relating to original article in Pharmaceutical Research (USA), Mar 1997, vol. 14, pp. 303-308.
- Full Text: false
- Date Issued: 1998
Evaluation of the proposed FDA pilot-dose response methodology for topical corticosteroid bioequivalence testing
- Demana, Patrick H, Smith, Eric W, Walker, Roderick B, Haigh, John M, Kanfer, Isadore
- Authors: Demana, Patrick H , Smith, Eric W , Walker, Roderick B , Haigh, John M , Kanfer, Isadore
- Date: 1997
- Language: English
- Type: Article
- Identifier: vital:6356 , http://hdl.handle.net/10962/d1006047
- Description: The American FDA has recently released a Guidance document for topical corticosteroid bioequivalence testing. The purpose of this study was to evaluate the recommendations of this document for appropriateness. The new specifications require a dose-vasoconstriction response estimation by the use of a Minolta chromameter in a preliminary pilot study to determine the parameters for use in a pivotal bioequivalence study. Methods. The visually-assessed human skin blanching assay methodology routinely practiced in our laboratories was modified to comply with the requirements of the pilot study so that visual and chromameter data could be compared. Two different cream formulations, each containing 0.12% betamethasone 17-valerate, were used for this comparison. Results. Visual data showed the expected rank order of AUC values for most dose durations whereas the chromameter data did not show similar results. The expected rank order of AUC values for both chromameter and visual data was not observed at very short dose durations. In fitting the data to pharmacodynamic models, equivalent goodness of fit criteria were obtained when several different parameter estimates were used in the model definition, however the visual data were best described by the sigmoid E[subscript max] model while the chromameter data were best described by the simple E[subscript max] model. Conclusions. The E[subscript max] values predicted by the models were close to the observed values for both data sets and, in addition, excellent correlation between the AUC values and the maximum blanching response (R[subscript max]) (r > 0.95) was noted for both methods of assessment. The chromameter ED[subscript 50] values determined in this study were approximately 2 hours for both preparations. At this dose duration the instrument would not be sensitive enough to distinguish between weak blanching responses and normal skin for bioequivalence assessment purposes.
- Full Text: false
- Date Issued: 1997
- Authors: Demana, Patrick H , Smith, Eric W , Walker, Roderick B , Haigh, John M , Kanfer, Isadore
- Date: 1997
- Language: English
- Type: Article
- Identifier: vital:6356 , http://hdl.handle.net/10962/d1006047
- Description: The American FDA has recently released a Guidance document for topical corticosteroid bioequivalence testing. The purpose of this study was to evaluate the recommendations of this document for appropriateness. The new specifications require a dose-vasoconstriction response estimation by the use of a Minolta chromameter in a preliminary pilot study to determine the parameters for use in a pivotal bioequivalence study. Methods. The visually-assessed human skin blanching assay methodology routinely practiced in our laboratories was modified to comply with the requirements of the pilot study so that visual and chromameter data could be compared. Two different cream formulations, each containing 0.12% betamethasone 17-valerate, were used for this comparison. Results. Visual data showed the expected rank order of AUC values for most dose durations whereas the chromameter data did not show similar results. The expected rank order of AUC values for both chromameter and visual data was not observed at very short dose durations. In fitting the data to pharmacodynamic models, equivalent goodness of fit criteria were obtained when several different parameter estimates were used in the model definition, however the visual data were best described by the sigmoid E[subscript max] model while the chromameter data were best described by the simple E[subscript max] model. Conclusions. The E[subscript max] values predicted by the models were close to the observed values for both data sets and, in addition, excellent correlation between the AUC values and the maximum blanching response (R[subscript max]) (r > 0.95) was noted for both methods of assessment. The chromameter ED[subscript 50] values determined in this study were approximately 2 hours for both preparations. At this dose duration the instrument would not be sensitive enough to distinguish between weak blanching responses and normal skin for bioequivalence assessment purposes.
- Full Text: false
- Date Issued: 1997
The human skin blanching assay for in vivo topical corticosteroid assessment. II. Subject- and observer-dependent variation in blanching responses
- Haigh, John M, Meyer, Eric, Smith, Eric W, Kanfer, Isadore
- Authors: Haigh, John M , Meyer, Eric , Smith, Eric W , Kanfer, Isadore
- Date: 1997
- Language: English
- Type: text , Article
- Identifier: vital:6382 , http://hdl.handle.net/10962/d1006300
- Description: The human skin blanching (vasoconstriction) assay for the assessment of topical corticosteroids has been in use for over 30 years, the intensity of the drug-induced blanching being assessed subjectively by eye. Both arms of several male and female volunteers are used for product application and more than one observer is used to estimate the degree of induced blanching. There are, therefore, numerous variables which are inherent in the assay procedure. This investigation consisted of three identical trials performed at 8-week intervals, utilising the same 18 volunteers and the same three observers in an attempt to address the question of reproducibility of the assay. From the results obtained it is clear that the assay methodology is capable of consistently distinguishing, on a rank order basis, between preparations which show similar blanching (chemically-equivalent formulations). The similarity of the results for the three individual trials gives considerable confidence to results produced using this methodology. An experiment designed to test the reproducibility of the blanching scores showed that the observers are capable of producing identical results even though visual observation is highly subjective.
- Full Text:
- Date Issued: 1997
- Authors: Haigh, John M , Meyer, Eric , Smith, Eric W , Kanfer, Isadore
- Date: 1997
- Language: English
- Type: text , Article
- Identifier: vital:6382 , http://hdl.handle.net/10962/d1006300
- Description: The human skin blanching (vasoconstriction) assay for the assessment of topical corticosteroids has been in use for over 30 years, the intensity of the drug-induced blanching being assessed subjectively by eye. Both arms of several male and female volunteers are used for product application and more than one observer is used to estimate the degree of induced blanching. There are, therefore, numerous variables which are inherent in the assay procedure. This investigation consisted of three identical trials performed at 8-week intervals, utilising the same 18 volunteers and the same three observers in an attempt to address the question of reproducibility of the assay. From the results obtained it is clear that the assay methodology is capable of consistently distinguishing, on a rank order basis, between preparations which show similar blanching (chemically-equivalent formulations). The similarity of the results for the three individual trials gives considerable confidence to results produced using this methodology. An experiment designed to test the reproducibility of the blanching scores showed that the observers are capable of producing identical results even though visual observation is highly subjective.
- Full Text:
- Date Issued: 1997
The human skin-blanching assay for in vitro topical corticosteroid assessment. I. Reproducibility of the assay
- Haigh, John M, Meyer, Eric, Smith, Eric W, Kanfer, Isadore
- Authors: Haigh, John M , Meyer, Eric , Smith, Eric W , Kanfer, Isadore
- Date: 1997
- Language: English
- Type: text , Article
- Identifier: vital:6381 , http://hdl.handle.net/10962/d1006299
- Description: The human skin blanching (vasoconstriction) assay for the assessment of topical corticosteroids has been in use for over 30 years, the intensity of the drug-induced blanching being assessed subjectively by eye. Both arms of several male and female volunteers are used for product application and more than one observer is used to estimate the degree of induced blanching. There are, therefore, numerous variables which are inherent in the assay procedure. This investigation consisted of three identical trials performed at 8-week intervals, utilising the same 18 volunteers and the same three observers in an attempt to address the question of reproducibility of the assay. From the results obtained it is clear that the assay methodology is capable of consistently distinguishing, on a rank order basis, between preparations which show similar blanching (chemically-equivalent formulations). The similarity of the results for the three individual trials gives considerable confidence to results produced using this methodology. An experiment designed to test the reproducibility of the blanching scores showed that the observers are capable of producing identical results even though visual observation is highly subjective.
- Full Text:
- Date Issued: 1997
- Authors: Haigh, John M , Meyer, Eric , Smith, Eric W , Kanfer, Isadore
- Date: 1997
- Language: English
- Type: text , Article
- Identifier: vital:6381 , http://hdl.handle.net/10962/d1006299
- Description: The human skin blanching (vasoconstriction) assay for the assessment of topical corticosteroids has been in use for over 30 years, the intensity of the drug-induced blanching being assessed subjectively by eye. Both arms of several male and female volunteers are used for product application and more than one observer is used to estimate the degree of induced blanching. There are, therefore, numerous variables which are inherent in the assay procedure. This investigation consisted of three identical trials performed at 8-week intervals, utilising the same 18 volunteers and the same three observers in an attempt to address the question of reproducibility of the assay. From the results obtained it is clear that the assay methodology is capable of consistently distinguishing, on a rank order basis, between preparations which show similar blanching (chemically-equivalent formulations). The similarity of the results for the three individual trials gives considerable confidence to results produced using this methodology. An experiment designed to test the reproducibility of the blanching scores showed that the observers are capable of producing identical results even though visual observation is highly subjective.
- Full Text:
- Date Issued: 1997
Pharmacokinetics of cyclizine following intravenous administration to human volunteers
- Kanfer, Isadore, Walker, Roderick B
- Authors: Kanfer, Isadore , Walker, Roderick B
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184389 , vital:44214 , xlink:href="https://doi.org/10.1016/0928-0987(96)00177-7"
- Description: The pharmacokinetics of cyclizine, a piperazine derivative useful in the prevention and treatment of nausea and vomiting, was investigated in six healthy male volunteers following an intravenous bolus dose. The drug is extensively distributed with a mean volume of distribution of 16.50 ± 3.33 l/kg and a mean total clearance of 0.870 ± 0.105 l/h per kg. Urinary excretion data showed that less than one percent of the dose was excreted up to 36 h as unchanged drug in the urine. The extremely low mean renal clearance (0.005 ± 0.002 l/h per kg) for the parent drug comprised only a small proportion of total clearance indicating that urinary excretion of parent drug is not a major route of elimination for cyclizine. The drug appears to exhibit biexponential pharmacokinetics and has a terminal elimination half-life of approximately 13 h.
- Full Text:
- Date Issued: 1996
- Authors: Kanfer, Isadore , Walker, Roderick B
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184389 , vital:44214 , xlink:href="https://doi.org/10.1016/0928-0987(96)00177-7"
- Description: The pharmacokinetics of cyclizine, a piperazine derivative useful in the prevention and treatment of nausea and vomiting, was investigated in six healthy male volunteers following an intravenous bolus dose. The drug is extensively distributed with a mean volume of distribution of 16.50 ± 3.33 l/kg and a mean total clearance of 0.870 ± 0.105 l/h per kg. Urinary excretion data showed that less than one percent of the dose was excreted up to 36 h as unchanged drug in the urine. The extremely low mean renal clearance (0.005 ± 0.002 l/h per kg) for the parent drug comprised only a small proportion of total clearance indicating that urinary excretion of parent drug is not a major route of elimination for cyclizine. The drug appears to exhibit biexponential pharmacokinetics and has a terminal elimination half-life of approximately 13 h.
- Full Text:
- Date Issued: 1996
Sensitive high-performance liquid chromatographic determination of cyclizine and its demethylated metabolite, norcyclizine, in biological fluids using coulometric detection
- Walker, Roderick B, Kanfer, Isadore
- Authors: Walker, Roderick B , Kanfer, Isadore
- Date: 1995
- Language: English
- Type: text , Article
- Identifier: vital:6452 , http://hdl.handle.net/10962/d1006640 , http://dx.doi.org/10.1016/0378-4347(95)00202-T
- Description: An accurate, sensitive, selective and reproducible high-performance liquid chromatographic method with coulometric detection for the determination of cyclizine and its inactive demethylated metabolite, norcyclizine, in biological fluids has been developed. The drugs were separated using a custom packed reversed-phase C18 analytical column and phosphate buffer (0.05 M, pH 3)-acetonitrile (7:3) as mobile phase. The dual electrode coulometric detector was operated in the "oxidative-screen" mode with the upstream electrode (detector 1) set at 0.55 V and the downstream electrode (detector 2) set at 0.90 V. Serum and urine samples were prepared for analysis by solid-phase extraction, followed by a simple phase-separation step. The limit of quantitation was 1 ng/ml for both cyclizine and norcyclizine in serum and urine.
- Full Text:
- Date Issued: 1995
- Authors: Walker, Roderick B , Kanfer, Isadore
- Date: 1995
- Language: English
- Type: text , Article
- Identifier: vital:6452 , http://hdl.handle.net/10962/d1006640 , http://dx.doi.org/10.1016/0378-4347(95)00202-T
- Description: An accurate, sensitive, selective and reproducible high-performance liquid chromatographic method with coulometric detection for the determination of cyclizine and its inactive demethylated metabolite, norcyclizine, in biological fluids has been developed. The drugs were separated using a custom packed reversed-phase C18 analytical column and phosphate buffer (0.05 M, pH 3)-acetonitrile (7:3) as mobile phase. The dual electrode coulometric detector was operated in the "oxidative-screen" mode with the upstream electrode (detector 1) set at 0.55 V and the downstream electrode (detector 2) set at 0.90 V. Serum and urine samples were prepared for analysis by solid-phase extraction, followed by a simple phase-separation step. The limit of quantitation was 1 ng/ml for both cyclizine and norcyclizine in serum and urine.
- Full Text:
- Date Issued: 1995
Comparison of the blanching activities of Dermovate, Betnovate and Eumovate creams and ointments
- Meyer, Eric, Magnus, Ashley D, Haigh, John M, Kanfer, Isadore
- Authors: Meyer, Eric , Magnus, Ashley D , Haigh, John M , Kanfer, Isadore
- Date: 1988
- Language: English
- Type: Article
- Identifier: vital:6393 , http://hdl.handle.net/10962/d1006315
- Description: The human skin blanching assay was used to determine the blanching activities of Dermovate, Betnovate and Eumovate creams and ointments. Dermovate was found to elicit a superior blanching response to Betnovate which in turn elicited a superior blanching response to Eumovate, except in the comparison of Betnovate and Eumovate ointments under occlusion. The importance of employing the correct methodology of the blanching assay is emphasized and the good correlation between the results of this study and clinical trials is indicated.
- Full Text: false
- Date Issued: 1988
- Authors: Meyer, Eric , Magnus, Ashley D , Haigh, John M , Kanfer, Isadore
- Date: 1988
- Language: English
- Type: Article
- Identifier: vital:6393 , http://hdl.handle.net/10962/d1006315
- Description: The human skin blanching assay was used to determine the blanching activities of Dermovate, Betnovate and Eumovate creams and ointments. Dermovate was found to elicit a superior blanching response to Betnovate which in turn elicited a superior blanching response to Eumovate, except in the comparison of Betnovate and Eumovate ointments under occlusion. The importance of employing the correct methodology of the blanching assay is emphasized and the good correlation between the results of this study and clinical trials is indicated.
- Full Text: false
- Date Issued: 1988
Potency ranking of two new topical corticosteroid creams containing 0.1% desonide or 0.05% halometasone utilizing the human skin-blanching assay
- Meyer, Eric, Smith, Eric W, Haigh, John M, Kanfer, Isadore
- Authors: Meyer, Eric , Smith, Eric W , Haigh, John M , Kanfer, Isadore
- Date: 1988
- Language: English
- Type: Article
- Identifier: vital:6400 , http://hdl.handle.net/10962/d1006327
- Description: The human blanching assay was used to assess the potency of two new proprietary corticosteroid creams. The blanching abilities of 0.1% desonide cream and 0.05% halometasone cream were evaluated relative to the blanching elicited by 0.05% clobetasol 17-propionate cream, 0.1% betamethasone 17-valerate cream and 0.05% clobetasone 17-butyrate cream. The results of the trial indicated that the 0.1% desonide cream falls into the potent group of topical corticosteroid preparations and the 0.05% halomethasone cream falls into the moderately potent group.
- Full Text:
- Date Issued: 1988
- Authors: Meyer, Eric , Smith, Eric W , Haigh, John M , Kanfer, Isadore
- Date: 1988
- Language: English
- Type: Article
- Identifier: vital:6400 , http://hdl.handle.net/10962/d1006327
- Description: The human blanching assay was used to assess the potency of two new proprietary corticosteroid creams. The blanching abilities of 0.1% desonide cream and 0.05% halometasone cream were evaluated relative to the blanching elicited by 0.05% clobetasol 17-propionate cream, 0.1% betamethasone 17-valerate cream and 0.05% clobetasone 17-butyrate cream. The results of the trial indicated that the 0.1% desonide cream falls into the potent group of topical corticosteroid preparations and the 0.05% halomethasone cream falls into the moderately potent group.
- Full Text:
- Date Issued: 1988
A stability-indicating liquid chromatographic method for the analysis of erythromycin in stored biological fluids using amperometric detection
- Stubbs, Christopher, Haigh, John M, Kanfer, Isadore
- Authors: Stubbs, Christopher , Haigh, John M , Kanfer, Isadore
- Date: 1987
- Language: English
- Type: Article
- Identifier: vital:6430 , http://hdl.handle.net/10962/d1006592
- Description: A simple, sensitive and reliable high-performance liquid chromatographic procedure has been developed for the determination of erythromycin in human serum and urine using amperometric detection. A solid-phase extraction procedure was used followed by chromatography on a reverse-phase column. The mean recovery of erythromycin from serum and urine was 80%. This method allows both erythromycin and its principle degradation product, anhydroeythromycin, to be determined during a period of sample storage at 4 degree C and minus 15 degree C. The method is sufficiently sensitive and precise and is thus highly suited for use in both pharmacokinetic and stability studies.
- Full Text:
- Date Issued: 1987
- Authors: Stubbs, Christopher , Haigh, John M , Kanfer, Isadore
- Date: 1987
- Language: English
- Type: Article
- Identifier: vital:6430 , http://hdl.handle.net/10962/d1006592
- Description: A simple, sensitive and reliable high-performance liquid chromatographic procedure has been developed for the determination of erythromycin in human serum and urine using amperometric detection. A solid-phase extraction procedure was used followed by chromatography on a reverse-phase column. The mean recovery of erythromycin from serum and urine was 80%. This method allows both erythromycin and its principle degradation product, anhydroeythromycin, to be determined during a period of sample storage at 4 degree C and minus 15 degree C. The method is sufficiently sensitive and precise and is thus highly suited for use in both pharmacokinetic and stability studies.
- Full Text:
- Date Issued: 1987