Development and assessment of a USP Apparatus 3 dissolution test method for sustained-release Nevirapine matrix tablets
- Mwila, Chiluba, Khamanga, Sandile M M, Walker, Roderick B
- Authors: Mwila, Chiluba , Khamanga, Sandile M M , Walker, Roderick B
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184779 , vital:44271 , xlink:href="https://doi.org/10.14227/dt230316p22"
- Description: Dissolution testing is a quality control tool used to assess batch-to-batch performance of dosage forms, thereby providing continued assurance of product quality. Analytical methods for the assessment of pharmaceutical product quality must be validated according to regulatory guidelines to ensure that tests are reliable and valid. Agitation rate, mesh pore size, surfactant concentration, and dissolution medium molarity are experimental parameters that may affect nevirapine (NVP) release and were investigated and optimized to ensure that consistent, reliable, and valid results using Apparatus 3 were produced. Agitation rate was investigated to establish an equivalent response to that observed for NVP release using Apparatus 2 at 50 rpm. A reciprocation rate of 5–10 dpm produced dissolution profiles that were similar to those observed using Apparatus 2. An increase in the molarity of the dissolution medium slightly increased the release rate of NVP, and a 50 mM buffer maintained at pH values mimicking gastrointestinal tract (GIT) conditions was selected for all experiments. With the addition of 2% sodium lauryl sulfate (SLS) to the dissolution medium, >80% NVP was released from the tablets over the test period. The NVP release rate increased with an increase in the mesh pore size; however, the extent of release was not affected by this parameter. Dissolution test samples were analyzed using HPLC, and dissolution methods were validated for NVP stability in the dissolution medium, specificity, linearity and range, repeatability, intermediate precision, and accuracy as defined by ICH. The dissolution method used for testing NVP tablets can be regarded as an appropriate tool for the evaluation of sustained-release (SR) NVP formulations and the impact of formulation composition and product quality attributes on drug release.
- Full Text:
- Date Issued: 2016
- Authors: Mwila, Chiluba , Khamanga, Sandile M M , Walker, Roderick B
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184779 , vital:44271 , xlink:href="https://doi.org/10.14227/dt230316p22"
- Description: Dissolution testing is a quality control tool used to assess batch-to-batch performance of dosage forms, thereby providing continued assurance of product quality. Analytical methods for the assessment of pharmaceutical product quality must be validated according to regulatory guidelines to ensure that tests are reliable and valid. Agitation rate, mesh pore size, surfactant concentration, and dissolution medium molarity are experimental parameters that may affect nevirapine (NVP) release and were investigated and optimized to ensure that consistent, reliable, and valid results using Apparatus 3 were produced. Agitation rate was investigated to establish an equivalent response to that observed for NVP release using Apparatus 2 at 50 rpm. A reciprocation rate of 5–10 dpm produced dissolution profiles that were similar to those observed using Apparatus 2. An increase in the molarity of the dissolution medium slightly increased the release rate of NVP, and a 50 mM buffer maintained at pH values mimicking gastrointestinal tract (GIT) conditions was selected for all experiments. With the addition of 2% sodium lauryl sulfate (SLS) to the dissolution medium, >80% NVP was released from the tablets over the test period. The NVP release rate increased with an increase in the mesh pore size; however, the extent of release was not affected by this parameter. Dissolution test samples were analyzed using HPLC, and dissolution methods were validated for NVP stability in the dissolution medium, specificity, linearity and range, repeatability, intermediate precision, and accuracy as defined by ICH. The dissolution method used for testing NVP tablets can be regarded as an appropriate tool for the evaluation of sustained-release (SR) NVP formulations and the impact of formulation composition and product quality attributes on drug release.
- Full Text:
- Date Issued: 2016
Electrode modification using alkyne manganese phthalocyanine and click chemistry for electrocatalysis
- O'Donoghue, Charles St John Nqwabuko, Fomo, Gertrude, Nyokong, Tebello
- Authors: O'Donoghue, Charles St John Nqwabuko , Fomo, Gertrude , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188541 , vital:44763 , xlink:href="https://doi.org/10.1002/elan.201600379"
- Description: In this work, azidobenzene diazonium salt is grafted onto a glassy carbon electrode (GCE) followed by clicking of manganese tetrahexynyl phthalocyanine for the electrocatalysis of hydrazine. The GCE was first grafted via the in situ diazotization of a diazonium salt, rendering the GCE surface layered with azide groups. From this point, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper catalyst was utilized to ‘click’ the manganese tetrahexynyl phthalocyanine to the surface of the grafted GCE. This new platform was then characterized using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM) and X-ray photoelectron spectroscopy (XPS). Based on the cyclic voltammetry calibration curve of electrocatalysis for hydrazine, the clicked Mn phthalocyanine electrode proved to be an effective sensor with a sensitivity of 27.38 µA mM−1 and the limit of detection (LoD) of 15.4 pM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2016
- Authors: O'Donoghue, Charles St John Nqwabuko , Fomo, Gertrude , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188541 , vital:44763 , xlink:href="https://doi.org/10.1002/elan.201600379"
- Description: In this work, azidobenzene diazonium salt is grafted onto a glassy carbon electrode (GCE) followed by clicking of manganese tetrahexynyl phthalocyanine for the electrocatalysis of hydrazine. The GCE was first grafted via the in situ diazotization of a diazonium salt, rendering the GCE surface layered with azide groups. From this point, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper catalyst was utilized to ‘click’ the manganese tetrahexynyl phthalocyanine to the surface of the grafted GCE. This new platform was then characterized using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM) and X-ray photoelectron spectroscopy (XPS). Based on the cyclic voltammetry calibration curve of electrocatalysis for hydrazine, the clicked Mn phthalocyanine electrode proved to be an effective sensor with a sensitivity of 27.38 µA mM−1 and the limit of detection (LoD) of 15.4 pM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2016
MCD spectroscopy and TD-DFT calculations of magnesium tetra-(15-crown-5-oxanthreno)-phthalocyanine
- Mack, John, Mkhize, Scebi, Safonoya, Evgeniya A, Gorbunova, Yulia G, Tsivadze, Aslan Yu, Nyokong, Tebello
- Authors: Mack, John , Mkhize, Scebi , Safonoya, Evgeniya A , Gorbunova, Yulia G , Tsivadze, Aslan Yu , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240743 , vital:50867 , xlink:href="https://doi.org/10.1142/S1088424616500322"
- Description: An analysis of the MCD spectroscopy and TD-DFT calculations of magnesium tetra-(15-crown-5-oxanthreno)-phthalocyanine is reported. This study provides a reassessment of an earlier study on the nature of the bands in UV-visible absorption spectra of magnesium and zinc tetra-(15-crown-5-oxanthreno)-phthalocyanine that was based on an analysis of TD-DFT calculations for a series of model complexes with the B3LYP functional. A detailed analysis of MCD spectral data and TD-DFT calculations with the CAM-B3LYP functional for the complete Mg(II) complex provides an additional insight into the optical properties and electronic structures of tetra-(15-crown-5-oxanthreno)-phthalocyanines. Thus, the bands in the Q-band region are reassigned as being due exclusively to the Q transition of Gouterman’s 4-orbital model, since intense pseudo-A1𝒜1 terms are observed in the MCD spectrum in a spectral region that had previously been assigned as charge transfer bands.
- Full Text:
- Date Issued: 2016
- Authors: Mack, John , Mkhize, Scebi , Safonoya, Evgeniya A , Gorbunova, Yulia G , Tsivadze, Aslan Yu , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240743 , vital:50867 , xlink:href="https://doi.org/10.1142/S1088424616500322"
- Description: An analysis of the MCD spectroscopy and TD-DFT calculations of magnesium tetra-(15-crown-5-oxanthreno)-phthalocyanine is reported. This study provides a reassessment of an earlier study on the nature of the bands in UV-visible absorption spectra of magnesium and zinc tetra-(15-crown-5-oxanthreno)-phthalocyanine that was based on an analysis of TD-DFT calculations for a series of model complexes with the B3LYP functional. A detailed analysis of MCD spectral data and TD-DFT calculations with the CAM-B3LYP functional for the complete Mg(II) complex provides an additional insight into the optical properties and electronic structures of tetra-(15-crown-5-oxanthreno)-phthalocyanines. Thus, the bands in the Q-band region are reassigned as being due exclusively to the Q transition of Gouterman’s 4-orbital model, since intense pseudo-A1𝒜1 terms are observed in the MCD spectrum in a spectral region that had previously been assigned as charge transfer bands.
- Full Text:
- Date Issued: 2016
Nonlinear optical behavior of alkyne terminated phthalocyanines in solution and when embedded in polysulfone as thin films: effects of aggregation
- Bankole, Owolabi M, Yilmaz, Yusuf, Nyokong, Tebello
- Authors: Bankole, Owolabi M , Yilmaz, Yusuf , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189110 , vital:44817 , xlink:href="https://doi.org/10.1016/j.optmat.2015.11.041"
- Description: We report here for the first time, on the comparative studies of the photophysical and optical limiting behavior of our two novel phthalocyanines namely 2(3), 9(10), 16(17), 23(24)-tetrakis-(4-(5-methylhex-1-yn-3-yloxy)) phthalocyanines 2, and 2(3), 9(10), 16(17), 23(24)-tetrakis-(4-(5-methylhex-1-yn-3-yloxy)) phthalocyaninato zinc (II) (3) in solution and thin films. Nonlinear optical (NLO) properties of the samples in solution and contained in polysulfone (PSU) thin films were evaluated using Z-scan technique at 532 nm and 10 ns pulsed duration. Effects of aggregation and disaggregation on the NLO performance of metal-free phthalocyanine are reported in detail. Our findings showed that the prepared Pcs show larger nonlinear absorption coefficient and lower limiting thresholds when embedded in polysulfone films compared to in solutions. The values of nonlinear susceptibility and hyperpolarizability recorded for 3-PSU in this work are respectively, ∼2.09 × 10−8 esu and ∼1.02 × 10−26 esu. These values are among the largest values reported for phthalocyanines and other macrocycles doped on polymer matrices.
- Full Text:
- Date Issued: 2016
- Authors: Bankole, Owolabi M , Yilmaz, Yusuf , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189110 , vital:44817 , xlink:href="https://doi.org/10.1016/j.optmat.2015.11.041"
- Description: We report here for the first time, on the comparative studies of the photophysical and optical limiting behavior of our two novel phthalocyanines namely 2(3), 9(10), 16(17), 23(24)-tetrakis-(4-(5-methylhex-1-yn-3-yloxy)) phthalocyanines 2, and 2(3), 9(10), 16(17), 23(24)-tetrakis-(4-(5-methylhex-1-yn-3-yloxy)) phthalocyaninato zinc (II) (3) in solution and thin films. Nonlinear optical (NLO) properties of the samples in solution and contained in polysulfone (PSU) thin films were evaluated using Z-scan technique at 532 nm and 10 ns pulsed duration. Effects of aggregation and disaggregation on the NLO performance of metal-free phthalocyanine are reported in detail. Our findings showed that the prepared Pcs show larger nonlinear absorption coefficient and lower limiting thresholds when embedded in polysulfone films compared to in solutions. The values of nonlinear susceptibility and hyperpolarizability recorded for 3-PSU in this work are respectively, ∼2.09 × 10−8 esu and ∼1.02 × 10−26 esu. These values are among the largest values reported for phthalocyanines and other macrocycles doped on polymer matrices.
- Full Text:
- Date Issued: 2016
Optical limiting response of multi-walled carbon nanotube-phthalocyanine nanocomposite in solution and when in poly (acrylic acid)
- Sekhosana, Kutloano E, Nyokong, Tebello
- Authors: Sekhosana, Kutloano E , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188628 , vital:44770 , xlink:href="https://doi.org/10.1016/j.molstruc.2016.03.067"
- Description: Bis{23-(3,4-di-yloxybenzoic acid)-(2(3), 9(10), 16(17), 23(24)-(hexakis-pyridin-3-yloxy phthalocyaninato)} dineodymium (III) acetate (3) is linked to amino-functionalized multi-walled carbon nanotubes (MWCNT) to form 3-MWCNT. Z-scan technique was employed to experimentally determine the nonlinear absorption coefficient from the open-aperture data. The limiting threshold values as low as 0.045 J cm−2 were found in solution. The conjugate (3-MWCNT) gave better optical limiting behavior than complex 3 alone.
- Full Text:
- Date Issued: 2016
- Authors: Sekhosana, Kutloano E , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188628 , vital:44770 , xlink:href="https://doi.org/10.1016/j.molstruc.2016.03.067"
- Description: Bis{23-(3,4-di-yloxybenzoic acid)-(2(3), 9(10), 16(17), 23(24)-(hexakis-pyridin-3-yloxy phthalocyaninato)} dineodymium (III) acetate (3) is linked to amino-functionalized multi-walled carbon nanotubes (MWCNT) to form 3-MWCNT. Z-scan technique was employed to experimentally determine the nonlinear absorption coefficient from the open-aperture data. The limiting threshold values as low as 0.045 J cm−2 were found in solution. The conjugate (3-MWCNT) gave better optical limiting behavior than complex 3 alone.
- Full Text:
- Date Issued: 2016
Photophysical properties of tetraphenylporphyrinsubphthalocyanine conjugates
- Managa, Muthumuni, Mack, John, Remiro-Buenamañana, Sonia, Tshangana, Charmaine, Cammidge, Andrew N, Nyokong, Tebello
- Authors: Managa, Muthumuni , Mack, John , Remiro-Buenamañana, Sonia , Tshangana, Charmaine , Cammidge, Andrew N , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240766 , vital:50869 , xlink:href="https://doi.org/10.1142/S1088424615500959"
- Description: Novel tetraphenylporphyrin-subphthalocyanine conjugates have been prepared and characterized. An analysis of their optical spectroscopy and electronic structures using fluorescence emission and magnetic circular dichroism (MCD) spectroscopy and TD-DFT calculations, demonstrates that the two chromophores do not interact to any significant extent.
- Full Text:
- Date Issued: 2016
- Authors: Managa, Muthumuni , Mack, John , Remiro-Buenamañana, Sonia , Tshangana, Charmaine , Cammidge, Andrew N , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240766 , vital:50869 , xlink:href="https://doi.org/10.1142/S1088424615500959"
- Description: Novel tetraphenylporphyrin-subphthalocyanine conjugates have been prepared and characterized. An analysis of their optical spectroscopy and electronic structures using fluorescence emission and magnetic circular dichroism (MCD) spectroscopy and TD-DFT calculations, demonstrates that the two chromophores do not interact to any significant extent.
- Full Text:
- Date Issued: 2016
Screening of entomopathogenic fungi against citrus mealybug, Plannococcus citri (Hemiptera: Pseudococcidae)
- Chartier Fitzgerald, Veronique, Hill, Martin P, Moore, Sean D, Dames, Joanna F
- Authors: Chartier Fitzgerald, Veronique , Hill, Martin P , Moore, Sean D , Dames, Joanna F
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407059 , vital:70333 , xlink:href="https://hdl.handle.net/10520/EJC195093"
- Description: Planococcus citri (citrus mealybug) is a common and damaging citrus crop pest which has proven difficult to control using conventional methods, such as chemical pesticides and insect growth regulators, particularly late in the citrus growing season. The virulence of two entomopathogenic fungal species was studied in laboratory bioassays against the crawlers and adults of P. citri. Isolates of Metarhizium anisopliae and Beauveria bassiana, collected from citrus orchards in the Eastern Cape Province in South Africa, were verified using and molecular techniques. Mealybug bioassays were performed in 24-well plates. Beauveria bassiana (GAR 17 B3) and M. anisopliae (FCM AR 23 B3) isolates both resulted in 67.5 % mortality of mealybug crawlers and B. bassiana (GB AR 23 13 3) resulted in 64 % crawler mortality with concentrations of 1 x 107 conidia/ml. These three isolates were further tested in multipledose bioassays to determine the median lethal concentration (LC50), which were 5.29 x 105conidia/ml for the M. anisopliae isolate (FCM AR 23 B3), 4.25 x 106 conidia/ml for B. bassiana (GAR 17 B3), and 6.65 x 107 conidia/ml B. bassiana (GB AR 23 13 3) for crawlers, respectively. The results of this study suggested that two isolates (M. anisopliae FCM AR 23 B3 and B. bassiana GAR 17 B3) showed potential for further development as biological control agents against citrus mealybug. Further research would be required to determine their ability to perform under field conditions.
- Full Text:
- Date Issued: 2016
- Authors: Chartier Fitzgerald, Veronique , Hill, Martin P , Moore, Sean D , Dames, Joanna F
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407059 , vital:70333 , xlink:href="https://hdl.handle.net/10520/EJC195093"
- Description: Planococcus citri (citrus mealybug) is a common and damaging citrus crop pest which has proven difficult to control using conventional methods, such as chemical pesticides and insect growth regulators, particularly late in the citrus growing season. The virulence of two entomopathogenic fungal species was studied in laboratory bioassays against the crawlers and adults of P. citri. Isolates of Metarhizium anisopliae and Beauveria bassiana, collected from citrus orchards in the Eastern Cape Province in South Africa, were verified using and molecular techniques. Mealybug bioassays were performed in 24-well plates. Beauveria bassiana (GAR 17 B3) and M. anisopliae (FCM AR 23 B3) isolates both resulted in 67.5 % mortality of mealybug crawlers and B. bassiana (GB AR 23 13 3) resulted in 64 % crawler mortality with concentrations of 1 x 107 conidia/ml. These three isolates were further tested in multipledose bioassays to determine the median lethal concentration (LC50), which were 5.29 x 105conidia/ml for the M. anisopliae isolate (FCM AR 23 B3), 4.25 x 106 conidia/ml for B. bassiana (GAR 17 B3), and 6.65 x 107 conidia/ml B. bassiana (GB AR 23 13 3) for crawlers, respectively. The results of this study suggested that two isolates (M. anisopliae FCM AR 23 B3 and B. bassiana GAR 17 B3) showed potential for further development as biological control agents against citrus mealybug. Further research would be required to determine their ability to perform under field conditions.
- Full Text:
- Date Issued: 2016
Spectroscopic investigations and theoretical calculations of DABCO induced xanthene bridged self-assembled zinc (II) porphyrin dimer
- Xu, Li, Huang, Tingting, Liang, Xu, Mack, John, Harris, Jessica, Nyokong, Tebello, Li, Minzhi, Zhu, Weihua
- Authors: Xu, Li , Huang, Tingting , Liang, Xu , Mack, John , Harris, Jessica , Nyokong, Tebello , Li, Minzhi , Zhu, Weihua
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240732 , vital:50866 , xlink:href="https://doi.org/10.1142/S1088424616500231"
- Description: An in-depth study of the electronic structure of a 1,4-diazabicyclo[2.2.2]octane (DABCO) induced molecular self-assembled xanthene-bridged and amide-bonded porphyrin dimer is reported. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations are used to identify trends in the optical spectroscopic properties. B3LYP geometry optimization predicts the formation of an almost perfectly eclipsed structure with respect to the two porphyrin rings with the analogous pyrrole nitrogens separated by 7.7–8.1 Å. The observed distinctive derivative-shaped band morphology of the pseudo-Faraday-A11 terms in the MCD spectra has been used to identify the main electronic Q and B-bands and to validate the TD-DFT calculations. The absence of a discernible splitting of the redox steps or a quenching of the fluorescence demonstrates that there is no significant exciton coupling between the two porphyrin rings.
- Full Text:
- Date Issued: 2016
- Authors: Xu, Li , Huang, Tingting , Liang, Xu , Mack, John , Harris, Jessica , Nyokong, Tebello , Li, Minzhi , Zhu, Weihua
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240732 , vital:50866 , xlink:href="https://doi.org/10.1142/S1088424616500231"
- Description: An in-depth study of the electronic structure of a 1,4-diazabicyclo[2.2.2]octane (DABCO) induced molecular self-assembled xanthene-bridged and amide-bonded porphyrin dimer is reported. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations are used to identify trends in the optical spectroscopic properties. B3LYP geometry optimization predicts the formation of an almost perfectly eclipsed structure with respect to the two porphyrin rings with the analogous pyrrole nitrogens separated by 7.7–8.1 Å. The observed distinctive derivative-shaped band morphology of the pseudo-Faraday-A11 terms in the MCD spectra has been used to identify the main electronic Q and B-bands and to validate the TD-DFT calculations. The absence of a discernible splitting of the redox steps or a quenching of the fluorescence demonstrates that there is no significant exciton coupling between the two porphyrin rings.
- Full Text:
- Date Issued: 2016
Synthesis and dark toxicity of 5-(4-carboxyphenyl)-10, 15, 20-tris (phenyl)-porphyrinato chlorido gallium (III) when conjugated to δ-aminolevulinic acid
- Managa, Muthumuni, Mkhize, Scebi, Britton, Jonathan, Prinsloo, Earl, Nyokong, Tebello
- Authors: Managa, Muthumuni , Mkhize, Scebi , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240014 , vital:50789 , xlink:href="https://doi.org/10.1080/00958972.2016.1223292"
- Description: 5-(4-Carboxyphenyl)-10,15,20-tris(phenyl)-porphyrinato chlorido gallium(III) (2) was synthesized and then linked to ethyl ester δ-aminolevulinic acid to form 3. There was no shift in Soret band following conjugation. The fluorescence and singlet oxygen generating behavior of the porphyrins were also investigated. The highest singlet oxygen quantum yield (ΦΔ) obtained was that of 3. Complexes 2 and 3 as well as metal free 5-(4-carboxyphenyl)-10,15,20-tris(phenyl)-porphyrinato showed no dark toxicity on MCF-7 breast cancer cells.
- Full Text:
- Date Issued: 2016
- Authors: Managa, Muthumuni , Mkhize, Scebi , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240014 , vital:50789 , xlink:href="https://doi.org/10.1080/00958972.2016.1223292"
- Description: 5-(4-Carboxyphenyl)-10,15,20-tris(phenyl)-porphyrinato chlorido gallium(III) (2) was synthesized and then linked to ethyl ester δ-aminolevulinic acid to form 3. There was no shift in Soret band following conjugation. The fluorescence and singlet oxygen generating behavior of the porphyrins were also investigated. The highest singlet oxygen quantum yield (ΦΔ) obtained was that of 3. Complexes 2 and 3 as well as metal free 5-(4-carboxyphenyl)-10,15,20-tris(phenyl)-porphyrinato showed no dark toxicity on MCF-7 breast cancer cells.
- Full Text:
- Date Issued: 2016
Synthesis and photophysicochemical properties of BODIPY dye functionalized gold nanorods for use in antimicrobial photodynamic therapy
- Kubheka, Gugu, Uddin, Imran, Amuhaya, Edith, Mack, John, Nyokong, Tebello
- Authors: Kubheka, Gugu , Uddin, Imran , Amuhaya, Edith , Mack, John , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239897 , vital:50778 , xlink:href="https://doi.org/10.1142/S108842461650070X"
- Description: A series of boron dipyrromethene (BODIPY) dyes with properties that are ideal for a good photosensitizer have been prepared. Functionalization with bromine atoms and attachment to gold nanoparticles through a meso-aniline group results in high singlet oxygen quantum yields and low fluorescent quantum yields. Molecular modelling was used to analyze trends in the MO energies of various brominated aniline BODIPY dyes.
- Full Text:
- Date Issued: 2016
- Authors: Kubheka, Gugu , Uddin, Imran , Amuhaya, Edith , Mack, John , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239897 , vital:50778 , xlink:href="https://doi.org/10.1142/S108842461650070X"
- Description: A series of boron dipyrromethene (BODIPY) dyes with properties that are ideal for a good photosensitizer have been prepared. Functionalization with bromine atoms and attachment to gold nanoparticles through a meso-aniline group results in high singlet oxygen quantum yields and low fluorescent quantum yields. Molecular modelling was used to analyze trends in the MO energies of various brominated aniline BODIPY dyes.
- Full Text:
- Date Issued: 2016
Synthesis, Characterization, and Electronic Structures of Porphyrins Fused with Polycyclic Aromatic Ring Systems
- Okujima, Tetsuo, Mack, John, Nakamura, Jun, Kubheka, Gugu, Nyokong, Tebello, Zhu, Hua, Komobuchi, Naoki, Ono, Noboru, Yamada, Hiroko, Uno, Hidemitsu, Kobayashi, Nagao
- Authors: Okujima, Tetsuo , Mack, John , Nakamura, Jun , Kubheka, Gugu , Nyokong, Tebello , Zhu, Hua , Komobuchi, Naoki , Ono, Noboru , Yamada, Hiroko , Uno, Hidemitsu , Kobayashi, Nagao
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240360 , vital:50827 , xlink:href="https://doi.org/10.1002/chem.201602213"
- Description: A series of porphyrins fused with acenaphthylene, phenanthroline, and benzofluoranthene polycyclic aromatic rings were prepared by means of a 3+1 porphyrin synthesis approach and subsequent retro-Diels–Alder reaction of bicyclo[2.2.2]octadiene-fused precursors. Analysis of the magnetic circular dichroism spectra and the results of time-dependent DFT calculations are used to identify the reasons for the trends observed in the wavelengths and relative intensities of the Q bands of the products. Michl's perimeter model is used as a conceptual framework to explain the changes in the relative energies of the frontier π-molecular orbitals.
- Full Text:
- Date Issued: 2016
- Authors: Okujima, Tetsuo , Mack, John , Nakamura, Jun , Kubheka, Gugu , Nyokong, Tebello , Zhu, Hua , Komobuchi, Naoki , Ono, Noboru , Yamada, Hiroko , Uno, Hidemitsu , Kobayashi, Nagao
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240360 , vital:50827 , xlink:href="https://doi.org/10.1002/chem.201602213"
- Description: A series of porphyrins fused with acenaphthylene, phenanthroline, and benzofluoranthene polycyclic aromatic rings were prepared by means of a 3+1 porphyrin synthesis approach and subsequent retro-Diels–Alder reaction of bicyclo[2.2.2]octadiene-fused precursors. Analysis of the magnetic circular dichroism spectra and the results of time-dependent DFT calculations are used to identify the reasons for the trends observed in the wavelengths and relative intensities of the Q bands of the products. Michl's perimeter model is used as a conceptual framework to explain the changes in the relative energies of the frontier π-molecular orbitals.
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- Date Issued: 2016
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