The use of response surface methodology in the evaluation of captopril microparticles manufactured using an oil in oil solvent evaporation technique
- Khamanga, Sandile M, Walker, Roderick B
- Authors: Khamanga, Sandile M , Walker, Roderick B
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184221 , vital:44191 , xlink:href="https://doi.org/10.3109/02652048.2011.629744"
- Description: Captopril (CPT) microparticles were manufactured by solvent evaporation using acetone (dispersion phase) and liquid paraffin (manufacturing phase) with Eudragit® and Methocel® as coat materials. Design of experiments and response surface methodology (RSM) approaches were used to optimize the process. The microparticles were characterized based on the percent of drug released and yield, microcapsule size, entrapment efficiency and Hausner ratio. Differential scanning calorimetry (DSC), Infrared (IR) spectroscopy, scanning electron microscopy (SEM) and in vitro dissolution studies were conducted. The microcapsules were spherical, free-flowing and IR and DSC thermograms revealed that CPT was stable. The percent drug released was investigated with respect to Eudragit® RS and Methocel® K100M, Methocel® K15M concentrations and homogenizing speed. The optimal conditions for microencapsulation were 1.12 g Eudragit® RS, 0.67 g Methocel® K100M and 0.39 g Methocel® K15M at a homogenizing speed of 1643 rpm and 89% CPT was released. The value of RSM-mediated microencapsulation of CPT was elucidated.
- Full Text:
- Date Issued: 2012
- Authors: Khamanga, Sandile M , Walker, Roderick B
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184221 , vital:44191 , xlink:href="https://doi.org/10.3109/02652048.2011.629744"
- Description: Captopril (CPT) microparticles were manufactured by solvent evaporation using acetone (dispersion phase) and liquid paraffin (manufacturing phase) with Eudragit® and Methocel® as coat materials. Design of experiments and response surface methodology (RSM) approaches were used to optimize the process. The microparticles were characterized based on the percent of drug released and yield, microcapsule size, entrapment efficiency and Hausner ratio. Differential scanning calorimetry (DSC), Infrared (IR) spectroscopy, scanning electron microscopy (SEM) and in vitro dissolution studies were conducted. The microcapsules were spherical, free-flowing and IR and DSC thermograms revealed that CPT was stable. The percent drug released was investigated with respect to Eudragit® RS and Methocel® K100M, Methocel® K15M concentrations and homogenizing speed. The optimal conditions for microencapsulation were 1.12 g Eudragit® RS, 0.67 g Methocel® K100M and 0.39 g Methocel® K15M at a homogenizing speed of 1643 rpm and 89% CPT was released. The value of RSM-mediated microencapsulation of CPT was elucidated.
- Full Text:
- Date Issued: 2012
Top-Down Synthesis of a Lamivudine-Zidovudine Nano Co-Crystal
- Witika, Bwalya A, Smith, Vincent J, Walker, Roderick B
- Authors: Witika, Bwalya A , Smith, Vincent J , Walker, Roderick B
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183172 , vital:43918 , xlink:href="https://doi.org/10.3390/cryst11010033"
- Description: Lamivudine (3TC) and zidovudine (AZT) are antiretroviral agents used to manage HIV/AIDS infection. A wet media milling top-down approach was used to develop and produce nano co-crystals of 3TC and AZT. Micro co-crystals were prepared by solvent evaporation and subsequently milled in the presence of two surfactants, viz., sodium lauryl sulfate (SLS) and α-tocopheryl polyethylene glycol succinate 1000 (TPGS 1000). Optimisation was undertaken using design of experiments (DoE) and response surface methodology (RSM) to establish and identify parameters that may affect the manufacturing of nano co-crystals. The impact of SLS and TPGS 1000 concentration, milling time, and number of units of milling medium on the manufacturing of nano co-crystals, was investigated. The critical quality attributes (CQA) monitored were particle size (PS), Zeta potential (ZP), and polydispersity index (PDI). Powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, transmission electron microscopy, energy dispersive X-ray spectroscopy scanning electron microscopy, and cytotoxicity assays were used for additional characterization of the optimised nano co-crystal. The mean PS, PDI, and ZP of the optimised top-down nanocrystal were 271.0 ± 92.0 nm, 0.467 ± 0.073, and −41.9 ± 3.94 mV, respectively. In conclusion, a simple, inexpensive, rapid, and precise method of nano co-crystal manufacturing was developed, validated, and optimised using DoE and RSM, and the final product exhibited the target CQA.
- Full Text:
- Date Issued: 2021
- Authors: Witika, Bwalya A , Smith, Vincent J , Walker, Roderick B
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183172 , vital:43918 , xlink:href="https://doi.org/10.3390/cryst11010033"
- Description: Lamivudine (3TC) and zidovudine (AZT) are antiretroviral agents used to manage HIV/AIDS infection. A wet media milling top-down approach was used to develop and produce nano co-crystals of 3TC and AZT. Micro co-crystals were prepared by solvent evaporation and subsequently milled in the presence of two surfactants, viz., sodium lauryl sulfate (SLS) and α-tocopheryl polyethylene glycol succinate 1000 (TPGS 1000). Optimisation was undertaken using design of experiments (DoE) and response surface methodology (RSM) to establish and identify parameters that may affect the manufacturing of nano co-crystals. The impact of SLS and TPGS 1000 concentration, milling time, and number of units of milling medium on the manufacturing of nano co-crystals, was investigated. The critical quality attributes (CQA) monitored were particle size (PS), Zeta potential (ZP), and polydispersity index (PDI). Powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, transmission electron microscopy, energy dispersive X-ray spectroscopy scanning electron microscopy, and cytotoxicity assays were used for additional characterization of the optimised nano co-crystal. The mean PS, PDI, and ZP of the optimised top-down nanocrystal were 271.0 ± 92.0 nm, 0.467 ± 0.073, and −41.9 ± 3.94 mV, respectively. In conclusion, a simple, inexpensive, rapid, and precise method of nano co-crystal manufacturing was developed, validated, and optimised using DoE and RSM, and the final product exhibited the target CQA.
- Full Text:
- Date Issued: 2021
Ultrasound-Triggered Release of 5-Fluorouracil from Soy Lecithin Echogenic Liposomes
- Ezekiel, Charles I, Bapolisi, Alain M, Walker, Roderick B, Krause, Rui W M
- Authors: Ezekiel, Charles I , Bapolisi, Alain M , Walker, Roderick B , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183115 , vital:43913 , xlink:href="https://doi.org/10.3390/pharmaceutics13060821"
- Description: Colorectal cancer is the third most diagnosed cancer and the second leading cause of death. The use of 5-fluorouracil (5-FU) has been the major chemotherapeutic treatment for colorectal cancer patients. However, the efficacy of 5-FU is limited by drug resistance, and bone marrow toxicity through high-level expression of thymidylate synthase, justifying the need for improvement of the therapeutic index. In this study, the effects of ultrasound on echogenic 5-FU encapsulated crude soy liposomes were investigated for their potential to address these challenges. Liposomes were prepared by thin-film hydration using crude soy lecithin and cholesterol. Argon gas was entrapped in the liposomes for sonosensitivity (that is, responsiveness to ultrasound). The nanoparticles were characterized for particle size and morphology. The physicochemical properties were also evaluated using differential scanning calorimetry, Fourier transform infrared and X-ray diffraction. The release profile of 5-FU was assessed with and without 20 kHz low-frequency ultrasound waves at various amplitudes and exposure times. The result reveal that 5-FU-loaded liposomes were spherical with an encapsulation efficiency of approximately 60%. Approximately 65% of 5-FU was released at the highest amplitude and exposure time was investigated. The results are encouraging for the stimulated and controlled release of 5-FU for the management of colorectal cancer.
- Full Text:
- Date Issued: 2021
- Authors: Ezekiel, Charles I , Bapolisi, Alain M , Walker, Roderick B , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183115 , vital:43913 , xlink:href="https://doi.org/10.3390/pharmaceutics13060821"
- Description: Colorectal cancer is the third most diagnosed cancer and the second leading cause of death. The use of 5-fluorouracil (5-FU) has been the major chemotherapeutic treatment for colorectal cancer patients. However, the efficacy of 5-FU is limited by drug resistance, and bone marrow toxicity through high-level expression of thymidylate synthase, justifying the need for improvement of the therapeutic index. In this study, the effects of ultrasound on echogenic 5-FU encapsulated crude soy liposomes were investigated for their potential to address these challenges. Liposomes were prepared by thin-film hydration using crude soy lecithin and cholesterol. Argon gas was entrapped in the liposomes for sonosensitivity (that is, responsiveness to ultrasound). The nanoparticles were characterized for particle size and morphology. The physicochemical properties were also evaluated using differential scanning calorimetry, Fourier transform infrared and X-ray diffraction. The release profile of 5-FU was assessed with and without 20 kHz low-frequency ultrasound waves at various amplitudes and exposure times. The result reveal that 5-FU-loaded liposomes were spherical with an encapsulation efficiency of approximately 60%. Approximately 65% of 5-FU was released at the highest amplitude and exposure time was investigated. The results are encouraging for the stimulated and controlled release of 5-FU for the management of colorectal cancer.
- Full Text:
- Date Issued: 2021