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Sandile Khamanga
Rhodes University

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Preprint content
Published: 01 July 2021
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Background: Management of arthritis requires frequent administration of medications at high doses that may lead to unwanted side effects and diminished patient adherence to the therapy. Devil’s claw extract, a herbal medicine from the Kalahari sands possess similar therapeutic efficacy with less side effects as the commercialized NSAIDs. The objectives of this study were to formulate, develop and assess novel phyto-elastosomes loaded with Devil’s claw extract in order to combat the toxicity levels associated with Devil’s claw and enhance penetration of harpagoside to intended targeted site.Methods: Screening studies were undertaken to determine the ideal amount of Tween® 80, cholesterol, ethanol, diacetyl phosphate and the pH of the hydration medium necessary to produce stable Devil’s claw-loaded phyto-elastosomes. Parameters monitored were particle size, polydispersity index, zeta potential, entrapment efficiency and deformability index.Results: The use of 20 % v/v ethanol was sufficient to produce novel phyto-elastosomes capable of deforming with minimal size alterations. Hydration of thin films in acidic solution produced phyto-elastosomal dispersions with high entrapment efficiency. The presence of cholesterol impeded harpagoside entrapment and increased cholesterol content affected the stability of vesicles by causing agglomeration. Conversely, increasing Tween® 80 concentration promoted harpagoside entrapment. Diacetyl phosphate promoted the stability of vesicle through charge induction.Conclusions: Development of Devil’s claw loaded phyto-elastosomes is useful in ensuring harpagoside reach the target site of action in arthritis-affected patients. Incorporation of these elastic vesicles in transdermal dosage forms may significantly improve the management of arthritis in the near future.

ACS Style

Pascal Ntemi; Roderick B Walker; Sandile Khamanga. Formulation, Development and Assessment of Novel Phyto-Elastosomes Loaded with Devil’s Claw Extract. 2021, 1 .

AMA Style

Pascal Ntemi, Roderick B Walker, Sandile Khamanga. Formulation, Development and Assessment of Novel Phyto-Elastosomes Loaded with Devil’s Claw Extract. . 2021; ():1.

Chicago/Turabian Style

Pascal Ntemi; Roderick B Walker; Sandile Khamanga. 2021. "Formulation, Development and Assessment of Novel Phyto-Elastosomes Loaded with Devil’s Claw Extract." , no. : 1.

Journal article
Published: 23 August 2020 in Pharmaceutics
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The formation, manufacture and characterization of low energy water-in-oil (w/o) nanoemulsions prepared using cold pressed flaxseed oil containing efavirenz was investigated. Pseudo-ternary phase diagrams were constructed to identify the nanoemulsion region(s). Other potential lipid-based drug delivery phases containing flaxseed oil with 1:1 m/m surfactant mixture of Tween® 80, Span® 20 and different amounts of ethanol were tested to characterize the impact of surfactant mixture on emulsion formation. Flaxseed oil was used as the oil phase as efavirenz exhibited high solubility in the vehicle when compared to other vegetable oils tested. Optimization of surfactant mixtures was undertaken using design of experiments, specifically a D-optimal design with the flaxseed oil content set at 10% m/m. Two solutions from the desired optimization function were produced based on desirability and five nanoemulsion formulations were produced and characterized in terms of in vitro release of efavirenz, physical and chemical stability. Metastable nanoemulsions containing 10% m/m flaxseed oil were successfully manufactured and significant isotropic gel (semisolid) and o/w emulsions were observed during phase behavior studies. Droplet sizes ranged between 156 and 225 nm, zeta potential between −24 and −41 mV and all formulations were found to be monodisperse with polydispersity indices ≤ 0.487.

ACS Style

Priveledge Mazonde; Sandile M. M. Khamanga; Roderick B. Walker. Design, Optimization, Manufacture and Characterization of Efavirenz-Loaded Flaxseed Oil Nanoemulsions. Pharmaceutics 2020, 12, 797 .

AMA Style

Priveledge Mazonde, Sandile M. M. Khamanga, Roderick B. Walker. Design, Optimization, Manufacture and Characterization of Efavirenz-Loaded Flaxseed Oil Nanoemulsions. Pharmaceutics. 2020; 12 (9):797.

Chicago/Turabian Style

Priveledge Mazonde; Sandile M. M. Khamanga; Roderick B. Walker. 2020. "Design, Optimization, Manufacture and Characterization of Efavirenz-Loaded Flaxseed Oil Nanoemulsions." Pharmaceutics 12, no. 9: 797.

Articles
Published: 21 August 2020 in Drug Development and Industrial Pharmacy
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The aim of this research was to develop lamotrigine containing thermosetting hydrogel for intranasal administration to manage and treat generalised epilepsy. Thermosetting hydrogels were prepared using different ratios of poloxamer 407 (L127), poloxamer 188 (L68) and Carbopol® 974P NF (C974) using the cold production process. The in situ thermosetting hydrogel was optimised using Box Behken design. Co-solvency approach was used to increase the solubility of lamotrigine by dissolving it in propylene glycol and polyethylene glycol 400 (0.2: 0.8) and the resultant solution was incorporated in the hydrogel to manufacture an LTG hydrogel. The presence of a higher amount of L127 resulted in higher viscosity at 22 °C and 34 °C and decreased the overall release of LTG. An increase in the amount of C974 resulted in a decrease in the pH of the hydrogel. The results show that formulations F10, F12, F13, F14, F15, F16 and F17 exhibited acceptable thermosetting behaviour, pH and released adequate Lamotrigine above the minimum effective concentration to treat generalised epilepsy. The optimised formulation exhibited acceptable thermosetting behaviour, pH and lamotrigine release but formed a stiff gel at 22 °C. The average LTG content of the optimised hydrogel was 5.00 ± 0.0225 mg/ml with % recovery of 99.17%. The amount of LTG released at 12 hours from the optimised hydrogel was 3.21 ± 0.0155 mg and will be therapeutically effective in the brain after absorption via the olfactory region in the nasal cavity.

ACS Style

S. Melamane; R.B. Walker; S.M.M. Khamanga. Formulation optimization of smart thermosetting lamotrigine loaded hydrogels using response surface methodology, Box Benhken design and artificial neural networks. Drug Development and Industrial Pharmacy 2020, 46, 1 -32.

AMA Style

S. Melamane, R.B. Walker, S.M.M. Khamanga. Formulation optimization of smart thermosetting lamotrigine loaded hydrogels using response surface methodology, Box Benhken design and artificial neural networks. Drug Development and Industrial Pharmacy. 2020; 46 (9):1-32.

Chicago/Turabian Style

S. Melamane; R.B. Walker; S.M.M. Khamanga. 2020. "Formulation optimization of smart thermosetting lamotrigine loaded hydrogels using response surface methodology, Box Benhken design and artificial neural networks." Drug Development and Industrial Pharmacy 46, no. 9: 1-32.

Journal article
Published: 30 July 2020 in Pharmaceutics
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Cardiovascular diseases such as hypertension and cardiac failure in South African children and adolescents are effectively managed long term, using a combination treatment of captopril and hydrochlorothiazide. The majority of commercially available pharmaceutical products are designed for adult patients and require extemporaneous manipulation, prior to administration to paediatric patients. There is a need to develop an age appropriate microparticulate dosing technology that is easy to swallow, dose and alter doses whilst overcoming the pharmacokinetic challenges of short half-life and biphasic pharmacokinetic disposition exhibited by hydrochlorothiazide and captopril. An emulsion solvent evaporation approach using different combinations of polymers was used to manufacture captopril and hydrochlorothiazide microparticles. Design of experiments was used to develop and analyse experimental data, and identifyoptimum formulation and process conditions for the preparation of the microparticles. Characterisation studies to establish encapsulation efficiency, in vitro release, shape, size and morphology of the microparticles were undertaken. The microparticles produced were in the micrometre size range, with an encapsulation efficiency >75% for both hydrochlorothiazide and captopril. The microparticulate technology is able to offer potential resolution to the half-life mediated dosing frequency of captopril as sustained release of the molecule was observed over a 12-h period. The release of hydrochlorothiazide of >80% suggests an improvement in solubility limited dissolution.

ACS Style

Mellisa T. R. Chikukwa; Roderick B. Walker; Sandile M. M. Khamanga. Formulation and Characterisation of a Combination Captopril and Hydrochlorothiazide Microparticulate Dosage Form. Pharmaceutics 2020, 12, 712 .

AMA Style

Mellisa T. R. Chikukwa, Roderick B. Walker, Sandile M. M. Khamanga. Formulation and Characterisation of a Combination Captopril and Hydrochlorothiazide Microparticulate Dosage Form. Pharmaceutics. 2020; 12 (8):712.

Chicago/Turabian Style

Mellisa T. R. Chikukwa; Roderick B. Walker; Sandile M. M. Khamanga. 2020. "Formulation and Characterisation of a Combination Captopril and Hydrochlorothiazide Microparticulate Dosage Form." Pharmaceutics 12, no. 8: 712.

Journal article
Published: 07 June 2020 in International Journal of Environmental Research and Public Health
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Pharmaceuticals are emerging contaminants in the aquatic environments. Their presence poses toxicological effects in humans and animals even at trace concentrations. This study investigated the presence of antibiotics, anti-epilepsy and anti-inflammatory drugs in river water of selected rivers in the Eastern Cape Province in South Africa. Enzyme-linked immunosorbent assay was used for screening of sulfamethoxazole and fluoroquinolones antibiotics. The samples were collected in upper-stream, middle-stream and lower-stream regions of the rivers and effluent of selected wastewater treatment plants. Pre-concentration of the samples was conducted using lyophilisation and extraction was conducted using solid phase extraction (SPE) on Waters Oasis hydrophilic-lipophilic-balanced cartridge. The percentage recovery after sample clean-up on SPE was 103% ± 6.9%. This was followed by ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry. The detected analytes were sulfamethoxazole, erythromycin, clarithromycin and carbamazepine. Carbamazepine and erythromycin were detected in high concentrations ranging from 81.8 to 36,576.2 ng/L and 11.2 to 11,800 ng/L respectively, while clarithromycin and sulfamethoxazole were detected at moderate concentrations ranging from 4.8 to 3280.4 ng/L and 6.6 to 6968 ng/L, respectively. High concentrations of pharmaceuticals were detected on the lower-stream sites as compared to upper-stream sites.

ACS Style

Sesethu Vumazonke; Sandile Maswazi Khamanga; Nosiphiwe Ngqwala. Detection of Pharmaceutical Residues in Surface Waters of the Eastern Cape Province. International Journal of Environmental Research and Public Health 2020, 17, 4067 .

AMA Style

Sesethu Vumazonke, Sandile Maswazi Khamanga, Nosiphiwe Ngqwala. Detection of Pharmaceutical Residues in Surface Waters of the Eastern Cape Province. International Journal of Environmental Research and Public Health. 2020; 17 (11):4067.

Chicago/Turabian Style

Sesethu Vumazonke; Sandile Maswazi Khamanga; Nosiphiwe Ngqwala. 2020. "Detection of Pharmaceutical Residues in Surface Waters of the Eastern Cape Province." International Journal of Environmental Research and Public Health 17, no. 11: 4067.

Articles
Published: 29 November 2019 in Pharmaceutical Development and Technology
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The objective of the study was to mask the unpleasant taste of captopril. Taste masking was achieved by complexation of captopril with a basic ion exchange resin, Dowex® 66, using the batch method. Dowex® 66 was used for the adsorption of captopril, and physical and chemical parameters of the captopril resinates complex were evaluated. A Central Composite Design was used to generate the experiments for the manufacture of resinates using different process and formulation variables. In-vitro dissolution studies were performed for 2 hours in 0.01N HCl (pH 1.6) using USP Apparatus I .The compatibility of captopril and the resin was evaluated by FTIR, DSC and PXRD. The resinates were evaluated for micromeritic properties and further characterized using FTIR, DSC and PXRD. Response surface methodology was used to determine the significance of input variables on the captopril content and release. The captopril resin ratio was found to have a significant impact on content of the resinates and on captopril release. The formulations were also studied for taste masking ability by means of an electronic gustatory system – electronic tongue.

ACS Style

Mellisa T. R. Chikukwa; Małgorzata Wesoly; Aleksandra B. Korzeniowska; Patrycja Ciosek-Skibinska; Roderick B. Walker; Sandile M. M. Khamanga. Assessment of taste masking of captopril by ion-exchange resins using electronic gustatory system. Pharmaceutical Development and Technology 2019, 25, 281 -289.

AMA Style

Mellisa T. R. Chikukwa, Małgorzata Wesoly, Aleksandra B. Korzeniowska, Patrycja Ciosek-Skibinska, Roderick B. Walker, Sandile M. M. Khamanga. Assessment of taste masking of captopril by ion-exchange resins using electronic gustatory system. Pharmaceutical Development and Technology. 2019; 25 (3):281-289.

Chicago/Turabian Style

Mellisa T. R. Chikukwa; Małgorzata Wesoly; Aleksandra B. Korzeniowska; Patrycja Ciosek-Skibinska; Roderick B. Walker; Sandile M. M. Khamanga. 2019. "Assessment of taste masking of captopril by ion-exchange resins using electronic gustatory system." Pharmaceutical Development and Technology 25, no. 3: 281-289.

Journal article
Published: 16 November 2019 in Scientia Pharmaceutica
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An isocratic high-performance liquid chromatographic method using electrochemical detection (HPLC-ECD) for the quantitation of clarithromycin (CLA) was developed using Response Surface Methodology (RSM) based on a Central Composite Design (CCD). The method was validated using International Conference on Harmonization (ICH) guidelines with an analytical run time of 20 min. Method re-validation following a change in analytical column was successful in reducing the analytical run time to 13 min, decreasing solvent consumption thus facilitating environmental and financial sustainability. The applicability of using the United States Pharmacopeia (USP) method scaling approach in place of method re-validation using a column with a different L–designation to the original analytical column, was investigated. The scaled method met all USP system suitability requirements for resolution, tailing factor and % relative standard deviation (RSD). The re-validated and scaled method was successfully used to resolve CLA from manufacturing excipients in commercially available dosage forms. Although USP method scaling is only permitted for columns within the same L-designation, these data suggest that it may also be applicable to columns of different designation.

ACS Style

Pedzisai A. Makoni; Mellisa T. R. Chikukwa; Sandile M. M. Khamanga; Roderick B. Walker. Stability Indicating HPLC-ECD Method for the Analysis of Clarithromycin in Pharmaceutical Dosage Forms: Method Scaling versus Re-Validation. Scientia Pharmaceutica 2019, 87, 31 .

AMA Style

Pedzisai A. Makoni, Mellisa T. R. Chikukwa, Sandile M. M. Khamanga, Roderick B. Walker. Stability Indicating HPLC-ECD Method for the Analysis of Clarithromycin in Pharmaceutical Dosage Forms: Method Scaling versus Re-Validation. Scientia Pharmaceutica. 2019; 87 (4):31.

Chicago/Turabian Style

Pedzisai A. Makoni; Mellisa T. R. Chikukwa; Sandile M. M. Khamanga; Roderick B. Walker. 2019. "Stability Indicating HPLC-ECD Method for the Analysis of Clarithromycin in Pharmaceutical Dosage Forms: Method Scaling versus Re-Validation." Scientia Pharmaceutica 87, no. 4: 31.

Journal article
Published: 07 March 2019 in Pharmaceutics
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The impact of formulation and process variables on the in-vitro release of prednisone from a multiple-unit pellet system was investigated. Box-Behnken Response Surface Methodology (RSM) was used to generate multivariate experiments. The extrusion-spheronization method was used to produce pellets and dissolution studies were performed using United States Pharmacopoeia (USP) Apparatus 2 as described in USP XXIV. Analysis of dissolution test samples was performed using a reversed-phase high-performance liquid chromatography (RP-HPLC) method. Four formulation and process variables viz., microcrystalline cellulose concentration, sodium starch glycolate concentration, spheronization time and extrusion speed were investigated and drug release, aspect ratio and yield were monitored for the trained artificial neural networks (ANN). To achieve accurate prediction, data generated from experimentation were used to train a multi-layer perceptron (MLP) using back propagation (BP) and the Broyden-Fletcher-Goldfarb-Shanno (BFGS) 57 training algorithm until a satisfactory value of root mean square error (RMSE) was observed. The study revealed that the in-vitro release profile of prednisone was significantly impacted by microcrystalline cellulose concentration and sodium starch glycolate concentration. Increasing microcrystalline cellulose concentration retarded dissolution rate whereas increasing sodium starch glycolate concentration improved dissolution rate. Spheronization time and extrusion speed had minimal impact on prednisone release but had a significant impact on extrudate and pellet quality. This work demonstrated that RSM can be successfully used concurrently with ANN for dosage form manufacture to permit the exploration of experimental regions that are omitted when using RSM alone.

ACS Style

Arthur Manda; Roderick B. Walker; Sandile M. M. Khamanga. An Artificial Neural Network Approach to Predict the Effects of Formulation and Process Variables on Prednisone Release from a Multipartite System. Pharmaceutics 2019, 11, 109 .

AMA Style

Arthur Manda, Roderick B. Walker, Sandile M. M. Khamanga. An Artificial Neural Network Approach to Predict the Effects of Formulation and Process Variables on Prednisone Release from a Multipartite System. Pharmaceutics. 2019; 11 (3):109.

Chicago/Turabian Style

Arthur Manda; Roderick B. Walker; Sandile M. M. Khamanga. 2019. "An Artificial Neural Network Approach to Predict the Effects of Formulation and Process Variables on Prednisone Release from a Multipartite System." Pharmaceutics 11, no. 3: 109.