Browsing by Author "Samsodien, Halima"
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Item Biosimilar’s Growth in Pharmerging Markets: An Analysis of the Regulatory Environments(University of the Western Cape, 2020) Batel, Ryma; Samsodien, HalimaThe introduction of biosimilars to health care markets across the globe has had some success in increasing competition and improving the cost of healthcare. While savings are important for driving the biosimilar uptake, this is not the only consideration for the growth of biosimilars onto emerging markets. A systematic review of the literature to assess the growth of biosimilars onto the emerging market was conducted using the following data sources: PubMed, Website of the Generics and Biosimilars Initiative (GaBI) journal, ProQuest, Google Scholar. Studies that provided evidence of biosimilars onto the emerging market through surveys and other sources of existing data were included. The systematic review process followed Wichor et al. (2018) and the PRISMA checklist (PRISMA, 2009). The search strategy for the review provided a total of 71studies, which underwent title, abstract and full text review to give 20 articles that fit the inclusion criteria for the aimed study. A quality assessment was conducted on the 20 articles and by using the Hawker et al. (2002) quality tool and directed research questions to set variables, the data analysis of 13 articles emerged. The included studies agreed on the growth of biosimilars onto the emerging market and on the switch to biosimilars to improve access to therapies. However, International Nonproprietary Name (INN) and physician confidence were still considered as hurdles. The two most successful drivers of the growth of biosimilars onto the emerging market based on this review was certainly the regulation of the process followed by the cost of biosimilars. To conclude, data analysis of 13 articles determined that the general perception of using biosimilars in emerging markets is positive. However, for successful integration into routine healthcare and uptake into these markets, there must be a direct focus on the regulation of BiosimilarsItem Challenges relating to comparison of flavonoid glycosides dissolution profiles from Sutherlandia frutescens products(De Gruyter Open, 2017) Mbamalu, Oluchi; Syce, James; Samsodien, HalimaUnlike the case of conventional drug formulations, dissolution tests have hitherto not been required for herbal medicinal products commercially available in South Africa. This study investigated dissolution of the South African Sutherlandia frutescens using selected flavonoid glycosides as marker compounds. Dissolution of markers was assessed in three dissolution media at pH 1.2, 4.5 and 6.8, and samples were analysed using a validated HPLC method. The dissolution profile of each marker varied for the different materials investigated. All three media utilised showed differences in flavonoid glycoside dissolution between the S. frutescens products evaluated, with f2 values <50 for comparison of flavonoid dissolution from any two of the materials. Dissolution of S. frutescens materials could thus be characterised using the markers in all the media tested. This tool may be employed in the future for comparison of orally administered S. frutescens products, provided between batch variability is evaluated and found less than between-sample variability.Item Content levels, in vitro dissolution and predicted bioavailability of flavonoids from Sutherlandia frutescens leaf powder and aqueous extracts(University of the Western Cape, 2015) Mbamalu, Oluchi Nneka; Syce, James; Samsodien, HalimaVarious formulations of the popular South African medicinal plant, Sutherlandia frutescens,are commercially available, with no documented specifications for quality assessment. With plans already underway for a clinical trial to assess its efficacy in HIV patients, there is a need for scientifically validated tests for the quality control of products of this plant. Chemical constituents of the plant are many and varied but it is still unclear which might be the most appropriate ones to monitor for activity or to describe the quality of the plant’s products. For quality control and regulatory purposes, the content and dissolution of flavonoids in the plant products can be assessed. However, these compounds are not monitored for regulation and there are as yet no HPLC or dissolution methods that can be employed for quality control of herbals like S. frutescens. Therefore, the objectives of this study were to assess the suitability of its flavonoid constituents as quality control (QC) marker compounds, and the suitability of content levels and dissolution tests of flavonoids as QC tools for S. frutescens products. To realise the afore-mentioned objectives, non-commercially available flavonoid compounds (sutherlandins) that could be used as marker compounds were isolated from S. frutescens. An HPLC assay was developed and validated for determination of flavonoid content in solution. Five S. frutescens materials viz leaf powder (LP), spray-dried aqueous extract (SDAE) and freeze-dried aqueous extracts (FDAE) were analysed for flavonoid content and dissolution. Dissolution tests were conducted for different S. frutescens materials and dissolution profiles of flavonoids in capsules containing these materials were compared using Q-release values, the similarity factor (f2) and mathematical models. To predict in vivo bioavailability of the flavonoids, in silico assessment of in vivo bioavailability of flavonoids (glycosides and aglycones) that may be contained in different S. frutescens materials was conducted. Sutherlandins A, B, C and D were successfully isolated (percentage purity approximately99 % for sutherlandins A, C and D, and 90 % for sutherlandin B) and identified, and used, along with other flavonoid compounds, for the development of a simple and robust HPLC method. Content of sutherlandins A, B, C and D, quercetin and kaempferol in different plant materials were 0.4 ± 0.3, 0.8 ± 0.2, 1.3 ± 0.2, 0.6 ± 0.1, 0.01 ± 0.02 and 0.08 ±0.1 %,respectively, and differed significantly (p < 0.001). In vitro dissolution showed faster dissolution of flavoniod glycosides compared to aglycones. The flavonoids from the LP and SDAE materials showed characteristics of immediate release with Q75 in ≤ 45 minutes, and delayed release from the FDAE material, i.e. Q75 > 45 minutes. The dissolution profiles of each flavonoid compared from different S. frutescens materials were different as signified by their f2 values which were all below 50. The mathematical models describing release were also different for each flavonoid from the different S. frutescens materials. For in vivo bioavailability modelling and prediction studies, the flavonoid aglycones met the conditions for oral bioavailability while the flavonoid glycosides did not. In conclusion, the sutherlandins isolated from S. frutescens proved to be good markers for HPLC assay and dissolution tests of S. frutescens materials. The HPLC method was suitable for assessing flavonoid levels in S. frutescens materials, and also showed differences in flavonoid content in these materials. The dissolution method was simple and reproducible, and Q-release values, the f2 and mathematical models proved to be good tools for differentiating between S. frutescens materials. In silico modelling showed that the flavonoid glycosides and aglycones differed in oral bioavailability. Although not presently required by the Medicines Control Council (MCC), quantification, release and dissolution studies and specifications may be employed as tools for routine analysis and for quality control of herbal drug formulations containing S. frutescens.Item A crystal engineering study of selected sulfa drugs and trimethoprim(University of the Western Cape, 2014) Elbakush, Rasha Elmheidi; Samsodien, Halima; Caira, Mino.RThe objective was to prepare new solid phases, i.e. co-crystal forms, of two sulfa antibiotic drugs (sulfamethoxazole and sulfasalazine) with trimethoprim and fourteen potential co-formers with GRAS status. Trimethoprim was chosen for its synergistic effects with both sulfa drugs and the other co-formers were selected in an attempt to improve the physicochemical properties of the antibiotics. A variety of co-crystallization techniques, including solvent assisted grinding, slow evaporation, slurry method and solidification of the melt were used to obtain these results. From these methods, three new solid phases were successfully isolated for the sulfamethoxazole antibiotic, viz. sulfamethoxazole-benzoic anhydride (SMZ-BAN) co-crystal by the slurry method, amorphous sulfamethoxazole-trimethoprim (SMZ-TMP) form by solidification of the melt and amorphous sulfamethoxazole-oxalic acid (SMZ-OA) by slow evaporation. For the sulfasalazine antibiotic, co-crystallization experimentation produced, sulfasalazine-trimethoprim salt (SSZ-TMPs) by slow evaporation, sulfasalazine-trimethoprim co-crystal (SSZ-TMP) by solvent assisted grinding and sulfasalazine-nicotinamide co-crystal (SSZ-NC) by solidification of the melt. Of these six compounds subjected to single crystal X-ray analysis, only one of their structures was elucidated i.e. the salt, SSZ-TMPs. Different techniques that were used to assess the thermal behaviour of the products included hot stage microscopy, differential scanning calorimetry and thermogravimetric analysis. FTIR provided information on the purity of the compounds and the suggested host-guest interaction sites. X-ray powder diffraction supported the determination of the new phase comparative to the parent compounds. Finally dissolution testing was carried out for successful candidates with encouraging recommendations for future work.Item Design and evaluation of fast dispersible tablets of lamivudine using selected natural superdisintegrants(University of the Western Cape, 2018) Noutchang, Yves Roland Tchakounte; Samsodien, Halima; Dube, AdmireFast dispersible tablets (FDTs) are solid single-unit dosage forms that are placed in the mouth and allowed to disperse or dissolve in the saliva without the need of water. The basic approach to formulating FDTs consists of adding a superdisintegrant to a tablet formulation. These tablets offer both the advantages of conventional tablets and liquid dosage forms along with distinctive properties which include accurate dosing, ease of administration, quick onset of action, enhanced bioavailability, and increased patient adherence. FDTs have been found to be effective in remedying therapeutic in-adherence caused by dysphagia (swallowing difficulties) particularly in paediatric and geriatric subjects. There is a strong correlation between therapeutic success and patient adherence especially with HIV/AIDS treatment regimens, consequently the dosage form should be patient friendly and devoid of unappealing characteristics. This study aimed at developing a cost effective fast dispersible tablet of lamivudine using alternative excipients and conventional techniques. Only conventional tablets and oral liquid dosage forms of lamivudine are available on the South African market. Two natural polymers reported to have superdisintegrating properties were selected to serve as multipurpose excipients in this study. The polymers were identified, characterised and compared using thermal, spectroscopic and micromeritic analytical tools. The polymer that displayed the best characteristics in terms of micromeritic, tableting and disintegrating properties was retained and used for the optimum formulation. The optimum formulation was composed of 150 mg of lamivudine, 23% w/w unripe banana powder and 2% w/w magnesium stearate. FDTs of lamivudine were obtained using the compression technique with and without wet granulation. The tablets were assessed as per the United States Pharmacopoeia (USP) guidelines and other evaluation procedures pertaining to FDTs. The wet granulated tablets were found to be less friable and thus more resilient than the directly compressed tablets. In-vitro disintegration of the wet granulated tablets occurred within 50±3 sec in deionised water (pH 7) and 35±2 sec in a phosphate buffer solution (pH 6.8). Consequently, the innovative tablets fulfilled the core requirement of FDTs i.e. rapid disintegration. Drug release studies were carried out by analysing dissolution aliquots of the innovative tablets using a validated High Performance Liquid Chromatography (HPLC) method, and comparing them to Aspen Lamivudine®, a conventional tablet of lamivudine presently on the South African market. Complete dissolution in deionised water (pH 7) was attained within 10 minutes and 30 minutes for the innovative tablets and Aspen Lamivudine® respectively.Item Development of rifampicin loaded in surface-modified 4.0 G PAMAM dendrimer as a novel antituberculosis pulmonary drug delivery system(University of the Western Cape, 2020) Ahmed, Rami M. Y.; Samsodien, HalimaIntroduction: Tuberculosis (TB) is a serious bacterial infections caused by the Mycobacterium Tuberculosis (MTB) organism affecting mainly the lungs. Occasionally, MTB bacilli may be transported out of the pulmonary region and infect peripheral organs causing extra-pulmonary tuberculosis. Many therapeutic agents were developed over the years to combat TB, however the rapid emergence of resistant strains hampered their use. Furthermore, most of the current anti-TB drugs experience many challenges, which can be summarized in treatment regimen factors, drug-drug interactions, and physicochemical characteristics factors (such as hydrophobicity and low permeability into alveolar macrophages). These challenges have a significant role in treatment failure and the emergence of resistant TB. Due to the lack of newly discovered anti-TB drugs, and the absence of effective vaccines, many scientists have suggested the use of novel modalities for the current anti-TB drugs to enhance their efficacy and overcome some of the drawbacks. One of these modalities is nanotechnology-based drug delivery systems. Most of the anti-TB drugs experience low drug distribution to the lung and particularly alveolar macrophages within which the MTB resides, leading to treatment failure. Employing nanoparticles as drug delivery systems can have a significant impact on improving the pharmacokinetic profile of anti-TB drugs, the feasibility of different routes of administration, enhancing drug permeability, controlled/sustained drug release, and targeting specific disease sites. Collectively, these impacts will aid in enhancing drug concentration at the site of infection and reduce dosing and regimen duration. Dendrimers, such as polyamidoamine (PAMAM) dendrimers, are synthetic polymeric nanoparticles that have unique features that afford a dendrimer-conjugate complex the possibility to overcome the most common hurdles associated with drug delivery and treatment of diseases. Obstacles associated with solubility, permeability, inadequate biodistribution associated side effects may be enhanced. Manipulating the outermost surface functional groups with various ligands and polymers, will enhance the dendrimer properties and targeting potential. Aim: This study aims to develop a novel pulmonary delivery system for the anti-TB drug rifampicin using surface-modified G4 PAMAM dendrimer nanoparticles (polyethylene glycol (PEG) or mannose moieties), to improve drug solubility, prolong-release, enhance permeability into the macrophages, and decrease the toxicity of the drug-dendrimer conjugates. Methods: PAMAM dendrimers having increasing concentrations of poly(ethylene glycol) (PEG) 2 kDa or mannose residues were synthesized. The 4-nitrophenyl chloroformate was used as an activator in the case of PEG functionalization, while for the mannose conjugation the 4-isothiocyanatophenyl alpha-D-mannopyranoside (4-ICPMP) directly interacted with the primary amines of the dendrimer. The conjugated PEG polymers and mannose moieties on the dendrimer periphery were confirmed using FTIR and 1H NMR analytical techniques. Thereafter, rifampicin was loaded into the native and surface-modified dendrimers via a simple dissolution solvent evaporation method. Rifampicin-loaded dendrimers were then characterized using several analytical techniques namely; FTIR, DSC, NMR, SEM, and DLS. The polymer encapsulation efficiency (EE%) and percentage of drug loading (DL%) were determined directly using a validated HPLC method. In vitro drug release was studied at pH 7.4 and pH 4.5. The MTT technique was used to assess the cytotoxicity of the dendrimer formulations against raw 264.7 cell lines. Finally, the uptake of dendrimer nanoparticles by raw macrophages was studied using a flow cytometer and fluorescence microscopy techniques. Results: The percentage coverage of 4.0 G PAMAM dendrimer peripheral with PEG was achieved in a range of 38% - 100%, while for mannose moieties was from 44% - 100%. The EE% of unmodified dendrimer was 7.5% (w/w). The EE% of PEGylated dendrimers ranged from 65.0% - 78.75% (w/w), whereas for mannosylated dendrimers was from 43.43% - 57.91% (w/w). The size of the unloaded dendrimer nanoparticles was less than 25 nm, a gradual increase in the size after drug conjugation followed. The zeta potential of dendrimers was positive with values greater than 12 mV, the nanoparticle's zeta potential decreased upon increasing the density of PEG/mannose and after drug loading. FTIR and NMR data showed that rifampicin molecules were conjugated to the dendrimer at three sites; at the surface amines via electrostatic linkages, within the PEG/mannose, and into the dendrimer interior. SEM images of dendrimer nanoparticles confirmed the spherical shape of particles, and DSC data verified drug entrapment. Drug release was found to be affected by the pH of the medium and the extent of dendrimer functionalization. At the physiologic pH, surface-modified dendrimers showed a slower release rate compared to the unmodified dendrimer and free drug. Among surface-modified dendrimers, the release rate was inversely associated with the density of PEG/mannose molecules. At pH 4.5, a relatively higher drug release from all formulations was observed which suggests a burst release inside the alveolar macrophages. Toxicity studies showed that the unmodified dendrimer experienced time-dependent and concentration-dependent cytotoxicity against raw 264.7 cells. The toxicity gradually decreased upon increasing the density of PEG/mannose, and negligible toxicity was detected for formulations with 100% functionalization. Dendrimer nanoparticles were successfully internalized into raw cells after 24 hrs of incubation. The order of nanoparticles permeability was PEG 100% < PEG 85% < PEG 70% < PEG 49% < PEG 38% < unmodified dendrimer < mannose 44% < mannose 69% < mannose 93% < mannose 100%. The significant increase in the uptake of mannosylated dendrimers was due to the interaction with lectin receptors at the surface of raw macrophages, whereas the lower internalization of PEGylated dendrimers was due to the shielding of the surface positive charges. Conclusion: The in-vitro and ex-vivo data studies suggested that the developed novel surface-modified G4 PAMAM dendrimers are suitable drug carriers in terms of biocompatibility, release behaviour, and site-specific delivery of the anti-TB drug rifampicin.Item Dissolution and antiviral activity of a novel nevirapine formulation(University of the Western Cape, 2014) Geldenhuys, Brandon Lindsay; Samsodien, Halima; Botes, VictorThe author’s objective was to follow the product life-cycle process of a novel antiretroviral, nevirapine formulation in South Africa, to generate and compile data to pursue market registration. Five supramolecular co-crystals, viz. nevirapine-saccharin (NVSC), nevirapine-DL-tartaric acid (NVTTA), nevirapine-maleic acid (NVMLE), nevirapine-glutaric acid (NVGLT) and nevirapine-salicylic acid (NVSLI) were reproduced and confirmed by powder X-ray diffraction (PXRD). A pre-formulation study ensued to identify the most appropriate co-former candidate to formulate a tablet dosage form comparative to the proprietor brand, Viramune®. The co-crystals were synthesized by the co-precipitation and solvent-drop grinding techniques and identified by hot stage microscopy (HSM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), fourier transform infra-red spectrophotometry (FTIR), PXRD and single X-ray diffraction (SXRD). The solubility, dissolution and antiviral activity profiles of these co-crystals were assessed and compared to pure NV and NV:co-former mixtures in a 1:1 ratio. The preliminary dissolution analysis applied the BP 2005 rotating-basket method with water as dissolution medium. Initially, the dissolution samples were assayed with UV/VIS spectrophotometry which led to a more convincing quantitative approach where dissolution samples were assayed by HPLC. Solubility data revealed a fivefold increase in solubility of NV co-crystallized with maleic acid. Dissolution data, however revealed NVGLT as the best performing co-crystal with a 59 % NV drug release in water (dissolution media) with the remaining 4 co-crystals all indicating an enhanced aqueous solubility of NV. The antiviral activity of all 5 co-crystals performed by the National Institute of Communicable Diseases of South Africa determined whether the co-crystals had an improved antiviral activity against HIV-1 compared to pure NV. The results indicated that NVSC and NVSLI had the greatest antiviral activity compared to pure NV and the remaining co-crystals. The pre-formulation results formed the basis for the selection of the best co-former candidate for a NV co-crystal tablet formulation by direct compression. All solid dosage form quality control tests according to the USP 364 was performed on the prototype co-crystal tablet and the Viramune® tablet. Comparative dissolution analysis to evaluate bioequivalence was conducted and assayed by HPLC. The dissolution analysis utilized 3 media, viz. HCl buffer (pH 1.2), acetate buffer (pH 4.5) and a phosphate buffer (pH 6.8) which displayed no similarity in the dissolution profile of the prototype and the proprietor brand. Solution stability of NV in these buffered media was assessed after 4 weeks exposure of the dissolution samples to cold chain (2 - 8 °C, 0 % RH) and accelerated environmental conditions (40 °C, 75 % RH). The results indicated no significant degradation of NV in the prototype co-crystal tablet and the proprietor brand during the accelerated stability tests. Cytotoxicity against a host cell 293T and antiviral activity against the pseudo-HIV-1 virus of the prototype and proprietor brand was further determined. The antiviral activity results were favourable for both the prototype co-crystal and the proprietor brand tablet.Item Efavirenz pre-formulation study : selection of a cyclodextrin inclusion complex or co-crystal complex for tabletting(University of the Western Cape, 2015) Rafieda, Ali Mohamed Omar; Samsodien, Halima; Ebrahim, NaushaadEfavirenz is a non-nucleoside reverse transcriptase inhibitor used as an anti-retroviral for the treatment of human immunodeficiency virus (HIV) type I. It is classified as a class IΙ drug under the Biopharmaceutical Classification System (BCS) and exhibits a low solubility (aqueous solubility of 9.0 μg/ml) and high permeability (variable oral bioavailability). This study aims to choose a pre-formulation protocol with the best efavirenz derivative in literature between co-crystals and CD inclusion complexes. Upon selection of the efavirenz derivative, the complications of both small scale and large scale laboratory pre-formulation production is highlighted for formulation of a tablet dosage form. Numerous variables were selected for the pre-formulation protocol. Physical, chemical, pharmacological, pharmaceutical and economical variables were investigated. Citric acid monohydrate (CTRC) was chosen as the best co-former for a co-crystal while hydroxypropyl-beta-cyclodextrin (HP-β-CD) was selected as a host for an inclusion complex. Pharmaceutically, the angle of repose, Carr’s index, Hausner’s ratio, moisture content, disintegration time, hardness/resistance to crush, manufacturing process problems and particle size of the CTRC and HP-β-CD were all evaluated. The CTRC was ultimately selected for formulation of a tablet. The preparation of small laboratory scale of EFA/CTRC co-crystal was successfully achieved after several attempts. The large laboratory scale of EFA/CTRC was prepared under various environmental seasons which were indicated as batches 1-6 for purposes of this study. Characterization of the large laboratory scale EFA/CTRC co-crystals was performed by scanning electron microscopy (SEM), hot-stage microscopy (HSM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and by physical inspection (i.e. season, texture, colour, shape and particle size) of the EFA/CTRC product. Batch 1 and 2 were prepared during the summer season. The SEM analysis showed that the particles were needle-like shaped. The thermal analysis values of batch 1 by HSM, DSC and TGA results were 123 °C, 119 °C and 1.68 % of mass loss, respectively. In batch 2, morphology results by SEM revealed spikes of irregular and agglomerated particles. Batch 2 melted at 123 °C and a small unmelted quantity was observed at 143 °C. The DSC and TGA (mass loss) analysis were 118 °C and 0.75 % respectively. The hardness test of EFA/CTRC tablet prepared in batch 2 was extremely hard hence failed the disintegration test. The EFA/CTRC prepared in batches 3, 4 and 5 was during the winter season which is associated with high humidity and wet weather conditions. The SEM, DSC, TGA results were significantly different from the previous batches. The SEM morphology was highly irregular particles for batch 3, clustered and randomly size particle for batch 4 and irregular, needle-like, spikes and spherical shaped particles for batch 5, respectively. The thermal results HSM, DSC and TGA confirmed the presence of moisture in the prepared EFA/CTRC products. The HSM melting point results of batches 3, 4 and 5 were 123 °C, 115 °C and 121 °C, respectively. The DSC results of 110 °C, 105 °C and 118 °C were observed for batches 3, 4 and 5 respectively. The mass loss i.e. TGA results for batches 3, 4 and 5 were 1.178%, 1.5 % and 2.235 % respectively. In batch 6, EFA/CTRC was prepared using a different commercial batch of EFA and CTRC. The SEM results indicated the formation of needle-like and clustered particles. The values obtained from HSM, DSC and TGA results were 124 °C, 114 °C and 0.54 % in mass loss. The physical appearance of EFA/CTRC prepared from batch 1 and 2 were white in colour while batch 3, 4, 5 and 6 of the prepared EFA/CTRC was pink in colour. The physical appearance of the individual batches differed but the identity of the sample remained intact implying the same pharmacological effects with differing pharmaceutical properties impacting the dosage form preparation.Item The effect of co-crystallization and polymorphism on the physicochemical properties of amoxicillin tri-hydrate(University of the Western Cape, 2013) Jaaida, Nesren Al-Hadi; Samsodien, HalimaMany active pharmaceutical ingredients (APIs) have poor physicochemical properties such as solubility, dissolution and chemical stability. Several strategies are used to enhance and improve these properties of the API. Co-crystallization and polymorphism studies are possible strategy used in pre-formulation studies to optimize these properties of the drug without modifying its pharmacological effect. The purpose of this research was to investigate the polymorphism and co-crystallization effects of the penicillin-type antibiotic, amoxicillin tri-hydrate. Several techniques such as: slow evaporation, slow cooling, vapour diffusion, sublimation, grinding and solvent assisted grinding was employed. In producing co-crystals, the API was non-covalently bound to selected co-formers such as: saccharin, nicotinamide, salicylic acid, L-tartaric acid, D-tartaric acid, L-aspartic acid, stearic acid, benzoic anhydride, oxalic acid di-hydrate, cinnamic acid, succinic acid and citric acid monohydrate. Nine co-crystals of amoxicillin tri-hydrate had been formed. Differential scanning calorimetry (DSC), hot stage microscopy (HSM) and thermal gravimetric analysis (TGA) was conducted to analyse the thermal behaviour of the co-crystals. Powder X-ray diffraction (PXRD) and spectroscopic techniques [infra-red (FTIR) and H1-nuclear magnetic resonance (H1MNR)] were employed for screening of the co-crystal forms. Furthermore, dissolution testing was conducted to investigate the application of the newly derivatised forms.Item The formulation and characterisation of corticosteroid loaded Ethosomes for topical delivery(University of the Western Cape, 2020) Martin, Björn Franklin; Samsodien, HalimaBackground/Introduction: Atopic dermatitis (AD) is one of the most prevalent diseases worldwide. It is a rapidly growing field of study with several research avenues to explore its pathophysiology and to find innovative treatment and management regimens. Clinically, it is classified as a non-contagious, intensely pruritic, inflammatory, chronic skin disorder mediated by abnormalities associated with atopy. Symptoms include inflammation, redness, pain and a negative impact on the patient‘s overall quality of life. Chronic itching often leads to the formation of lichenified skin, which may increase the thickness of the epidermis and exacerbate the barrier function of the skin. AD is treated with topical corticosteroids which help to decrease inflammation. However, lichification of the skin may decrease the efficacy of topical dosage forms. Nanomedicine is a rapidly developing field where advances have been made using ethosomes for topical delivery. As such, corticosteroid loaded ethosomal formulations containing hydrocortiosone acetate (HCA) and betamethasone valerate (BMV) were developed and characterised to develop novel tools for topical drug delivery. Aim: This study aimed at developing corticosteroid loaded ethosomes as a pre-formulation component for inclusion in a topical dosage form. To date, no ethosmal formulation with HCA and BMV has been investigated for topical drug delivery. Method: Ethosomes were synthesised using the hot method and the cold method, a modified version of a double emulsion (o/w/o), solvent evaporation technique, as developed by Touitou et al, 2007.1 Ethosomes were prepared using fixed concentrations of either BMV or HCA (10 mg/ml), ethanol (30% v/v) and purified water (70% v/v) and were comminuted using bath sonication or mini-extrusion. Centrifugation and centrifugal drying were used to purify and isolate the ethosomes for solid state characterisation. The morphology was determined using Scanning electron microscopy (SEM). Ethosomes were characterised using: dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), hot stage microscopy (HSM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The encapsulation efficiency (EE) and drug loading (DL) were determined using validated HPLC methods. Finally, the drug release was determined using Franz diffusion cells and mathematical models were fitted to the % cumulative release data to determine the release kinetics. Results: Ethosomes were assessed according to the following criteria for topical drug delivery which were determined using dynamic light scattering (DLS): Hydrodynamic diameter (HdD), ~ 200 nm, polydispersity index (PdI) < 0.5 and zeta potential (ζp) ± 30 mV. The optimum formulations contained phosphatidylcholine (PC) 50 mg/ml. Extrusion was found to be the best method for particle reduction based on the reproducibility of the results. The HdD was 163.8±31.99 and 147.7±19.91 for BMV loaded ethosomes and HCA loaded ethosomes respectively and both formulations had an acceptable PdI of 0.049 and 0.111, respectively. SEM analyses indicated that the ethosomes had a spherical shape. Encapsulation of the APIs was verified by the thermoanalyses and possible intermolecular interactions were identified using FTIR. BMV loaded and HCA loaded ethosomes had a respective EE of 74.57 % and 37.30 %, and a DL of 14.91 % and 7.46 %, respectively. The release kinetics best fit the Peppas-Sahlin model indicative of an anomalous non-Fickian diffusion coupled with polymer relaxation and zero order release. Conclusions: BMV and HCA loaded ethosomes for topical drug delivery were successfully synthesised and characterised. These novel nanoparticles have provided an array of avenues for further investigation and application in the topical delivery of corticosteroidsItem Formulation and evaluation of polymeric micelles for improved oral delivery of tenofovir disoproxil fumarate and zidovudine using poly-lactic-co-glycolic acid nanoparticles(University of the Western Cape, 2018) Tenghe, Lovette Asobo; Samsodien, Halima; Mbamalu, OluchiBackground: Tenofovir disoproxil fumarate (TDF) and Zidovudine (AZT) are both nucleotide and nucleoside analogue reverse transcriptase inhibitors (NtRTIs and NRTIs), respectively. They are used for the management and prevention of the Human Immunodeficiency Virus (HIV) infection. These drugs are faced with oral delivery challenges such as low intestinal permeability and extensive first pass liver metabolism for TDF and AZT, respectively. Their use may also be limited by dose-dependent adverse effects, which may result in treatment failure when patients become non-compliant and non-adherent to their prescribed antiretroviral (ARV) regimen. Non-compliance and non-adherence to ARV regimen may lead to drug resistance and a need for change in regimen, which can be very expensive, not only financially but in terms of morbidity and mortality. To solve such issues, a new drug can be formulated, or an existing drug can be modified. The development and formulation of a new drug is time consuming and expensive, especially with no available data and a high probability of failure. Modifying existing drugs is a cheaper, less time-consuming option with lower probability of failure. Such modification can be achieved via non-covalent interactions using various methods such as preparation of nano-particulates with polymeric micelles (a non-covalent interaction). Polymeric micelles offer a variety of polymers to choose from for drug modification purposes. Purpose: The aim of this study was to formulate polymeric nanoparticles of TDF and AZT using different ratios of poly-lactic-co-glycolic acid (PLGA), characterize the formulated nanoparticles (using the following analyses: particle size, zeta potential, encapsulation efficiency, hot stage microscopy, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy and scanning electron microscopy), analyze for stability during storage (2-8˚C) and determine the release rate of the active pharmaceutical ingredients in the formulated nanoparticles. Methods: Nanoparticles were prepared using a modified version of the double emulsion (water-in-oil-in-water) solvent evaporation and diffusion method. Two ratios of PLGA (50:50 and 85:15) were used to prepare four formulations (two each of TDF and AZT). Thereafter, the physicochemical and pharmaceutical properties of the formulations were assessed by characterizing the nanoparticles for particle size, zeta potential, polydispersity index, percentage yield, release profile and particle morphology, using the suggested analytical techniques. Results: For TDF-PLGA 85:15, TDF-PLGA 50:50, AZT-PLGA 85:15 and AZT-PLGA 50:50, nanoparticles of 160.4±1.7 nm,154.3±3.1 nm,127.0±2.32 nm and 153.2±4.3 nm, respectively, were recovered after washing. The polydispersity index (PDI) values were ≤0.418±0.004 after washing, indicating that the formulations were monodispersed. The zeta potential of the particles was -5.72±1 mV, -19.1 mV, -12.2±0.6 mV and -15.3±0.5 mV for TDF-PLGA 85:15, TDF-PLGA 50:50, AZT-PLGA 85:15 and AZT-PLGA 50:50 respectively after washing. The highest percentage yield was calculated to be 79.14% and the highest encapsulation efficiency obtained was 73.82% for AZT-PLGA 50:50, while the particle morphology showed spherical nanoparticles with signs of coalescence and aggregation for all formulated nanoparticles. The release profiles were biphasic; that is, an initial burst which indicated the presence of surface API followed by sustained release. Comparing the release profiles of AZT and TDF at pH 1.2 and 7.4, it was indicative that more AZT was released at pH 1.2 while more TDF was released at pH 7.4. On computing the release data further into various mathematical models, the Weibull model was found to be the best fit. The loaded nanoparticles showed an increase in stability after washing; however, they showed signs of gradual decrease in stability after 10 days of storage at 2-8°C. Conclusions: Relatively small, spherical and smooth nanoparticles were formulated. The nanoparticle release profile was indicative of sustained release; however, there was no conclusive indication that 48 hours duration was sufficient to release all encapsulated drug. Further studies with an increased API or polymer ratio in the formulation needs to be performed to determine if the encapsulation efficiency can be improved and in-vivo studies are required for a better understanding of the API release from formulations as well as its absorption in the body.Item Formulation and evaluation of zidovudine cyclodextrin inclusion complex to enhance acid lability and palatability(University of the Western Cape, 2016) Al-Derbali, Meftah Abdulhafied; Samsodien, Halima; Mbamalu, OluchiBackground: Zidovudine (AZT) is a very useful drug for the management of Human Immunodeficiency Virus (HIV) infection. Its optimal use is limited by its bitter taste, sparing solubility (20.1 mg/ml) and acid lability. Cyclodextrins (CD) are a class of compounds which can be used to form inclusion complexes with drugs such as AZT to improve it is taste, solubility and palatability. Purpose: This study complexed hydroxypropyl-beta-cyclodextrin (HPβCD) with AZT. The formulated inclusion complex was evaluated for suitability as a dosage form and as a tool for improving AZT’s palatability, solubility and acid liability. Method: AZT was complexed with HPβCD using the lyophilisation method. The binding constant for the formulation was determined by the phase solubility method, and complex formation between AZT and HPβCD evaluated using proton nuclear magnetic resonance (1H NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and hot stage microscopy (HSM). Tablets of the inclusion complex were formulated by direct compression, using the least possible amount of excipients, and the dosage form evaluated for hardness, friability, durability, disintegration time and dissolution. Results: The binding constant of the formulation was 3.919, and the degree of incorporation was 4.0 mg AZT/g of CD per complex. 1H NMR showed significant chemical shifts between the inclusion complex and AZT. DSC and TGA analyses showed significant differences in the curves for the pure AZT and HPβCD. Values for tablet hardness, friability, durability and disintegration time were 236 ± 20 N, 0.7 %, 1.02 % and 10.25 minutes, respectively. The solubility of the formulation was 148.08 mg/ml, and its dissolution profile was different from that of the branded formulation. Conclusions: AZT-HPβCD inclusion complex, with a 7.4-fold increase in AZT solubility, was successfully prepared using the lyophilisation method. The binding constant and friability of the formulation were within acceptable limits. Although the hardness value is high, the tablet still disintegrated within acceptable specified times. This study has significant implications for anti-retroviral complex formulations.Item Formulation of a nevirapine co-crystal as a liquid dosage form(University of the Western Cape, 2016) Injety, Sahana; Samsodien, Halima; Rossiter, RichardCo-crystals are a solid phase phenomena that could enhance the physicochemical properties of an active pharmaceutical ingredient. A co-crystal has never been incorporated into a liquid dosage form with the assurance of maintaining its co-crystal state until absorption under defined conditions. This study aims to develop a liquid formulation with a nevirapine co-crystal. A protocol was developed to investigate all the five co-formers that were used to make the nevirapine co-crystals to-date. The most appropriate co-former was selected for a liquid dosage form to study the integrity and the scaling up of the co-crystal in a suspension formulation. Co-formers used were viz. saccharin, glutaric acid, salicylic acid, rac-tartaric acid and maleic acid. These were characterized according to their physical, chemical, pharmacological and pharmaceutical properties. A grading scale was used to select the most appropriate co-former for a suspension formulation. Comparatively, saccharin produced the best combination of physical, chemical, pharmacological and pharmaceutical properties, especially with regard to the particle size and the specific gravity which proved to be very useful as optimal criteria for suspension formulation. Upon selection of the ideal co-former, scale-up of the nevirapine saccharin co-crystal was performed from a small scale of 350 mg to a large scale of 5 g. Nevirapine-saccharin (NVSC) co-crystals were prepared utilizing the slow evaporation technique, using methanol as the solvent and the percentage yield of the co-crystals were > 80 %. The identity of co-crystals was confirmed using hot stage microscopy (HSM), differential scanning calorimetry (DSC), fourier transform infra- red (FTIR) and thermogravimetric analysis (TGA). Three co-crystal suspension formulations were prepared using the excipients identified in the branded, Viramune® suspension, with each formulation containing viscosity enhancers such as aerosil 200, carbopol 971G and carbopol 974P. To ascertain the co- crystal integrity in the suspension, it was filtered and the filtrate was identified with DSC and FTIR while the filtered solution was identified with ultraviolet spectroscopy (UV). The co-crystal suspension formulation with optimal pH, viscosity and assurance of co-crystal integrity was the carbopol 974P formulation. The UV and DSC of the filtrate of the suspension revealed that the co-crystal had not separated into its individual components and remained intact while in suspension form irrespective of the excipients added. This formulation proceeded to the quality control stage. It was assessed for its pH, viscosity and dissolution according to the USP 32 standards and compared to the branded nevirapine suspension, Viramune ®, presently on the market. The suspension was characterized for particle size, zeta potential and polydispersity index. The dissolution results assayed by High Performance Liquid Chromatography (HPLC) revealed a drug release of 86 % in the Viramune® suspension while the NVSC co- crystal suspension achieved a drug release of 94% within 30 minutes of dissolution.Item FTIR, dissolution and anti-viral activity of nevirapine co-crystals(OMICS International, 2017) Samsodien, Halima; Bapoo, Rafik; Doms, T.I.; Harneker, Z.; Louw, A.S.; Scheepers, I.C.; Sonday, A.B.; Geldenhuys, B.The study uses Fourier Transform Infrared (FTIR) spectroscopy to identify five Nevirapine (NV) co-crystals, determines the dissolution profile of the co-crystals and the antiviral activity comparative to pure NV. Hot stage microscopy measured the purity and integrity of each co-crystal. FTIR analysis was used to identify the co-crystals to make recommendations regarding the future use of the technique to identify the NV co-crystals. Dissolution studies of the NV co-crystals prepared with maleic acid, salicylic acid and glutaric acid (NVMLE, NVSLI and NVGLT, respectively) were completed using the rotating basket method. Assays were conducted using High Performance Liquid Chromatography and compared to pure NV and the five NV: co-former mixtures. The antiviral activity was tested to determine whether the co-crystals had an improved activity against HIV-1 compared to pure NV. All co-crystals, except NVTTA (a NV co-crystal prepared with rac-tartaric acid), were pure and maintained their integrity for approximately one year. NVGLT, NVMLE and NVTTA, 1:1 molar ratio co-crystals were identified by FTIR. The C=O stretching frequency of the carboxylic acid groups of NV and GLT were observed at 1638.15 cm-1 and 1719.23 cm-1 in the NVGLT co-crystal which corresponded with spectra of NVMLE and NVTTA. In NVMLE the C=O stretching frequency of the C=O of NV and MLE were observed at 1640.58 cm-1 and 1694.10 cm-1 and in NVTTA it was at 1637.25 cm-1 and 1708.50 cm-1, suggesting the presence of both parent molecules in the new phase for NVGLT, NVMLE and NVTTA. Dissolution studies suggested that NVGLT was the only co-crystal that yielded better results than both NV and its physical mixture. The antiviral activity of the NVSC (an NV co-crystal prepared with saccharin) and NVSLI cocrystals in DMSO was significantly different to pure NV, demonstrating an improvement in anti-viral activity.Item HPLC determination of selected flavonoid glycosides and their corresponding aglycones in Sutherlandia frutescens materials(OMICS, 2016) Mbamalu, Oluchi; Antunes, E.; Silosini, N.; Samsodien, Halima; Syce, JamesSutherlandia frutescens is a popular South African plant commercially available in a range of formulations. However, reference standards for quality and stability assessment are lacking. This work reports the development and validation of a reversed phase HPLC method for the analysis of flavonoid glycosides and their corresponding aglycones in S. frutescens products. Five materials containing either leaf powder (LP) or spray-dried aqueous extract (SDAE) of S. frutescens were analysed for flavonoid content. A primary objective was to isolate non-commercially available flavonoid glycoside compounds (sutherlandins) for use as reference standards. Sutherlandins A, B, C and D were successfully isolated, and used, with other flavonoid compounds for HPLC assay development. The developed HPLC method was linear in the range of 0.2 to 60 µg/ml for quercitrin; 0.2 to 120 µg/ml for quercetin and kaempferol; 0.2 to 200 µg/ml for rutin and kaempferol-3-O-rutinoside; 4 to 180 µg/ml for sutherlandins A and D; and 4 to 200 µg/ml for sutherlandins B and C. Percentage content of sutherlandins A, B, C and D, quercetin and kaempferol in different plant materials were significantly different (P<0.001). The developed HPLC method is simple, precise and robust; and can be employed for the simultaneous determination of flavonoid glycosides and aglycones for quality control of S. frutescens products.Item Mechanochemical synthesis and physicochemical characterization of isoniazid and pyrazinamide co-crystals with Glutaric acid(Frontiers Media S.A., 2020) Ngilirabanga, Jean Baptiste; Aucamp, Marique Elizabeth; Samsodien, HalimaThe present work reports two novel pharmaceutical co-crystals; 2:1 isoniazid-glutaric acid (INHGA) and 2:1 pyrazinamide-glutaric acid (PGA). Isoniazid and pyrazinamide are key first-line drugs used for the treatment of tuberculosis. The co-crystals were produced via solid-state and solvent assisted grinding methods. Thermal characteristics of the samples were obtained using the differential scanning calorimetry, hot stage microscopy, and thermogravimetric analyses. The morphology of the powder samples by scanning electron microscopy, structural analysis by Fourier transform infrared spectroscopy and powder X-rays diffraction ensured co-crystal formation. Thermal analyses confirmed the co-crystals with new melting transitions ranging between their respective starting materials. Unique morphologies of the co-crystal particles were clear in SEM micrographs. The formation of intermolecular interactions with the co-crystal former was confirmed by the FT-IR spectral band shifting and was supported by distinct PXRD patterns of co-crystals thereby authenticating the successful co-crystal formation. In vitro solubility evaluation of the synthesized co-crystals by HPLC suggested a remarkable increase in solubility of both INH and PZA in their respective co-crystals.Item Selected antiretroviral and anti-tuberculosis drug combinations by non-covalent bonding(University of Western Cape, 2021) Ngilirabanga, Jean Baptiste; Samsodien, HalimaTreatment of the human immunodeficiency virus (HIV) and tuberculosis (TB) infections have become very complicated due to the advent of drug resistance. Drug combinations offer an alternative approach to reducing the emergence of drug resistance. Pharmaceutical co-crystals have provided the pharmaceutical industry with the ability to optimise the physicochemical properties of active pharmaceutical ingredients (APIs) while preserving the biological activity. Pharmaceutical co-crystals are formed between APIs and suitable co-formers that are biologically safe or even a second or third API.Item A supramolecular derivatised study of BIS(Adamantan-1- Aminium) carbonate(University of the Western Cape, 2014) Ngilirabanga, Jean Baptiste; Samsodien, Halima; Joubert, JacquesIn this study, new solid supramolecular derivatised forms of bis(adamantine-1-aminium) carbonate (ADTCO3) were prepared. ADTCO3 is a derivative of amantadine used for Parkinson’s disease and has antiviral properties against influenza-A, dengue fever and pharmacological activity towards Parkinson’s disease. The new forms prepared were polymorphic and co-crystal forms of ADTCO3. Polymorphism is a phenomenon where the ability of a substance to exist in two or more crystalline forms occurs when crystallised under different conditions and co-crystallization is the process of formation of multicomponent crystals of a drug substance. New solid forms often display different mechanical, physicochemical and thermal properties that can remarkably influence the bioavailability, hygroscopicity and stability of active pharmaceutical ingredients (APIs). For the formation of polymorphs of ADTCO3, techniques such as dry grinding, solvent-drop grinding, co-precipitation, sublimation and vapour diffusion were applied. For the development of co-crystals and/or complex formation, ADTCO3 was treated in combination with ten selected co-formers viz; benzoic acid, 4-hydroxybenzoic acid, cinnamic acid, 4-hydroxycinnamic acid, succinic acid, tartaric acid, salicylic acid, L-glutamic acid, citric acid monohydrate and L-glutaric acid using similar techniques as applied in the polymorphism study. The first four co-formers were selected for their potential biological activity and the latter six were selected for their generally regarded as safe (GRAS) status. All products were isolated and characterized using different analytical techniques to assess the thermal behaviour of the products by hot stage microscopy (HSM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). FTIR spectroscopy and proton-nuclear magnetic resonance (1HNMR) were used to identify and determine the purity of the parent compounds and the modified forms. X-ray powder diffraction was used to determine the formation of a new phase and single crystal X-ray diffraction was applied at the initial stages to identify ADTCO3 by its unit cell parameters. Furthermore, the Cambridge Structural Database (CSD) and other resources were used to generate information on the molecular structures of all elucidated parent compounds, their polymorphs and reported co-crystals. Four different polymorphic forms of ADTCO3 were identified (viz. ADTCO3 Forms I to IV) and sixteen co-crystals (viz. ADTCO3BA1 to ADTCO3BA5, ADTCO3HBA, ADTCO3CIN, ADTCO3HCIN, ADTCO3SUC, ADTCO3LTTA, ADTCO3SA, ADTCO3CA, ADTCO3GLA, ADTCO3GA) were synthesised. Of the sixteen co-crystals 5 were identified as ADTCO3BA “salt” co-crystal polymorphic forms and 2 as ADTCO3SUC co-crystal polymorphic forms. Two solvated “salt” co-crystal forms were also identified, namely; ADTCO3GLA and ADTCO3LTTA. ADTCO3GLA had a mass loss of 10.3% (n = 2.4) and ADTCO3LTTA had a mass loss of 5.25% (n = 0.86). Finally, the rest of the co-crystals ADTCO3HBA, ADTCO3CIN, ADTCO3HCIN, ADTCO3SA, ADTCO3CA and ADTCO3GA all crystallised as “salt” co-crystals.