Malaria is a life–threatening disease caused by Plasmodium spp and causes over one million deaths annually. The complex life cycle of the malaria parasite offers several points of attack for the antimalarial drugs. The rapid spread of resistance against antimalarial drugs, especially chloroquine and pyrimethamine–sulphadoxine, emphasises the need for new alternatives or modification of existing drugs. Artemisinin–based combination therapies (ACT’s) with different targets prevent or delay the development of drug resistance and therefore have been adopted as first–line therapy by all endemic countries. Proguanil–dapsone, an antifolate combination is more active than pyrimethamine–sulphadoxine and is being considered as an alternative to pyrimethamine–sulphadoxine. Artesunate–proguanil–dapsone is a new ACT that has wellmatched pharmacokinetics and is relatively rapidly eliminated; therefore there is a reduced risk of exposure to any single compound and potentially a decreasing risk of resistance. A few studies have been done on a triple fixed–dose combination therapy for malaria treatment and such a combination for artesunate, proguanil and dapsone are not currently investigated, manufactured or distributed. The aim of this study was to develop a triple fixed–dose combination for artesunate, proguanil and dapsone. The formulation was developed in three phases; basic formulation development, employing factorial design to obtain two possible optimised formulations and evaluating the optimised formulations. During the formulation development the most suitable manufacturing procedure and excipients were selected. A full 24 factorial design (four factors at two levels) was used to obtain the optimised formulations. As end–points to identify the optimised formulations, weight variation, friability, crushing strength and disintegration of the tablets, were used. Statistical analysis (one way ANOVA) was used to identify optimal formulations. To identify any interaction between the active pharmaceutical ingredients (API’s) and the API’s and excipients, differential scanning calorimetry was done. Flow properties of the powder mixtures (of the optimised formulations) were characterised by means of angle of repose; critical orifice diameter (COD); bulk density and tapped density; and flow rate. Tablets of the two optimised powder formulations were compressed. The tablets were evaluated and characterised in terms of weight variation, friability, crushing strength, disintegration and dissolution behaviour. Initial formulation development indicated that wet granulation was the most suitable manufacturing method. The results from the factorial design indicated that different amounts (% w/w) of the lubricant and binder as well as two different fillers influenced the weight variation, crushing strength and disintegration statistically significant. Two formulations containing two different fillers (microcrystalline cellulose or Avicel® PH 101, and lactose or Granulac® 200) were found to be within specifications and ideal for manufacturing. Tablets prepared from the FA formulation (formulation containing Avicel® PH 101) complied with the standards and guidelines for weight variation, friability, crushing strength and disintegration as set by the British Pharmacopoeia (BP). Tablets had an average crushing strength of 121.56 ± 0.022 N. Tablets disintegrated within 52.00 seconds and a maximum weight loss of 0.68% occurred during the friability test. Weight variation of the tablets prepared from the FG formulation (formulation containing Granulac® 200) complied with the standards. Average crushing strength was 91.99 ± 6.008 N and the tablets disintegrated within 140.00 seconds. Percentage friability (1.024%) did not comply with the guideline of a percentage friability of less than 1%, however, no cracked or broken tablets were seen. Dissolution showed that 98, 93 and 94% of artesunate, proguanil and dapsone were respectively released (of the label value) within 15 minutes for the FA formulations. Release of artesunate, proguanil and dapsone for the FG formulation was 62, 85 and 92% for the same time period. The release of the three API’s (the FG formulation) increased to 78, 89 and 92%, respectively, after 45 minutes. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2012.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The Mycobacterium genus includes M. tuberculosis complex (CMTB) species and others called nontuberculous mycobacteria (MNT). The CMTB bacilli cause tuberculosis (TB), a bacterial infectious disease, which commonly affects the lungs. Since the MNT cause other mycobacterial infections. The correct diagnosis of diseases caused by mycobacteria is essential for determining treatment. The tuberculosis treatment regimen in Brazil is recommended by the National Tuberculosis Control/Ministry of Health (PNCT/MS) and was recently modified. The main changes proposed by the Technical Advisory Committee of PNCT/MS were: to introduce a fourth drug, ethambutol, during the attack and take the combination of drugs in tablet form, with fixed-dose combinations (FDC) 4 in 1, for intensive treatment phase, and 2 in 1 for the maintenance phase. Due to the high incidence of tuberculosis in Brazil and worldwide, the emergence of resistant strains and the deployment of new therapies by the Ministry of Health, this study aimed to evaluate the susceptibility to antituberculosis or individually associated clinical isolates of Mycobacterium tuberculosis from the University Hospital Mary. The antimicrobial susceptibility alone or associated (rifampicin, isoniazid, pyrazinamide and ethambutol) was evaluated using the microdilution method (MMC) and compared to the proportion method (MP), gold standard method for susceptibility to mycobacteria. The MMC has proven to be a rapid, easily performed and well correlated with the MP. We have found various clinical isolates of M. tuberculosis resistant to one, two or three drug when tested against four drugs alone. However, when they were tested against four drugs associated with the FDC no strain was considered resistant. This fact is against the concept of FDC which aims to unite the four anti-TB drugs to combat the resistance of the bacilli. / O gênero Mycobacterium é constituído por espécies do Complexo M. tuberculosis (CMTB) e outras denominadas de micobactérias não tuberculosas (MNT). Os bacilos do CMTB causam a tuberculose (TB), uma doença infecciosa bacteriana, a qual comumente afeta os pulmões. Já as MNT causam outras micobacterioses. O diagnostico correto das doenças causadas pelas micobactérias é essencial para a definição do tratamento. O esquema de tratamento para a tuberculose no Brasil é preconizado pelo Programa Nacional de Controle da Tuberculose/Ministério da Saúde (PNCT/MS) e foi recentemente modificado. As principais mudanças propostas pelo Comitê Técnico Assessor do PNCT/MS foram: introduzir um quarto fármaco, o etambutol, na fase de ataque e adotar a associação dos fármacos em forma de comprimidos, com doses fixas combinadas (DFC) 4 em 1, para a fase de tratamento intensivo, e, 2 em 1, para fase de manutenção. Devido à grande incidência da tuberculose no Brasil e no mundo, à emergência de cepas resistentes e à implantação de novas terapias pelo Ministério da Saúde, este trabalho objetivou avaliar a suscetibilidade aos tuberculostáticos associados ou individualmente dos isolados clínicos de Mycobacterium tuberculosis do Hospital Universitário de Santa Maria. A suscetibilidade aos antimicrobianos isolados ou associados (rifampicina, isoniazida, pirazinamida e etambutol) foi avaliada através do método de microdiluição em caldo (MMC) e comparados ao método das proporções (MP), método padrão ouro para suscetibilidade de micobactérias. O MMC mostrou-se ser um método rápido, de fácil realização e boa correlação com o MP. Foram encontrados vários isolados clínicos de M. tuberculosis resistentes a um, dois ou três fármacos quando testados frente aos quatro fármacos isoladamente. Porem, quando estes foram, testados contra os quatro fármacos da DFC associados nenhuma cepa foi considerada resistente. Este fato vem de encontro ao conceito da DFC a qual pretende unir os quatro medicamentos anti-TB para combater a resistência dos bacilos.

Introduction: No Fixed-Dose Combination (FDC) formulations currently exist for pediatric tuberculosis (TB) treatment. Earlier work implemented, in the software NONMEM, a rational method for optimizing design and individualization of pediatric anti-TB FDC formulations based on patient body weight, but issues with parameter estimation, dosage strata heterogeneity and representative pharmacokinetics remained. Aim: To further develop the rational model-based methodology aiding the selection of appropriate FDC formulation designs and dosage regimens, in pediatric TB treatment. Materials and Methods: Optimization of the method with respect to the estimation of body weight breakpoints was sought. Heterogeneity of dosage groups with respect to treatment efficiency was sought to be improved. Recently published pediatric pharmacokinetic parameters were implemented and the model translated to MATLAB, where also the performance was evaluated by stochastic estimation and graphical visualization. Results: A logistic function was found better suited as an approximation of breakpoints. None of the estimation methods implemented in NONMEM were more suitable than the originally used FO method. Homogenization of dosage group treatment efficiency could not be solved. MATLAB translation was successful but required stochastic estimations and highlighted high densities of local minima. Representative pharmacokinetics were successfully implemented. Conclusions: NONMEM was found suboptimal for the task due to problems with discontinuities and heterogeneity, but a stepwise method with representative pharmacokinetics were successfully implemented. MATLAB showed more promise in the search for a method also addressing the heterogeneity issue.