Publications by authors named "Shewiyo D"

The aim of this study was to develop and validate a High-Performance Thin Layer Chromatographic (HPTLC) method for simultaneous determination of ceftriaxone and ceftriaxone e-isomer in powder for injection formulation. Ceftriaxone sodium injection is an antibiotic that used globally. It has Z/E geometrical conformation, in which ceftriaxone sodium and 3 ene-isomer have Z- conformation while (E)-isomer has E- conformation and the potential toxicity of ceftriaxone (E)-isomer has been reported.

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The use of chiral medicines (possessing center(s) of asymmetric carbon) may cause adverse drug reactions (ADRs). The safety assurance of these medicines is critical. We aimed to evaluate registered and commonly used anti-infective chiral medicines circulating in the Tanzanian market to establish their safety profile to protect public health.

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Objectives: The quality of amoxicillin capsules, ceftriaxone for injection, and ciprofloxacin tablets was evaluated to determine whether there is any difference in quality when comparing the country of origin. This was undertaken because it has been claimed that antibiotics manufactured in Europe are of superior quality to those originating from Africa or Asia.

Methods: Samples of amoxicillin capsules, ceftriaxone for injection, and ciprofloxacin tablets were collected from three randomly selected wholesale pharmacies in each city, namely Arusha, Dar es Salaam and Mwanza, Tanzania.

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Under-reporting of adverse drug events (ADEs) is a challenge facing developing countries including Tanzania. Given the high magnitude of under-reporting, it was necessary to develop and assess the effectiveness of a 'structured stimulated spontaneous safety monitoring' (SSSSM) reporting program of ADEs which aimed at strengthening pharmacovigilance system in Tanzania. A quasi-experimental design and data mining technique were used to assess the effect of intervention after the introduction of program in seven tertiary hospitals.

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Background: Veterinary medicines have been widely used for the prevention and treatment of animal diseases. Globally, the veterinary medicine industry is growing. However, there is a significant increase of concern on the quality of veterinary medicines in various developing countries' legal markets.

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Background: Antiretroviral drugs (ARVs) have significantly reduced morbidity, mortality and improved the quality of life of people living with HIV infection. Poor quality ARVs may result in harmful consequences such as adverse drug reactions, treatment failure and development of drug resistant strains and sometimes death, which in turn may undermine the healthcare delivery system. To ensure optimal treatment outcomes, medicines quality control must be undertaken regularly.

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Medicines with a stereogenic center (asymmetric carbon) are mainly present as racemates with a mixture of equal amounts of enantiomers. One enantiomer may be active while the other inactive, alternatively one may produce side-effects and even toxicity. However, there is lack of information on the chirality status (either racemates, single active enantiomer or achiral) of medicines circulated on the market particularly in African countries.

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Background And Objective: Artemisinin combination therapies such as artemether-lumefantrine (AL) are effective for first-line treatment of uncomplicated acute Plasmodium falciparum malaria. However, the safety profile of AL in large populations has not been fully assessed. The objective of this study was to establish the safety of AL in public health facilities in Tanzania using the Cohort Event Monitoring (CEM) method.

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The accuracy profile, based on total error, integrates several validation parameters, such as trueness, precision and linearity, providing one statistic which enables decision on the suitability of a method for its intended purpose. Two assay methods for formulations are validated using accuracy profiles as an alternative approach to classic method validation. It concerns high-performance thin-layer chromatography (HPTLC) methods, which initially were validated using the classic approach.

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This paper presents the development of a new RP-HPTLC method for the separation of pyrazinamide, isoniazid, rifampicin and ethambutol in a four fixed-dose combination (4 FDC) tablet formulation. It is a single method with two steps in which after plate development pyrazinamide, isoniazid and rifampicin are detected at an UV wavelength of 280 nm. Then ethambutol is derivatized and detected at a VIS wavelength of 450 nm.

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High-performance thin-layer chromatography (HPTLC) is still increasingly finding its way in pharmaceutical analysis in some parts of the world. With the advancements in the stationary phases and the introduction of densitometers as detection equipment, the technique achieves for given applications a precision and trueness comparable to high-performance liquid chromatography (HPLC). In this review, the literature is surveyed for developed and validated HPTLC methods to assay active ingredients in pharmaceutical formulations published in the period 2005-2011.

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This paper presents the development and validation of an improved method for the simultaneous analysis of lamivudine (LVD), stavudine (STV) and nevirapine (NVP) using high-performance thin-layer chromatography (HPTLC) with densitometric detection. Separation was performed on silica gel 60F(254) plates. The mobile phase is comprised of ethylacetate, methanol, toluene and concentrated ammonia (38.

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Pneumocystis carinii pneumonia (PCP) is often the ultimate mortal cause for immunocompromised individuals, such as HIV/AIDS patients. Currently, the most effective medicine for treatment and prophylaxis is co-trimoxazole, a synergistic combination of sulfamethoxazole (SMX) and trimethoprim (TMP). In order to ensure a continued availability of high quality co-trimoxazole tablets within resource-limited countries, Medicines Regulatory Authorities must perform quality control of these products.

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Objective: The quality of 33 formulations of essential antimicrobial and antimalarial drugs (amoxicillin capsules, metronidazole tablets, sulfamethoxazole/trimethoprim tablets, quinine tablets and sulphadoxine/pyrimethamine tablets) marketed in Rwanda and Tanzania was assessed and the influence of tropical storage conditions on potency and in vitro dissolution investigated.

Methods: Drug content and in vitro dissolution were determined immediately after purchase and during 6-month storage under simulated tropical conditions (75% relative humidity, 40 degrees C) using the methods described in the USP 24 monographs on the drugs concerned.

Results And Discussion: At the time of purchase, the drug content of all the formulations was within the limits recommended by the USP 24, but after 6-month storage, the drug content of one sulfamethoxazole/trimethoprim and one quinine formulation were found to be substandard.

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We evaluated the in vitro availability and its stability under simulated tropical conditions of various formulations of four essential drugs marketed in Tanzania. We obtained 22 formulations (containing paracetamol, acetylsalicylic acid, chloroquine or sulphadoxine/pyrimethamine) from wholesale pharmacies in Dar es Salaam and the Medical Stores Department (Tanzania). The drug content, in vitro availability (dissolution) and its stability under simulated tropical conditions were determined using methods specified in the United States Pharmacopoeia (USP) 24 monograph of the respective drugs.

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