Microbiological assessment of Oral liquid formulations manufactured in Dar-es-Salaam, Tanzania

Abstract

Seven hundred and twenty drug formulations collected from retail pharmacies and drug stores were analysed. Three hundred and twenty (44.4%) were syrups and 400 (55.6%) were mixtures. Total viable aerobic count for the formulations were determined using the plate count method, and the organisms isolated were identified by conventional microbiological/biochemical methods. The study revealed that microbial growth in mixtures was 49.0% and in syrups 42.8%; however, this difference was not significant. Different organisms were identified from the two formulations and their distribution pattern was found to be significantly different. It was shown that Gram-negative rods were found only in mixtures. Potential pathogens isolated were found more in mixtures (10.5%) than in syrups (0.3 %). Mixtures of Magnesium trisilicate, Kaolin and Belladona, contained more potential pathogens as compared to the rest of the mixtures. Water used during manufacturing of the formulations was considered to be the main source of contamination. Of concern was the presence of potential pathogenic /

iv microbes in high numbers. The extreme degradative nature of the Pseudomonas and many yeast cells isolated should make one seriously consider the possible degree of drug destruction. In view of the above findings, it is recommended that the authorities responsible for issuing of licences for drug manufacturing should be more strict, and adherence to Good Manufacturing Practice (GMP) should be emphasized. In addition, every manufacturing unit must have a functioning water purification system, and there should be frequent inspection of the microbial quality of locally manufactured drug formulations. Strong warning should be given for non-compliance and if necessary legal action be taken. The findings of this study, provide baseline information which may be of use in an attempt to improve the quality of pharmaceutical products and in setting up local standards in Tanzania.