Development and application of a photometric method in quality evaluation of benzimidazole anthelminthics in Nairobi city county.

Abstract

Introduction: Neglected Tropical Diseases (NTDs) are a group of communicable diseases which are prevalent in the tropics affecting more than one billion people. Helminthiases are classified among NTDs. Treatment and prevention of these infections is very costly to developing economies. The communities most afflicted are poor and have limited access to essential resources for their livelihood. Poor quality drugs for NTDs may lead to death or prolonged treatment without achieving the desired results. The limited resources used in purchasing poor quality drugs will therefore be wasted instead of being put to good use. Study Objectives: The general objective of the study was to determine the quality of benzimidazole anthelminthics in the Kenyan market using a simple, rapid and inexpensive spectroscopic method. More specifically, the study aimed to explore the utility of an ultraviolet (UV) spectroscopic method in the determination of the quality of benzimidazole anthelminthics in the Kenyan market. Method: The adaptability of a method reported in the literature by Agrawal et al for the analysis of albendazole was investigated for the analysis of albendazole and mebendazole. In the method development phase, two solvents were investigated; 0.1M hydrochloric acid (HCl) with 0.05% sodium lauryl sulphate and 0.1M methanolic HCl. Two wavelengths for detection were also investigated; 233 and 294 nm. The working concentration (12 μg/ml) was adapted from the method used by Agrawal et al. The method was validated for precision, accuracy, specificity, linearity and range as per the International Council for Harmonization (ICH) guidelines. The developed method was then used in the assay of commercial products available in pharmaceutical wholesale outlets in Nairobi. Results and discussion: The suitable solvent of analysis for the analytes was found to be 0.1M methanolic HCl. The wavelength of analysis was set at 294 nm. The range was over which linearity was established was way beyond the 80 to 120% of the working concentration specified by the ICH. Upon validation, the method was found to have good linearity (R2 = 0.9988 for both albendazole and mebendazole). The method exhibited good precision with the same day coefficient of variation (CV) of 0.184 and 0.579% and the intermediate CV of 0.230 and 0.162% for mebendazole and albendazole respectively against the ICH limit of 2%. This meant that the developed method was precise for the analytes. Out of 32 commercial samples analysed, five (15.6%) did not comply with compendial specifications. Of great concern is that three (9.4%) of the non-compliant samples were low cost generic products. These are the products which are popular with the majority members of the society who have a low income. Intra-brand batch variation was also observed. Out of three batches of product A002T analysed, one did not comply with compendial specifications. It was also observed that both batches of product M001S, the suspension of an innovator product, did not comply with compedial specifications. Utility of results: A major limitation in the analysis of benzimidazole anthelminthics is the lack of reliable, simple, rapid and low-cost methods of analysis. The developed method serves to fill this gap. It can be used in the analysis of raw materials and finished products. It can also be used in the establishment of the quality of products prior to registration. The method will prove very useful in post market surveillance of quality of benzimidazole anthelminthics.