Current quality status of some paediatric metronidazole suspensions in Nigeria

Abstract

The study evaluated the quality of practitioners’ preferred brands of paediatric metronidazole suspension in Nigeria. Same batch of each brand was randomly purchased from different zones of the country, labeled A - I and assessed for microbial contamination, pH, sedimentation volume/rate, flow rate, redispersibility, rheology, drug crystal characteristics, content/uniformity and dissolution profile using standard protocols. No product showed growth in MacKonkey agar and Sabourad dextrose media after 48 h; products pH were: 5.46±0.015(E) - 6.29±0.021(D). Sedimentation volumes were: 0.13 - 1, with products C, E and F sedimenting relatively fast within 24 h, whereas D, G and H showed no visible sedimentation over 42 days. Product I exhibited the fastest flow rate, while product E was the slowest. Product A was difficult to redisperse, whereas products D, G and H did not sediment, hence were easy to redisperse. The apparent viscosity values of products decreased with increasing shear rate, with product E exhibiting the highest viscosity profile. Photomicrographs revealed that particles of product A were almost oval, while the others were planar/triclinical in shape. Percentage contents of metronidazole were: 98.91±1.8(A), 99.70±0.59(B), 98.19±0.56(C), 99.55±1.30(D), 99.22±1.35(E), 99.54±1.54(F), 100.05±2.12(G), 98.92±1.39(H) and 99.09±1.56%(I); with coefficient of variation of < ±5% for all products. Dissolution profiles revealed that the products (except D and C) released > 60% of drug within 30 min, and at 60 min, products A, B, E, F and I released ≥ 90% drug content in 5 ml. The qualities of products assessed were within acceptable limits; however, some products’ dissolution characteristics need improvement.

Keywords: Metronidazole, paediatric, oral suspension, quality