Microbiological Risk Assessment of Pharmaceutical Raw Materials Imported and Stored in Lagos, Lagos State

The microbiological integrity of pharmaceutical raw materials at the point of importation and during warehouse storage is a critical quality assurance concern in Nigeria's pharmaceutical manufacturing sector. This study performed a microbiological risk assessment of selected active pharmaceutical ingredients (APIs) and excipients imported and stored in pharmaceutical warehouses in Lagos, South West Nigeria. Thirty raw material batches from 10 warehouses were sampled at port entry and again after 30 and 90 days of storage. Total aerobic microbial count (TAMC), total combined yeast and mold count (TYMC), and pharmacopoeial-specified organism testing for E. coli, Salmonella, Pseudomonas aeruginosa, and S. aureus were performed per USP and BP compendial methods. Warehouse environmental monitoring including temperature, humidity logging, and airborne particle counts was documented. Results showed that 26.7 percent of raw material batches failed one or more microbiological limits at the 90-day storage mark, compared to 10 percent at port entry. Excipients including starch and lactose exhibited the greatest susceptibility to microbial proliferation under sub-optimal storage conditions. Temperature excursions above 25°C correlated significantly with increases in TAMC. These findings highlight the cumulative microbiological risk introduced during extended warehouse storage and emphasize the need for validated storage condition monitoring, humidity-controlled warehouses, and shortened raw material hold times in Nigerian pharmaceutical supply chains. Keywords: pharmaceutical raw materials, microbiological risk, warehouse storage, TAMC, Lagos.