A COMPARATIVE STUDY FOR THE DETECTION OF CERTAIN MICROBIAL CONTAMINANTS IN PHARMACEUTICAL PREPARATIONS USING CONVENTIONAL AND MOLECULAR METHODS

Abstract

A total of 280 nonsterile pharmaceutical preparations were subjected to microbial limit testing, which included microbial enumeration tests using the spread plate technique and tests for specified microbial contaminants using both standard conventional techniques and molecular techniques. These preparations, which comprised 165 preparations for oral use and 115 preparations for topical use, were either obtained from different pharmaceutical companies or purchased randomly from various retail pharmacies in Egypt. The oral pharmaceutical preparations included syrups, tablets, capsules and powders whereas the topical preparations included creams, ointments, lotions and gels. Attempts were also made to identify other contaminants. Sample preparation was conducted using methods that have been shown to be suitable for the type of product to be tested and verified for the recovery process using a standard test microorganism (Staphylococcus aureus ATCC 433001). After verification, microbial testing revealed that microbial contaminants could be recovered from 76 out of 275 preparations with a percentage of 27.6%. No contaminants were recovered from 5 tested powder preparations. Microbial load varied among the pharmaceutical preparations with oral preparations showing a higher incidence of contamination (33.75%) in comparison to the topical preparations (19.1%).The level of fungal contamination was less than that of bacteria (11.3% and 20% respectively). Interestingly, it was observed that a single microbial contaminant was isolated from each contaminated preparation in all cases with few exceptions, where two bacterial contaminants were recovered from 5 preparations and one bacterial plus one fungal contaminant were recovered from 10 out of 275 preparations. SUMMARY 184 For bacterial counts, over 95% of the items tested contained fewer than 2 X 10² CFU/ml and 2.2% of the products contained (2-20) X 10² CFU/ml whilst only 0.73% contained more than 2 X 10³ CFU/ml. Six products were found to exceed the USP specified limits. For fungal counts, about 95% of the items tested contained fewer than 10¹ CFU/ml and 4.4% of the products contained 10-20 CFU/ml whilst only 1.8% contained more than 20 CFU/ml. Three oral preparations exceeded the USP specified limits. From all dosage forms tested, tablets were shown to exhibit the highest bacterial and fungal counts, other dosage forms did not show counts in this range. Regarding the isolates, a total of 60 bacterial and 31 fungal isolates were recovered. Of these isolates, 41 bacterial and 26 fungal isolates