Microbial evaluation of some syrups in Syrian pharmacies

Microbial contamination of syrups can bring clinical hazards to patients as well as physical and chemical changes in the product.

Studying the influence of the war on the Syrian pharmaceutical industry from a microbiological point of view by assessing the microbiological quality of syrup samples taken from Syrian pharmacies.

Fifty different syrups from 29 different companies having various manufacture dates were collected during validity period between 9-2019 and 6-2021 in Aleppo, Syria. Membrane filtration technique was performed to quantify microbial contamination of the collected syrup samples. This involved passing the samples through filter nitrocellulose membrane disks with a pore size of 0.45 μm then transferring the filter disks alongside any collected microorganisms into Tryptone Soya Agar, Sabouraud Dextrose agar, Xylose lysine Deoxycholate agar and Eosin Methylene Blue agar plates. Colonies observed on these plates were counted and the number of viable microbes in the original sample was expressed as colony forming units per milliliter (CFU/mL). Investigation of Escherichia coli in all syrup samples and Salmonella in herbal syrup samples was also performed.

This study revealed that 28 syrups (56%) had no growth of either bacterial or fungal colonies; 33 syrups (66%) had no growth of bacterial colonies; 43 syrups (86%) had no growth of fungal colonies. On the other hand, 7 syrups (14%) exceeded the pharmacopoeial limit for bacterial growth and 6 syrups (12%) exceeded that for fungal growth. Furthermore, 5 syrup samples (10%) were on the high permissible limits for bacterial contamination and none for fungal contamination.All syrups were free from E. coli and all herbal syrups were free from Salmonella. Taken together, out of the fifty syrups examined 13 syrups (26%) exceeded the pharmacopoeial limits and therefore pharmacopoeial accepted syrups constitute a percentage of (74%).

Although the majority of samples tested showed compliance with the pharmacopoeial limits of microbiological contamination, the small proportion of syrups in the Syrian market exceeding the pharmacopoeial limit is still concerning and reveals the implications of post-war conditions on the quality of manufacturing in the Syrian pharmaceutical industry. That said, it remained within the proper limits compared to studies conducted in other countries in similar situations.This study, therefore, highlights the need to apply the Good Manufacturing Practice (GMP) rules more strictly in order to limit microbiological contamination in pharmaceutical syrups to ensure the quality of products and safety of users. We suggest that further quality control studies are conducted on a larger scale and repeated more frequently.