International Journal of Pharmacology1811-77751812-5700Asian Network for Scientific Information10.3923/ijp.2009.319.322KhanfarM. KhalilR. AbuJafalA. 5200955The aim of the current investigation is to assess the efficacy of different preservatives ingredients of different expectorant cough syrups manufactured by different pharmaceutical companies by comparing the growth of five microorganisms of known quanta of S. aureus, E. coli, P. aeruginosa and C. albicans. The microorganisms were inoculated into syrup A (glycerol and propylene glycol), syrup B (propylene glycol and glycerin), syrup C (glycerin, propylene glycol and butyl paraben), syrup D (methyl paraben and probylparaben) and normal saline as a control. All microorganisms were taken from standard stock cultures and incubated for 24 h. Growth of microorganisms into syrup was compared by counting the CFUs from a subculture of inoculated syrup at zero, 3, 6, 12, 24 and 48 h intervals. The data showed that all the combinations of the preservatives in the four studied cough syrups behaved similarly in term of antimicrobial efficiency. The findings suggested that the preservatives mixtures of propylene glycol with glycerol or with glycerin or with butyl paraben preservatives as well as methyl paraben with probylparaben are acceptable clinically and have considerably antimicrobial activity against infectious bacteria during the 48 h studied period.]]>Allen, L.V., N.G. Popovich and H.C. Ansel,20058th Edn.,Aulton, M.E.,20022nd Edn.,Cremieux, A., S. Cupferman and C. Lens,200527223236EMEA.,19981998EMEA.,20032003Hugo, B.W. and A.D. Russells,20057th Edn.,Wachowski, I., D.T. Jolly, J. Hrazdil, J.C. Galbraith, M. Greacen and A.S. Clanachan,199988209212Crowther, J., J. Hrazdil, D.T. Jolly, J.C. Galbraith, M. Greacen and M. Grace,199682475478Rosenthall, R.A., S.L. Buck, C.L. Henry and B.A. Schlech,200622440448Souza, M.R. and M.T. Ohara,200354411420Spiegeleer, B., E. Wattyn, G. Sleggers, V. Meeren, K. Vlamick and L. Vooren,200611275284