Physicochemical and microbiological evaluation of ibuprofen suspension produced using Detarium microcarpum as suspending agent

Abstract

Suspensions are two phase systems composed of solid materials dispersed in liquid. Detarium microcarpum gum (DMG) was obtained by acetone precipitation of filtrate obtained from maceration of Detarium microcarpum seed powder using distilled water. Ibuprofen was pulverized using a mortar and dispersed in distilled water to form ibuprofen suspension formulation (IS1). Five other ibuprofen suspension formulations were prepared using either DMG or acacia as the suspending agent (IS2-IS6). Benzoic acid was added during the preparation of formulations IS4 and IS6 as preservative. Physicochemical properties like pH, viscosity and the total microbial count for the suspensions were evaluated. Drug-excipient compatibility was studied using FTIR spectroscopy. The pH of the suspensions ranged from 3.7±0.0 -5.3±0.0 on day 0 to 3.9±0.0 - 6.3±0.0 on day 35. Flow rate was from 2.21±0.13 – 33.00±3.70 mls-1 on day 0 to 1.88±0.12 – 20.19±0.16 mls-1 on day 35. The viscosity at 25oC ranged from 2391.3 – 5702.2 mPas on day 0 to 3793.0 – 3828.2 mPas on day 35. It was a shear thinning system. Formulation IS6 was the most stable and IS1 was the least stable. The suspensions contained high level of bacteria on day 0 which increased significantly on day 35, with exception of formulations IS4 and IS6. Ibuprofen suspensions with good physicochemical properties were produced using DMG but the level of microbial contamination observed highlighted the need of having good environmental hygiene and use of preservatives when natural gums are used in formulations.
 Keywords: ibuprofen, Detarium microcarpum, suspension, suspending agent, microorganisms