Evaluation of Cross-linked Methylcellulose and cross-linked Acacia gum as suspending agents in Ibuprofen oral suspension

Abstract

The existing pharmaceutical oral suspensions in commerce are marred with inadequacies such as poor: redispersibility, sedimentation rate, degree of flocculation, stability, and inadequate dosing. A moderate polymer with superior properties than the parent polymer for more stable and accurate dosing of medicated oral suspension was designed. Methylcellulose (MC), and Acacia gum (AG) were cross-linked separately using citric acid. The products were characterized by Fourier transforms infrared radiation (FTIR), swelling index, viscosity, and pH. The ibuprofen suspensions were prepared by using crosslinked MC (c-MC), crosslinked AG (c-AG), pure MC, and pure AG as suspending agents at concentrations of 1, 2, and 3% w/v (batches A1-3, B1-3, C1-3, and D1-3) respectively. They were evaluated for sedimentation volume, pH stability, viscosity, particle size, drug release, and stability. The results of the study indicate that increasing the concentration of crosslinked polymer powder in suspensions improved physical stability. Formulation B3 contained 3.0% MC and was found to be extremely viscous, inability to flocculate, and had zero flow characteristics. Both A3 and C3 showed satisfactory physical stability (in terms of pH and viscosity); and were redispersed by shaking 6 and 4 times respectively. The degree of flocculation for B3 (MC) was 0.0 and redispersibility was impossible and therefore implies that there was no room for sedimentation of drug particles. Sedimentation rate, viscosity, degree of flocculation, redispersibility, and T90% for A3 were 0.86 cm3/day, 155.5 + 2.5 mPaS, 3.3.3, 6, and 45 min.; for C3 the results were 0.86 cm3/day, 174.1+0.5 mPaS, 3.3 + 0.1, 4 and 25 min respectively. Among the formulated suspensions batches A3 and C3 containing 3 % c-MC and c-AG respectively showed better sedimentation rate, redipersibility, degree of flocculation, as well as better physical stability (pH) and in vitro drug release profile compared to other formulated suspensions (MC and AG). Both A3 and C3 formulations meet the characteristics of an ideal pharmaceutical suspension