Research Information System
EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS, vol.38, no.2, pp.82-88, 1992 (SCI-Expanded)
The purpose of this study was to investigate the formulation of loperamide hydrochloride suspensions. Thickening agents sodium carboxymethyl cellulose and methyl cellulose of low and high viscosity, hydroxypropylmethyl cellulose, acacia, tragacanth and Veegum(R) were used at different concentrations, as well as sweeteners such as sorbitol and saccharin. Methyl and propyl parabens were added as preservatives. The suspensions were analysed for their sedimentation parameters, redispersibility, rheological properties, particle size distribution, and loperamide hydrochloride content. In all of these formulas, loperamide hydrochloride, methyl and propyl parabens were added in concentrations of 0.08, 0.18, and 0.02%. Deflocculated suspensions with sodium carboxymethyl cellulose of high viscosity 0.75%, sorbitol 10% (Formula 4); sodium carboxymethyl cellulose of high viscosity 1%, saccharin 0.05% (Formula 10); Veegum(R) 1.5%, sorbitol 10% (Formula 64) and Veegum(R) 2%, saccharin 0.05% (Formula 70) showed the highest sedimentation volume ratios. Flocculated suspensions with sodium carboxymethyl cellulose of high viscosity 0.5%, potassium dihydrogen phosphate 0.005%, sorbitol 10% (Formula 24) and sodium carboxymethyl cellulose of high viscosity 0.5%, potassium dihydrogen phosphate 0.008%, saccharin 0.05% (Formula 28) had the highest degree of flocculation. All of these formulas also showed relatively short redispersibility time, homogeneous particle size distribution, and pseudoplastic or thixotropic flow properties.