The influence of various amphiphilic excipients on the physicochemical properties of carbamazepine-loaded microparticles

The objective of the present study was to prepare multiple-unit formulations of carbamazepine (CBZ) using an emulsion congealing technique. CBZ-hydrogenated castor oil (HCO) (Cutina? HR) wax microparticles were prepared without organic solvents as an alternative to polymeric microparticles. The process involved emulsification and solidification of CBZ-HCO melt at a significantly low temperature (5°C). Five amphiphilic excipients (Pluronic F-68 (PL), Labrasol (LB), Gelucire 44/14 (GL 44/14), D-α-tocopheryl PEG 1000 succinate (TPGS) and Docusate sodium (DOSS) were added with the wax melt. The microparticles were characterized with respect to their particle size distribution, drug loading, morphological character, drug-excipient interaction, differential scanning calorimetry, Fourier-transform infra-red (FT-IR) and release properties. An average value for production yield was 83.45%. Evaluation of the release data indicates that the release mechanism from the prepared Cutina? HR microparticles follows both the Higuchi model of diffusion and anomalous release mechanism. Microparticles containing 5% Labrasol, TPGS and GL 44/14 had the highest extent of dissolution.