FORMULATION AND EVALUATION OF SUSTAINED RELEASE AMBROXOL HYDROCHLORIDE MICROSPHERES

Polymethyl mehtacrylates polymers such as Eudragit RL100 have been used in preparation of matrix type oral sustained release, coating and in microencapsulation of drug. Embedding of drug within an insoluble matrix is convenient way of controlling the drug release. The prepared microspheres by emulsion solvent evaporation technique was simple and reproducible, possessed good sphericity, smooth surface morphology, uniform and narrow size distribution (170-200 mu m), when analyzed by scanning electron microscopy, and optical microscopy. Method of preparation has influenced the particle size and drug loading efficiency. The carrier ethyl cellulose and Eudragit RL100 are easily available and compatible. Drug-polymer compatibility was confirmed by Fourier transform infrared spectroscopy and DSC and X-ray diffraction studies revealed that the drug was dispersed inside the microspheres in the form of an insoluble matrix. The formation of microspheres was affected by glass transition temperature of the polymer, surfactant, type of plasticizers, volume of internal phase, stirrer speed etc. IR of Eudragit RL indicated high thermal stability of the polymer. Percentage loading increases with the increase in concentration of ethyl cellulose (F5). The resulting microspheres have smooth surface and good physical stability. Micromeritic studies of prepared microspheres showed good flowability (according to Carr's index) and uniformity in size and satisfactory results for compression (according to Hausner's ratio). In vitro studies showed formulation F5 well suited to be sustained release product. From the data obtained it is concluded that drug loaded microspheres appears to be a suitable delivery system for Ambroxol, which may reduce number of doses of drug and frequency of administration.