ABSTRACT:
Microspheres (MS) of Tramadol Hydrochloride (TM) were prepared by coacervation method without the use of chemical cross–linking agent (glutaraldehyde) to avoid the toxic reactions and other undesirable effects of the chemical cross-linking agent. Alternatively, ionotropic gelation was employed by using sodium-tripolyphosphate (Na-TPP) as cross linking agent. Chitosan was used as polymer. All the prepared microspheres were subjected to various physico-chemical studies, such as drug-polymer compatibility by thin layer chromatography (TLC) and Fourier Transform Infrared Spectroscopy (FTIR), surface morphology by scanning electron microscopy (SEM), frequency distribution, encapsulation efficiency by High Performance Thin Layer Chromatography (HPTLC), in-vitro drug release characteristics and release kinetics. TLC and FTIR studies indicated no drug-polymer incompatibility. Surface smoothness of MS was increased by increasing the polymer concentration, which was confirmed by SEM. As the drug to polymer ratio was increased, the mean particle size (MPS) of TM microspheres was also increased. A maximum of 87% of drug entrapment efficiency was obtained by the method employed. All the MS showed initial burst release followed by a Fickian diffusion mechanism. It is possible to design a controlled drug delivery system for the prolonged release of TM, improving therapy by possible reduction of time intervals between administrations.