Formulation and evaluation of Zidovudine loaded chitosan Microspheres for controlled release

The aim of this study was to formulate and evaluate zidovudine loaded chitosan microspheres for controlled drug release. Microspheres were prepared by emulsification method using gluteraldehyde as crosslinking agent. The prepared microspheres were characterized for their yield and drug loading, as well by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffractometry and Scanning electron microscopy. The in vitro release studies were performed in pH 7.4, phosphate buffer. The prepared microspheres were free flowing and spherical in shape. The drugloaded microspheres showed 72-94% of entrapment and release was extended up to 12h. The infrared spectra showed stable character of zidovudine in the drugloaded microspheres and revealed the absence of drugpolymer interactions. X-ray diffraction patterns showed that there was decrease in crystallinity of the drug. Scanning electron microscopy study revealed that the microspheres were spherical and porous in nature. It was found that the drug: polymer ratio, the stirring speed, the concentration of surfactant, and the amount of gluteraldehyde used for crosslinking were the most significant variables which influenced the size of the chitosan microspheres under the applied experimental condition. *Corresponding author, Mailing address: Kesari Asha Email: [email protected], [email protected] Cell: 09437502189, 09178140373 Article History:-----------------------Date of Submission: 11-11-2011 Date of Acceptance: 14-11-2011 Conflict of Interest: NIL Source of Support: NONE F U L L L e n g t h R e s e a r c h P a p e r C o v e r e d i n I n d e x C o p e r n i c u s w i t h I C V a l u e 4 .6 8 f o r 2 0 1 0 Int. J. Drug Dev. & Res., Jan-March 2012, 4 (1): 96-105 Covered in Scopus & Embase, Elsevier 96 oral bioavailability and administration of zidovudine exhibits many dose dependant side effects. Hence a properly designed and optimized dosage form is needed which will not only provide control release of zidovudine but also will minimize the risk of side effects thus making zidovudine treatment more patient friendly. Chitosan, a natural compound obtained by alkaline deacetylation of chitin, is a unique cationic polymer [1]. Being non toxic, biodegradable and biocompatible, chitosan has been widely used in the formulation of particulate drug delivery systems to achieve controlled drug delivery [2, 3]. Microspheres can be defined as solid, spherical empty particles ranging in size from 1 to 1000 μm [4]. Solid biodegradable microspheres incorporating a drug dispersed or dissolved throughout particle matrix have the potential for the controlled release of drug[5,6,7]. With this background, combination of chitosan and zidovudine were selected as core material for formulation of microspheres to achieve controlled drug release [8, 9]. The objective of the present work was to design, formulate, optimize and evaluate zidovudine loaded chitosan microspheres for controlled drug release [6]. Hence different batches of microspheres were prepared according to the working plan [10, 11]. The resultant microspheres were evaluated /characterized for percentage yield, entrapment efficiency, particle size and in vitro drug release [12]. The effect of process variables on microspheres was also studied. MATERIALS AND METHODS Materials Zidovudine was obtained as a gift from m/s Aurobindo Laboratories Ltd, Hyderabad. Chitosan was obtained as a gift sample from Central Institute of Fisheries Technology, Cochin. All other reagents and solvents used were of pharmaceutical or analytical grade. The equipment used was centrifuge, sonicator, UV spectrophotometer, FTIR, X -RD, Particle size analyzer, Zetasizer and scanning electron microscope.