Development and In vitro Evaluation of Flurbiprofen Microcapsules Prepared by Modified Solvent Evaporation Technique

Purpose: To develop modified release microcapsules of flurbiprofen for sustained release and reduced gastrointestinal side effects. Method: A co-polymer containing Eudragit RS 100 and hydroxypropyl methylcellulose (HPMC) in different drug/co-polymer ratios was used for microencapsulation of flurbiprofen by modified emulsion solvent evaporation (MESE) technique. The microcapsules were evaluated by x-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infra-red spectroscopy (FTIR) and scanning electron microscopy (SEM). Dissolution study was conducted in 0.1 M HCl for 2 h and phosphate buffer (pH 7.4) for 8 h, and the resulting data were analyzed by various pharmacokinetic models. Results: The data obtained from pre-formulation confirmed the purity of flurbiprofen. Particle size, flow rate and angle of repose showed good flow properties. FTIR and DSC confirmed the absence of incompatibilities among the drug and polymers. XRD of flurbiprofen showed characteristic sharp peaks confirming the crystalline nature of the drug which, however, decreased slightly in the formulation. SEM revealed that microencapsules of spherical shape and rough surface were produced at lower drug to copolymer ratio in contrast to the higher ratio which produced irregular microcapsules. Encapsulation efficiency was 65 85 % while regression coefficient (R2) values from kinetic analysis showed that release followed Korsmeyer-Peppas model with “n” > 1 indicating release mechanism followed super case II transport. Conclusion: MESE technique using Eudragit RS 100/HPMC polymer blend is a suitable approach to development of modified release flurbiprofen microcapsules.