Encapsulation and characterization of controlled release flurbiprofen loaded microspheres using beeswax as an encapsulating agent

Abstract

The aim of the present study was to extend the use of flurbiprofen in clinical settings by avoiding its harmful gastric effects. For this purpose, we designed the controlled release solid lipid flurbiprofen microspheres (SLFM) by emulsion congealing technique. Drug was entrapped into gastro resistant biodegradable beeswax microspheres which were prepared at different drug/beeswax ratios 1:1, 1:2 and 1:3 using gelatin and tween 20 as emulsifying agents. The effect of emulsifiers and the effect drug/beeswax ratios were studied on hydration rate, encapsulating efficiency, micromeritic properties, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (X-RD) analysis and in vitro drug release at pH 1.2 for 2 h and at pH 6.8 for 10 h. SEM revealed that microspheres made with tween 20 were smooth while microspheres made with gelatin showed porous morphology, however, they were all spherical in nature. The practical yield (recovery) showed a dependence on drug-beeswax ratio and it was variable from 53 to 84%. High loading encapsulating efficiency of flurbiprofen from 8 to 94% was achieved. FTIR and DSC analysis confirmed the absence of any drug polymer interaction indicating drug stability during microencapsulation. X-RD of pure flurbiprofen shows sharp peaks, which decreases on encapsulation, indicating decrease in the crystallinity of drug in microspheres. The micromeritic studies confirmed the presence of excellent and good flow properties of microspheres. Entrapment efficiency, morphology, practical yield, hydration rate, flow properties demonstrated their dependence on the HLB value of emulsifiers and emulsifiers with higher HLB were found more appropriate for effective microencapsulation of flurbiprofen. The release kinetics followed zero order mechanism of drug release at pH 6.8. Release pattern depends on the morphology of flurbiprofen microspheres and amount of beeswax used in the microspheres preparation. The microspheres prepared with high HLB values i.e., tween 20 showed effective control of drug release from microspheres. The absence of drug release at pH 1.2 proved the suitability of beeswax for its use as a gastro resistant material.

Bioadhesive vaginal tablets containing spray dried microspheres loaded with clotrimazole for treatment of vaginal Candidiasis

“…Samples were tapped until no further reduction in volume of the sample was observed. Carr's index was calculated (10).…”

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

“…Thermogram of HPMC and Eudragit RS 100 represented the amorphous nature of the substances. Formulation "A1" presenting a decrease in sharpness of the peak along with slight shift in temperature showing decrease in crystallinity of the substance [12]. XRD pattern of formulation A1 presented the characteristic peak in the same region with slight depression in the sharpness showed a little reduction in crystallinity of flurbiprofen.…”

“…FTIR spectrum of flurbiprofen showed the presence of (C=O) carbonyl compound. Absorbance below 1700 cm -1 gives an idea of conjugation with another carbonyl group or aromatic ring [11,12]. FTIR spectrum of physical mixture showed little change in the position and sharpness of the peaks [12,13].…”

“…Absorbance below 1700 cm -1 gives an idea of conjugation with another carbonyl group or aromatic ring [11,12]. FTIR spectrum of physical mixture showed little change in the position and sharpness of the peaks [12,13]. This alteration could be due to variations in the resonance structure, stretching and bending, rotation of a part of molecule or certain bonds or minor distortion of bond angle during formulation development [14].…”

Formulation and Characterization of Ketorolac Tromethamine Nanoparticle with Eudragit RS-100 and RL-100 by Nano precipitation Method

“…Samples (3-4 mg) were placed in aluminum pan and heated at a rate of 10°C/min, in an atmosphere of nitrogen to a temperature of 300°C, using indium in the reference pan [16].…”