Encapsulation of vitamin C in tripolyphosphate cross-linked chitosan microspheres by spray drying

Abstract

This paper describes vitamin C-encapsulated chitosan microspheres cross-linked with tripolyphosphate (TPP) using a new process prepared by spray drying intended for oral delivery of vitamin C. Thus, prepared microspheres were evaluated by loading efficiency, particles size analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), zeta potential and in vitro release studies. The microspheres so prepared had a good sphericity and shape but varied with the volume of cross-linking agent solution added. They were positively charged. The mean particle size ranged from 6.1-9.0 microm. The size, shape, encapsulation efficiency, zeta potential and release rate were influenced by the volume of cross-linking agent. With the increasing amount of cross-linking agent, both the particle size and release rate were increased. Encapsulation efficiency decreased from 45.05-58.30% with the increasing amount of TPP solution from 10-30 ml. FTIR spectroscopy study showed that the vitamin C was found to be stable after encapsulation. XRD studies revealed that vitamin C is dispersed at the molecular level in the TPP-chitosan matrix. Well-defined change in the surface morphology was observed with the varying volume of TPP. The sphericity of chitosan microspheres was lost at higher volume of cross-linking agent. The release of vitamin C from these microspheres was sustained and affected by the volume of cross-linking agent added. The release of vitamin C from TPP-chitosan microspheres followed Fick's law of diffusion.

Optimization of prednisolone acetate-loaded chitosan microspheres using a 23factorial design for preventing restenosis

“…Ganza-Gonzales et al (1999) reported encapsulation efficiencies between 63-72% of microspheres prepared by spray-drying technique using chitosan polymer. Desai and Park (2005) also developed the spray-dried medium M w chitosan microspheres, and reported encapsulation efficiencies of 45-58%, which are similar to our results. …”

“…At the same time, the internal surface of the gels eroded slowly as a result of its contact with the solvent. This gelling mechanism decreased the drug release from the microspheres (Martinac et al, 2002;Desai & Park, 2005). The formulations prepared with medium M w chitosan showed slower and extended PA release and also increased t 50% values, which are given in Table 4.…”

“…These results can be attributed to the fact that higher M w chitosan solutions form more viscous solutions than those with low M w . Thus, medium M w chitosan solution droplets could be attached to a greater extent inside the main chamber of the spraydrying apparatus (Desai & Park, 2005).…”

“…Spray-drying is a high yield production method for preparing microparticulate systems (He et al, 1999a;Martinac et al, 2002;Desai & Park, 2005). The spraydrying technique for encapsulating drugs in biodegradable polymer matrices has been evaluated by several authors (He et al, 1999a;Guinchedi et al, 2002;Agnihotri et al, 2004;Desai & Park, 2005). Spray-drying is a one step procedure which produces small microspheres with smooth surface and spherical shape.…”

“…There are different in vitro release techniques in the literature for evaluating drug release from chitosan microspheres. Desai and Park (2005) used a dialysis technique while Ganza-Gonzales et al (1999) and Gavini et al (2006) used the USP basket method. The in vitro release technique used in our study was used by Filipovic-Grcic et al (2000) and the results obtained from our in vitro release study were concordant with those studies.…”