pH Sensitive Interpenetrating Network Bio Containers of Gum Ghatti for Sustained Release of Glipizide.

OBJECTIVE: A novel natural polymer, Gum Ghatti (GG) was explored to develop a new polymeric system that will combine the biodegradable and biocompatible properties of GG and mechanical properties of poly vinyl alcohol (PVA) for drug delivery application. METHODS: Smart pH sensitive, porous, glutaraldehyde (GA) crosslinked interpenetrating network (IPN) microspheres loaded with glipizide were developed by the emulsion crosslinking method. The drug entrapment efficiency was 92.85±1.5%. FTIR confirmed the formation of IPN structure. Drug release can be extended upto 7 hours by modulating the concentration of crosslinking agent. Swelling study and diffusion co-efficient (D) of water transport were performed in order to understand the phenomenon of water penetration through the microsphere. In vivo antidiabetic activity performed on alloxane induced diabetic rats indicated that in case of pure glipizide sudden reduction of elevated blood glucose was observed after 3 hours. RESULTS: In case of rats treated with glipizide loaded IPN microparticles, the initial percentage reduction of blood glucose level was slow within the first 3 hours of administration, as compared to pure glipizide but after 6 hours 90% reduction was observed which confirmed sustained release nature of microspheres. CONCLUSION: Thus IPN microparticles were found suitable for sustained delivery of BCS class II drug glipizide.

Development of smart hydrogels of etherified gum ghatti for sustained oral delivery of ropinirole hydrochloride.

Gum Ghatti (GG) is a water soluble complex polysaccharide obtained from Anogeissus latifolia. Due to its non toxic and excellent emulsifying characteristics, it was widely used in different pharmaceutical preparations. Currently another facet was explored for its utility as release retardant polymer in oral controlled drug delivery system. As GG solely was incapable of forming microspheres therefore modification of GG to Sodium carboxymethyl (NaCMGG) derivative was done by carboxymethylation process and its gel forming capacity was explored by the use of trivalent cation (Aluminium chloride) which results into complete microbead system in a complete aqueous environment for controlled delivery of Ropinirole Hydrochloride (RHCl). Rheological property of NaCMGG showed pseudoplastic shear thinning behavior. Spherical shape of bead was observed under scanning electron microscope. Depending upon the formulation variables, Drug entrapment efficiency (DEE) varies from 47.66±3.51 % to 71.4±2.65%., and 80 to 90% drug was released in 6h in pH 6.8 phosphate buffer. Drug release was governed by both fickian diffusion and polymer relaxation simultaneously. Compatible environment for drug entrapment was established by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). Thus the modified derivative NaCMGG could be a promising polymer in biomedical application.

Novel interpenetrating network microspheres of xanthan gum-poly(vinyl alcohol) for the delivery of diclofenac sodium to the intestine--in vitro and in vivo evaluation.

Xanthan gum (XG), a trisaccharide branched polymer and poly vinyl alcohol (PVA), was used to develop pH-sensitive interpenetrating network (IPN) microspheres by emulsion cross-linking method in the presence of glutaraldehyde as a cross-linker to deliver model anti-inflammatory drug, diclofenac sodium (DS) to the intestine. Various formulations were prepared by changing the ratio of XG:PVA, extent of cross-linking in order to optimize the formulation variables on drug encapsulation efficiency, and release rate. Formation of interpenetrating network and the chemical stability of DS after penetration of microspheres was confirmed by Fourier Transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis were done on the drug loaded microspheres which confirmed molecular dispersion of DS in the IPN. Microspheres formed were spherical with smooth surfaces, as evidenced by scanning electron microscopy (SEM), and mean particle size, as measured by laser light scattering technique ranged between 310.25-477.10 microm. Drug encapsulation of up to 82.94% was achieved as measured by UV method. Both equilibrium and dynamic swelling studies and in vitro release studies were performed in pH 1.2 and 6.8. Release data indicated a Fickian trend of drug release which depends on the extent of cross-linking and the ratio of XG:PVA present in the microsphere. When subjected to in vivo pharmacokinetic evaluation in rabbits, microparticles show slow and prolonged drug release when compared with DS solution. Based on the results of in vitro and in vivo studies it was concluded that these IPN microspheres provided oral controlled release of water-soluble DS.