Alginate-okra gum blend beads of diclofenac sodium from aqueous template using ZnSO4 as a cross-linker.

Zinc (Zn(2+))-ion induced diclofenac sodium (DS)-loaded alginate-okra (Hibiscus esculentus) gum (OG) blend beads was successfully formulated through Zn(2+)-ion induced ionic-gelation cross-linking method in a complete aqueous environment. Effects of polymer-blend ratio and cross-linker concentration on drug encapsulation efficiency (DEE) and cumulative drug release at 8 h (R8h) were optimized by 3(2)-factorial design. The optimized formulation of Zn(2+)-ion induced DS-loaded alginate-OG beads demonstrated 89.27±3.58% of DEE and 43.73±2.83% of R8h. The bead sizes were within 1.10±0.07 to 1.38±0.14 mm. The bead surface morphology was analyzed by SEM. The drug-polymer interaction in the optimized bead matrix was analyzed by FTIR and P-XRD. These beads exhibited sustained in vitro drug release over a prolonged period of 8h and followed controlled-release (zero-order) pattern with super case-II transport mechanism. The swelling and degradation of the optimized beads was influenced by the pH of test mediums, which might be suitable for intestinal drug delivery.

Okra (Hibiscus esculentus) gum-alginate blend mucoadhesive beads for controlled glibenclamide release.

The utility of isolated okra (Hibiscus esculentus) gum (OG) was evaluated as a potential sustained drug release polymer-blends with sodium alginate in the development of controlled glibenclamide release ionically-gelled beads for oral use. OG was isolated from okra fruits and its solubility, pH, viscosity and moisture content were studied. Glibenclamide-loaded OG-alginate blend beads were prepared using CaCl2 as cross-linking agent through ionic-gelation technique. These ionically gelled beads showed drug entrapment efficiency of 64.19 ± 2.02 to 91.86 ± 3.24%. The bead sizes were within 1.12 ± 0.11 to 1.28 ± 0.15 mm. These glibenclamide-loaded OG-alginate blend beads exhibited sustained in vitro drug release over a prolonged period of 8 h. The in vitro drug release from these OG-alginate beads were followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads was influenced by the pH of the test medium. These beads also exhibited good mucoadhesivity with goat intestinal mucosa.

Chitosan phthalate microspheres for oral delivery of insulin: preparation, characterization, and in vitro evaluation.

Chitosan phthalate polymer was synthesized and its microspheres were prepared by emulsion phase separation technique. The characterization of microspheres was determined by means of FTIR spectroscopy, electron microscopy, particle size, and zeta potential. The insulin was loaded to the microspheres by passive absorption technique. The peptic and tryptic enzymes degradation of insulin in microspheres was investigated. The in vitro release behavior of the microspheres was investigated under different pH conditions (pH 2.0 and pH 7.4). The degree of phthalate substitution in the synthesized polymer was 20%. The prepared microspheres were spherical with an average diameter 46.34 micro m. The insulin-loading capacity was 62%. Chitosan phthalate microspheres protect the insulin from gastric enzymes degradation that may enhance the oral stability of insulin. The encapsulated insulin was quickly released in a phosphate buffer saline (pH 7.4), whereas a small amount of insulin was released under acidic condition (0.1N HCl; pH 2.0) because under acidic conditions, carboxylic groups present in the system exist in nonionized form and are poorly hydrophilic. However, in alkaline conditions, it exists in ionized form and is considerably hydrophilic. The results suggest that chitosan phthalate microspheres may be used as a potential carrier for oral insulin delivery.