To develop a novel neomycin sulfate-loaded hydrogel dressing (HD), numerous neomycin sulfate-loaded HDs were prepared with various amounts of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) and sodium alginate (SA) using freeze-thawing technique, and their physical dressing properties, drug release, in vivo wound curing and histopathology in diabetic-induced rats were assessed. SA had a positive effect on a swelling capacity, but a negative effect on the physical dressing properties and drug release of HD. However, PVP did the opposite. In particular, the neomycin sulfate-loaded HD composed of drug, PVA, PVP and SA at the weight ratio of 1/10/0.8/0.8 had excellent swelling and bioadhesive capacity, good elasticity and fast drug release. Moreover, this HD gave more improved wound curing effect compared to the commercial product, ensured the disappearance of granulation tissue and recovered the wound tissue to normal. Therefore, this novel neomycin sulfate-loaded HD could be an effective pharmaceutical product for the treatment of wounds.

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To develop the long acting nifedipine oral delivery with enhanced bioavailability, nifedipine-loaded gelatin microcapsule containing nifedipine and ethanol in gelatin shell was prepared using a spray-dryer, and then coated microcapsule was prepared by coating the gelatin microcapsule with Eudragit acrylic resin. The dissolution test and the bioavailability of the coated microcapsule in rats were evaluated compared to nifedipine powder. The amount of nifedipine dissolved from gelatin microcapsule for 30 min increased about 5-fold compared to nifedipine powder in pH 1.2 simulated gastric fluid. Nifedipine released from the coated microcapsule was retarded in pH 1.2 simulated gastric fluid compared with that from gelatin microcapsule. Furthermore, the coated gelatin microcapsule maintained the plasma level of nifedipine over 4 h and gave significantly higher AUC of nifedipine than nifedipine powder. Thus, the Eudragit-coated gelatin microcapsule, which could maintain the plasma level of nifedipine over a longer period without the initial burst-out plasma concentration, is a preferable delivery system for poorly water-soluble nifedipine.