Bioactive thermoresponsive polyblend nanofiber formulations for wound healing.

The rationale of this work is to develop new bioactive thermoresponsive polyblend nanofiber formulations for wound healing (topical). Various polymer compositions of thermoresponsive, poly(N-isopropylacrylamide), egg albumen and poly(ε-caprolactone) blend solutions with and without a drug [gatifloxacin hydrochloride, Gati] were prepared. Non-woven nanofibers of various compositions were fabricated using an electrospinning technique. The morphology of the nanofibers was analyzed by an environmental scanning electron microscope. The morphology was influenced by the concentration of polymer, drug, and polymer blend composition. Fourier transform infrared spectroscopy analysis showed the shift in bands due to hydrogen ion interactions between polymers and drug. Thermogram of PNIPAM/PCL/EA with Gati recorded a shift in lower critical solution temperature (LCST) and glass transition temperature (Tg) of PNIPAM. Similarly Tg and melting temperature (Tm) of PCL were shifted. X-ray diffraction patterns recorded a decrease in the crystalline state of PCL nanofibers and transformed crystalline drug to an amorphous state. In vitro release study of nanofibers with Gati showed initial rapid release up to 10h, followed by slow and controlled release for 696h (29days). Nanofiber mats with Gati exhibited antibacterial properties to Staphylococcus aureus, supported suitable controlled drug release with in vitro cell viability and in vivo wound healing.

Gelatin hydrogels: enhanced biocompatibility, drug release and cell viability.

Biodegradability and enhanced biocompatibility with pH-sensitivity of hydrogels are becoming very important issues for biomaterials applications so as to minimize the host-body reactions such as, inflammatory, antigenic, and immunogenic problems. This study involves development of hydrogel matrices of gelatin conjugated/modified with highly hydrophilic, pH-sensitive and biocompatible polymer, poly (2-ethyl-2-oxazoline) and glyoxylic acid respectively. Various compositions of gelatin conjugated/modified with poly (2-ethyl-2-oxazoline) (gp) and glyoxylic acid (gg) were synthesized. The swelling kinetics, cell viability and drug release capability from the gels at pH 4.5 and 7.4 were investigated. The results of swelling kinetics showed that, both the degree of swelling (DS) and the maximum degree of swelling (MDS) increased as function of modification (increase in modification) and pH with an increase of time, which is due to increase in ionic groups. The drug-release (1% chlorhexidine) studies at pH 7.4 and 4.5 confirmed a proportional drug release with an increase in degree of swelling. The results of in-vitro cytotoxicity tests using mouse embryonic 3T3 fibroblast cells indicated, an improved cell viability for gelatin gels conjugated/modified with poly (2-ethyl-2-oxazoline) (gp) and glyoxylic acid (gg) gels, when compared with 1% glutaraldehyde cross-linked gelatin gels (gx). Hence, cross-linked gelatin gels can be replaced with gp/gg for potential use in biomedical applications as a matrix for drug delivery.