Microparticles bioavailability enhancing

Cyclodextrins Natural Solubihty And Bioavailability Enhancer, Drug Stabihzation, Microparticles, Peptide Dehvery, Permeation Enhancer, Nanoparticles and Nanocapsule Sulindac, Paclitaxel Hydrocortisone... 

The topic of ocular bioavailability of indomethacin administered in a sub-micrometer emulsion was al.so examined by the research group led by M, J. Alon.so at the University of Santiago de Compo-stela, Spain (32). These workers tested several carriers in vivo in rabbits nanopaiticles, nanocapsules, microparticles, and a submicrometer emulsion. The latter, prepared by the method of Yu et al. (33) with poloxamer 188 and soybean lecithin and containing 0.1% w/v indomethacin, had particles of diameter 0.21 0.02 im. The submicrometer systems (nanoparticles, nanocapsules, and emulsion) increased by more than three-fold the indomethacin concentration in the cornea, aqueous humor, and iris-ciliary body at 0.S and 1.0 h post instillation. Furthermore, an increased indomethacin bioavailability of 300% was observed in comparison with the value obtained for an aqueous commercial solution. Confocal laser scanning microscopy studies indicated (hat the submtcion particles penetrated into the comeal epithelium cells by endocyiosis (he audiors further suggested that the vehicle components (lecithin in the case of emulsions) may act as penetration enhancers or as endocytotic stimulators. 

Thiolated chitosans, in particular, seem to be suitable for overcoming the above-mentioned drawbacks owing to their permeation-enhancing effect. To prove the efficacy of thiolated chitosans for nasal drug targeting, insulin was chosen as model dmg. Insulin-loaded chitosan-TBA microparticles were administered to the nostrils of male Wister rats, using an intravenous injection of insulin as a positive control. It was found that the absolute bioavailability of insulin loaded in chitosan-TBA microparticles was 7.24 0.76%, which was more than 3.5-fold higher than the absolute bioavailability obtained from the unmodified chitosan/insulin microparticles [78]. 

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