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Paclitaxel (PTX) is a frequently prescribed chemotherapy drug used to treat a wide variety of solid tumors. Oligo(lactic acid)8-PTX prodrug (o(LA)8-PTX) loaded poly(ethylene glycol)-b-poly(lactic acid) (PEG-b-PLA) micelles have higher loading, slower release and higher antitumor efficacy in murine tumor models over PTX-loaded PEG-b-PLA micelles. The goal of this work is to study plasma stability of o(LA)8-PTX-loaded PEG-b-PLA micelles and its pharmacokinetics after IV injection in rats. In rat plasma, o(LA)8-PTX prodrug is metabolized into o(LA)1-PTX and PTX. In human plasma, o(LA)8-PTX is metabolized more slowly into o(LA)2-PTX, o(LA)1-PTX, and PTX. After IV injection of 10 mg/kg PTX-equiv of o(LA)8-PTX prodrug loaded PEG-b-PLA micelles in Sprague–Dawley rats, metabolite abundance in plasma follows the order: o(LA)1-PTX > o(LA)2-PTX > o(LA)4-PTX > o(LA)6-PTX. Bile metabolite profiles of the o(LA)8-PTX prodrug is similar to plasma metabolite profiles. In comparison to equivalent doses of Abraxane®, plasma PTX exposure is two orders of magnitude higher for Abraxane® than PTX from o(LA)8-PTX prodrug loaded PEG-b-PLA micelles, and plasma o(LA)1-PTX exposure is fivefold higher than PTX from Abraxane®, demonstrating heightened plasma metabolite exposure for enhanced antitumor efficacy. [ABSTRACT FROM AUTHOR]

The main aim of the present study was to produce natural chitosan with different deacetylation degree from shrimp shells. Three deacetylation degrees of chitosan were obtained through boiling the chitin in NaOH (50% (w/v)) at 110 °C for 4 h. The samples were labelled as NCS1, NCS2 and NCS3 according to the number of times they were treated with alkaline solution. The functional groups of the obtained products and the degree of deacetylation were determined through Fourier transformed infra-red spectroscopy. Scanning electron microscope was employed to characterise the morphology of the produced materials. Cell viability assay was carried out using mesenchymal stem cells cultured on the samples for 7 days. The results showed that the deacetylation degree of chitin, NCS1, NCS2 and NCS3 became 50.1, 73.5, 82.3 and 82.5%, respectively. The natural chitin had carnation-like morphology. NCS1, NCS2 and NCS3 had the raised hills with the smaller and denser Gulbergs, however, there was no significant difference between NCS2 and NCS3 regarding the structure and deacetylation degree. Moreover, the result of the cell culture experiment indicated that the number of cells on the NCS1 was less than that of the NCS2 after 7 days. [ABSTRACT FROM AUTHOR]

The aim of this research was to develop chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis, which was fabricated through an environmental friendly process. Mucoadhesive films increase the advantage of higher efficiency and drug localization in the affected region. In this research, mucoadhesive films, for the release of hydrocortisone sodium succinate, were prepared using different ratios of chitosan, gelatin and keratin. In the first step, chitosan and gelatin proportions were optimized after evaluating the mechanical properties, swelling capacity, water uptake, stability, and biodegradation of the films. Then, keratin was added at different percentages to the optimum composite of chitosan and gelatin together with the drug. The results of surface pH showed that none of the samples were harmful to the buccal cavity. FTIR analysis confirmed the influence of keratin on the structure of the composite. The presence of a higher amount of keratin in the composite films resulted in high mechanical, mucoadhesive properties and stability, low water uptake and biodegradation in phosphate buffer saline (pH = 7.4) containing 104 U/ml lysozyme. The release profile of the films ascertained that keratin is a rate controller in the release of the hydrocortisone sodium succinate. Finally, chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate can be employed in dental applications. [ABSTRACT FROM AUTHOR]