Chitosan-telmisartan polymeric cocrystals for improving oral absorption: In vitro and in vivo evaluation.

This study describes the development of polymeric cocrystals of chitosan-telmisartan (TEL) to improve the oral bioavailability of TEL, which has poor oral solubility and bioavailability. The polymeric cocrystal was prepared using chitosan a biopolymer with the aid of sodium citrate as a salting-out agent. The cocrystals were characterized by FT-IR spectroscopy, scanning electron microscopy, differential scanning calorimeteri (DSC), thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD). The improved solubility of TEL was observed with cocrystals as compared to that of pure drug in solubility studies with phosphate buffer (pH 7.4). The in vivo pharmacokinetics properties of cocrystal were studied by an animal model using rats after a single dose oral administration. The results showed an increased plasma drug concentration (Cmax) of 1.47, µg/ml for cocrystals when compared to pure TEL with 0.96 µg/ml with one-fold increased bioavailability (F%) that is, the cocrystals increases the solubility of the drug and the paracellular drug absorption by tight junction modulation. Further the elimination constant Kel resulted with higher value of about 0.0085 h-1 when compared to pure drug with0.0048 h-1 along with improved AUC (14.62 µg/ml).

Capecitabine encapsulated chitosan succinate-sodium alginate macromolecular complex beads for colon cancer targeted delivery: in vitro evaluation.

The present study aims to investigate the efficacy of the novel biopolymeric complex multiparticulate system consisting of chitosan succinate and alginate for the capecitabine-targeted delivery to colon cancer. A Box-Behnken design was used to optimize the CS-SA beads by considering the effect of three factors: CS (A;X1), CaCl2 (B;X2), and SA (C;X3), on the response variables Y1 (EE), Y2 (Size), and Y3 (Release). The results of response surface plots allowed an optimized bead to be identified with high drug EE and maximum drug release at colon. The swelling index showed that the beads reached a maximum good swelling at pH 7.4, and nil or little swelling at acidic pH, which proves that the beads completely protect the release of drug. The in vitro release portrayed a maximum release at pH 7.4, due to the large swelling force that was created by electrostatic repulsion between the ionized carboxylic acid groups of the CS-SA network. In vitro cytotoxicity assay (MTT) of CS-SA beads shows inhibition of the proliferation of HT-29 tumour cell to induce apoptosis over a longer period of time. The above results show that CS-SA beads prolong the release of CP in the colonic region, and also enhance antitumor efficacy.

Carbopol-based gels for nasal delivery of progesterone.

The purpose of this study was to investigate the nasal absorption of progesterone from carbopol-based nasal gels in rabbits. Progesterone nasal gels were prepared by dispersing carbopol 974 (1%, 1.5%, and 2%) in distilled water followed by addition of progesterone/progesterone-beta cyclodextrin complex dissolved in propylene glycol then neutralization. The potential use of beta cyclodextrin (CD) as nasal absorption enhancer by simple addition, as a physical mixture and as a complex with progesterone was investigated. The absolute bioavailability of progesterone from nasal gels in rabbits was studied by estimating the serum progesterone level by competitive solid-phase enzyme immunoassay in comparison to intravenous injection. The carbopol gel formulations produced a significant increase in bioavailability. CD complex promotes the nasal absorption of progesterone from carbopol gels as compared with gels where the CD is added by simple addition and gels which do not contain CD. This method of addition of CD as an inclusion complex in the gels could be considered as a preferred platform in nasal drug administration.