Covalently crosslinked organophosphorous derivatives-chitosan hydrogel as a drug delivery system for oral administration of camptothecin.

Hydrogels are widely studied as drug delivery system. In this work we propose the employment of tetrakis(hydroxymethyl)phosphonium chloride as crosslinking agent to obtain covalent hydrogels based on chitosan. These hydrogels are obtained by Mannich reaction between the amino groups of chitosan with the hydroxymethyl groups of the crosslinker molecule.

Ionic Hydrogel Based on Chitosan Cross-Linked with 6-Phosphogluconic Trisodium Salt as a Drug Delivery System.

In this work, 6-phosphogluconic trisodium salt (6-PGNa) is introduced as a new aqueous and nontoxic cross-linking agent to obtain ionic hydrogels. Here, it is shown the formation of hydrogels based on chitosan cross-linked with 6-PGNa. This formulation is obtained by ionic interaction of cationic groups of polymer with anionic groups of the cross-linker.

A promising camptothecin derivative: Semisynthesis, antitumor activity and intestinal permeability.

Oral administration of camptothecin (CPT) derivatives and other antitumoral agents is being actively developed in order to improve the quality of life of patients with cancer. Though several lipophilic derivatives of CPT have shown interesting oral bioavailability in preclinical and clinical studies, only Topotecan has been approved for this route of administration. Semisynthesis, antitumor activity, biological inhibition mechanism, and in situ intestinal permeability of 9, 10-[1,3]-Dioxinocamptothecin (CDiox), an unexplored CPT derivative, have been studied in this paper.

Semisynthesis, cytotoxic activity, and oral availability of new lipophilic 9-substituted camptothecin derivatives.

Despite that 9-substituted camptothecins are promising candidates in cancer therapy, the limited accessibility to this position has reduced the studies of these derivatives to a few standard modifications. We report herein a novel semisynthetic route based on the Tscherniac-Einhorn reaction to synthesize new lipophilic camptothecin derivatives with amidomethyl and imidomethyl substitutions in position 9. Compounds were evaluated for their antiproliferative activity, topoisomerase I inhibition, and oral availability.