Thiolated chitosans: useful excipients for oral drug delivery.
To improve the bioavailability of orally administered drugs, formulations based on polymers are of great interest for pharmaceutical technologists. Thiolated chitosans are multifunctional polymers that exhibit improved mucoadhesive, cohesive and permeation-enhancing as well as efflux-pump-inhibitory properties. They can be synthesized by derivatization of the primary amino groups of chitosan with coupling reagents bearing thiol functions. Various data gained in-vitro as well as in-vivo studies clearly demonstrate the potential of thiolated chitosans for oral drug delivery. Within the current review, the synthesis and characterization of thiolated chitosans so far developed is summarized. Features of thiolated chitosans important for oral drug delivery are discussed as well. Moreover, different formulation approaches, such as matrix tablets and micro-/nanoparticles, as well as the applicability of thiolated chitosans for the oral delivery of various substance classes including peptides and efflux pump substrates, are highlighted.
Werle
Martin
M
ThioMatrix GmbH, Research Center Innsbruck, Mitterweg 24, 6020 Innsbruck, Austria. m.werle@thiomatrix.com
Bernkop-Schnürch
Andreas
A
D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D048271:Chitosan / Q000138:chemical synthesis / Q000737:chemistry*; D004304:Dosage Forms; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry*; D005079:Excipients / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D010455:Peptides / Q000008:administration & dosage / Q000493:pharmacokinetics; D011506:Proteins / Q000008:administration & dosage / Q000493:pharmacokinetics; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis / Q000737:chemistry
D004304:Dosage Forms; D004337:Drug Carriers; D005079:Excipients; D010455:Peptides; D011506:Proteins; D013438:Sulfhydryl Compounds; D048271:Chitosan