Cyclodextrins in nasal drug delivery

Nasal drug delivery is an attractive approach for the systemic delivery of high potency drugs with a low oral bioavailability due to extensive gastroi ntestinal breakdown and high hepatic first-pass effect. For lipophilic drug s nasal delivery is possible if they can be dissolved in the dosage form. P eptide and protein drugs often have a low nasal bioavailability because of their large size and hydrophilicity, resulting in poor transport properties across the nasal mucosa. Cyclodextrins are used to improve the nasal absor ption of these drugs by increasing their aqueous solubility and/or by enhan cing their nasal absorption. With several cyclodextrins very efficient nasa l drug absorption has been reported, but also large interspecies difference s have been found. Studies concerning the safety of cyclodextrins in nasal drug formulations demonstrate the non-toxicity of the cyclodextrins and als o clinical data show no adverse effects. Therefore, some cyclodextrins can be expected to become effective and safe excipients in nasal drug delivery. (C) 1999 Elsevier Science B.V. All rights reserved.