Issue 72, 2015

Comparative pharmacokinetics and bioavailability of intranasal and rectal midazolam formulations relative to buccal administration in rabbits

Abstract

Midazolam (MDZ) is effective in treating seizures in a medical emergency service. However, intravenous (i.v.) administration requires skillful trained personnel. Alternative routes such as rectal, buccal, sublingual, or intranasal administration are established choices for drug application in an out-patient service. The aim of this work was to use rabbit as a model to compare the pharmacokinetics of midazolam and its 1′-hydroxy metabolite (1′-OH-MDZ) via i.v., rectal, intranasal and buccal administration with novel formulations. A single-dose, randomized, open-label, four-period crossover pharmacokinetic study was conducted with a three-day washout period between each segment. CYP3A activities were compared by studying the enzyme kinetics of midazolam in rabbit (CYP3A6) and human (CYP3A4/5) liver microsomes to qualify rabbit as a model species to predict human metabolic activity. From this study, a comparable apparent Km (7.86 vs. 8.66 μM) but a slightly higher Vmax (2117 vs. 1361 pmol min−1 mg−1) was observed in rabbits, and this resulted in a 1.72-fold higher intrinsic clearance. Midazolam had comparable bioavailability among 4 routes tested (60–70%) which is higher than oral (35–44%) administration. The absorption was faster in intranasal and rectal (∼10 min) than the buccal administration (∼20 min). The in vivo study also indicated that female rabbits had around 2-fold higher activity (1′-OH-MDZ/MDZ) in CYP3A6 than the male rabbits suggested that male rabbits may be closer to human in CYP3A activity. Overall, the rectal and intranasal formulations under current development might have the potential for administering midazolam in an out-patient emergency service when i.v. administration is not an option.

Graphical abstract: Comparative pharmacokinetics and bioavailability of intranasal and rectal midazolam formulations relative to buccal administration in rabbits

Supplementary files

Article information

Article type
Paper
Submitted
03 Jun 2015
Accepted
22 Jun 2015
First published
29 Jun 2015

RSC Adv., 2015,5, 58880-58888

Author version available

Comparative pharmacokinetics and bioavailability of intranasal and rectal midazolam formulations relative to buccal administration in rabbits

X. Zhuang, X. Wang, J. Wang, J. Li, A. Zheng, C. Lu and Z. Zhang, RSC Adv., 2015, 5, 58880 DOI: 10.1039/C5RA10549H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements