Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Enhancement of solubility and bioavailability of Candesartan cilexetil using natural p-plycoprotein inhibitors

Noor Ahmad Zulal, P K Lakshmi

G Pulla Reddy College of Pharmacy, Mehdipatnam, Hyderabad, AP, India 500 028;

For correspondence:- P Lakshmi Email: drlakshmisuresh@gmail.com

Received: 6 March 2014 Revised: 29 November 2014 Published: 30 January 2015

Citation: Zulal NA, Lakshmi PK. Enhancement of solubility and bioavailability of Candesartan cilexetil using natural p-plycoprotein inhibitors. Trop J Pharm Res 2015; 14(1):21-26 doi: 10.4314/tjpr.v14i1.4

© 2015 The authors.
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Abstract

Purpose: To enhance the otherwise poor solubility and bioavailability of candesartan cilexetil (CDS).

Methods: This study involved enhancing drug solubility by various solid dispersion (SD) methods. The drug: carrier ratio was as follows: for urea (1:2, 1:4 and 1:6; for polyethylene glycol 6000 (PEG, 1:2 and 1:4, 1:8); and mannitol (1:2, 1:4 and 1:6. Piperin and quercetin (natural P-glycoprotein inhibitors) were used as bioavailability enhancers. Bioavailability stdies were carried out in a rat model with the SDs formulated in a suspension form and administered by the oral route.

Results: All the carriers enhanced drug dissolution in water 2 to 4-fold depending on drug/carrier ratio. Release kinetics from solid dispersions made with mannitol showed zero order drug release. Urea and PEG 6000-based solid dispersions showed 1st order drug release kinetics. FTIR studies confirmed transformation to an amorphous form of CDS in mannitol solid dispersion; this was buttressed by release kinetic studies. Bioavailability of the drug in the animals was enhanced by 27 and 68 % when quercetine and piperine, respectively, were incorporated.

Conclusion: Formation of solid dispersion enhances the solubility and bioavailability of CDS when natural P-glycoprotein inhibitors such as piperin and quercetin are incorporated as enhancers.

Keywords: Solid dispersion, Candesartan, Cilexetil, Bioavailability, P- Glycoprotein, Piperin, Quercetin