Direct Measurement of Lipase Inhibition by Orlistat Using a Dissolution Linked <em>In Vitro</em> Assay | OMICS International | Abstract
ISSN: 2167-065X

Clinical Pharmacology & Biopharmaceutics
Open Access

Our Group organises 3000+ Global Conferenceseries Events every year across USA, Europe & Asia with support from 1000 more scientific Societies and Publishes 700+ Open Access Journals which contains over 50000 eminent personalities, reputed scientists as editorial board members.

Open Access Journals gaining more Readers and Citations
700 Journals and 15,000,000 Readers Each Journal is getting 25,000+ Readers

This Readership is 10 times more when compared to other Subscription Journals (Source: Google Analytics)

Research Article

Direct Measurement of Lipase Inhibition by Orlistat Using a Dissolution Linked In Vitro Assay

Daniel R Lewis1 and Dongzhou J Liu2*
1New Products Research and Development, GlaxoSmithKline, Parsippany, NJ, USA
2Department of Chemical & Biochemical Engineering, Rutgers University, Piscataway, NJ, USA
Corresponding Author : Dongzhou J Liu
Department of Chemical & Biochemical Engineering
Rutgers University, 1500 Littleton Rd
Parsippany, NJ, USA
Tel: 973-8894468
Fax: 973-8892460
E-mail: [email protected]
Received July 24, 2012; Accepted September 04, 2012; Published September 11, 2012
Citation: Lewis DR, Liu DJ (2012) Direct Measurement of Lipase Inhibition by Orlistat Using a Dissolution Linked In Vitro Assay. Clinic Pharmacol Biopharm. 1:103. doi:10.4172/2167-065X.1000103
Copyright: © 2012 Lewis DR, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Purpose: To develop a bio-assay that would be able to directly test gastrointestinal and/or dissolution samples to determine lipase activity and inhibition by Orlistat.
Methods: Enzyme assays were performed with porcine pancreatic lipase and para-Nitrophenyl Palmitate (pNPP) in pH 8.0 reaction buffer at 37°C. Substrate hydrolysis was monitored by absorbance changes at 410 nm. The dissolution of two Orlistat formulations was tested with a USP II apparatus. Samples were HPLC analyzed to determine release profile in addition to being diluted and directly assayed for inhibitory effect.
Results: The lipase-pNPP system demonstrates linearity and Michalis-Menten kinetics with a Km=2.7 ± 0.2 μM and Kcat = 0.019 s-1. Orlistat showed highly potent and time dependent inhibition with 5 ng/ml effecting 50% activity after 5 minutes in the Lipase-pNPP system. Dissolution studies showed a correlation of the drug release profile to the inhibitory effect of dissolution samples in the assay.
Conclusions: The lipase-pNPP method can be used as an in vitro assay to monitor orlistat inhibition from drug release or dissolution samples.