Segmental-Dependent Solubility and Permeability as Key Factors Guiding Controlled Release Drug Product Development

Milica Markovic; Moran Zur; Noa Fine-Shamir; Ester Haimov; Isabel González-Álvarez; Arik Dahan

doi:10.3390/pharmaceutics12030295

Segmental-Dependent Solubility and Permeability as Key Factors Guiding Controlled Release Drug Product Development

Pharmaceutics. 2020 Mar 24;12(3):295. doi: 10.3390/pharmaceutics12030295.

Authors

Milica Markovic¹, Moran Zur¹, Noa Fine-Shamir¹, Ester Haimov¹, Isabel González-Álvarez², Arik Dahan¹

Affiliations

¹ Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
² Department of Pharmacokinetics and Pharmaceutical Technology, Miguel Hernandez University, 03550 San Juan de Alicante, Spain.

Abstract

The main factors influencing the absorption of orally administered drugs are solubility and permeability, which are location-dependent and may vary along the gastrointestinal tract (GIT). The purpose of this work was to investigate segmental-dependent intestinal absorption and its role in controlled-release (CR) drug product development. The solubility/dissolution and permeability of carvedilol (vs. metoprolol) were thoroughly studied, in vitro/in vivo (Octanol-buffer distribution coefficients (Log D), parallel artificial membrane permeability assay (PAMPA), rat intestinal perfusion), focusing on location-dependent effects. Carvedilol exhibits changing solubility in different conditions throughout the GIT, attributable to its zwitterionic nature. A biorelevant pH-dilution dissolution study for carvedilol immediate release (IR) vs. CR scenario elucidates that while the IR dose (25 mg) may dissolve in the GIT luminal conditions, higher doses used in CR products would precipitate if administered at once, highlighting the advantage of CR from the solubility/dissolution point of view. Likewise, segmental-dependent permeability was evident, with higher permeability of carvedilol vs. the low/high P_eff marker metoprolol throughout the GIT, confirming it as a biopharmaceutical classification system (BCS) class II drug. Theoretical analysis of relevant physicochemical properties confirmed these results as well. A CR product may shift the carvedilol's solubility behavior from class II to I since only a small dose portion needs to be solubilized at a given time point. The permeability of carvedilol surpasses the threshold of metoprolol jejunal permeability throughout the entire GIT, including the colon, establishing it as a suitable candidate for CR product development. Altogether, this work may serve as an analysis model in the decision process of CR formulation development and may increase our biopharmaceutical understanding of a successful CR drug product.

Keywords: biopharmaceutics classification system; controlled release drug product; drug permeability; drug solubility; location-dependent absorption.