PhD Scientific Days 2026

Poster Session 1.F - Pharmaceutical Sciences and Health Technologies

Influence of Pharmaceutical Polymers on the Solubility–Permeability Interplay of Curcumin

Name of the presenter

Szolláth, Rita

Institute/workplace of the presenter

Semmelweis University, Department of Pharmaceutical Chemistry

Authors

Rita Szolláth¹, Vivien Bárdos¹
1: Semmelweis University, Department of Pharmaceutical Chemistry

Text of the abstract

Introduction: Curcumin is a poorly water-soluble active pharmaceutical ingredient with limited oral bioavailability. Solubility enhancement is a key strategy to improve oral absorption; however, increasing apparent solubility often reduces membrane permeability. Therefore, understanding the solubility–permeability interplay is essential for formulation design and early biopharmaceutical optimization. Aims: This study aimed to investigate how polymers influence solubility and passive permeability. A further objective was to compare excipient performance within and across polymer families and to evaluate the relationship between solubility improvement and permeability reduction. Methods: Measurements were performed in the presence of PEGs, poloxamers, PVPs, PVPVA copolymer at 37°C. The polymers were added in 5m/V% to pH2 Britton Robinson buffer solutions. Thermodinamic solubility was measured with the saturation shake flask method, while kinetic solubility was determined using the cosolvent-shift method. Permeability studies were conducted using the Parallel Artificial Membrane Permeability Assay (PAMPA). Results: All polymers increased the solubility, the extent depended on polymer type and molecular weight. Higher molecular-weight variants generally produced greater solubility enhancement within each polymer class. PEGs showed the smallest, while PVPVA and several PVP polymers produced the largest effect. While kinetic solubility values are considerably higher compared to thermodinamic values, the extent of polymer-induced enhancement followed very similar trends. Permeability decreased in all cases where solubility improved, confirming a solubility–permeability trade-off. However, the gain in solubility exceeded the loss in permeability, suggesting a favorable biopharmaceutical effect. Kinetic solubility data correlated more strongly with permeability than thermodynamic data. Conclusions: Polymer selection plays a critical role in optimizing formulation strategies for poorly soluble drugs. Although solubility enhancement was consistently accompanied by reduced permeability, in most cases the overall balance remained advantageous. Stronger association between kinetic solubility and permeability indicates that kinetic measurements may be more suitable than equilibrium methods for early formulation screening and assessing solubility-permeability interplay.