  Citation: Józó, M.; Simon, N.; Yi, L.; Móczó, J.; Pukánszky, B. Improved Release of a Drug with Poor Water Solubility by Using Electrospun Water-Soluble Polymers as Carriers. Pharmaceutics 2022, 14, 34. https:// doi.org/10.3390/pharmaceutics 14010034 Academic Editor: Gareth R. Williams Received: 15 November 2021 Accepted: 20 December 2021 Published: 24 December 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). pharmaceutics Article Improved Release of a Drug with Poor Water Solubility by Using Electrospun Water-Soluble Polymers as Carriers Muriel Józó 1,2 ,Nóra Simon 1,2 , Lan Yi 1,2 ,János Móczó 1,2, * and Béla Pukánszky 1,2 1 Laboratory of Plastics and Rubber Technology, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, H-1521 Budapest, Hungary; jozo.muriel@vbk.bme.hu (M.J.); nora.smn@hotmail.com (N.S.); MinozBoGum@gmail.com (L.Y.); pukanszky.bela@vbk.bme.hu (B.P.) 2 Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, ELKH Eötvös Loránd Research Network, H-1519 Budapest, Hungary * Correspondence: jmoczo@edu.bme.hu; Tel.: +36-1-382-6569 Abstract: In an attempt to improve the solubility of valsartan, a BCS II drug, fibers containing the drug were prepared from three water-soluble polymers, hydroxypropyl-methyl-cellulose (HPMC), polyvinyl-pyrrolidone (PVP), and polyvinyl-alcohol (PVA). Fiber spinning technology was optimized for each polymer separately. The polymers contained 20 wt% of the active component. The drug was homogenously distributed within the fibers in the amorphous form. The presence of the drug interfered with the spinning process only slightly, the diameters of the fibers were in the same range as without the drug for the HPMC and the PVA fibers, while it doubled in PVP. The incorporation of the drug into the fibers increased its solubility in all cases compared to that of the neat drug. The solubility of the drug itself depends very much on pH and this sensitivity remained the same in the HPMC and PVP fibers; the release of the drug is dominated by the dissolution behavior of valsartan itself. On the other hand, solubility and the rate of release were practically independent of pH in the PVA fibers. The different behavior is explained by the rate of the dissolution of the respective polymer, which is larger for HPMC and PVP, and smaller for PVA than the dissolution rate of the drug. The larger extent of release compared to neat valsartan can be explained by the lack of crystallinity of the drug, its better dispersion, and the larger surface area of the fibers. Considering all facts, the preparation of electrospun devices from valsartan and water-soluble polymers is beneficial, and the use of PVA is more advantageous than that of the other two polymers. Keywords: valsartan; hydroxypropyl-methyl-cellulose; polyvinyl-pyrrolidone; polyvinyl-alcohol; drug morphology; distribution; pH; drug release 1. Introduction The most convenient method for the application of a drug is oral administration [1–3]. The approach has several advantages including the good cooperation of the patient, formu- lation freedom, and cost effectiveness. Consequently, pharmaceutical companies prefer the production of drugs for oral administration. However, in many cases, the physical-chemical characteristics of the drug do not favor oral administration because of either limited solubil- ity or poor permeability [4–9]. The most important drawback of oral administration is small bioavailability and one of the basic conditions of large bioavailability is the sufficient solu- bility of the drug in water-based solution, like body fluids. The solubility of many drugs, especially those belonging to the Biopharmaceutics Classification System (BCS II) class, is small, thus various measures must be taken to increase it and improve bioavailability. After the recognition of the importance of solubility in drug delivery, various physical and chemical approaches have been developed to improve it. Chemical methods, i.e., the modification of the chemical structure of the drug [10,11], are usually complicated and expensive, thus physical methods are preferred, if their use is possible. The most impor- tant physical methods are the decrease of particle size [3], the change of crystallization Pharmaceutics 2022, 14, 34. https://doi.org/10.3390/pharmaceutics14010034 https://www.mdpi.com/journal/pharmaceutics