Spectral studies of Donepezil release from streched PVA polymer films Cristina-Delia Nechifor a , Carmen-Beatrice Zelinschi b , Iuliana Stoica c , Valentina Closca b , Dana-Ortansa Dorohoi b,⇑ a Department of Physics, Ias ßi, Dimitrie Mangeron Bvd., No. 67, ‘‘Gheorghe Asachi’’ Technical University of Iasi, RO 700050, Romania b Department of Plasma Physics, Polymer Physic, Optics and Spectroscopy, Ias ßi, Carol I Bvd., No. 11, ‘‘AL. I. Cuza’’ University of Iasi, RO 700506, Romania c Laboratory of Physical Chemistry of Polymers, Ias ßi, Aleea Gr. Ghica Voda ˘ 41 A, ‘‘Petru Poni’’ Institute of Macromolecular Chemistry, RO 700487, Romania highlights " Characterization of PVA membranes containing 2% Donepezil using contact angle measurements, AFM images and optical means. " Investigation of the stretching process influence on the Donepezil release from PVA foils. " Elucidating the mechanisms involved in kinetic dynamics of drug delivery into human body as function of stretching degree. " Establishment of the dependence for drug delivery kinetics on the stretching degree of PVA foils. article info Article history: Available online xxxx Keywords: PVA stretched films Donepezil release Induced birefringence Surface roughness and polarity abstract The focus of this research is to obtain poly vinyl alcohol (PVA) polymer foils containing Donepezil in dif- ferent concentration, in order to be used in controlled drug release as a palliative treatment of mild to moderate Alzheimer’s disease. The influence of polymeric foil stretching degree on drug release was ana- lyzed using spectral measurements. Aiming to evidence the stretching degrees of PVA foils influence on drug release the membranes con- taining 2% Donepezil were obtained and characterized. The morphology of pure PVA and polymeric films with Donepezil at different stretching degrees was investigated. In vitro evaluation of drug release from the polymeric foils was made for different stretching degrees. The absorbance of the solution was measured at 232 nm in each case; the amount of drug release after each time interval was calculated and a cumulative addition was made. The mechanism involved in drug release process was evaluated using Korsmeyer–Peppas empirical equation. Surface roughness and pro- file of drug release are affected by the stretching degree of PVA foils. The dependence of the release profile on the characteristics of polymer foils containing Donepezil and the manner in which the stretching degree of the PVA with Donepezil films modify the kinetics of drug release were emphasized in this study. Ó 2012 Elsevier B.V. All rights reserved. 1. Introduction Donepezil, 2-[(1-benzyl-4-piperidyl)methyl]-5,6-dimethoxy- 2,3dihydroinden-1-one, is a drug belonging to the category of ace- tylcholinesterase inhibitors [1,2]. Donepezil is used in the palliative treatment of mild to moderate forms of Alzheimer disease [3–7]. The chemical structure of Donepezil is C 24 H 29 NO 3 , Fig. 1a. The systems with controlled release permit a pre-determined, predictable and reproducible drug delivery. In the systems with controlled delivery, the active substance is dispersed in a polymer matrix from which it is released after a kinetic profile correspond- ing to a given treatment of the disease [8–10]. The controlled release of a therapeutically agent facilitates the maintenance of a constant and optimal dose during the treatment. The drugs incor- porated in different polymer matrices and directed to a specified target have low toxicity and eliminate the discontinuity of treatment. The progresses in obtaining the controlled release of the drugs offer a significant degree of freedom in choosing of the target; the systems containing the drug can be placed in a cavity of the organism, or they can be attached on the skin [11]. The systems with controlled delivery are composed from an active substance embedded in a biocompatible and biodegradable polymer matrix, which permit directional drug diffusion. The polymer matrix must contain an excess of therapeutically agent in order to assure con- stant and continuous release into human body. 0022-2860/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.molstruc.2012.10.006 ⇑ Corresponding author. Tel.: +40 2 3220 1182; fax: +40 2 3220 1150. E-mail addresses: cristina.nechifor@tuiasi.ro (C.-D. Nechifor), ddorohoi@uaic.ro (D.-O. Dorohoi). Journal of Molecular Structure xxx (2012) xxx–xxx Contents lists available at SciVerse ScienceDirect Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstruc Please cite this article in press as: C.-D. Nechifor et al., J. Mol. Struct. (2012), http://dx.doi.org/10.1016/j.molstruc.2012.10.006