Applied Surface Science 257 (2011) 10780–10788 Contents lists available at ScienceDirect Applied Surface Science jou rn al h om epa g e: www.elsevier.com/locate/apsusc Biocompatible polymeric implants for controlled drug delivery produced by MAPLE Irina Alexandra Paun a , Antoniu Moldovan b , Catalin Romeo Luculescu b , Maria Dinescu b,∗ a Faculty of Applied Sciences, University Politehnica of Bucharest, RO-060042 Bucharest, Romania b National Institute for Laser, Plasma and Radiation Physics, RO-077125 Magurele, Bucharest, Romania a r t i c l e i n f o Article history: Received 20 April 2011 Received in revised form 20 July 2011 Accepted 22 July 2011 Available online 2 August 2011 Keywords: MAPLE Thin films Polymers Biocompatibility Drug delivery a b s t r a c t Implants consisting of drug cores coated with polymeric films were developed for delivering drugs in a controlled manner. The polymeric films were produced using matrix assisted pulsed laser evapora- tion (MAPLE) and consist of poly(lactide-co-glycolide) (PLGA), used individually as well as blended with polyethylene glycol (PEG). Indomethacin (INC) was used as model drug. The implants were tested in vitro (i.e. in conditions similar with those encountered inside the body), for predicting their behavior after implantation at the site of action. To this end, they were immersed in physiological media (i.e. phosphate buffered saline PBS pH 7.4 and blood). At various intervals of PBS immersion (and respectively in blood), the polymeric films coating the drug cores were studied in terms of morphology, chemistry, wettabil- ity and blood compatibility. PEG:PLGA film exhibited superior properties as compared to PLGA film, the corresponding implant being thus more suitable for internal use in the human body. In addition, the implant containing PEG:PLGA film provided an efficient and sustained release of the drug. The kinetics of the drug release was consistent with a diffusion mediated mechanism (as revealed by fitting the data with Higuchi’s model); the drug was gradually released through the pores formed during PBS immersion. In contrast, the implant containing PLGA film showed poor drug delivery rates and mechanical failure. In this case, fitting the data with Hixson–Crowell model indicated a release mechanism dominated by polymer erosion. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Within the last decades, extensive research has been dedicated to the development of polymeric implants that release drugs in a controlled manner [1–3]. These systems offer outstanding advan- tages compared to traditional drug administration pathways, i.e. ability to control the drug release rates and to deliver the drugs directly to the site of action, increased comfort and low toxicity for the patients [1–8]. A widely used implant is the “reservoir” type, which consists of a drug core encapsulated in a polymeric film (i.e. membrane) that controls the drug release [2,9–11]. For these systems, the drug release is mostly controlled by the properties of the polymeric films ([2,3] and Refs. therein). Therefore, obtaining polymeric films with well-defined and adjustable properties is critical for a proper functionality of the implants. Previous studies on polymeric films (i.e. coatings) have generally addressed key parameters such as morphology, chemistry and wettability [12–23]. The morphology ∗ Corresponding author. Fax: +40 214 574 467. E-mail address: dinescum@nipne.ro (M. Dinescu). influences the drug delivery rates and, in correlation with sur- face wettability, determines the biological properties of the films; furthermore, the chemical composition of the polymeric films influ- ences the mechanisms of polymer degradation and drug release. Moreover, after implantation inside the body, the implants surfaces (i.e. the polymeric films) interact with body fluids and undergo changes that affect their functionality ([12] and Refs. therein). These aspects have been addressed by studies carried out in vitro, in media similar with those inside the body ([12,22] and Refs. therein). For depositing polymeric films, conventional techniques such as spray coating or spin coating have significant limitations, espe- cially because they use solvents to dispense the polymers on the surfaces. For producing implants consisting of drug cores coated with polymeric films, the use of solvents for coating the drug with the polymeric layer is problematic, because solvents may dissolve/affect the underlying layer (i.e. the drug); furthermore, uneven wetting, distribution and evaporation of the solvent result in non-uniform coatings with uncontrollable thickness [24,25]. A recent developed laser-based deposition technique called matrix assisted pulsed laser evaporation (MAPLE) overcomes these limitations, offering the benefit of a “dry” physical vapor tech- nique where the solvent is eliminated during the deposition process 0169-4332/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2011.07.097