Page | 1621 Pt(II) complex @mesoporous silica: preparation, characterization and study of release Maria Luisa Saladino 1,2,* , Simona Rubino 1 , Paola Colomba 1 , Maria Assunta Girasolo 1 , Delia F. Chillura Martino 1,2 , Caglar Demirbag 3 , Eugenio Caponetti 1,2 1 Dipartimento Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche - STEBICEF and INSTM UdR - Palermo, Università di Palermo, Parco d’Orleans II, Viale delle Scienze pad.17, Palermo I-90128, Italy 2 Centro Grandi Apparecchiature-ATeN Center, Università di Palermo, Via F. Marini 14, Palermo I-90128, Italy 3 Marmara University, Faculty of Pharmacy, Department of Analytical Chemisty, Tibbiye Street 49, Haydarpasa 34668 Istanbul, Turkey *corresponding author e-mail address: marialuisa.saladino@unipa.it ABSTRACT Cisplatin analogs, having cytotoxic activity higher than that exerted by cisplatin, have recently triggered considerable interest by the community. The cis-[PtCl 2 (DMSO)HL]·2DMSO, where HL = 7-amino-2-(methylthio)[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylic acid, has shown a potent cytotoxic activity on HepG2 hepatocarcinoma cells, while under identical conditions, it did not affect normal immortalized human liver cells (Chang). In this work, the above complex has been incorporated into MCM41 mesoporous silica, pure and functionalized with amino group, which is considered one of the best host for a drug delivery system for carrying high dosages of a variety of drugs in their mesopores. Since the controlled release of an anticancer drug helps to maintain its therapeutic level for an extended time period while minimizing undesirable high peaks immediately following administration, the in vitro tests have been performed in order to obtain the corresponding drug release profile. The investigated system demonstrated to be an efficient system for pharmaceutic controlled release. A deepened characterization of the systems has been performed in order to known their structure and features and to speculate the mechanisms involved in the release. Keywords: MCM41, amino groups, Cisplatin analogs, XRD, 29 Si { 1 H} CP-MAS NMR, controlled release. 1. INTRODUCTION Drug carriers play a critical role for the loading and the release of the drug. Promising frontiers is represented by a new class of innovative medicines based on directional transport vehicles "drug delivery" and consist of assembled structures carrier (nano)-drug. Silica-based materials, nontoxic, biocompatible, have been used as adjuvant and excipient in pharmaceutical technology. Within this class of compounds, mesoporous silica materials such as MCM41, SBA-15 and HMS have been investigated for medication and drug delivery due to their properties. The large surface area and pore volume, together with the nanoporous structure facilitate the control release of drugs. Many papers report the incorporation and the release of drugs and vitamins from MCM41 framework [1-5]. The resulting materials exhibit unique physicochemical properties determined by the state of the guest molecules, in addition to the nature of the mesoporous and its features (structure and pore size) and to the functional groups on the surface [6,7]. In fact, the functionalization with several kinds of molecules of the porous internal surface can influence the physical - chemical interactions between the mesoporous and the drug, thus controlling the delivery in terms of kinetics. In particular, the synthetic drug delivery systems have great potential to overcome the problems associated with systemic toxicity of chemotherapy, including treatment with platinum-based drugs [8]. For these reasons, some authors have reported the incorporation of the cisplatin in mesoporous compounds investigating the controlled release in vitro at human condition [9-14]. In the meantime, the discovery of successful candidates and strategies for the selective directionality of platinum drugs is a very active area of research. Novel platinum(II) complexes including nanotechnology applications and complexes containing heterocyclic ligands with N and S donor atoms are under study with the aim to reduce and overcome the toxicity of cisplatin and its analogues, and to decrease the nephrotoxicity of platinum complexes [15]. Recently, a new anticancer drug, the cis- [PtCl2(DMSO)HL]·2DMSO, where HL = 7-amino-2- (methylthio)[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylic acid, hereafter called complex (1), has been synthesized and tested by some of us [15]. The class of compounds of triazolopyrimidine shows antimicrobial and antitumor properties and can be used to study metal-ligand interaction in biological systems. The complex (1) exhibited a very marked biological activity on HepG2 hepatocarcinoma cells while under identical conditions it did not affect normal immortalized human liver cells (Chang Liver cells). The mechanism of anti-proliferative effect of the complex (1) on HepG2 was pro-apoptotic and the antiproliferative efficacy was twofold higher than that shown by cisplatin. In this work, due to the observed properties and the potential in the enhanced anticancer activity, the complex (1) has been incorporated in a mesoporous materials in order to obtain a controlled release system. Similar study on cisplatin analogues has not yet investigated to the best of our knowledge. Since many authors claim the importance of a proper support selection as a strategy to control the delivery of active molecules, making a correlation between textural properties and release kinetics, the Volume 6, Issue 6, 2016, 1621 - 1626 ISSN 2069-5837 Open Access Journal Received: 23.09.2016 / Revised: 20.10.2016 / Accepted: 30.10.2016 / Published on-line: 05.11.2016 Original Research Article Biointerface Research in Applied Chemistry www.BiointerfaceResearch.com