Pharmacological activity of ibuprofen released from mesoporous silica Y. Lang • D. P. Finn • A. Pandit • P. J. Walsh Received: 21 July 2011 / Accepted: 5 November 2011 / Published online: 22 November 2011 Ó Springer Science+Business Media, LLC 2011 Abstract Novel drug delivery systems (DDS) to improve the pharmacokinetic profile of hydrophobic drugs follow- ing oral administration are an area of keen interest in drug research. An ideal DDS should not adversely affect drug activity, be capable of delivering a therapeutic dose of drug, and allow homogenous drug loading and drug release. Mesoporous silica has been proposed for this application, with ibuprofen employed as the model drug. It was hypothesised that mesoporous silica MCM-41 is capable of delivering a pharmacologically therapeutic dose of ibuprofen. Ibuprofen-loaded MCM-41 can be prepared reproducibly at a drug to carrier ratio of 30% (wt/wt). The release profile was seen to be 90% within 2 h. Initial assessment of COX-1 inhibitory activity suggests the absence of adverse effects attributable to drug-carrier interaction. The results of this study provide further evi- dence in support of the proposed use of mesoporous silica in drug delivery. 1 Introduction Biomedical applications of mesoporous materials includ- ing both systemic and implantable drug delivery are currently being investigated. One such material is meso- porous silica (MS), first reported in 2001 as a potential candidate for drug delivery using MS MCM-41 (MCM- 41) with ibuprofen as the model drug [1]. Since this initial report, there has been extensive research into many forms of MS as a drug delivery system (DDS) with the majority of papers investigating ibuprofen as the drug of interest [2, 3]. Other drugs that have been studied include vancomycin [4], gentamicin [5], famotidine [6], and itr- aconazole [7]. The degree of drug loading is dependent on many fac- tors including pore size [8, 9], loading procedure and sol- vent used [10], and drug to carrier ratio [11]. However, there is high variation in the degree of drug loading (11–41% wt/wt) reported [1, 8–11]. It is evident that there is a need to develop a procedure that will yield a repro- ducible degree of drug loading, such that a known thera- peutic dose of ibuprofen can be administered reliably and consistently from the MCM-41 matrix. A fundamental property of any carrier system is its ability to release the drug in its active form in vivo. Fur- thermore, it is important that any procedure required to load a drug within a DDS must not interfere with the activity of the drug. To date no studies investigating the activity of ibuprofen upon release from MCM-41 have been published. We hypothesise that ibuprofen can be reproducibly and homogenously loaded into MCM-41 without adversely affecting the activity of ibuprofen. This is the first study to examine ibuprofen drug activity after release from MCM-41. Y. Lang (&)  A. Pandit  P. J. Walsh Network of Excellence for Functional Biomaterials, National University of Ireland, Galway, Ireland e-mail: y.lang1@nuigalway.ie Y. Lang  D. P. Finn Department of Pharmacology and Therapeutics, National University of Ireland, Galway, Ireland Y. Lang  D. P. Finn Centre for Pain Research, National University of Ireland, Galway, Ireland P. J. Walsh School of Biological Sciences, Queen’s University, Belfast BT9 7BL, Northern Ireland, UK 123 J Mater Sci: Mater Med (2012) 23:73–80 DOI 10.1007/s10856-011-4488-z