Effect of particle morphology and pore size on the release kinetics of ephedrine from mesoporous MCM-41 materials Dua’a M. Marzouqa • Mohammad B. Zughul • Mutasem O. Taha • Hamdallah A. Hodali Published online: 4 December 2011 Ó Springer Science+Business Media, LLC 2011 Abstract Ephedrine was loaded onto siliceous mesopor- ous materials of different pore sizes, and the corresponding drug release into simulated body fluid at pH 7.4 and 37 °C was measured against time over a period of 72 h. The mesoporous materials designated MCM-41(C N ) were pre- pared at different pore sizes using a self-assembly mech- anism. The pore size was controlled by the use of alkyltrimethylammonium bromide (C N TAB) surfactants having different alkyl chain lengths (C 10 ,C 12 , and C 14 ). The three mesoporous materials showed good ephedrine- loading capacities from dry ethanolic solutions, which slightly increased with the pore size of MCM-41(C N ). From the drug release profiles, the overall release of ephedrine followed the order: MCM-41(C 12 ) [ MCM- 41(C 14 ) [ MCM-41(C 10 ), with the release of ephedrine attaining 92% of the drug load from MCM-41(C 12 ). Ephedrine release approached 60% of the drug load in 6 h and 92% in 20 h. The results of in vitro release kinetics indicate that pore size is not the only factor affecting ephedrine release, but also pore channel length and overall particle morphology. Keywords Drug delivery  Ephedrine  MCM-41  Mesoporous materials Abbreviations SBF Simulated body fluid C N TMB Alkyltrimethylammonium bromide MCM-41 Mobil crystalline material no. 41 DW Deionized water 1 Introduction The synthesis of a new family of silica-based mesoporous materials in the early nineties [1, 2], designated as MCM- 41 (Mobil Crystalline Material number 41), indicated a great potential for new applications involving relatively bulk molecules [3]. This class of mesporous materials possesses uniformly organized porous structures, which comprise hexagonally arranged channels having diameters between 1.5 and 10 nm [4]. These systems exhibit some favorable physical properties that have attracted the attention of scientists, including their highly ordered structures, very high specific surface areas, adaptability to pore size control, and moderate thermal and hydrothermal stabilities. With these unique features, members of MCM- 41 are regarded as good materials for hosting drug mole- cules of several sizes, shapes and functionalities, and are thus advocated for utilization as drug delivery vehicles [5]. Inorganic microporous and mesoporous materials based on clays and silica have shown adequate and, in some cases, favorable physical characteristics [5, 6]. Several research groups have utilized the highly ordered mesoporus material MCM-41 as a drug delivery system. Examples of the drugs that have been studied are: aspirin [7], atenolol [8], captopril [9], coumarin derivatives [10], diflunisal [11], hydrochlorothazide [12], ibuprofen [4, 5, 13–16], metho- trexate [17], naproxine [13], and sertraline hydrochloride D. M. Marzouqa  M. B. Zughul  H. A. Hodali (&) Department of Chemistry, Faculty of Sciences, University of Jordan, Amman 11942, Jordan e-mail: h-hodali@ju.edu.jo M. O. Taha Drug Discovery Unit, Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Jordan, Amman 11942, Jordan 123 J Porous Mater (2012) 19:825–833 DOI 10.1007/s10934-011-9537-y