Research Article Volume 26 Issue 2 (2015) 94 Indonesian J. Pharm. Vol. 26 No. 2 : 94 – 102 ISSN-p : 2338-9427 DOI: 10.14499/indonesianjpharm26iss2pp94 IN VITRO RELEASE MODELING OF ASPIRIN FLOATING TABLETS USING DDSOLVER Agus Siswanto 1,2 , Achmad Fudholi 1* , Akhmad Kharis Nugroho 1 , Sudibyo Martono 1 1 Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara Jogjakarta 55281, Indonesia 2 Faculty of Pharmacy, Muhammadiyah University of Purwokerto, Jl. Raya Dukuh Waluh Purwokerto 53142, Indonesia Submitted: 14-01-2015 Revised: 10-02-2015 Accepted: 25-03-2015 *Corresponding author Achmad Fudholi Email: fudholiugm@yahoo.com ABSTRACT Aspirin has low solubility in water therefore, dissolution is a rate limiting step for absorption. Floating tablet formulation is designed to improve the bioavailability of aspirin. The objective of this study was to determine in vitro dissolution study of aspirin floating tablet release kinetics model. The floating tablets were prepared by a direct compression method using Methocel K4M CR, NaHCO 3 , Ethocel, Aerosil, and dicalcium phosphate anhydrous as excipients. Tablets were evaluated by different parameters such as physicochemical properties, floating lag time (F lag time ), total floating time, and dissolution. The result showed that the tablet mass has good flow properties of 13.54 g/sec. Aspirin floating tablets had a weight uniformity (CV=1.45%), good hardness (6.42kg), and low friability (0.158%). The tablet has a short F lag time of 25.16 sec and long floating time of 8 hours. Dissolution data were evaluated using DDSolver conducted by (1) Statistical parameters: R 2 adjusted , AIC, MSC; (2) Visual goodness of fit (GOF). The results showed that aspirin floating tablets release kinetics followed the Korsmeyer-Peppas model. Aspirin release occurs through the mechanism of anomalous transport which combines Fickian diffusion and polymer relaxation. Key words: aspirin floating tablet, DDSolver, modeling of drug release INTRODUCTION Aspirin is used as an antiplatelet for stroke prophylaxis (Laurer, 2002; Awtry and Loscalzo, 2000; Patrono and Rocca, 2008). Aspirin prevents blood from clotting by inhibiting cyclooxygenase, the enzyme responsible for the formation of thromboxane A2, which is a mediator of platelet aggregating (Kannan et al., 2010; Awtry and Loscalzo, 2000). Aspirin has a low bioavailability due to first-pass effect and hydrolysis to salicylate metabolism in the gut wall (Sweetman, 2009). Aspirin is rapidly absorbed in the upper gastrointestinal tract, especially in the portion of the small intestine (Awtry and Loscalzo, 2000; Sweetman, 2009). Therefore, formulation of floating drug delivery system (floating on the gastric fluid) are designed to improve the bioavailability of aspirin (Suratri, 2008). Aspirin has low solubility in water (1:300) (Moffat et al., 2011; Sweetman, 2009) therefore, dissolution is one of the rate limiting step in their absorption and bioavailability (Gordon et al., 1994; Wells, 2002). Information on the mechanisms and kinetics of dissolution is important to estimate the absorption of aspirin floating tablet. Several mathematical models were developed to analyze dissolution data such as the zero-order, first-order, Higuchi, Weibull, Korsmeyer-Peppas, Hixson- Crowell, Baker-Lonsdale, and Hopfenberg. The nonlinear fitting of dissolution data can be performed using a professional statistical programs such as Micro-Math Scientist, GraphPad Prism, SigmaPlot, or SYSTAT. However, these programs require the user to define the equations manually and need the initial value for each parameter (Zhang et al., 2010). DDSolver is a new software developed for the kinetic analysis of dissolution data (Murtaza et al., 2012) with a non-linear regression approach. DDSolver is a menu- driven add-in program for Microsoft Excel written in Visual Basic for Applications. Calculation using Excel offers a number of advantages over other software. The most attractive of advantages is the easy of use. Most scientists are already familiar with Excel because of its wide availability