International Journal of Pharmaceutics 242 (2002) 191 – 195 Note The effects of pressure and direct compression on tabletting of microsponges Tansel C ¸ omoglu, Nurs ¸in Go ¨nu ¨ l *, Tamer Baykara Department of Pharmaceutical Technology, Faculty of Pharmacy, Ankara Uniersity, 06100 Tandog ˘an, Ankara, Turkey Received 22 October 2001; received in revised form 25 November 2001; accepted 26 November 2001 Abstract Microsponges are porous, polymeric microspheres that are used mostly for topical and recently for oral administration. Ketoprofen was used as a model drug for systemic drug delivery of microsponges in the study. Ketoprofen microsponges were prepared by quasi-emulsion solvent diffusion method with Eudragit RS 100 and afterwards tablets of microsponges were prepared by direct compression method. Different pressure values were applied to the tablet powder mass in order to determine the optimum pressure value for compression of the tablets. Results indicated that microsponge compressibility was much improved over the physical mixture of the drug and polymer and owing to the plastic deformation of sponge-like structure, microsponges produce mechanically strong tablets. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Microsponges; Modified release; Ketoprofen; Direct compression www.elsevier.com/locate/ijpharm Ketoprofen [2-(3-benzoylphenyl) propionic acid] is a non-steroidal anti-inflammatory (NSAI) drug which has been widely used in clinical prac- tice. Following oral administration of regular re- lease preparations, ketoprofen is rapidly absorbed with peak concentrations occuring between 0.5 and 2 h after the dose and it has a short half life in plasma about 1–3 h (Borsa et al., 1983; Dennis et al., 1985; Oka and Aoshima, 1985; McCrea et al., 1986; Ollagnier et al., 1987; Foster et al., 1988; Jamali and Brocks, 1990). Ketoprofen causes gas- trointestinal (GI) side effects like other NSAI drugs (Thomas and Kantar, 1986). The present study was designed to improve ketoprofen’s phar- macokinetic properties and reduce GI side effects by means of microsponge system. In the first step, microsponges of ketoprofen were prepared and in the second step, the effects of pressure on the compressibility of the microsponges were investi- Table 1 Composition of microsponges Internal phase External phase 200 ml Ketoprofen Distilled water 0.288 g/ml Ethyl alcohol 10 ml Eudragit RS 100 0.2 g/ml PVA 0.096 g/ml 0.0192 g/ml TEC * Corresponding author. Fax: +90-312-212-71-28 E-mail address: tcomoglu@hotmail.com (N. Go ¨nu ¨ l). 0378-5173/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved. PII:S0378-5173(02)00155-2