ABSTRACT
Diclofenac is a nonsteroidal compound with analgesic, antiin ammatory, and antipyretic properties. It is a weak acid (pKa 4.0) used to relieve mild to moderate pain from injury, menstrual cramps, arthritis, and other musculoskeletal conditions. It is widely used because of its robust analgesic, antipyretic, and antiin ammatory effects (Kreilgaard, 2002; Lawrence and Rees, 2000; Steer et al., 2003), thus making it one of the most widely prescribed antiin ammatory drugs. The most common approaches to improving the solubility of drugs are the formation of salts (e.g., hydrochlorides, sulfates, nitrates, maleates, citrates, and tartarates) of the basic drugs possessing a net negative electrical charge and reduction of the particle size of the powdered drugs by new milling technologies or by applying new crystallization processes. Because of its poor solubility, short in vitro (shelf-life) and in vivo (half-life) stability, low bioavailability, and strong side effects, diclofenac delivery should be targeted. One approach to conquer these problems is to enfold the drug into a delivery service system. The integration of the drug into a delivery system can be envisaged to protect it against degradation in vitro as well as in vivo; the release can be controlled, and targeting can be achieved. Different colloidal systems were used as diclofenac delivery vehicles to improve its bioavailability (Beck et al., 2006; Cevc, 2004; Fanun, 2007a; Kantarci et al., 2005; Kreilgaard, 2002; Kweon et al.,
11.1 Introduction .......................................................................................................................... 271 11.2 Phase Behavior ..................................................................................................................... 273 11.3 Solubilization Capacity ......................................................................................................... 273
11.3.1 Alcohol-Free System ................................................................................................ 273 11.3.2 Systems with Alcohol as Cosurfactant ..................................................................... 275
11.4 Solubilization Evaluation ...................................................................................................... 277 11.4.1 Alcohol-Free System ................................................................................................ 277 11.4.2 Systems with Alcohol as Cosurfactant ..................................................................... 279
11.5 Electrical Conductivity of Drug-Loaded Microemulsions ................................................... 282 11.6 Dynamic Viscosity of Drug-Loaded Microemulsions .........................................................285 11.7 Microstructure of Drug-Loaded Microemulsions ................................................................287 11.8 Conclusions ........................................................................................................................... 295 Abbreviations ................................................................................................................................. 295 Symbols.......................................................................................................................................... 295 References ......................................................................................................................................296
