Research Paper Development and Characterization of Aspirin-Phospholipid Complex for Improved Drug Delivery A. Semalty * , M. Semalty, D. Singh and M.S.M. Rawat H.N.B. Garhwal University, Srinagar, India. ABSTRACT: Aspirin (acetylsalicylic acid) is one of the most widely used analgesic. Aspirin is poorly soluble in water and causes gastrointestinal (GI) irritation. To improve the solubility (and hence the bioavailability) and minimize the GI irritation, its complexes with soya-phospholipid-80 % (in 1: 1 molar ratio) were prepared in an organic solvent and evaluated for solubility, drug content, scanning electron microscopy (SEM), FT-IR spectra, X ray diffraction, differential scanning calorimetry (DSC) and in vitro dissolution study. Aspirin-phospholipid complex were found to be disc shaped with rough surface in SEM. Drug content in the complex was found to be 95.6 %. DSC thermograms, XRD and FTIR confirmed the formation of phospholipid complex. Solubility of the prepared complex was found to be improved. Aspirin complex and aspirin showed 90.93 % and 69.42 % of drug release at the end of 10 h in dissolution study in pH 1.2 acid buffer. It was concluded that the phospholipid complex of aspirin may be of potential use for improving the solubility of aspirin and hence its bioavailability. The complexes may also reduce GI toxicity of the drug. KEYWORDS: Pharmacosomes; Phospholipids complex; Aspirin; NSAIDs Introduction Aspirin (acetylsalicylic acid, ASA) is one of the most widely used therapeutic substances due to its analgesic, antipyretic and anti-inflammatory properties. Despite the proliferation in development of new non-steroidal anti- inflammatory drugs (NSAIDs), ASA remains one of the most effective ‘over-the-counter’ drugs in the treatment of rheumatic diseases. Furthermore, due to its anti-thrombotic properties, ASA is now prescribed at low doses in the prevention and treatment of cardiovascular diseases, strokes and disorders associated with platelet aggregability (Van and Botting, 1992). ASA use is commonly associated with gastrointestinal (GI) side-effects ranging from dyspeptic symptoms and ulceration to life-threatening episodes of bleeding (Hollander, 1994). ASA is poorly soluble in the acidic conditions of the stomach, which can delay absorption of high doses for 8 to 24 hours. Modifying the water solubility of aspirin may prove to be beneficial for improving its absorption. The rate of release of a drug is a function of its intrinsic solubility and influenced by particle size, crystallinity, drug derivatization and formation of more-soluble complexes (Leuner and Dressmann, 2002; Rabinow, 2004 ; Patravale et al.. 2004; Kesisoglon et al. 2007; Nijlen 2003; Nokhodchi, 2005). Various approaches have been investigated to improve the absorption and permeation of biologically active constituents of synthetic and natural origin. These include, development of more soluble pro- drug, solid dispersions, preparing complexes with complexing agents like metals, cyclodextrin and phospholipids. Apart from other methods used for modifying the solubility, the complexation with phospholipids have been found to show improvement in both, absorption as well as permeation of the active constituents (Semalty et al., 2009a; Semalty et al., 2009b). Phospholipids (like phosphatidylcholine) play a major role in drug delivery due to its amphiphilic nature, that can modify the rate of drug release for the enhancement of drug absorption across biological barriers. Developing of amphiphilic drug-lipid complexes or pharmacosomes may prove to be a potential approach for improving therapeutic efficacy of the drugs by improving the bioavailability (through improvement in solubility in GI fluid and permeation across the biomembranes). Any drug possessing an active hydrogen atom (-COOH, -OH, -NH2, etc.) can be esterified to the lipid, with or without spacer chain. Synthesis of such compound may be guided in such International Journal of Pharmaceutical Sciences and Nanotechnology Volume 3 • Issue 2 • July - September 2010 * For correspondence: A. Semalty, E-mail: semaltyajay@gmail.com 940