Quercetin-phospholipid complex: an amorphous pharmaceutical system in herbal drug delivery

Development of amphiphilic drug-lipid complexes is a potential approach for improving therapeutic efficacy of the drugs by increasing solubility, release profile and oral bioavailability. Quercetin (3, 3', 4', 5, 7-pentahydroxyflavone), a polyphenolic flavonoid, shows several biological effects like anti-inflammatory, anti-cancer, antiproliferative, antimutagenic and apoptosis induction but its use is limited due to its low aqueous solubility. To overcome this limitation, a value added phospholipid complex of quercetin was developed to improve its aqueous solubility for better absorption through the gastrointestinal tract and this might result in improved bioavailability. The quercetin-phospholipid complex thus prepared was evaluated for various physico-chemical parameters like infra red spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD), scanning electron microscopy (SEM) and solubility study. The In vitro antioxidant activity was also studied. The phospholipid complex of quercetin was found to be fluffy and porous with rough surface in SEM. FTIR, DSC and XRPD data confirmed the formation of phospholipid complex. The water solubility of quercetin was improved by 12 folds (from 3.44 μg/ ml to 36.81 μg/ ml) in the prepared complex. There was no statistical difference between the quercetin complex and quercetin in the In vitro anti-oxidant activity, indicating that the process of complexation did not adversely affect the bioactivity of the active ingredient.