Preparation, therapeutic evaluation and pharmacokinetic study of quercetin-phospholipid complex in rats

The dissolution and bioavailability studies are influenced by the biopharmaceutical properties and potency which together contribute to the clinical efficacy of the drugs. In the present study phyto-phospholipid complex was prepared in order to enhance the delivery of poorly soluble quercetin (QT). The preparation of quercetin-phospholipid complex (QPC) was done and investigated for various physico- Parameters using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), aqueous/ n-octanol solubility and dissolution study. The investigation of antidiabetic activity by OGTT in normoglycemic and diabetic rats for QT and QPC at different time intervals was carried out along with the effect of QT and QPC (50 and 100 mg/kg b.w. p.o. respectively) in STZ induced diabetic rats for single day and fifteen days was studied. This is followed by estimation of serum glucose (SG) and lipid parameters. In order to support the above fact the histopathology studies of pancreatic tissue and bioavailability studies of QT & QPC were also studied. SEM photographs of QPC was found fluffy and porous with rough surface morphology. FTIR, DSC and SEM data confirmed the formation of phospholipid complex. The solubility of QT and QPC was improved in water/ n-octanol. The antidiabetic studies indicated that, the bioactivity of QT was maintained even after being complexed with the phospholipid. The SG levels were significantly reduced and also the altered lipid parameters were restored after the treatment of QPC (50 mg/kg b.w. p.o). Histopathological studies revealed that QPC also restored back the size of pancreatic islets and maintained the normal β-cells. Bioavailability and pharmacokinetic studies confirmed that QPC can produce better therapeutic effect in rats and stayed for longer period of time as compared to free QT through sustained release property followed by decreasing the rate of elimination.