Physicochemical, pharmacokinetics, and histological evaluation of new naproxen-quercetin co-lyophilizate to diminish drug-induced gastric irritations in rats.

Quercetin (QUE) is a flavonoid found in several plants and commonly distributed in edible vegetables and fruits. To evaluate the effect of co-lyophilization of naproxen (NPX) with QUE at different weight ratios on physicochemical characteristics induced gastric irritation, and drug pharmacokinetics. NPX binary systems with QUE in different weight ratios were prepared by freeze-drying alkalinized solutions, and were characterized in terms of physicochemical properties as well as NPX dissolution rate in acidic pH. NPX-induced gastric inflammation studies were carried out in rats for 7 days. The pharmacokinetics of the two formulations were assessed to evaluate the bioavailability of NPX-QUE 1:2 co-lyophilizate. Westar rats were administered oral doses equivalent to 40 mg kg^-1 of NPX and blood samples were taken from the retro-orbital vein of rats at 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0 12.0, and 24.0 h post dosing. Co-lyophilization of NPX with QUE enhanced drug dissolution rate in the acidic medium, which was correlated with an increased QUE weight ratio in the co-lyophilizates. Rat stomachs from group V (NPX-QUE 1:2 co-lyophilizate) showed non-significant changes, and biopsies from this group showed no significant leukocyte infiltration and edema in the mucosa. The bioavailability of NPX-QUE 1: 2 co-lyophilizate was similar to the control sample. NPX-QUE 1: 2 co-lyophilizate could be an alternative to NPX in the treatment of arthritis as it minimizes the potential for gastric irritation and enhances safety while retaining the same efficacy and bioavailability.