Pharmacokinetics of Piroxicam Pharmaceutical Forms: An Experimental Study

Abstract

Research into new ways to administer medications within the body remains relevant. The study aims to analyze the particularities of piroxicam kinetics in zein-pectin complexes during ex vivo experiments in a medium simulating the gastrointestinal tract of laboratory rats. Studies were performed in 2019 with 30 laboratory Wistar rats. During 3 days, rats received 2.5 ml of 2% pectin solution per day. The ratio between pectin and zein was 3:1. Rats were mortified, and their intestines were then dissected into 3-cm fragments. The obtained samples were placed in containers with 5 ml of saline phosphate buffer solution (solution pH = 6.4). Gastrointestinal contents and pectin apple and citrus complexes with low methylation were incubated to study the kinetics of piroxicam. Pectin complexes varied in dry carrier mass: the citrus complex was 1.3 times greater than the apple complex (pd”0.05). It was also observed that the release time of 50% of the volume of piroxicam was 1.3 times faster for the citrus complex (pd”0.05) than for the apple complex. In terms of swelling index, citrus complexes were 1.9 times larger than apple complexes (pd”0.01). Citrus complexes contained a lower concentration of piroxicam (1.3 times, pd”0.05) relative to apple complexes. The longterm effect of piroxicam release from pectin complexes was established during the experiment. This is likely due to the slow swelling of the ion part of the polymer mesh under hydrophobic solution conditions. The latter was represented in the experiment by the phosphate buffer and the content of the gastrointestinal tract. The limiting factor that influenced the release kinetics of piroxicam from pectin complexes is its diffusion process from the pectin complex. A high correlation was observed between the 50% piroxicam release and the square root of time in both complexes (0.98). Apple pectin was 3.0 times larger than the constant (p d”0.01). The kinetics analysis demonstrated their linear directionality over approximately 40 hours.