Pharmacokinetics of oxycodone in rats: Influence of micronized magnesium lactate on oxycodone bioavailability.

This article presents studies on the pharmacokinetics of oxycodone hydrochloride and the influence of micronized magnesium lactate on its bioavailability and pharmacokinetic parameters. Two methods, HPLC-DAD, and HPLC-MS/MS, were developed and validated to investigate the content of oxycodone hydrochloride in the developed medicinal products and, oxymorphone in blood serum using an isotopic dilution method. The aim was to develop a novel pharmaceutical formulation combining oxycodone hydrochloride with Mg2+, which could increase the efficacy of analgesia while reducing the opioid dose. Experiments were conducted on Wistar rats, analyzing the changes in plasma concentrations of oxycodone hydrochloride and its metabolite oxymorphone after intragastric administration of two formulations: one containing oxycodone hydrochloride alone and the other with the addition of micronized magnesium lactate. The results indicate that the presence of Mg2+ decrease the bioavailability of oxycodone, which is related to chemical reactions between the formulation components. This phenomenon has been overlooked by other researchers determining the interaction of Mg2+ with opioids in enhancing the antinociceptive effect of opioids.