Development and Validation of a Novel HPLC Method to Analyse Metabolic Reaction Products Catalysed by the CYP3A2 Isoform: In Vitro Inhibition of CYP3A2 Enzyme Activity by Aspirin (Drugs Often Used Together in COVID-19 Treatment)

Abstract

Aspirin (also known as acetylsalicylic acid) is a drug intended to treat fever, pain, or inflammation. Treatment of moderate to severe cases of COVID-19 using aspirin along with dexamethasone has gained major attention globally in recent times. Thus, the purpose of this study was to use High-Performance Liquid Chromatography (HPLC) to evaluate the in vitro inhibition of CYP3A2 enzyme activity using aspirin in rat liver microsomes (RLMs). In this study, an efficient and sensitive HPLC method was developed using a reversed phase C18 column (X Bridge 4.6 mm × 150 mm, 3.5 µm) at 243 nm using acetonitrile and water (70:30 v/v). The linearity (r2 > 0.999), precision (<15%), accuracy and recovery (80–120%), limit of detection (5.60 µM and 0.06 µM), limit of quantification (16.98 µM and 0.19 µM), and stability of the newly developed method were validated for dexamethasone and 6β-hydroxydexamethasone, respectively, following International Conference on Harmonization (ICH) guidelines. This method was applied in vitro to measure CYP3A2 activity. The results showed that aspirin competitively inhibits 6β-hydroxylation (CYP3A2 activity) with an inhibition constant (Ki) = 95.46 µM and the concentration of the inhibitor causing 50% inhibition of original enzyme activity (IC50) = 190.92 µM. This indicated that there is a minimal risk of toxicity when dexamethasone and aspirin are co-administrated and a very low risk of toxicity and drug interaction with drugs that are a substrate for CYP3A2 in healthcare settings.

Potential Effects of Ibuprofen, Remdesivir and Omeprazole on Dexamethasone Metabolism in Control Sprague Dawley Male Rat Liver Microsomes (Drugs Often Used Together Alongside COVID-19 Treatment)

“…The optimised incubation time was 40 min [ 17 ]. For optimisation of substrate concentration, a series of dexamethasone concentrations (10–200 µM) was added to the incubation system in vitro.…”

“…A compound with an IC 50 value below 1 µM is considered to be a strong inhibitor, and it is considered to be a weak inhibitor if the IC 50 value is more than 50 µM [ 17 ]. Thus, the high values of IC 50 of remdesivir in rat liver microsomes would have a low potential of drug interaction and in causing toxicity involving CYP enzymes.…”

“…There are no data relating to the effects of ibuprofen, remdesivir, and omeprazole on dexamethasone metabolism (CYP3A2 activity). Our previous study showed that aspirin exhibits a weak competitive inhibition of CYP3A2 isoenzyme activity and has little potential to cause drug–drug toxicity [ 17 ].…”