Pharmacogenetic and Pharmacokinetic Assays from Saliva Samples Can Guarantee Personalized Drug Prescription

Abstract

Saliva is widely used for clinical and laboratory analysis. This study proposed to use DNA extracted from saliva for genotyping and pharmacokinetics of piroxicam. A fast and efficient genotyping method was used to determine relevant allelic variants of CYP2C9 (*2 and *3), since genetic factors can influence in non-steroidal anti-inflammatory drugs (NSAIDs) metabolization. DNA Extract All Reagents Kit® was used for DNA extraction and genotyping was performed using TaqMan® GTXpress™ Master Mix, SNP genotyping assays and a Viia7 Real-Time PCR system. Volunteers performed sequential collections of saliva samples before and after taking a single dose of piroxicam (0.25 to 72 h) which were used for pharmacokinetics assays. Piroxicam concentrations were analyzed using LC-MS/MS. Sixty-six percent of volunteers were ancestral homozygous (CYP2C9*1/*1), and 34% showed one or both polymorphisms. Of these 34%, 22 individuals showed CYP2C9*2 polymorphism, 8 CYP2C9*3, and 4 CYP2C9*2/*3. Piroxicam pharmacokinetics were performed in 5 subjects. Areas under the curve (AUC0-t(h*ng/mL)) for CYP2C9*1/*1, *1/*2 and *1/*3 were, respectively, 194.33±70.93, 166 and 303. Maximum concentrations (Cmax(ng/mL)) for these genotypes were respectively 6.46±2.56, 4.3 and 10.2. Saliva sampling was a very effective matrix for both pharmacogenetic and pharmacokinetic tests, ensuring the speed of the procedure and the well-being and agreement of the participants. Once having the knowledge about the slow and fast metabolizers, it is possible to make an adequate prescription in order to avoid the adverse effects of the medication and to guarantee greater analgesic comfort to the patients respectively.

Simultaneous separation of naproxen and 6-O-desmethylnaproxen metabolite in saliva samples by liquid chromatography-tandem mass spectrometry: Pharmacokinetic study of naproxen alone and associated with esomeprazol—Results

“…Both naproxen and 6-0-desmethylnaproxen are further metabolized to their respective metabolite conjugates with acylglucuronide [ 5 ]. Considering that naproxen is a drug that is highly protein bound (~99%), like most NSAIDs, we can observe that the proportionality of drug and metabolite concentrations found in each volunteer was maintained (on line resource), showing that the use of saliva samples for this experiment was successful [ 1 , 2 , 6 – 8 ]. The high adherence of volunteers, in addition to the ease of collecting saliva, encourages us to increasingly use this proposed methodology.…”

“…As with the concentrations of naproxen in saliva samples, the concentrations of its main metabolite, 6-O-desmethylnaproxen, are extremely low in this fluid (~1.9 μg/mL of naproxen and ~0.5 μg/mL of 6-O-desmethylnaproxen), demonstrating the need to use LC MS/MS for its detection [ 1 , 2 , 6 , 7 ]. Also showing that the extraction methodology used in this part of the research was quite effective.…”

Saliva Sampling in Therapeutic Drug Monitoring and Physiologically Based Pharmacokinetic Modeling: Review

“…The computational models of the PBPK approach can extend in predicting and better understanding the mechanistic change of drug response in different populations or disease cases based on saliva samplings [39,40]. Studies showed that sing saliva samples are a highly successful strategy for phar-macogenetics and pharmacokinetics studies [45]. Therefore, incorporating saliva samplings with PBPBK modelling may have potential in personalized medicine studies, which can optimize treatment and reduce the cost, time and resources.…”