Development of HPLC Method for the Determination of Buspirone in Rat Plasma Using Fluorescence Detection and Its Application to a Pharmacokinetic Study

Abstract

A simple and sensitive analytical method for the quantitative determination of buspirone in rat plasma by HPLC with fluorescence detection was developed and validated using naproxen as an internal standard. A relatively small-volume (150 µL) aliquot of rat plasma sample was prepared by a simple deproteinization procedure using acetonitrile as a precipitating organic solvent. Chromatographic separation was performed using Kinetex ® C8 column with an isocratic mobile phase consisting of acetonitrile and 10-mM potassium phosphate buffer (pH 6.0) at a flow rate of 1.0 mL/min. The eluent was monitored by fluorescence detector at a wavelength pair of 237/380 nm (excitation/emission). The linearity was established at 20.0-5000 ng/ mL, and the limit of detection was 6.51 ng/mL. The precision (≤14.6%), accuracy (89.2-108%), and stability (89.1-101%) were within acceptable ranges. The newly developed method was successfully applied to intravenous and oral pharmacokinetic studies of buspirone in rats.Key words buspirone; HPLC; fluorescence detection; rat plasma; pharmacokinetics [4,5] decane-7,9-dione), an azapirone, is an antianxiety agent that has dopaminergic, noradrenergic, and serotonin-modulating activity.1) It is chemically unrelated to benzodiazepines or barbiturates, and it exerts a pharmacologically unique anxiolytic effect without sedative, muscle relaxant, and anticonvulsant properties.2,3) Oral buspirone formulation (e.g., Buspar ® ) is currently used in the treatment of anxiety disorders and the short-term relief of the symptoms of anxiety. 4) Orally administered buspirone is rapidly absorbed but it undergoes first-pass metabolism, resulting in a low bioavailability of less than 5%. 5,6) Buspirone is metabolized primarily by CYP450 3A4-mediated oxidation. 7,8) However, little information is available regarding important pharmacokinetic issues that include the exact reason for the low bioavailability, kinetics of organ clearance, and mechanisms of elimination of buspirone in animals or humans.9) Therefore, development of analytical tools for quantification of buspirone in various biological fluids will contribute to the progress of mechanistic pharmacokinetic and pharmacological studies of buspirone in a pre-clinical or clinical setting.A few analytical methods have been reported for the determination of buspirone in human plasma by HPLC with ultraviolet spectrophotometry (UV) method 2) and HPLC with tandem mass spectrometry (HPLC-MS/MS) method, 8,10) and in rabbit serum by HPLC-UV method.5) However, these methods have several limitations such as a relatively large sample volume (i.e., 500 µL) and costly and/or laborious sample preparation procedures that include a liquid-liquid or solid phase extraction. Moreover, mass spectrometry requires relatively expensive equipment and highly skilled technical expertise, which may not always be feasible for most laboratories in resource-limited settings.11) Previously, we reported the plasma concentration versus time profiles of buspirone in rats using a HPLC-UV method ...

Differential regulation of intestinal and hepatic CYP3A by 1α,25‐dihydroxyvitamin D3: Effects on in vivo oral absorption and disposition of buspirone in rats

“…To investigate the effects of 1,25(OH) 2 D 3 on the in vivo fate of a CYP3A substrate drug in biological systems, we selected buspirone, an anxiolytic drug, that is metabolized primarily via the rat and human CYP3A subfamily (Kim et al, ). The intravenous and oral doses of buspirone were selected based on our previous studies (Kim et al, ; Kim, Cho, Kim, Kim, & Yoon, ).…”

“…The F of a drug depends on the fraction absorbed ( F abs ), intestinal first‐pass extraction ratio ( E G ), and hepatic first‐pass extraction ratio ( E H ), that is, F = F abs × (1 − E G ) × (1 − E H ) (Cho, Kim, Kim, & Yoon, ). Although the exact mechanism of the low F of buspirone in rats and humans remains unclear, buspirone administered orally is believed to undergo extensive first‐pass metabolism in humans (Kim et al, ). In particular, previous studies have reported the markedly high E G of buspirone in humans, which was calculated to be 0.89 according to the grape fruit juice (GFJ) method (Gertz, Davis, Harrison, Houston, & Galetin, ) and 0.78 according to the drug–drug interaction (DDI) method (Hisaka, Nakamura, Tsukihashi, Koh, & Suzuki, ; Xie, Ding, & Zhang, ).…”

“…The concentrations of buspirone in the plasma samples were determined according to a method reported previously with slight modifications (Kim et al, ). A 150‐μL microsomal sample was deproteinized using 500‐μL acetonitrile containing IS (naproxen, 0.1 μg/mL).…”

“…Buspirone is primarily prescribed for the treatment of generalized anxiety disorder and also commonly used as an effective augmentation agent in the treatment of major depressive disorder (Howland, ; Kim et al, ). Recently, several studies have reported that psychiatric disorders such as anxiety and depression are associated with reduced serum vitamin D levels, and that vitamin D supplements can improve mood (anxiety and depression) and mental health status (Bicikova et al, ; Penckofer et al, ; Pu et al, ).…”

In Vitro and In Vivo Assessment of Metabolic Drug Interaction Potential of Dutasteride with Ketoconazole

“…Moreover, LC-MS/MS systems require high instrumentation and maintenance expenses, which may not be affordable for many institutions in resource-limited conditions [10,11]. In this regard, HPLC with fluorescence detection (HPLC-FL) methods can be a good alternative, because they are more accessible and cost effective than LC-MS/MS systems, and they generally offer better sensitivity and selectivity than HPLC-UV systems [12,13]. Additionally, the blood levels of H-DUT, the major active metabolite, need to be monitored together with those of DUT [6].…”