Determination of moxifloxacin in dried blood spots using LC–MS/MS and the impact of the hematocrit and blood volume

Abstract

a b s t r a c tMoxifloxacin (MFX) is a potential oral agent use in the treatment of multidrug-resistance tuberculosis (MDR-TB). Due to variability in pharmacokinetics and in vitro susceptibility of causative bacteria, therapeutic drug monitoring (TDM) of MFX is recommended. Conventional plasma sampling for TDM is facing logistical challenges, especially in limited resource areas, and dried blood spots (DBS) sampling may offer a chance to overcome this problem. The objective of this study was to develop a LC-MS/MS method for determination of MFX in dried blood spots (DBS) that is applicable for TDM. The influence of paper type, the hematocrit (Hct) and the blood volume per spot (V b ) on the estimated blood volume in a disc (V est ) was investigated. The extracts of 8 mm diameter discs punched out from DBS were analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS) with cyanoimipramin as internal standard. The method was validated with respect to selectivity, linearity, accuracy, precision, sensitivity, recovery and stability. The effect of Hct and V b on LC-MS/MS analytical result was also investigated. The relationship between MFX concentrations in venous and finger prick DBS and those in plasma was clinically explored. V est was highly influenced by Hct while the effect of V b appeared to be different among paper types. Calibration curves were linear in the range of 0.05-6.00 mg/L with inter-day and intra-day precisions and biases of less than 11.1%. The recovery was 84.5, 85.1 and 92.6% in response to blood concentration of 0.15, 2.50 and 5.00 mg/L, respectively. A matrix effect of less than 11.9% was observed. MFX in DBS was stable for at least 4 weeks at room condition (temperature of 25 • C and humidity of 50%). A large range of Hct value produced a significant analytical bias and it can be corrected with resulting DBS size. A good correlation between DBS and plasma concentrations was observed and comparable results between venous DBS and finger prick DBS was attained. This fully validated method is suitable for determination of MFX in dried blood spot and applicable for TDM.

Why Dried Blood Spots Are an Ideal Tool for CYP1A2 Phenotyping

“…Hct and blood volume had a considerable impact on the concentrations of caffeine and paraxanthine, similar to that described for several other small molecules [32][33][34][35]. The range in which the impact of Hct was evaluated, 0.20 -0.60, was considered to be relevant and sufficient, as it covers approximately 99.5% of a hospital population (including both 'normal' and 'critically ill' patients) [10].…”

Current status and opportunities for therapeutic drug monitoring in the treatment of tuberculosis

“…Hereafter, the dried blood sample is ready to be analyzed. [25] Blood concentrations of anti-TB drugs can be determined from the DBS using high performance liquid chromatography techniques coupled to mass spectrometry. [65,66] Allanson and colleagues were the first to examine the possibility of using DBS in the determination of the first-line anti-TB drug rifampicin in human plasma and blood spots.…”

Simultaneous Estimation of Moxifloxacin Hydrochloride and Dexamethasone Sodium Phosphate in Bulk and in Ophthalmic Solution by Rp- HPLC

“…In literature, several analytical methods such as RP-HPLC [3][4][5][6][7][8][9][10][11] , UPLC 12 and some hyphenated techniques such as LC/MS/MS 13 , LC-MS 14,15 have been reported for the determination of MOX single and in combination in biological fluids. Few RP-HPLC 16,17 , UV-Spectrophotometric, [18][19][20][21] and HPTLC 22,23 methods have been studied for determination of MOX in bulk and in pharmaceutical formulations.…”