液质联用检测人体血浆中的阿奇霉素

采用高效液相色谱串联质谱技术(HPLC-MS/MS)测定人体血浆中阿奇霉素的浓度. 选用Lichrospher CN 柱, 流动相为V(乙腈)∶V(水)=40∶60(水中含体积分数为0.1%的甲酸和质量分数为0.1%的醋酸铵), 电喷雾离子源正离子方式检测. 该方法在2.34~600 ng/mL范围内线性关系良好, 定量下限为2.34 ng/mL(S/N>10), 回收率94.13%~97.42%, 基质效应92.50%~107.87%, 日内和日间测定药物浓度的相对标准偏差(RSD)均小于10.0%. 用该方法测定了24名男性健康志愿者单剂量口服500 mg阿奇霉素试剂和参比制剂于192 h内的血药浓度, 并进行了生物等效性研究.     

Recent advances in clinical microdialysis

Clinical microdialysis (MD) is a minimally invasive sampling technique that offers selective in-vivo measurement of free, active drug or biomolecule concentrations in human tissues and organs. From a regulatory perspective, MD can thus be seen as a suitable scientific tool that meets regulatory requirements for the study of tissue distribution or bioequivalence during drug development. From a clinical perspective, the use of MD in different applications has shown the potential to rationalize drug-dosing regimens and to influence clinical decision-making, although validation and correlation of MD-derived results with clinical response are required to promote routine clinical use of the technique. From an analytical perspective, highly sensitive analytical systems have increasingly become available for MD-sample analysis, and these have further improved the quality and the power of MD-derived information. Given the constant development in recent years, MD data might become an important part of new drug submissions and clinical treatment algorithms, and might positively influence patient benefit in the future.     

Bioequivalence evaluation of Florfenicol pharmaceutics in pigs using liquid chromatography-tandem mass spectrometry

The bioequivalence of two Florfenicol (FF) products in pigs was evaluated. A 2?×?2 crossover trial with a 14 days wash-out period was performed. The pigs were orally administered in a single dose (2?mg/kg b.w of FF). Serum samples were analyzed using a liquid chromatography-tandem mass spectrometry method. The limit of quantification was 0.1?ng/mL, and the calibration range was 1.0–100.0?ng/mL. Furthermore, intraday and interday were 5.43–9.09% and 6.23–9.68%, respectively. The areas under the curve (AUC_0–48) for the test product B of FF and reference product A were 7289.61?±?1750.44 and 6545.01?±?2766.25?h?×?ng/mL, respectively. The highest concentrations of FF in the serum (C_max) were 726.05?±?211.77 and 641.97?±?117.94?ng/mL. The mean retention times (MRT) was 7.91?±?1.98 and 7.76?±?2.89?h while the half-lives (T_1/2) were 4.07?±?1.71 and 4.99?±?3.30?h. From the analysis of variance results, the p values of C_max and AUC_0–∞ for the 90% confidence interval were 0.492 and 0.320 (p?>?0.05), respectively. A comparison between the test product and the reference product showed no significant difference. Both products showed bioequivalence after being administered in pigs.     

Quantification of piperazine phosphate in human plasma by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry employing precolumn derivatization with dansyl chloride

This paper describes a novel method that combines dansyl chloride (DNS-CL) derivatization with high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS) for the sensitive and selective determination of piperazine phosphate in human plasma. After addition of ondansetron hydrochloride as internal standard (IS), piperazine phosphate was derivatized and then extracted with ethyl acetate. After being evaporated and reconstituted, the sample was analyzed using LC-ESI/MS/MS. Separation was achieved using an Agilent ZORBAX SB-C₁₈ (150 mm × 2.1 mm I.D., 3.5 μm) column and isocratic elution with 10 mM ammonium acetate solution (pH 3.0)-methanol (50: 50, v/v). Detection was performed on a triple-quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operating in positive ion and selected reaction monitoring (SRM) mode with the precursor to product ion transitions m/z 320 → 171 for DNS-CL-piperazine phosphate and m/z 294 → 170 for the IS. The method was fully validated for its selectivity, sensitivity, linearity, precision, accuracy, recovery, matrix effect and stability. The coefficient (r) of piperazine phosphate with a linear range of 0.1-15 μg mL⁻¹ was 0.9974-0.9995. The limit of detection and lower limit of quantification in human plasma were 0.01 and 0.1 μg mL⁻¹, respectively. The validated LC-ESI/MS/MS method has been successfully applied to a bioequivalence study of piperazine phosphate trochiscus in Chinese healthy male volunteers.     

Development of a high-throughput method for the determination of itraconazole and its hydroxy metabolite in human plasma, employing automated liquid–liquid extraction based on 96-well format plates and LC/MS/MS

A semi-automated liquid chromatography–tandem mass spectrometry (LC/MS/MS) method was developed for the simultaneous quantification of the antifungal drug itraconazole (ITZ) and its coactive metabolite hydroxyitraconazole (OH-ITZ) in human plasma. The plasma samples underwent liquid–liquid extraction (LLE) in 2.2 mL 96 deepwell plates. ITZ, OH-ITZ and the internal standard (IS) R51012 were extracted from plasma, using a mixture of acetonitrile (ACN) and methyl t-butyl ether (MTBE) as the organic solvent. This specific mixture, due to its composition, had a significant impact on the performance of the assay. All liquid transfer steps, including preparation of calibration standards and quality control samples as well as the addition of the IS, were performed automatically using robotic liquid handling workstations for parallel sample processing. After vortexing, centrifugation and freezing, the supernatant organic solvent was evaporated. The analytes and IS were dissolved in a small volume of a reconstitution solution, an aliquot of which was analyzed by combined reversed phase LC/MS/MS, with positive ion electrospray ionization and a TurboIonSpray interface, using multiple reactions monitoring (MRM). The method was shown to be sensitive and specific to both ITZ and OH-ITZ, it revealed excellent linearity for the range of concentrations 2–500 ng mL⁻¹ for ITZ and 4–1000 ng mL⁻¹ for OH-ITZ, it was very accurate and it gave very good inter- and intra-day precisions. The proposed high-throughput method was employed in a bioequivalence study after per os administration of two 100 mg tablets of ITZ, and it allowed this study to be completed in under four days.     

Analysis of carbamazepine and its active metabolite, carbamazepine-10,11-epoxide, in human plasma using high-performance liquid chromatography

A sensitive method based on high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection was developed for the determination of carbamazepine (CBZ) and one of its active metabolites, carbamazepine-10,11-epoxide (CBZ-E) in human plasma. CBZ, CBZ-E and the internal standard (IS) 10,11-dihydrocarbamazepine were extracted from human plasma into methyl tert-butyl ether. CBZ, CBZ-E and the IS were successfully separated on an RP C18 column with a mobile phase of acetonitrile:methanol:water (18:19:63, v/v/v) and monitored via UV detection at 210 nm. The calibration curves were linear over the concentration ranges of 0.01–10 μg/mL for CBZ and 0.005–5 μg/mL for CBZ-E in human plasma, respectively. The method displayed excellent sensitivity, precision and accuracy, and was successfully applied to the quantification of CBZ and CBZ-E in human plasma after oral administration of a single 200 mg CBZ CR tablet. This method is suitable for bioequivalence studies following single doses given to healthy volunteers.     

Liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry for Simultaneous Determination of Metformin and Glimepiride in Beagle Dog Plasma and Bioequivalence Study

A sensitive and selective liquid chromatography-electrospray ionization tandem mass spectrometry(LCESI- MS/MS) was used for the simultaneous determination of metformin and glimepiride in beagle dog plasma with glipizide as internal standard(IS). After simplified protein precipitation with methanol, both the analytes and IS were chromatographed on a Zorbax CN column via gradient elution with methanol(containing 5 mmol/L ammonium acetate) and 5 mmol/L aqueous ammonium acetate as the mobile phase. Detection was performed by multiple reaction monitoring(MRM) scanning via ESI source operated in positive ionization mode. Specificity, linearity, accuracy, precision, recovery, matrix effect and stability were validated for metformin and glimepiride in beagle dog plasma. The calibration curves were linear in a concentration range of 10―10000 ng/mL for metformin and 4―4000 ng/mL for glimepiride with both correlation coefficients higher than 0.99. The recoveries obtained for the analytes and IS were all between 82.7% and 101.2%. The method exhibited excellent performance in terms of selectivity, robustness, short analytical time and simplicity of sample preparation. Finally, the proposed method was applied to a bioequivalence study of self-made bilayer tablet and commercial formulation containing 500 mg of metformin and 1 mg of glimepiride in beagle dogs.     

Rapid high-performance liquid chromatography-tandem mass spectrometry method for determination of pentoxifylline and its active metabolites M1 and M5 in human plasma and its application in bioavailability study

A new rapid, sensitive and selective liquid chromatography coupled with mass spectrometry method was developed and validated for the simultaneous quantification of pentoxifylline (PTX) and two major active metabolites in human plasma (M1 and M5). After a deproteinization step, chromatographic separation of the selected analytes was performed on a RP-C18 column. The detection of target compounds was in multiple reaction monitoring mode using an ion trap mass spectrometer equipped with an electrospray ion source. The method was validated and proved to be linear, accurate and precise over the range 5.08-406.14, 10.08-806.40 and 20.15-1611.60 ng/mL in case of PTX, M1 and M5, respectively. The major advantages of this method are the small sample volume, simple sample processing technique, the high sensitivity and the very good selectivity guaranteed by the MS/MS (in case of PTX) or MS/MS/MS (in case of M1 and M5) detection. The validated method has been successfully applied to a bioequivalence study.     

On-Line SPE on Restricted Access Adsorbent for HPLC-MS/MS Analysis of Felodipine in Plasma Samples

Direct plasma loading on a LiChrospher ADS C18 cartridge on-line coupled to an analytical Zorbax XDB C18 column was used to analyze felodipine by means of positive atmospheric pressure chemical ionization (APCI) tandem mass spectrometric (MS/MS) detection. Appropriate sensitivity, accuracy, and precision were obtained using an ion trap mass analyzer operated in a multiple reaction monitoring (MRM) mode. Diethyl-4-(2,3-dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate) was used as an internal standard. The method was fully validated. The method was successfully applied to a pilot bioequivalence study made on extended release oral dosage forms containing 10 mg of felodipine, under fed and fasting conditions.     

比卡鲁胺片的相对生物利用度及生物等效性评价

采用同体交叉试验方法,对天津新新制药厂提供的比卡鲁胺片(受试制剂)与德国AstraZeneca公司进口的比卡鲁胺片(参比制剂)在健康人体内的生物等效性进行评价。18名健康志愿者分别单剂量口服受试制剂和参比制剂,应用高效液相色谱法测定血浆中比卡鲁胺药物浓度,绘制药时曲线,计算受试制剂和参比制剂的主要药代动力学参数,2种制剂的达峰时间Tmax分别为(4.94±0.24)h和(3.11±0.32)h,达峰时血中药物浓度Cmax分别为(3885.19±1924.55)ng/mL和(4319.88±2250.15)ng/mL,2种制剂的消除相半衰期t1/2分别为(12.59±3.31)h和(13.45±3.90)h,药时曲线下面积AUC0→48分别为(37966.35±9228.13)ng.h.mL-1和(36552.52±9591.71)ng.h.mL-1,AUC0→∞分别为(41451.43±10326.81)ng.h.mL-1和(40286.27±11573.62)ng.h.mL-1,相对生物利用度F为(104.85±9.62)%。研究结果表明受试制剂的AUC0→48、AUC0→∞的90%可信限落在参比制剂80%—125%范围内,Cmax落在70%—143%范围内。虽然受试制剂较参比制剂达峰慢,但2种制剂的Cmax、AUC0→48和AUC0→∞一致,可以认为受试制剂与参比制剂2种制剂生物等效。