Validated Ultra Performance Liquid Chromatography Research Articles

Hydrogen Peroxide Plasma Sterilization Sabotages the Efficacy of Lidocaine HCl Injection

Background: Lidocaine injection with 2% HCl as an anesthetic drug must guarantee its sterility to avoid microbial contamination. In efforts to maintain the sterile preparation of Lidocaine HCl 2% before use in hospitals, some anesthesiologists opt for re-sterilization. Objective: This study aimed to evaluate the impact of plasma sterilization using hydrogen peroxide on Lidocaine HCl levels employing a validated Ultra Performance Liquid Chromatography (UPLC) assay. Methods: The 2% Lidocaine HCl samples were separated into two groups, one undergoing re-sterilization with hydrogen peroxide and the other handled only with aseptic techniques. The chromatographic assay was performed using a Waters Corp Acquity UPLC® H-Class system and a Waters Corp Acquity UPLC® BEH C18 column, with a mobile phase of 20% Acetonitrile and 80% Acetate Buffer pH 3.4, flow rate of 0.3 mL/min, and total duration of 4.5 minutes. Results: The results showed a decrease in Lidocaine HCl levels to 1.88% after re-sterilization and 2.01% without re-sterilization. Conclusion: These findings suggest that re-sterilization with hydrogen peroxide plasma sterilization leads to a significant decrease in Lidocaine HCl levels, causing non-compliance with pharmacopoeia standards.

Cerebrospinal Fluid and Plasma Amine Profiles in Interictal Migraine.

Impaired amine metabolism has been associated with the etiology of migraine, that is, why patients continue to get migraine attacks. However, evidence from cerebrospinal fluid (CSF) is lacking. Here, we evaluated individual amine levels, global amine profiles, and amine pathways in CSF and plasma of interictal migraine patients and healthy controls. CSF and plasma were sampled between 8:30 am and 1:00 pm, randomly and interchangeably over the time span to avoid any diurnal and seasonal influences, from healthy volunteers and interictal migraine patients, matched for age, sex, and sampling time. The study was approved by the local medical ethics committee. Individual amines (n=31), global amine profiles, and specific amine pathways were analyzed using a validated ultraperformance liquid chromatography mass spectrometry platform. We analyzed n=99 participants with migraine with aura, n=98 with migraine without aura, and n=96 healthy volunteers. Univariate analysis with Bonferroni correction indicated that CSF L-arginine was reduced in migraine with aura (10.4%, p< 0.001) and without aura (5.0%, p= 0.03). False discovery rate-corrected CSF L-phenylalanine was also lower in migraine with aura (6.9%, p= 0.011) and without aura (8.1%, p= 0.001), p= 0.088 after Bonferroni correction. Multivariate analysis revealed that CSF global amine profiles were similar for both types of migraine (p= 0.64), but distinct from controls (p= 0.009). Global profile analyses were similar in plasma. The strongest associated pathways with migraine were related to L-arginine metabolism. L-Arginine was decreased in the CSF (but not in plasma) of interictal patients with migraine with or without aura, and associated pathways were altered. This suggests that dysfunction of nitric oxide signaling is involved in susceptibility to getting migraine attacks. ANN NEUROL 2023;93:715-728.

A Validated Ultra Performance Liquid Chromatography Method for Simultaneous Estimation of Diacerein and Aceclofenac in Bulk and Pharmaceutical Formulation

A simple, exceptionally cost-effective, extremely accurate, quite precise and highly reproducible analytical method was developed and validated for simultaneous estimation of Diacerein and Aceclofenac in bulk and Pharmaceutical formulation. The new Ultra Performance Liquid Chromatography technique was developed. Method- The separation has been done on column ACQUITY UPLC BEH Shield C18 (50 x 2.1mm), 1.7µm (40°C temperature). The mobile phase contained Buffer and Acetonitrile (Buffer: ACN) (55:45 V/V).. The flow rate was set at 0.4ml/min, and detected at 268nm with PDA detector. Mobile phase was sonicated for 15 min. before use. 5μl of samples of standard stock solution and tablet solution were injected. Different trials were performed to separate diacerein and aceclofenac. The total run time of the detection was 4 min. The developed method was validated against different validation parameters. Results - The retention times were obtained at 1.762min. and 2.891 min. for Diacerein and Aceclofenac respectively. Accuracy study was observed in the range of 100.33% to 101.67% with less than 2% RSD. LOQ was found to be 2.98μg/ml and 5.9041μg/ml. similarly LOD was found to be 0.9841μg/ml and 1.9467μg/ml. for Diacerein and Aceclofenac respectively. Precision %RSD for intraday and interday were found to be 0.19 and 0.18 for Diacerein , 0.44 and 0.16 for Aceclofenac respectively. Linearity was found in the range of 2.5-17.5μg/ml and 5-35μg/ml for Diacerein and Aceclofenac respectively. The method was found robust by deliberate changes in the flow rate, ratio of mobile phase and detection wavelength. Conclusion-The method was found to be satisfactory and can be used successfully for determination of Diacerein and Aceclofenac simultaneously in bulk and pharmaceutical dosage form.

Fatal pyrrolizidine alkaloid poisoning of infants caused by adulterated Senecio coronatus

Senecio coronatus (known as izonkozonko and ubulibazi in Zulu) is commonly used in traditional medicine in South Africa as purification purgative and enemas for infants during weaning. We show for the first time that this species does not contain pyrrolizidine alkaloids and that reported cases of fatal hepatic sinusoidal obstruction syndrome in infants were caused by wrongly identified Senecio species containing large amounts of retrorsine-N-oxide. A validated ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the detection and quantitation of pyrrolizidine alkaloids is described.

Pharmacokinetic profiles of levofloxacin after intravenous, intramuscular and subcutaneous administration to rabbits (Oryctolagus cuniculus).

Levofloxacin pharmacokinetic profiles were evaluated in 6 healthy female rabbits after intravenous (I/V), intramuscular (I/M), or subcutaneous (S/C) administration routes at a single dose of 5 mg/kg in a 3 × 3 cross-over study. Plasma levofloxacin concentrations were detected using a validated Ultra Performance Liquid Chromatography method with a fluorescence detector. Levofloxacin was quantifiable up to 10 h post-drug administration. Mean AUC0-last values of 9.03 ± 2.66, 9.07 ± 1.80, and 9.28 ± 1.56 mg/h*L were obtained via I/V, I/M, and S/C, respectively. Plasma clearance was 0.6 mL/g*h after I/V administration. Peak plasma concentrations using the I/M and S/C routes were 3.33 ± 0.39 and 2.91 ± 0.56 µg/mL. Bioavailability values, after extravascular administration were complete, - 105% ± 27% (I/M) and 118% ± 40% (S/C). Average extraction ratio of levofloxacin after I/V administration was 7%. Additionally, levofloxacin administration effects on tear production and osmolarity were evaluated. Tear osmolarity decreased within 48 h post-drug administration. All 3 levofloxacin administration routes produced similar pharmacokinetic profiles. The studied dose is unlikely to be effective in rabbits; however, it was calculated that a daily dose of 29 mg/kg appears effective for I/V administration for pathogens with MIC < 0.5 µg/mL.

Validated ultra performance liquid chromatography method for simultaneous quantitative analysis of antioxidant compounds in the leaves of Persicaria barbata (L.) H. Hara var. barbata

Validated ultra performance liquid chromatography method for simultaneous quantitative analysis of antioxidant compounds in the leaves of Persicaria barbata (L.) H. Hara var. barbata

Pharmacokinetics, pharmacodynamics and safety of a novel extrafine BDP/FF/GB combination delivered via metered-dose inhaler in healthy Chinese subjects

BackgroundBDP/FF/GB pMDI is a novel triple fixed-dose combination of extra-fine inhalation aerosol beclomethasone dipropionate (BDP)/formoterol fumarate (FF)/glycopyrronium bromide (GB). Limited data on the pharmacokinetic (PK) and pharmacodynamic (PD) properties of BDP/FF/GB fixed-dose combination in healthy subjects was available. PurposesThis study aimed to evaluate the pharmacokinetics, pharmacodynamics and safety of BDP/FF/GB pMDI in healthy Chinese subjects. MethodsThis is an open-label, parallel-group, randomized, single and multiple dose study. In the single dose group, subjects received single supra-therapeutic inhaled dose of BDP/FF/GB pMDI (BDP/FF/GB 400/24/50 µg). In the multiple dose group, subjects received therapeutic inhaled dose of BDP/FF/GB pMDI (BDP/FF/GB 200/12/25 µg), twice daily, for 7 consecutive days. Plasma BDP, B17MP, formoterol and GB were determined by a validated ultra performance liquid chromatography method with tandem mass spectrometric detection (UPLC/MS–MS). Heart rate (HR), QTcF, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were evaluated as the surrogate indicators of pharmacodynamic effects. ResultsA total of 24 subjects were randomized and 22 (11 in each group) completed the study. The dose adjusted pharmacokinetic profiles of BDP, beclomethasone-17-monopropionate (B17MP, the most active metabolite of BDP), formoterol and GB were overall similar in therapeutic and supra- therapeutic dose group, showing dose proportional increase of the systemic exposure to BDP, B17MP, formoterol and GB. The pharmacodynamic variables were within the normal range and showed no significant difference between the two groups. All the treatment-emergent adverse events (TEAEs) were mild and no severe TEAE was reported. ConclusionsDose adjusted PK profiles were similar between therapeutic and supra-therapeutic dose for all compounds, nearly dose proportional systemic exposure to B17MP, formoterol and GB after BDP/FF/GB pMDI administration in healthy Chinese subjects. BDP/FF/GB pMDI was safe and well tolerated in healthy Chinese subjects. The PK profiles were comparable to previously published data from Western European healthy Caucasian subjects.

A Validated Ultra-Performance Liquid Chromatography Tandem Triple Quadrupole Mass Spectrometric Method for Fast Determination of Losartan in Rabbit Plasma.

A rapid UPLC-MS-MS method was developed and validated for determination of losartan in rabbit plasma. Protonated adducts of losartan and eprosartan (IS) were monitored in multiple reaction monitoring mode. Molecular masses of daughter species of losartan were m/z 423.19 > 207 and m/z 423.19 > 180; and of eprosartan were m/z 425.11 > 135 and m/z 425.11 > 107. Losartan from plasma samples was extracted by protein precipitation method. The mobile phase comprising water (0.1% formic acid) (A) and acetonitrile (0.1% formic acid) (B) was used in gradient mode. Analytes were eluted on Acquity UPLC®BEH C18 1.7 μm, 2.1 × 50 mm column. Sample run time was 3.0 min. The validation parameters: accuracy, precision and recovery were within recommended limits. Losartan as well as internal standard remains stable in benchtop stability study as well as in post-preparative stability study. Pharmacokinetic parameters such as Cmax (182.79 ± 23.80 ng/mL), Tmax (1.16 ± 0.28 h), AUC0-t (1188.57 ± 404.60 ng h/mL) and Kel (0.0954 ± 0.0140 h-1) of losartan were measured. Method was successfully applied for pharmacokinetic investigation in rabbits and can be used for losartan determination in plasma sample obtained from other animals.

To ferment or not to ferment Sceletium tortuosum – Do our ancestors hold the answer?

The KhoiSan of southern Africa have used fermented Sceletium tortuosum preparations to induce psychoactive effects for centuries. It is claimed that the fermentation process changes the alkaloid composition, thereby increasing the potency of the psychoactive response. In this study, a validated ultra performance liquid chromatography–mass spectrometry method was used to quantify the content of alkaloids prior to, and after the controlled fermentation of samples of S. tortuosum. The results revealed that, despite only a slight change in the mesembrenol and mesembranol content during fermentation, the mesembrine content increased significantly from not detected – 1.6 μg/mL to 7.40–20.8 μg/mL. A corresponding decrease was found in the initial mesembrenone content of 8.00–33.0 μg/mL to 1.30–32.7 μg/mL after fermentation. The total alkaloid content also increased as a result of fermentation.

A Validated Ultra Performance Liquid Chromatography Method for Quantification of Metformin in Human Plasma

Metformin is oral hypoglycemic or blood sugar-lowering drug which is used for the first- line drug in the treatment of diabetes mellitus type 2. This study presented the validated Ultra Performance Liquid Chromatography UltraViolet (UPLC-UV) method for the determination of metformin in human plasma. Metformin levels were measured using UPLC with a UV detector and liquid-liquid extraction method. Separation was carried out on an Acquity UPLC HSS T3 100mm × 2.1mm i.d. column (1.8μm particle size) using gradient elution of acetonitrile and phosphate buffer 0.02 M (0.6 mL/min) as mobile phase at 30°C. The analyte was monitored at 236 nm. No endogenous substances were found to interfere with the peaks of drug and internal standard. The value of percent deviation and the coefficient variation obtained respectively less than the percentage set in the FDA guidelines. The linearity factor values were more than 0.997 and LOD was 0.01µg/mL. UPLC with UV detector is able to analyze metformin in a short time with good precision and accuracy which is useful for bioequivalence and bioavailability studies.

Development, validation, and application of an UPLC-MS/MS method for norvancomycin analysis in human blood plasma.

Norvancomycin (NVCM) is used in treating patients with infections caused by drug-resistant gram-positive bacteria. The NVCM plasma concentration varies greatly among individuals. To avoid the adverse drug reactions and prevent the presence of drug-resistant bacteria, the routine monitoring of NVCM in blood plasma was strongly recommended. However, there were few methods for plasma NVCM analysis. To the best of our knowledge, this is the first validated ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for plasma NVCM analysis. The ion transition for NVCM was m/z 718.5>144.1. The flow rate was 0.4mL/min with a run time of 3.5min. The calibration range of the UPLC-MS/MS method was 1-100mg/L. The intra-day and inter-day inaccuracy and imprecision were -7.39%-10.27% and less than 11.55%. The internal standard (IS) normalized recovery and matrix factor were 68.24%-78.24% and 94.53% to 115.80%, respectively. The coefficient variations of IS normalized recovery and matrix factor were less than 11.24% and 9.14%. Age, body weight, and creatinine clearance affect NVCM plasma concentrations in 20 patients. Further studies are warranted to confirm the results.

Identification and Determination of Phenolics in Lamiaceae Species by UPLC-DAD-ESI-MS/MS.

This study reports the phenolic profile screening of aromatic Lamiaceae species such as marjoram (Origanum majorana L.), lavender (Lavandula officinalis) and pennyroyal (Mentha pulegium L.) using a novel and validated ultra performance liquid chromatography method coupled with DAD diode array detector and tandem mass spectrometry (MS/MS) in negative mode of electrospray ionization. Identification and quantification of phenolics in these plant extracts has been realized within 12 min. This method showed good precision (percentage relative standard deviation; RSD% 0.54-2.72 for intra-day, 1.71-4.64 for inter-day), reproducibility (percentage recovery, REC% 92.0-109.0) and linearity (r = 0.9988-0.9999). Limits of detection ranged from 0.02 to 18.2 ng/mL. The extraction of plants was performed using microwave-assisted extraction technique and 60% (v/v) aqueous methanol solvent medium was selected as suitable solvent because of maximum extraction efficiency. Total antioxidant capacity, total phenolic content and free radical scavenging activity of these plant extracts were tested and the results correlated well among each other. According to the Folin assay, phenolic contents of Origanum majorana L., Mentha pulegium L. and Lavandula officinalis were calculated as 119 ± 3.4, 85.1 ± 2.8 and 57.8 ± 2.1 mg GAE/g dry matter, respectively.

Etravirine Pharmacokinetics in HIV-Infected Pregnant Women.

Background: The study goal was to describe etravirine pharmacokinetics during pregnancy and postpartum in HIV-infected women.Methods: IMPAACT P1026s and PANNA are on-going, non-randomized, open-label, parallel-group, multi-center phase-IV prospective studies in HIV-infected pregnant women. Intensive steady-state 12-h pharmacokinetic profiles were performed from 2nd trimester through postpartum. Etravirine was measured at two labs using validated ultra performance liquid chromatography (detection limits: 0.020 and 0.026 mcg/mL).Results: Fifteen women took etravirine 200 mg twice-daily. Etravirine AUC0–12 was higher in the 3rd trimester compared to paired postpartum data by 34% (median 8.3 vs. 5.3 mcg*h/mL, p = 0.068). Etravirine apparent oral clearance was significantly lower in the 3rd trimester of pregnancy compared to paired postpartum data by 52% (median 24 vs. 38 L/h, p = 0.025). The median ratio of cord blood to maternal plasma concentration at delivery was 0.52 (range: 0.19–4.25) and no perinatal transmission occurred.Conclusion: Etravirine apparent oral clearance is reduced and exposure increased during the third trimester of pregnancy. Based on prior dose-ranging and safety data, no dose adjustment is necessary for maternal health but the effects of etravirine in utero are unknown. Maternal health and infant outcomes should be closely monitored until further infant safety data are available.Clinical Trial registration: The IMPAACT protocol P1026s and PANNA study are registered at ClinicalTrials.gov under NCT00042289 and NCT00825929.

A Comparative Pharmacokinetics Study of the Anti-Parkinsonian Drug Pramipexole.

The present study aimed to compare pharmacokinetic parameters of two pramipexole 0.25 mg formulations in order to show bioequivalence. The study was conducted in a randomized, open-label, two-period, two-sequence, and crossover design, involving 23 healthy volunteers. One of the 0.25 mg formulations of pramipexole evaluated in the study was manufactured by PT Dexa Medica, Palembang, Indonesia, the other, used as the reference, by Boehringer Ingelheim Pharma GmbH & Co. KG, Ingelheim am Rhein, Germany. All eligible subjects were required to fast before each drug administration period, which was separated by a one-week washout period. Pramipexole concentrations in plasma were assayed using a validated ultra performance liquid chromatography with mass spectrometry (UPLC-MS/MS) detector. The evaluated pharmacokinetic parameters included the area under the plasma concentration curve from time zero to the last observed measurable concentration (AUC0-t), the area under the plasma concentration curve extrapolated to infinite time (AUC0-∞), the maximum plasma concentration (Cmax), the time to reach Cmax (tmax), and the plasma concentration half-life (t1/2). To evaluate the bioequivalence of those two pramipexole formulations, 90% confidence intervals (CIs) for geometric mean ratios of both formulations were calculated for AUC and Cmax parameters, while tmax and t1/2 differences were analyzed on the non-transformed data using Wilcoxon matched-pairs and a Student’s paired t-test, respectively. The 90% CIs for the geometric mean ratios of the two pramipexole formulations were 95.89% (90.73%–101.34%), 95.53% (89.75%–101.68%), and 92.11% (84.35%–100.58%) for AUC0-t, AUC0-∞, and Cmax, respectively. There were no statistically significant differences for tmax and t1/2 between the two pramipexole formulations. It is concluded that two pramipexole formulations in this study were bioequivalent.

Effects of Jia-Wei-Xiao-Yao-San on the Peripheral and Lymphatic Pharmacokinetics of Paclitaxel in Rats.

Paclitaxel is effective against breast cancer. The herbal medicine, Jia-Wei-Xiao-Yao-San (JWXYS), is the most frequent prescription used to relieve the symptoms of breast cancer treatments. The aim of the study was to investigate the herb-drug interaction effects of a herbal medicine on the distribution of paclitaxel to lymph. A validated ultraperformance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was used to determine the paclitaxel levels in rat plasma and lymph after intravenous infusion of paclitaxel alone with or without 7 days of JWXYS pretreatment. The pharmacokinetic results indicate that paclitaxel concentrations in plasma exceeded those in lymph by approximately 3.6-fold. The biodistribution of paclitaxel from plasma to lymph was 39 ± 5%; however, this increased to 45 ± 4% with JWXYS pretreatment. With JWXYS pretreatment, the AUC and C max of paclitaxel in plasma were significantly reduced by approximately 1.5-fold, compared to paclitaxel alone. Additionally, JWXYS decreased the AUC and C max of paclitaxel in lymph. However, the lymph absorption rate of paclitaxel with or without JWXYS pretreatment was not significantly changed (27 ± 3 and 30 ± 2%, resp.). Our findings demonstrate that when paclitaxel is prescribed concurrently with herbal medicine, monitoring of the blood pharmacokinetics of paclitaxel is recommended.

Optimized and Validated RP-UPLC Method for the Determination of Losartan Potassium and Chlorthalidone in Pharmaceutical Formulations.

A validated ultra performance liquid chromatography (UPLC) method has been developed and validated for the simultaneous determination of losartan potassium and chlorthalidone in pharmaceutical preparations. Waters-Acquity UPLC system equipped with Auto Sampler, PDA detector and operated with Empower-2 software was used for the present study. Detection was done at wavelength of 230 nm, HSS C18, 100 mm x 2.1x 1.8 μm column with a reverse phase elution and mobile phase composed of A and B mixed in the ratio 56:44 v/v (Where mobile phase A consists of potassium dihydrogen phosphate buffer of pH 3.0 and Mobile phase B consists of acetonitrile and methanol mixed in the ratio of 90:10 v/v) used at a flow rate of 0.4ml per minute. The retention times for losartan potassium and chlorthalidone were observed at 0.72 and 1.89 minutes. The developed method was validated as per ICH guidelines. Linearity ranges were found to be 12.5-125 μg/ml and 3.125-31.25 μg/ml for losartan potassium and chlorthalidone, respectively. This method is fast, accurate, precise and sensitive hence it can be employed for routine quality control of tablets containing both drugs in industries.

Abstract LB-231: A phase I pharmacokinetic study of OTX015 for the treatment of patients with hematologic malignancies

Abstract Background: OTX015 is a novel inhibitor of the bromodomain and extra-terminal (BET) protein family. This synthetic oral small molecule targets the BET transcriptional co-activator proteins BRD2/3/4, which are potential cancer targets particularly in hematologic malignancies. A phase Ib study with OTX015 administered to patients with hematologic malignancies was performed including a pharmacokinetic (PK) investigation. The PK objectives of this study were to determine the PK profile and perform a PK/PD modeling of oral OTX015 using a population approach. Materials and Methods: A multicenter, dose escalation study is underway in cohorts of 3 to 6 patients with acute leukemia and other hematologic malignancies. Patients received oral OTX015 at a starting dose of 10 mg once daily (QD). PK blood samples from 7 time points were collected over 24 h post-administration (complete PK) on Day 1 for leukemia patients and 4 blood samples over 8 h post-administration were collected for patients with other malignancies (limited sampling PK). Plasma concentrations of OTX015 were measured using validated Ultra Performance Liquid Chromatography with tandem Mass Spectrometry detection (UPLC-MS/MS) with a concentration range 1 - 250 ng/mL. Analyses and population PK (PPK) modeling were performed with the nonlinear mixed effect modeling software program Monolix version 4.2. Results: From January 2013 to January 2014, 36 patients were treated at four dose levels (10, 20, 40, 80 mg) QD and 40 mg BID. 302 plasma concentrations (289 + 13 BLQ) were analyzed. A 1-compartment open model adequately described the total OTX015 time-concentration curve. The PPK parameters obtained for the structural model were: Ka (absorption constant) = 1.12 h-1; V (distribution volume) = 68.6 L and CL (clearance) = 6.65 L/h with a relative standard error of 27%, 9% and 10% respectively. AUC values for all patients increased dose-proportionally (R²= 0.995). The absorption phase was linear and Tmax was between 1 and 4 hours. Mean elimination half-life of OTX015 for all patients was 7.16 h. The main covariate effects in PPK modeling were body weight (BW) which influenced CL, V. No significant gender influence on PK parameters was observed. Conclusions: The PK of OTX015 is best described by a one-compartment model. BW influenced significantly PK parameters of OTX015. AUC-dose proportionality was observed. Evaluation of glucuronidated metabolite concentrations is ongoing and will contribute to understanding the pathways involved in OTX015 metabolism. PK/PD modeling will be performed to describe toxicity and efficacy (6 experienced clinically meaningful activities) in terms of OTX015 PK. A comparison between QD and BID schemes will be performed in order to verify PK profile of OTX015 for each administration. Citation Format: Elodie Odore, Keyvan Rezai, Eugenia Riveiro, Fabrice Bourdel, Patrice Herait, Esteban Cvitkovic, Herve Dombret, Francois Lokiec. A phase I pharmacokinetic study of OTX015 for the treatment of patients with hematologic malignancies. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-231. doi:10.1158/1538-7445.AM2014-LB-231

Highly Sensitive and Simple Validated Ultra-performance Liquid Chromatography/ Tandem Mass Spectrometry Method for the Determination of Cinacalcet in Human Plasma

With the objective of decreasing analysis time and retaining good efficiency (UPLC-MS/MS) is an outstanding analytical approach for speedy biomedical analysis. The aim of this study was to develop validate a simple, rapid, sensitive and specific UPLC-MS/MS method for quantification of cinacalcet, a calcimimetic agent, which acts on a calcium sensing receptor of the parathyroid gland in human plasma. After following a liquid–liquid extraction procedure with diethyl ether–dichloromethane (70:30, v/v), cinacalcet (CIN) and internal standard (IS) abiraterone with C18 Acquity UPLC BEHTM column. m/z 358.07 > 155.0 and m/z 350.1 > 156.0 where the ion transitions recorded in the positive ion multiple reaction monitoring mode for cinacalcet for IS. The mobile phase consisted of acetonitrile: 10 mM ammonium acetate: formic acid (90:10:0.1% v/v/v) with a flow rate of 0.4 mL/min. The assay exhibited a linear dynamic range of 0.2–100 ng/mL for cinacalcet in human plasma with good correlation coefficient (IQ 0.995) and with an LOQ of 1 ng/mL. The intra- and inter-assay precisions were satisfactory; the relative standard deviations did not exceed 6.98 %. This method was simple, rapid and highly sensitive, hence could be used for analysis of cinacalcet in human plasma. Keywords: Cinacalcet, UPLC, LC-MS/MS, pharmacokinetic study, human plasma.

Bioequivalence of Omeprazole Delayed-Release Capsules in Healthy Filipino Subjects

Study background: Omeprazole is indicated for the treatment of various acid-related gastrointestinal disorders. It is acid labile and therefore administered orally as enteric-coated granules in capsules. Methods: This randomized, open-label, single dose, two-way cross-over clinical pharmacology study in healthy adult Filipino subjects evaluated the bioequivalence of a new 40 mg delayed-release (enteric-film coated) capsule formulation of omeprazole (Pfizer Inc., US) relative to the reference marketed Losec® capsule (2x20 mg; AstraZeneca, Sweden; enteric-coated granules in capsule) under fasted conditions. Pharmacokinetic blood sampling was carried out at various time points for 12 h post-dose and plasma samples were analysed using a fully validated ultra performance liquid chromatography with tandem Mass Spectrometry technology. The primary endpoints were area under plasma concentration-time curve (AUC) from time zero to the time of the last quantifiable concentration (AUClast) and maximum plasma concentration (Cmax) for omeprazole. Results: Twenty five subjects (12 females and 13 males; mean age 26 years; mean body mass index 24 kg/ m2) completed the study. When administered as one omeprazole 40 mg delayed-release capsule, the ratios of the adjusted geometric means of the primary endpoints, AUClast and Cmax, were contained within the established bioequivalence limits of 80 to 125% compared with two Losec® 20 mg capsules: 100.4% (90% confidence interval: 90.8–110.9%) and 90.4% (90% confidence interval: 81.2–100.6%), respectively. The two omeprazole formulations were well tolerated and no serious adverse event or other significant adverse event was noted. Conclusion: Based on the results of this study in healthy adult Filipino subjects, the new omeprazole 40 mg delayed-release capsule and the established marketed Losec® capsule (2x20 mg) are bioequivalent. Omeprazole 40 mg delayed-release capsule was safe and well tolerated.

Determination and pharmacokinetics of di-(2-ethylhexyl) phthalate in rats by ultra performance liquid chromatography with tandem mass spectrometry.

Di-(2-ethylhexyl) phthalate (DEHP) is used to increase the flexibility of plastics for industrial products. However, the illegal use of the plasticizer DEHP in food and drinks has been reported in Taiwan in 2011. In order to assess the exact extent of the absorption of DEHP via the oral route, the aim of this study is to develop a reliable and validated ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method to evaluate the oral bioavailability of DEHP in rats. The optimal chromatographic separation of DEHP and butyl benzyl phthalate (BBP; used as internal standard) were achieved on a C18 column. The mobile phase was consisted of 5 mM ammonium acetate-methanol (11:89, v/v) with a flow rate of 0.25 mL/min. The monitoring ion transitions were m/z 391.4 → 149.0 for DEHP and m/z 313.3 → 149.0 for BBP. The mean matrix effects of DEHP at low, medium and high concentrations were 94.5 ± 5.7% and 100.1 ± 2.3% in plasma and feces homogenate samples, respectively. In conclusion, the validated UPLC-MS/MS method is suitable for analyzing the rat plasma sample of DEHP and the oral bioavailability of DEHP was about 7% in rats.