Effect of age and renal impairment on the pharmacokinetics and safety of trimetazidine: An open-label multiple-dose study.

This study evaluated the effect of age and renal impairment on pharmacokinetics of trimetazidine (TMZ) in healthy elderly and renally impaired subjects and assess safety and tolerability. In this open-label, multi-dose study, 73 subjects were divided into six treatment groups: (1) 55-65 years; (2) 66-75 years; (3) >75 years (dosing for groups 1-3 [healthy]: B.D. for 4 days), (4) mild renally impaired (dosed B.D. for 8 days); (5) moderate renally impaired (dosed O.D. for 8 days); and (6) severe renally impaired-no dialysis (dosed once every 48 h for 8 days). Blood and urine samples were collected and analyzed. The geometric least squares mean ratios for; Group 2 and 1 of AUC(0-τ)ss was 112.2 (90% CI; 92.0-136.8) and Cmax,ss was 109.9 (89.6-134.8), Group 3 and 1 of AUC(0-τ),ss was 140.5 (115.9-170.3) and Cmax,ss was 137.8 (112.9-168.2), Group 4 and 1 of AUC(0-τ),ss was 114.2 (90.3-144.4) and Cmax,ss was 120.8 (92.5-157.8), Group 5 and 1 of; AUC(0-τ),ss was 213.0 (153.1-296.3) and Cmax,ss was 123.3 (92.2-164.7) and Group 6 and 1 of AUC(0-τ),ss was 247.4 (197.8-309.6) and Cmax,ss was 95.6 (73.0-125.1). Significant increase in systemic exposure of TMZ was observed in subjects; over 75 year's age and renally impaired compared to healthy subjects. TMZ was safe and well-tolerated.

Overcoming interference of plasma phospholipids using HybridSPE for the determination of trimetazidine by UPLC-MS/MS.

An improved, precise and reliable ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed for the quantification of trimetazidine, using trimetazidine-d8 as the internal standard (IS). Interference owing to plasma phospholipids during sample preparation was overcome using a hybrid solid-phase extraction-phospholipid ultra cartridge. The mean extraction recovery of trimetazidine (98.66%) and trimetazidine-d8 (97.63%) from spiked plasma was consistent and reproducible. Chromatographic analysis was performed on a UPLC Ethylene Bridged Hybrid (BEH) C18 (50 × 2.1 mm, 1.7 µm) column with isocratic elution using acetonitrile-5 mm ammonium formate, pH 3.5 (40:60, v/v) as the mobile phase. The parent → product ion transitions for trimetazidine (m/z 267.1 → 181.1) and trimetazidine-d8 (m/z 275.2 → 181.1) were monitored on a triple quadrupole mass spectrometer with electrospray ionization functioning in the positive multiple reaction monitoring mode. The linearity of the method was established in the concentration range of 0.05-100 ng/mL for trimetazidine. The intra-batch and inter-batch accuracy and precision (CV) were 97.3-103.1 and 1.7-5.3%, respectively. Qualitative and quantitative assessment of matrix effect showed no interference of endogenous/exogenous components. The developed method was used to measure plasma trimetazidine concentration for a bioequivalence study with 12 healthy subjects.

Salting-out-assisted liquid-liquid extraction with acetonitrile for the determination of trimetazidine in rat plasma using liquid chromatography-mass spectrometry.

A high-throughout bioanalytical method based on salting-out-assisted liquid/liquid extraction (SALLE) method with acetonitrile and mass spectrometry-compatible salts followed by LC-MS/MS analysis of trimetazidine in rat plasma is presented. It required only 50 µL of plasma and allows the use of minimal volumes of organic solvents. The seamless interface of SALLE and LC-MS eliminated the drying-down step and the extract was diluted and injected into an LC-MS/MS system with a cycle time of 2.5 min/sample. The retention times of trimetazidine and IS were approximately 1.1 and 1.7 min, respectively. Calibration curves were linear over the concentration range of 0.1-100 ng/mL, which can be extended to 500 ng/mL by dilution. The intra- and inter-batch precision, accuracy and the relative standard deviation were all <15%. This method was successfully applied to determine trimetazidine concentrations in rat plasma.

Chemiluminescence determination of trimetazidine via inducing the aggregation of gold nanoparticles.

A simple, rapid and sensitive chemiluminescence (CL) method combined with flow injection analysis was developed for the determination of trimetazidine. Trimetazidine was found to significantly increase the CL signal arising from N-bromosuccinimide-luminol reaction in the presence of gold nanoparticles. The enhanced CL intensity was proportional to trimetazidine concentration in the range of 0.01-5.0 µg/mL, with a limit of detection (3 sb) of 6.7 ng/mL. The relative standard deviation was 2.8% for 11 repetitive measurements of 0.1 µg/mL trimetazidine solution. The practicality of the method was evaluated by determining trimetazidine in pharmaceutical formulations and in spiked human serum samples. Moreover, the possible CL reaction mechanism was also discussed.

Hollow fiber-based liquid membrane microextraction combined with high-performance liquid chromatography for extraction and determination of trimetazidine in human plasma.

A hollow fiber-based liquid phase microextraction strategy combined with high-performance liquid chromatography was evaluated for the quantitative determination of trimetazidine in human plasma. Trimetazidine was extracted from a 2.1 mL basified plasma sample (donor phase) into the organic solvent (n-octanol) impregnated in the pores of a hollow fiber and then extracted into an acidic solution (acceptor phase) inside the lumen of the hollow fiber. The result showed that transport of drugs from alkaline sample solution into 0.5 m HCl occurred efficiently when 25 µL of 250 mm sodium 1-octanesulfonate was added into the donor phase. Several parameters influencing the efficiency of the method, such as the nature of organic solvent used to impregnate the membrane, compositions of donor phase and acceptor phase, type and concentration of carrier, extraction time, stirring rate and salt concentration, were investigated and optimized. Under the optimal conditions, the calibration curves were obtained in the range of 5-200 ng/mL with reasonable linearity (r > 0.9980). The method was successfully applied to determine the concentration of trimetazidine in human plasma.

[Pharmacokinetics and bioequivalence of domestic trimetazidine formulations].

OBJECTIVE: To compare the pharmacokinetics and bioequivalence between domestic hydrochloric trimetazidine capsules and imported hydrochloric trimetazidine tablets in healthy male Chinese volunteers after single oral administration. METHODS: A single oral dose (test and reference formulations) was given to 24 healthy male Chinese subjects according to an open randomized crossover design. The blood samples were collected before and after administration. Plasma trimetazidine concentration was determined by HPLC-MS/MS. The pharmacokinetic parameters were calculated by WinNonlin Ver 6.2.1 software. RESULTS: The main pharmacokinetic parameters of domestic and imported formulation of trimetazidine were similar: C(max) (70.9 ± 15.3), (66.4 ± 13.8) µg/ml; t(max) (1.70 ± 0.72), (1.85 ± 0.55) h; t(1/2z) (4.70 ± 1.75), (4.77 ± 1.96) h; AUC(0-24 h) (481 ± 176), (469 ± 171) µg×h×ml(-1); AUC(0-∞) (511 ± 189), (500 ± 188) µg×h×ml(-1). The estimated 90% CIs for the ratio of C(max) and AUC(0-24 h) were also similar: 101.9% - 112.5% and 99.4% - 104.9%. The relative bioavailability of domestic formulation was (102.2 ± 8.3)%. CONCLUSION: The results demonstrates that the domestic hydrochloric trimetazidine capsules and imported hydrochloric trimetazidine tablets are bioequivalent.

Application of liquid chromatography method with electrochemical detection for bioequivalence study of trimetazidine in human plasma.

A method to estimate trimetazidine (CAS: 13171-25-0) levels in human plasma by means of HPLC with electrochemical detection was developed. Trimethoprim (CAS: 26807-65-8) was used as an internal standard. This method of analysis was fully validated according to the guidelines of the United States Food and Drug Administration, European Medicines Agency and Organization for Economic Co-operation and Development and Good Laboratory Practice rules. The accuracy and precision of the developed method were found to be satisfactory and stability studies showed acceptable variation (below 15%) of trimetazidine concentrations when samples were stored frozen at -75 degrees C for 54 days. The developed method was successfully used for a comparative 2 x 2 period, crossover bioequivalence study of two extended-release preparations of trimetazidine performed on 24 healthy volunteers at the steady state after multiple dosing of 35 mg twice daily for 4 days and a single 35 mg dose on the 5th day and after a single dose of 35 mg under fasting or postprandial conditions.

Food effect on bioavailability of modified-release trimetazidine tablets.

This study aimed to investigate a food effect on the bio-availability of modified-release (MR) trimetazidine tablets in 36 healthy volunteers. Trimetazidine, an anti-ischemic drug, protects the myocardial cell from the harmful effects of ischemia. The authors investigated the effect of being under a fasting or fed state at the time of drug intake on the bioavailability of trimetazidine 35-mg MR tablets in a randomized, open-label, crossover, 2-arm, 4-period, 2-sequence bioequivalence study design with a 14-day washout period. Plasma concentration of trimetazidine was assayed in timed samples with a validated high- performance liquid chromatography/mass selective detector that had a lower limit of quantification of 2.5 ng/mL. Test and reference formulations gave a mean trimetazidine C(max) of 63.26 ng/mL and 69.18 ng/mL for the fasting state and 64.19 ng/mL and 63.11 ng/mL for the fed state, respectively. The AUC(0-tlast) mean of trimetazidine was 726.31 ng·h/mL and 733.01 ng·h/mL for the fasting state and 706.40 ng·h/mL and 691.40 ng·h/mL for the fed state for test/reference formulations. There were no significant differences in pharmacokinetic parameters between the 2 formulations and the fasting/fed states. The authors showed that there is no food effect and no need for a 4-period study to evaluate the bioequivalence of trimetazidine MR tablets.

A simple and sensitive liquid chromatography method for the determination of low dihydrocodeine concentrations in human plasma: its application in Chinese healthy volunteers.

A simple, sensitive and modified method was developed for determination of low dihydrocodeine (CAS 125-28-0) concentrations in human plasma by high performance-liquid chromatography (HPLC) with diode array detector. Measurement was performed on a Zorbax XDB-C18 analytical column together with a XDB-C18 precolumn at 40 degrees C after a simple one-step extraction. An isocratic mobile phase consisting of acetonitrile-0.1% trifluoroacetic acid (TFA)-water (12:40:48, v/v/v), was run at a flow rate of 1.0 mL/min. Good chromatographic separation was achieved in less than 6.2 min. This assay was linear over a concentration range of 2.50-100 ng/mL with a lower limit of quantification at 2.50 ng/mL. The intra- and inter-day precision (relative standard deviation) was less than 6.00 and 6.62%, respectively, at all concentration levels studied, while the intra- and inter-day accuracy was 1.50-3.73% and -1.35-1.92%, respectively. Recoveries were 76.10-83.81% with coefficients of variation of 1.86-6.93%. Stability of dihydrocodeine in plasma proved to be good. The validated method was successfully applied to a bioequivalence study of dihydrocodeine after a single oral administration of 20 mg dihydrocodeine tartrate in Chinese healthy male volunteers.

Development and validation of a simple and sensitive liquid chromatography-tandem mass spectrometry method for quantifying trimetazidine in human plasma.

1. A simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for quantifying trimetazidine in human plasma was developed and validated. Sample preparation was based on deproteinating with acetonitrile. 2. Chromatography was performed on a C18 analytical column (5 mum; 150 x 2.1 mm i.d.) and the retention times for trimetazidine and cetirizine (used as the internal standard) were 1.8 and 3.0 min, respectively. The ionization was optimized using an electrospray ionization source and enhanced selectivity was achieved using tandem mass spectrometry. The calibration curve ranged from 0.1 to 200 ng/mL. The inter-day precision, accuracy and the relative standard deviation (RSD) were all < 15%. The analyte was shown to be stable over the time-scale of the entire procedure. 3. The robustness of the method was demonstrated by the good reproducibility of the results obtained during the analysis of clinical samples.

Efecto de trimetazidina en la nefrotoxicidad por gentamicina / Trimetazidine effect on nephrotoxicity by gentamicyn

La Trimetazidina (TMZ) es una droga utilizada como cardioprotector, ya que previene la muerte celular secundaria a la isquemia miocárdica. Algunos investigadores le atribuyeron efecto reno-protector, actividad antioxidante y scavenger de radicales libres del oxígeno. El objetivo del presente trabajo es mostrar el efecto citoprotector de TMZ en las alteraciones inducidas por Gentamicina (G) a nivel de la célula del túbulo renal. Se diseñaron esquemas en animales de experimentación tratados con ambas drogas. Ratas macho Wistar de 180 a 200 g de peso fueron distribuidas en 5 grupos (n=8) y tratadas con: dieta estándar (A); suplementada con 20 mg/Kg/día de TMZ durante 27 días (B); suplementada con 50 mg/Kg/día de G durante 7 días(C); pretratadas 20 días con 20 mg/Kg/día de TMZ y los últimos 7 días con G (D) y tratadas simultáneamente durante 7 días con 20 mg/Kg/día de TMZ y 50 mg/Kg/día de G(E). Se midieron los compuestos nitrogenados urea y creatinina, la excreción de gamma glutamiltranspeptidasa urinaria y se efectuaron estudios estructurales con tinción de hematoxilina-eosina y ultraestructurales. Se utilizó el grupo C como testigo de nefrotoxicidad inducida por G. El pretratamiento durante 20 días con TMZ demostró el efecto protector para la nefrotoxicidad inducida, sin cambios bioquímicos-funcionales, ni alteración de la histoarquitectura, ni de la ultraestructura. El tratamiento simultáneo con TMZ y G no mostró efecto protector. Se concluye que en el modelo de ratas macho Wistar se demuestra el efecto citoprotector de TMZ en tratamiento previo por 21 días. El estudio histológico del tejido renal, bajo estas condiciones, presenta histoarquitectura conservada y función renal normal. Se infiere que el efecto citoprotector de TMZ que impide la nefrotoxicidad inducida por G se debe a la inhibición de la reabsorción y acumulación de Gentamicina en la célula del túbulo proximal del nefrón.

Trimetazidine (TMZ) is a drug used as a cardioprotector since it prevents cell death secondary to myocardial ischemia. Some investigators have attributed protective effect, antioxidant activity and oxygen free radical scavenging abilityt to TMZ. The aim of the present work is to show the cytoprotective effect of TMZ on Gentamicin (G)-induced alterations at the level of the renal tubular cell. Schemes were designed in experimental animals treated with both drugs. Male Wistar rats weighing 200 to 260 g were divided into 5 groups (n=8) and treated with: standard diet (A); standard diet supplemented with 20 mg/Kg/day of TMZ for 27 days (B); standard diet supplemented with 50 mg/Kg/day of G for 7 days (C), pretreated for 20 days with 20 mg/Kg/day of TMZ and for the last 7 days with G (D), and treated simultaneously for 7 days with 20 mg/Kg/day of TMZ and 50 mg/Kg/day of G (E). The nitrogen compounds urea and creatinine were measured and so was the excretion of urinary gamma-glutamyl transpeptidase. Structural studies with hematoxilin and eosin staining and ultrastructural studies were also performed. Gentamicin was used as a control for nephrotoxicity (group C). Pretreatment with TMZ showed a protective effect against induced nephrotoxicity, with no biochemical changes or alterations in the histoarchitecture. Simultaneous treatment with TMZ and G (group E) showed no protective effect. Conclusions: the cytoprotective effect of TMZ on G-induced nephrotoxicity would take place at the level of the proximal tubular cell of the brush border by inhibiting G reabsorption and accumulation.

Nonextractive procedure and precolumn derivatization with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole for trace determination of trimetazidine in plasma by high-performance liquid chromatography with fluorescence detection.

A highly sensitive high-performance liquid chromatographic method with fluorescence detection has been developed and validated in a single laboratory for the trace determination of trimetazidine (TMZ) in human plasma. Fluoxetine (FLX) was used as the internal standard. TMZ and FLX were isolated from plasma by protein precipitation with acetonitrile and derivatized by heating with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole in pH 8 borate buffer at 70 degrees C for 30 min. Separations were performed in the isocratic mode on a Nucleosil CN column with the mobile phase acetonitrile-10 mM sodium acetate buffer (pH 3.5)-methanol (47 + 47 + 6, v/v/v) at a flow rate of 1.0 mL/min. The derivatized samples were excited at 470 nm and monitored at an emission wavelength of 530 nm. Under the optimum chromatographic conditions, a linear relationship with a good correlation coefficient (r = 0.9997, n = 5) was obtained for the peak area ratio of TMZ to FLX and for TMZ concentrations of 1-120 ng/mL. The proposed method has the lowest limits of detection and quantitation reported to date for the determination of TMZ in plasma with values of 0.3 and 0.95 ng/mL, respectively. The values for intra- and interassay precision were satisfactory; the relative standard deviations were < or =4.04%. The accuracy of the method was demonstrated; the recoveries of TMZ from spiked human plasma were 98.13-102.83 +/- 0.2-4.04%. The method has high throughput because of its simple sample preparation procedure and short run time (<10 min). The results demonstrated that the proposed method would have great value when applied in pharmacokinetic studies for TMZ.

Liquid chromatography-tandem mass spectrometry method for the determination of trimetazidine in human plasma.

A sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) method was developed and validated for the determination of trimetazidine (CAS 13171-25-0) in human plasma, using pseudoephedrine as internal standard (IS). Plasma samples were simply pretreated with methanol for deproteinization. The chromatographic separation was performed on a C18 column with a mobile phase of 3 mmol/L ammonium acetate solution-methanol (15:85, v/v) at a flow rate of 0.3 mL/min. The chromatographic separation was achieved in less than 3.2 min. The linearity was established over the concentration range of 1-100 ng/mL. Both intra- and inter-batch standard deviations were less than 9.5%. The method was successfully applied to study the relative bioavailability of trimetazidine hydrochloride tablets in healthy Chinese volunteers and the pharmacokinetic parameters of the reference and test tablets were compared.

Sensitive and rapid method to determine trimetazidine in human plasma by liquid chromatography/tandem mass spectrometry.

A simple, sensitive, and rapid liquid chromatographic/tandem mass spectrometric (LC/MS/MS) method, using electrospray ionization, was developed and validated to quantify trimetazidine in human plasma using propranolol hydrochloride as an internal standard (IS). Samples were prepared by solid-phase extraction and analyzed without drying and reconstitution. The analyte and IS were chromatographed on a C18 reversed-phase column under isocratic conditions using 2 mM ammonium acetate (pH 3.5)-acetonitrile (40 + 60, v/v) as the mobile phase with a run time of 2.0 min. Quantitation was done on a triple-quadrupole mass analyzer API-3000, equipped with turbo ion spray interface and operating in multiple reaction monitoring mode to detect parent --> product ion (m/z 267.2 --> 181.4) transition. The method was validated for sensitivity, accuracy and precision, linearity, recovery, matrix effect, and stability. Linearity in plasma was observed over the concentration range of 1.5-300 ng/mL. Lower limit of quantification achieved was 1.5 ng/mL with precision < 10% using 10 microL injection volume. The mean relative recovery of analyte (97.36%) and IS (99.93%) was consistent and reproducible. Interbatch and intrabatch precision was < 8.0% and the accuracy determined was within +/- 8% in terms of relative error.

Limonene enhances the in vitro and in vivo permeation of trimetazidine across a membrane-controlled transdermal therapeutic system.

The objective of the study was to design membrane-controlled transdermal therapeutic system (TTS) for trimetazidine. The optimization of (i) concentration of ethanol-water solvent system, (ii) HPMC concentration of drug reservoir and (iii) limonene concentration in 2% w/v HPMC gel was done based on the in vitro permeation of trimetazidine across excised rat epidermis. A limonene-based membrane-controlled TTS of trimetazidine was fabricated and evaluated for its in vivo drug release in rabbit model. The in vitro permeation of trimetazidine from water, ethanol and selected concentrations (25, 50 and 75% v/v) of ethanol-water co-solvent systems showed that 50% v/v of ethanol-water solvent system provided an optimal transdermal flux of 233.1+/-3.8 microg/cm(2.)h. The flux of the drug decreased to 194.1+/-7.4 microg/cm(2.)h on adding 2% w/v of HPMC to ethanolic (50% v/v ethanol-water) solution of trimetazidine. However, on adding selected concentrations of limonene (0, 2, 4, 6 and 8% w/v) to 2% w/v HPMC gel drug reservoir, the flux of the drug increased to 365.5+/-7.1 microg/cm(2.)h. Based on these results, 2% w/v HPMC gel drug reservoir containing 6% w/v of limonene was chosen as an optimal formulation for studying the influence of rate-controlling EVA2825 membrane and adhesive-coated EVA2825 membrane. The flux of the drug across EVA2825 membrane (mean thickness 31.2 microm) decreased to 285.8+/-2.2 microg/cm(2.)h indicating that the chosen membrane was effective as rate-controlling membrane. On applying an adhesive coat (mean thickness 10.2 microm) to EVA2825 membrane, the drug flux further decreased to 212.4+/-2.6 microg/cm(2.)h. However, the flux of the drug across adhesive-coated EVA2825 membrane-rat epidermis composite was 185.9+/-2.9 microg/cm(2.)h, which is about 2-times higher than the desired flux. The fabricated limonene-based TTS patch of trimetazidine showed a mean steady state plasma concentration of 71.5 ng/mL for about 14 h with minimal fluctuation when tested in rabbits. It was concluded from the investigation that the limonene-based TTS patch of trimetazidine provided constant drug delivery across the skin in rabbit model.

Sensitive determination of trimetazidine in spiked human plasma by HPLC with fluorescence detection after pre-column derivatization with 9-fluorenylmethyl chloroformate.

A high-performance liquid chromatographic method for the determination of trimetazidine dihydrochloride (TMZ) in spiked human plasma is described. The method is based on the pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) using the fluorimetric detection technique. Fluoxetine HCl (FLX) was used as internal standard. Both, TMZ and FLX were completely derivatized after heating at 50 degrees C for 20 min in borate buffer pH 8.0. Samples were analyzed by high performance liquid chromatography (HPLC) using Zorbax-TMS column (250 mm x 4.6 mm, i.d., 5 microm) and mobile phase consist of acetonitrile, methanol and 20 mM sodium acetate pH 4.7 (44:6:50; v/v/v). Fluorescence detector (FLD) was adjusted at excitation and emission wavelengths; 265 and 311 nm, respectively. The linearity of the method was in the range of 4.5-200 ng/ml. Limits of detection (LOD) and quantification (LOQ) were 1.5 and 4.5 ng/ml, respectively. Trimetazidine recovery was 96.5+/-1.3% (n=6; RSD=2.1%).

Sensitive and rapid LC-ESI-MS method for the determination of trimetazidine in human plasma.

A sensitive method, based on liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS), was developed for the determination of trimetazidine in human plasma. Buflomedil was used as the internal standard (IS). Plasma samples were extracted with a mixture of cyclohexane-diethyl ether (1:1, v/v) and the analytes were chromatographically separated on a phenomenex Luna 5 mu C18 (2) 100A HPLC column with a mobile phase of 10 mM ammonium acetate buffer solution containing 0.1% acetic acid-methanol (45:55, v/v). The electrospray ionization was employed in a single quadrupole mass spectrometer for the analytical determination. The lower limit of quantification (LLOQ) was 0.5 ng/ml for trimetazidine and the measuring ranges were from 0.5 to 200 ng/ml. The intra- and inter-run standard deviation was less than 4.1% and 7.8%, respectively. The method was successfully applied to study the pharmacokinetics of trimetazidine in healthy Chinese volunteers.

Quantification of trimetazidine in human plasma by liquid chromatography-electrospray ionization mass spectrometry and its application to a bioequivalence study.

A rapid, sensitive and specific liquid chromatography-electrospray ionization mass spectrometric (LC-ESI-MS) method has been developed for the quantification of trimetazidine in human plasma. The analyte and the internal standard (pseudoephedrine) were extracted from plasma samples with n-hexane-dichloromethane (1:1, v/v) and analyzed on a C18 column. The chromatographic separation was achieved within 3.5 min using the mobile phase consisting of methanol/0.05% formic acid (80:20, v/v) and the flow rate was 1.0 ml/min. Ion signals m/z 181.0 and 148.0 were measured in the positive mode for trimetazidine and pseudoephedrine, respectively. The calibration curves were linear within the range of 0.4 to approximately 120 ng/ml. The lower limit of quantification (LLOQ) was 0.4 ng/ml with 0.5 ml plasma sample. The intra- and inter-day precisions were lower than 12% in terms of relative standard deviation (RSD). The inter-day relative error (RE) as determined from quality control samples (QCs), ranged from -1.4% to 3.3%. This validated method was successfully applied to the bioequivalent evaluation of two brands of trimetazidine tablets in 20 healthy volunteers.

LC/ESI-MS method for the determination of trimetazidine in human plasma: application to a bioequivalence study on Chinese volunteers.

A rapid liquid chromatography electrospray ionization mass spectrometry (LC/ESI-MS) method with good sensitivity and specificity has been developed and validated for the identification and quantification of trimetazidine in human plasma. Trimetazidine and lidocaine (internal standard) were isolated from plasma samples by protein precipitation with methanol. The chromatographic separation was accomplished on a Xterra MS C18 Column (150 mm x 4.6 mm, 5 microm particle size) with the mobile phase consisting of methanol and water (40:60, v/v) (pH 2.0, adjusted with trifluoroacetic acid), and the flow rate was set at 0.6 mL/min. Detection was performed on a single quadruple mass spectrometer by selected ion monitoring (SIM) mode (m/z 267.0 for trimetazidine and m/z 235.0 for lidocaine) with the retention time at about 3.47 and 5.05 min, respectively. The calibration curve for trimetazidine was satisfactory with regression coefficient 0.9995 over the range of 2.5-100 ng/mL in the plasma. The LOQ (S/N=10) was accordingly 2.5 ng/mL. The intra-day and inter-day precision expressed as relative standard deviation was 2.83-6.10% and 4.83-5.82%. The method was successfully applied to investigate the bioequivalence between two kinds of tablets (test versus reference product) in 19 healthy male Chinese volunteers. After a single 20 mg dose for the test and reference product, the resulting mean of major pharmacokinetic parameters such as AUC(0-24), AUC(0-infinity), Cmax, Tmax and t(1/2) of trimetazidine were (673.1+/-117.6 ng h mL(-1) versus 652.3+/-121.9 ng h mL(-1)), (717.1+/-120.9 ng h mL(-1) versus 692+/-128.6 ng h mL(-1)), (74.85+/-12.13 ng mL(-1) versus 71.93+/-14.32 ng mL(-1)), (2.312+/-0.663 h versus 2.211+/-0.608 h) and (4.785+/-0.919 h versus 4.740+/-0.823 h), respectively, indicating that these two kinds of tablets were bioequivalent in the Chinese population.

Non-extractive procedure followed by LC/APCI MS/MS analysis of trimetazidine in plasma samples for assessing bioequivalence of immediate/modified release formulations.

Trimetazidine and internal standard [1-(2,4,5-trimethoxybenzyl)piperazine] were isolated from plasma by protein precipitation with trifluoroacetic acid. The neutralized supernatant was separated on a C(8) column with methanol-aqueous 0.11% triethylamine adjusted to pH 3.3 with formic acid (1:4, v/v) at a flow rate of 0.85 mL/min. The separation was achieved within 8 min and the column ef fluent was transferred into an ion trap analyzer via an atmospheric pressure chemical ionization interface. The mass analyzer was used in the selected reaction monitoring mode, to enhance detection selectivity. The method was fully validated with a quantitation limit for trimetazidine of 1.5 ng/mL. The method was successfully applied to assess bioequivalence of two immediate and two modified commercially available pharmaceutical formulations containing 20 and 35 mg of trimetazidine, respectively.