Hair analysis, a reliable and non-invasive method to evaluate the contamination by clenbuterol.

The illegal use of clenbuterol has been an increasingly serious issue in today's livestock products industry. It becomes an important project to develop a reliable approach to detect its content in food animals. A simple and sensitive LC-MS/MS method was developed to detect clenbuterol residue in hair, with the low limit of quantitation (LLOQ) about 0.5ng/g. Hogs fed with 340µg/day of clenbuterol for 2 weeks were found a high clenbuterol residue in their hair approximately at 1-2 months after withdrawal. There remained 3.31ng/g clenbuterol in hog hair approximately 5 months after the last administration, focused on the tip of the hair (mainly in hogs with dark hair). An extensive contamination was observed in twenty investigated market hogs whose dark hair obviously had a higher clenbuterol residue than the light ones (p=0.017, t test). Volunteers (60.3 percent) from Xuhui district (Shanghai) were found to have a detectable amount of clenbuterol in their hair (>0.5ng/g). In conclusion, hair residue detection is a reliable method to evaluate the clenbuterol contamination in animals and humans. Meat supply in the Xuhui district might have serious potential safety risks which should be further investigated and discussed to determine the safety range of clenbuterol residue.

Development of a liquid chromatography-isotope dilution mass spectrometry method for quantification of fentanyl in human plasma.

Fentanyl is a potent analgesic drug in relieving chronic pain in patients. In this report, we present a simple, reliable and sensitive LC-ID/MS method for the quantification of fentanyl in human plasma. LC-ID/MS analysis was carried out on a triple quadrupole mass spectrometer operated in positive electrospray ionization multiple-reaction-monitoring using the transitions m/z 337.6 --> 187.9 for fentanyl and m/z 342.6 --> 187.9 for the internal standard (D5-fentanyl). The calibration curve covered the range 0.02-10 ng/mL. The intra- and inter-batch precision were less than 6.739 and 3.126% for fentanyl and IS, with accuracy from 94.16 to 102.0%. The lower limit of quantification was identifiable and reproducible at 0.02 ng/mL. The validated method offered increased sensitivity and wide linear concentration range. This method was successfully adopted for the evaluation of bioequivalence of two fentanyl transdermal preparations after single dose administration to 20 Chinese pain-patients.

Liquid chromatography tandem mass spectrometry method for determination of bisoprolol in human plasma using d5-bisoprolol as the internal standard.

A simple, reliable and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) protocol was developed and validated for quantification of bisoprolol in human plasma. The sample was pretreated with a simple procedure of protein precipitation and an isotope-labeled d5-bisoprolol was used as internal standard. The chromatographic separation was performed on a Capcell Pak C(18) MG III column (100 mm x 2.0 mm, 5 microm). The protonated ion of the analyte was detected in positive ionization by multiple reaction monitoring mode. The mass transition pairs of m/z 326.3 --> 116.3 and m/z 331.3 --> 121.3 were used to detect bisoprolol and the internal standard, respectively. Linearity, accuracy, precision, recovery, matrix effect, dilution test and stability were evaluated during method validation over the range of 0.5-100 ng/mL. The validated method was successfully applied to analyze human plasma samples in a bisoprolol bioavailability study.

Simultaneous determination of itraconazole and hydroxyitraconazole in human plasma by liquid chromatography-isotope dilution tandem mass spectrometry method.

A rapid and sensitive liquid chromatography-isotope dilution tandem mass spectrometry method was developed and validated for quantification of itraconazole (ITZ) and its active metabolite hydroxyitraconazole (OH-ITZ ) in human plasma. The plasma samples were extracted with tert-butyl methyl ether and two isotope-labeled internal standards (D5-itraconazole and D5-hydroxyitraconazole) were used. The chromatographic separation was performed on a Capcell Pak C(18) MG III (100 x 2 mm, 5 microm, Shiseido). The protonated ions of analytes were detected in positive ionization in multiple reaction monitoring mode. The plasma method has a lower limit of quantification of 1 ng/mL with a linearity range of 1-500 ng/mL for ITZ and OH-ITZ using 100 microL of plasma. The recoveries of the method were found to be 69.47-71.98% for ITZ and 75.68-82.52% for OH-ITZ. The intra- and inter-batch precision was less than 11% for all quality control samples at concentrations of 2.5, 200 and 400 ng/mL. These results indicate that the method was efficient with a short run time (4.5 min) and acceptable accuracy, precision and sensitivity.The validated method was successfully applied to analysis of human plasma samples in pharmacokinetics study.

Pharmacokinetics of depside salts from Salvia miltiorrhiza in healthy Chinese volunteers: A randomized, open-label, single-dose study.

BACKGROUND: Depside salts from Salvia miltiorrhiza, with active components of lithospermic acid B (LSB), rosmarinic acid (RA), and lithospermic acid (LA), are a multicomponent drug marketed in China for the treatment of coronary heart disease. OBJECTIVES: The aims of this study were to determine the concentrations of LSB, RA, and LA in human plasma and urine, and to compare the pharmacokinetic properties of depside salts from S miltiorrhiza in healthy Chinese volunteers. METHODS: A randomized, open-label, single-dose study was conducted in healthy Chinese volunteers. Participants were randomly assigned to receive a single intravenous infusion of 100 or 200 mg of depside salts from S miltiorrhiza. Blood was collected through a venous cannula prior to study drug administration (0 min) and at 10, 20, 30, 60, 65, 70, 80, and 90 minutes and 2, 3, 4, 6, 8, 12, and 24 hours after study drug administration. Urine samples were taken before study drug administration (0) and at 0 to 12 and 12 to 24 hours after study drug administration. LSB, RA, and LA concentrations in serum and urine were analyzed by an LC-MS/MS method. Tolerability was determined by clinical assessment; vital signs (ie, blood pressure, heart rate, breathing rate, body temperature) monitoring at baseline and at the end of the study, clinical laboratory tests (ie, hematology, blood biochemistry, hepatic function, renal function, urinalysis), 12-lead ECG measurements, and physical examinations at baseline and after completion of the study. RESULTS: Twelve Chinese volunteers (6 males, 6 females; mean [SD] age, 25.2 [3.8] years; mean height, 165.7 [8.9] cm; mean body mass index, 21.6 [2.5] kg/m(2)) were enrolled in the study. Peak plasma concentrations of LSB, RA and LA were observed at 0.3 to 1 hour following the 1-hour intravenous infusion, with respective mean (SD) Cmax of 4925 (1861), 174 (61), and 361 (101) ng/mL for the 100-mg dose and 10,285 (2259), 308 (77), and 674 (85) ng/mL for the 200-mg dose. The AUClast values for LSB, RA, and LA were 4537 (1265), 129 (28), and 1229 (330) ng/mL/h, respectively, for the 100-mg dose and 10,426 (2589), 260 (53), and 2792 (729) ng/mL/h for the 200-mg dose. No significant difference in pharmacokinetic parameters was observed between male and female subjects. Three metabolites were found in the plasma with low concentrations. The urinary excretion recoveries of LSB, RA, and LA were 0.58% (0.42%), 25.21% (20.61%), and 10.02% (7.72%) for the 100-mg dose and 0.38% (0.18%), 20.11% (10.50%), and 6.34% (3.20%) for the 200-mg dose. No adverse events were reported by the subjects or found by the investigators in the analysis of vital signs, 12-lead ECG measurements, physical examinations, or clinical laboratory tests. CONCLUSIONS: Following single intravenous infusion of 100 or 200 mg of depside salts from S miltiorrhiza to healthy Chinese subjects, no statistical differences in pharmacokinetic parameters were observed between males and females. The 2 doses of depside salts from S miltiorrhiza were clinically well tolerated during the study.

Development and validation of a liquid chromatography-isotope dilution tandem mass spectrometry for determination of olanzapine in human plasma and its application to bioavailability study.

A simple, reliable and sensitive liquid chromatography-isotope dilution mass spectrometry (LC-ID/MS) was developed and validated for quantification of olanzapine in human plasma. Plasma samples (50 microL) were extracted with tert-butyl methyl ether and isotope-labeled internal standard (olanzapine-D3) was used. The chromatographic separation was performed on XBridge Shield RP 18 (100 mm x 2.1 mm, 3.5 microm, Waters). An isocratic program was used at a flow rate of 0.4 m x min(-1) with mobile phase consisting of acetonitrile and ammonium buffer (pH 8). The protonated ions of analytes were detected in positive ionization by multiple reactions monitoring (MRM) mode. The plasma method, with a lower limit of quantification (LLOQ) of 0.1 ng x mL(-1), demonstrated good linearity over a range of 0.1 - 30 ng x mL(-1) of olanzapine. Specificity, linearity, accuracy, precision, recovery, matrix effect and stability were evaluated during method validation. The validated method was successfully applied to analyzing human plasma samples in bioavailability study.

[Simultaneous determination of the inhibitory potency of compounds on the activity of five cytochrome P-450 enzymes using a cocktail probe substrates method].

This study developed a method for simultaneously assessing the inhibitory potency of compounds on five major cytochrome P-450 ( CYP450) enzymes using a cocktail of probe substrates. A cocktail selective substrates consisting of the phenacetin (PN, CYP1A2), dextromethorphan (DM, CYP2D6), tolbutamide (TB, CYP2C9), omeprazole (OPZ, CYP2C19) and midazolam (MPZ, CYP3A4) was incubated with human liver microsomes. The concentrations of the substrate metabolites paracetamol, dextrorphan, 4-hydroxytolbutamide, 5-hydroxyomeprazole and 1'-hydroxymidazolam were determined by LC/MS/MS in a single assay sample. The method was validated by incubating known CYP inhibitors--alpha-naphthoflavone (ANF, CYP1A2), quinidine (QND, CYP2D6), sulfaphenazole (SUL, CYP2C9), fluconazole (FLU, CYP2C19) and ketoconazole (KET, CYP3A4) with the individual substrates and with the substrate cocktail. The IC50 values were then determined. The IC50s (micromol x L(-1)) were in good agreement with those obtained with individual substrates (alpha-naphthoflavone, 0.18 vs 0.26; quinidine, 0.058 5 vs 0.058 4; sulfaphenazole, 0.48 vs 0.45; fluconazol, 17.5 vs 11.4; ketoconazole, 0.22 vs 0.24) and with previously reported values in the literature. This cocktail probe substrate method can be utilized for the rapid simultaneous determination of the inhibition potential of compounds on the five CYP450 enzymes.

Oral Bioavailability and Mass Balance Studies of a Novel Anti-arrhythmic Agent Sulcardine Sulfate in Sprague-Dawley Rats and Beagle Dogs.

BACKGROUND AND OBJECTIVES: Sulcardine sulfate is a newly developed candidate drug used to control arrhythmias. The aim of this research was to investigate the pharmacokinetics, bioavailability and excretion characteristics of sulcardine in animals. METHODS: Sprague-Dawley rats were orally and intravenously given sulcardine at 20 and 40 mg/kg. Beagle dogs were also orally and intravenously dosed at 10 mg/kg. Both [3H]-labeled sulcardine and unlabeled sulcardine were given to rats. Feces, urine and bile were collected at 0-72 h for mass balance study. The contents of unlabeled sulcardine and radioactivity in samples were determined by a validated LC-MS/MS method and by liquid scintillation counting, separately. RESULTS: Sulcardine was rapidly eliminated in rats after dosing. The oral bioavailability was 34-35 % in rats, while a higher exposure was observed in dogs (bioavailability = 62.7 %). More than 90 % of dosed sulcardine was recovered, and approximately 20-40 % of the dose excreted into urine as the original form, and the remaining was found in feces and bile, most of which (about 40 %) was transformed into metabolites. No difference was observed between sexes. Metabolism may occur to a large extent after oral administration in rats but to a smaller extent in dogs. CONCLUSIONS: Sulcardine was extensively absorbed in both rats and dogs after oral administration. The mass balance data indicated that sulcardine was widely metabolized in rats after oral administration.

Bioequivalence and pharmacokinetic evaluation of two formulations of risperidone 2 mg : an open-label, single-dose, fasting, randomized-sequence, two-way crossover study in healthy male Chinese volunteers.

BACKGROUND: Risperidone is a benzisoxazole derivate and is effective in the treatment of schizophrenia and other psychiatric illnesses in adults and children. Although there are a few reports in the literature regarding the pharmacokinetic characteristics of risperidone, insufficient data on its pharmacokinetic properties in a Chinese population are available. OBJECTIVE: To meet the requirements for marketing a new generic product, this study was designed to compare the pharmacokinetic properties and bioequivalence of two 2 mg tablet formulations of risperidone: a newly developed generic formulation (test) and a branded formulation (reference) in healthy adult male Chinese volunteers. METHODS: A single-dose, open-label, randomized-sequence, 2 × 2 crossover study was conducted in fasted healthy male Chinese volunteers. Eligible participants were randomly assigned in a 1:1 ratio to receive 1 tablet (2 mg each) of the test formulation (Risperidone tablet; Dr. Reddy's Laboratories Ltd., Hyderabad, India) or the reference formulation (Risperdal(®) tablet; Xian-Janssen Pharmaceutical Ltd., Xi-an, China), followed by a 2-week washout period and subsequent administration of the alternate formulation. The study drugs were administered after a 10-hour overnight fast. Plasma samples were collected over 96 hours. Plasma concentrations of the parent drug, risperidone, and its active metabolite, 9-hydroxy-risperidone, were analyzed by a liquid chromatography-tandem mass spectrometry method. The formulations would be considered bioequivalent if the 90% confidence intervals (CIs) of the natural log-transformed values were within the predetermined 80-125% equivalence range for the maximum plasma drug concentration (Cmax) and the area under the plasma concentration-time curve (AUC), in accordance with guidelines issued by the US Food and Drug Administration. Assessment of tolerability was based on recording of adverse events (AEs), monitoring of vital signs, electrocardiograms, and laboratory tests at baseline and at completion of the study. RESULTS: A total of 24 healthy male Chinese volunteers (mean age 22.9 years [standard deviation (SD) 2.7, range 19.2-27.1]; weight 63.2 kg [SD 7.0, range 52.0-78.0]; and height 171.3 cm [SD 6.1, range 162.0-187.0]) were enrolled, and all completed the study. For the parent drug, risperidone, the 90% CIs of the relative values (test vs. reference) of the Cmax, AUC from time zero to time t (AUCt), and AUC from time zero to infinity (AUC∞) were 97.0-124.0%, 92.7-115.1%, and 92.8-114.2%, respectively. For the active metabolite, 9-hydroxy-risperidone, the values were 104.4-117.7%, 101.0-113.7%, and 100.4-113.4%, respectively. The two formulations met the predetermined criteria for bioequivalence. A total of 73 AEs were observed in 24 subjects during the study. The most common AE was sedation (48 events), followed by nasal reactions (14 events), postural hypotension (3 events), hypertriglyceridemia (2 events), dizziness (4 events), nausea (1 event), and anorexia (1 event). Their severity was as follows: 16 were mild, 57 were moderate, and none were severe. The majority of the AEs were considered to be related (48 events) or probably related (23 events) to the study medication. No clinically significant abnormalities on physical examination, vital sign measurements, or electrocardiographic recordings were reported. No serious AEs were reported. CONCLUSIONS: The data from this study in healthy adult male Chinese subjects suggest that the test formulation met the regulatory criteria for bioequivalence to the reference formulation, on the basis of the rate and extent of absorption. Both formulations were well tolerated.

Simultaneous determination of six alkaloids and one monoterpene in rat plasma by liquid chromatography-tandem mass spectrometry and pharmacokinetic study after oral administration of a Chinese medicine Wuji Pill.

A simple and sensitive method for simultaneous determination of seven active constituents, jatrorrhizine, berberine, coptisine, palmatine, evodiamine, rutacarpine and paeoniflorin, from a Chinese medicine Wuji Pill in rat plasma was developed based on a liquid chromatography and tandem mass spectrometry method. The separation of these seven compounds was carried out on a Shiseido CAPCELL PAK C(18) column using a mobile phase consisting of acetonitrile (containing 0.1% formic acid and water (containing 0.1% formic acid and 10 mmol/L ammonium acetate) and carbamazepine as an internal standard. Electrospray ionization in positive-ion mode and multiple reaction monitoring was used to identify and quantitate active components. All calibration curves gave good linearity (r>0.993) over the concentration range from 0.42-208.0 ng/mL to 4.18-418.0 ng/mL for all components. The precision of the in vivo study was evaluated by intra- and inter-day assays and the percentages of relative standard deviation were all within 15%. The method was successfully applied to pharmacokinetic study of all six alkaloids and one monoterpene in rat plasma after oral administration of the Wuji Pill.

Evaluating human liver reserve function by measuring serum concentrations of phenacetin and its metabolites.

OBJECTIVES: To evaluate human liver reserve function (LRF) by a simple and efficient method for measuring serum concentrations of phenacetin and its metabolites. METHODS: Overall 20 patients with liver cirrhosis (Child-Pugh score ≥ 7, aged 48-79 years), 30 healthy young volunteers (aged 18-40 years), and 20 healthy elderly volunteers (aged 61-80 years) were enrolled. All participants received a single oral dose of 0.5 g phenacetin. Liquid chromatography tandem mass spectrometry was used to determine the serum concentrations of phenacetin and its metabolites, including acetaminophen, acetaminophen glucuronide and acetaminophen sulfate. RESULTS: The serum concentration of phenacetin was significantly higher in cirrhotic patients than those in either of the healthy volunteer groups (P < 0.001). It was higher in healthy elderly volunteers than that in healthy young ones but there was no statistically significant difference (P > 0.05) between them. The serum concentrations of acetaminophen, acetaminophen glucuronide and acetaminophen sulfate were significantly lower in cirrhotic patients than in the healthy controls (P < 0.001). The serum concentrations of these three metabolites in healthy elderly volunteers were lower than those in healthy younger volunteers but again, there was no statistical significant difference (P > 0.05). The serum concentration of acetaminophen in healthy male volunteers was significantly higher than that in the women (P < 0.05). CONCLUSION: Monitoring cytochrome P450 1A2 (CYP450 1A2)-mediated phenacetin metabolism is a simple and efficient method for evaluating human LRF. This method would warrant further validation in a large cohort clinical study.

Relative bioavailability of generic and branded acetylcysteine effervescent tablets: A single-dose, open-label, randomized-sequence, two-period crossover study in fasting healthy Chinese male volunteers.

BACKGROUND: Acetylcysteine may be used as a muco- lytic agent for the treatment of chronic bronchitis, chronic obstructive pulmonary disease, and other pulmonary diseases complicated by the production of viscous mucus. However, little is known of its pharmacokinetic properties when given orally in healthy volunteers, particularly in a Chinese Han population. This study was conducted to provide support for the marketing of a generic product in China. OBJECTIVE: The purpose of this study was to compare the pharmacokinetics and relative bioavailability of a generic test formulation and a branded reference formulation of acetylcysteine in fasting healthy Chinese male volunteers. METHODS: A single-dose, open-label, randomized-sequence, 2-period crossover design with a 7-day washout period between doses was used in this study. Healthy Chinese male nonsmokers aged 18 to 40 years with a body mass index (BMI) of 19 to 25 kg/m(2) were selected. Eligible volunteers were randomly assigned to receive acetylcysteine 600 mg PO as either the test formulation (3 tablets of 200 mg each) or reference formulation (1 tablet of 600 mg) under fasting conditions. A total of 15 serial blood samples were collected over a 24-hour interval, and total plasma acetylcysteine concentrations were analyzed by a validated liquid chromatography-isotopic dilution mass spectrometry method. Pharmacokinetic parameters (C(max), T(max), t(½) AUC(0-t), and AUC(0-∞) were calculated and analyzed statistically. The 2 formulations were considered bioequivalent if the 90% CIs of the log-transformed ratios (test/reference) of C(max) and AUC were within the predetermined bioequivalence ranges (70%-143% for C(max); 80%-125% for AUC), as established by the State Food and Drug Administration of China. Tolerability was determined by vital signs, clinical laboratory tests, 12-lead ECGs, physical examinations, and interviews with the subjects about adverse events (AEs). RESULTS: A total of 24 healthy Chinese Han male volunteers were enrolled in and completed the study (mean [SD] age, 25.0 [2.4] years; height, 173.0 [5.6] cm; weight, 65.9 [6.4] kg; BMI, 22.0 [1.7] kg/m(2)). No formulation, period, or sequence effects were observed. The 90% CIs for the log-transformed C(max), AUC(0-t), and AUC(0-∞) were 89.7% to 103.8%, 86.7% to 101.7%, and 87.7% to 102.4%, respectively, which met the predetermined criteria for assuming bioequivalence. Two subjects (8.3%) experienced 2 mild AEs (increase in total bile acid and prolongation of the QT interval), which were not considered to be related to study drug administration. CONCLUSIONS: This single-dose study of acetylcysteine 600 mg PO found that the 3 tablets of the generic test formulation and 1 tablet of the branded reference formulation met the regulatory criteria for assuming bioequivalence in these fasting healthy Chinese male volunteers. Both formulations were generally well tolerated.

Pharmacokinetics and bioequivalence evaluation of two losartan potassium 50-mg tablets: A single-dose, randomized-sequence, open-label, two-way crossover study in healthy Chinese male volunteers.

BACKGROUND: Losartan is a nonpeptide angiotensin II receptor antagonist used as an antihypertensive agent. The relative bioavailability of a newly developed tablet compared with an established branded formulation has not been reported in a Chinese population. OBJECTIVE: To meet the requirements for marketing a new generic product, the study was designed to compare the pharmacokinetic parameters and relative bioavailability of a new generic losartan potassium 50-mg tablet (test formulation) with a branded 50-mg tablet (reference formulation) in healthy Chinese male volunteers. METHODS: A single-dose, randomized-sequence, openlabel, 2-way crossover study was conducted in healthy Chinese male volunteers. Eligible participants were randomly assigned in a 1:1 ratio to receive a single 50-mg tablet of the test or reference formulation, followed by a 1-week washout period and then administration of the alternate formulation. The study drugs were administered after a 10-hour overnight fast. Plasma samples were collected over 36 hours. Tolerability was evaluated by recording adverse events (AEs) and monitoring vital signs, ECGs, and laboratory tests at baseline and at completion of the study. Plasma concentrations of losartan and its active metabolite (EXP3174) were analyzed by LC-MS/MS. Pharmacokinetic parameters, including C(max), AUC(0-36), and AUC(0-infinity), were calculated. If the 90% CIs for the log-transformed values of AUC were within 80% to 125%, and that of C(max) was within 70% to 143%, the 2 products would be considered bioequivalent according to the guidelines of the US Food and Drug Administration and the State Food and Drug Administration of China. RESULTS: Twenty-seven healthy Chinese male volunteers participated in this study (mean [SD] age, 24.5 [2.3] years [range, 20-29 years]; weight, 64.6 [4.0] kg [range, 60.0-75.0 kg]; height, 172.2 [4.8] cm [range, 165.0183.0 cm]; and body mass index, 21.8 [1.2] kg/m(2) [range, 20.0-25.0 kg/m(2)]). One volunteer (3.7%) experienced an AE (microscopic hematuria) after administration of the test formulation. This resolved spontaneously after 10 days and was considered by the investigator as mild; the relationship with the study drug was uncertain. No serious AEs were reported. Both formulations were associated with significant reductions in systolic and diastolic blood pressure and significant increases in heart rate compared with baseline values (all, P < 0.05). No period, formulation, or sequence effects were observed for any pharmacokinetic parameter, except for a significant subject effect. For parent losartan, the 90% CIs for the ratios (test/reference) of C(max), AUC(0-36), and AUCAUC(0-infinity) were 83.65% to 113.36%, 89.79% to 98.25%, and 90.95% to 99.55%, respectively. For the metabolite EXP3174, the 90% CIs for the ratios of C(max), AUC(0-36), and AUCAUC(0-infinity) were 93.49% to 103.61%, 96.79% to 104.09%, and 97.06% to 105.83%. Both C(max) and AUC met the predetermined criteria for assuming bioequivalence. The relative bioavailability of the test formulation to the reference formulation was 93.92% for losartan and 100.40% for EXP3174. CONCLUSIONS: In this small study in healthy Chinese male volunteers, a single 50-mg oral dose of a losartan potassium tablet (test formulation) met the regulatory criteria for assuming bioequivalence to the established reference formulation. Both formulations were well tolerated.

Pharmacokinetic and bioequivalence comparison between orally disintegrating and conventional tablet formulations of flurbiprofen: a single-dose, randomized-sequence, open-label, two-period crossover study in healthy Chinese male volunteers.

BACKGROUND: Flurbiprofen, an NSAID, is used for the treatment of inflammation and pain caused by rheumatoid arthritis and osteoarthritis as well as soft-tissue injuries. A new orally disintegrating tablet (ODT) of flurbiprofen has recently been developed; this study was conducted to provide support for this drug to obtain marketing authorization in China. OBJECTIVE: The aim of the study was to compare the pharmacokinetic properties and bioequivalence of flurbiprofen 50-mg ODT (test) with a conventional flurbiprofen 50-mg tablet (reference) under fasting conditions in healthy volunteers. METHODS: This was a single-dose, randomized-sequence, open-label, 2-period crossover study. Healthy, nonsmoking Chinese male volunteers were randomly assigned to receive 150 mg (administered as three 50-mg tablets) of either the test or reference formulation of flurbiprofen, followed by a 7-day washout period and administration of the alternate formulation. Study drugs were administered after a 12-hour overnight fast. Blood samples were collected before dosing and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours after dosing. Serum flurbiprofen concentrations were analyzed using a validated nonstereospecific liquid chromatography/tandem mass spectrometry method. Pharmacokinetic parameters, including C(max), T(max), t(1/2), AUC(0-24), and AUC(0-infinity), were calculated and analyzed statistically. C(max), AUC(0-24), and AUC(0-infinity) were used to test for bioequivalence after natural logarithm (ln)-transformation. Tolerability was evaluated throughout the study by clinical assessments, vital sign monitoring, physical examinations, 12-lead ECG, clinical laboratory tests, and questioning subjects about adverse events (AEs). RESULTS: A total of 20 Chinese males (mean [SD] age, 21.4 [2.5] years [range, 19-28 years]; height, 174.4 [4.2] cm [range, 169-183 cm]; weight, 63.2 [5.1] kg [range, 56-78 kg]; body mass index, 20.8 [1.4] kg/m(2) [range, 19-24 kg/m(2)]) completed the study. No period or sequence effect was observed. The 90% CIs for the ln-transformed ratios of Cmax, AUC(0-24), and AUC(0-infinity) were 99.9% to 115.9%, 97.8% to 107.9%, and 100.3% to 110.9%, respectively, meeting the predetermined criteria for bioequivalence. Two subjects (10.0%) experienced 1 of 2 mild AEs (increase in total bilirubin and dizziness), which were not considered to be associated with study drug administration. CONCLUSIONS: This single-dose 150-mg (three 50-mg tablets) study of each formulation of flurbiprofen found that the test and reference products met the regulatory criteria for bioequivalence in these fasting healthy Chinese male volunteers. Both formulations were generally well tolerated. State Food and Drug Administration of China study registration number: 2005L04356.