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Epinephrine 5 mg administered via the intranasal (IN) route was shown to be bioequivalent to epinephrine 0.3 mg administered via the intramuscular (IM) route in our preliminary study.To investigate the pharmacokinetics and pharmacodynamics of IN and IM epinephrine absorption in a larger group of healthy adults (n = 12).Each subject was administered IN saline, IN epinephrine (5 mg), and IM epinephrine (0.3 mg) on 3 separate days. Plasma epinephrine levels were determined using liquid chromatography-tandem mass spectrometry.IN epinephrine administration showed significant systemic absorption compared to IN saline control with the areas under the curve (AUC0-180 min) of 4.4 (4.9) ± 4.0 and 0.2 (0.5) ± 0.3 ng.min/mL, respectively; the values are mean (median) ± standard deviation. IN epinephrine absorption was about 0.5-fold that of IM epinephrine (AUC0-180 min 10.0 (9.2) ± 8.6 ng.min/mL), but the difference was not statistically significant (p = 0.16). The mean peak epinephrine concentration and the time to reach it were also not significantly different between the IN and IM routes. The corresponding values were 120 pg/mL and 41 min for IN, and 209 pg/mL and 41 min for IM, respectively.The systemic absorption of IN epinephrine 5 mg was significantly different from the control IN saline and about 0.5-fold that of IM epinephrine 0.3 mg. Although epinephrine administration via the less invasive IN route is safe and feasible, further investigations are necessary to achieve an adequate and consistent systemic absorption comparable to that of the conventional IM injection.

Aim To determine the prevalence and to identify the risk factors of chloroquine maculopathy (CM), and to evaluate the association of plasma chloroquine (CQ) and desethylchloroquine (DCQ) levels and CM. Methods Rheumatoid arthritis (RA) patients who had taken CQ for at least 6 months and stable CQ dosage for at least 2 months were included. CM was diagnosed by dilated ocular examination and automated visual field. Plasma CQ and DCQ levels were determined by liquid chromatography tandem mass spectrometry method. Logistic regression was used to explore risk factors associated with CM. Results One hundred and ninety-three patients were included with median CQ duration (range) of 50.2 months (6.0–269.8) and cumulative dose of 137.4 g (16.4–1226.5). The prevalence of CM was 13.5%. Factors associated with CM identified from univariate analysis were age > 60 years, and creatinine clearance with odds ratio (OR) (95%CI) of 5.79 (2.42, 13.84), and 0.98 (0.96, 1.00). In multivariate analysis, older age, usage > 5 years, and current dose from 2.5 mg/kg ideal body weight [IBW]/day were the factors significantly associated with CM with OR of 5.89 (2.38, 14.57), 2.94 (1.10, 7.83), and 3.32 (1.04, 10.60), respectively, while plasma CQ and DCQ showed no association with CM. Conclusions The prevalence of CM was 13.5% among RA patients taking CQ for at least 6 months. Age > 60 years, duration of CQ usage > 5 years and current CQ dose ≥2.5 mg/kg IBW/day were the risk factors for CM. The plasma CQ or DCQ levels demonstrated no correlation in developing CM.

To evaluate the bioequivalence of50 mg cilostazol tablets manufactured locally (Citazol®) and originally (Pletaal®) in healthy Thai volunteers.An open-label, single dose, randomized, two-period, two-sequence, crossover study in 30 healthy volunteers. Each volunteer received a 50 mg cilostazol tablet of bothformulations with a washoutperiodofat least 14 days. Blood samples were obtained atpre-dose and over 48 hours after dosing. Cilostazolplasma concentrations were quantified by using liquid chromatography with tandem mass spectrometry (LC-MS/MS).The 30 volunteers completed the entire study. The geometric mean ratios (GAM) (test/reference) between the two formulations of cilostazol were 112.38% (101.70%-124.19%) for Cmax; 103.66% (96.06%-111.86%) for AUC0-48; and 95.14% (86.12%-105.12%)forAUC0-∞. There was no statistical difference ofthe Tmax between the twoformulations (p0.05). No serious adverse events related to the studied drugs were found.No significant difference in the analyzed pharmacokineticparameters was found between the twoformulations of 50 mg cilostazol tablets. Therefore, it can be concluded that these two cilostazol tablet formulations were considered bioequivalent.

Femoral nerve block is commonly established for postoperative analgesia in total knee arthroplasty but no evidence of plasma bupivacaine level has been reported.Determine the plasma concentrations of bupivacaine in patients who had single-injection of femoral nerve block.A prospective observational study was undertaken with 25 patients scheduled for unilateral total knee arthroplasty under spinal anesthesia and single shot femoral nerve block with 20 mL of 0.5% bupivacaine. Venous blood samples were collected at 0, 5, 10, 15, 30, 60, 90, and 120 minutes after femoral nerve block. Plasma bupivacaine levels were analyzed by high performance liquid chromatography with tandem mass spectrometry.Four males and 21 females, ASA I-II were enrolled in the present study. Mean age, body mass index, and serum albumin level were 69.9 +/- 5.95 years, 27 +/- 3.67 kg/m2, and 4.46 +/- 0.26 mg/dL, respectively. The median of peak plasma concentration was 538.35 ng/mL (min = 176.30, max = 1,383.99) at 60 minutes after femoral nerve block, while the maximal plasma concentration of bupivacaine was 1,883.39 ng/mL at 10 minutes. None showed signs or symptoms of bupivacaine toxicity.Peak plasma concentrations of bupivacaine were demonstrated at 60 minutes after a single shot femoral nerve block, and no signs or symptoms of bupivacaine toxicity were observed Therefore, single shot femoral nerve block with 20 mL of 0.5% bupivacaine is safe.

Background: We performed a nested case-control study of Thai women prescribed nevirapine-based antiretroviral therapy (ART) to determine if development of rash or hepatotoxicity during the first 24 weeks of treatment is associated with plasma nevirapine concentrations. Method: From May 2005-January 2007, we enrolled 217 women initiating nevirapine-based ART in Thailand. Cases (n = 54) were women who during the first 24 weeks of treatment with nevirapine developed rash (any grade, n = 42) or hepatotoxicity (≥grade 2, n = 22, [10 had both]). Controls were the next enrolled woman who was confirmed not to meet the case definition during the first 24 weeks. Nevirapine concentrations after the two week lead-in dose of 200 mg once daily were compared between cases and controls by Wilcoxon rank-sum tests. Results: We found no difference in Week 2 pre-dose nevirapine concentrations: cases median = 3,528 ng/mL (n = 24), controls median = 3,150ng/mL (n = 30), p = 0.5. Cases had higher post-dose nevirapine concentrations (median = 6,150 ng/mL, n = 21) than controls (median = 4,746 ng/mL, n = 20, p = 0.02). When limited to cases who developed a rash at Week 2, we found no differences in the pre-dose (median = 3,270 ng/mL, n = 12, p = 0.9) or post-dose nevirapine concentration (median = 5,443 ng/mL, n = 9, p = 0.4) compared with controls. Conclusions: We cannot conclude definitively that nevirapine concentrations at two weeks of therapy are associated with rash or hepatotoxicity. It is unlikely that therapeutic drug monitoring at that time will improve identification of patients at risk for rash or hepatotoxicity.

Glucosamine sulfate is widely used to relieve symptoms from osteoarthritis. This study was conducted in order to determine pharmacokinetic and assessed the in-vivo bioequivalence of two different hard capsule formulations of glucosamine sulfate when administered as equal dose of 1,500 mg. The two formulations contain different salt form where reference product is NaCl and test product is KCl. A randomized, single dose, two-treatment, two- period, two-sequence crossover study was conducted. Twenty-six healthy volunteers were recruited at Siriraj Clinical Research Unit. Each subject received a dose of 1,500 mg glucosamine sulfate of both formulations with at least a week washout period. Blood samples were collected over 24 hrs after the oral administration. The plasma fractions were analyzed for glucosamine using LC-MS/MS. Twenty-six volunteers enrolled in the present study. Pharmacokinetic parameters were determined using the non-compartment model. The 90% confidence intervals of the mean ratios (test/reference) of Cmax (111.19%; ranged from 93.01%-132.92%) and AUC0-t (107.24; ranged from 87.16%-131.93%) was not contained within the equivalence criteria of 80.00-125.00% (USFDA, 2003). However, this study showed the high intra-individual CV calculated from ANOVA for Cmax and AUC0-24 (≥ 30%). Thus, based on equivalence limits of USFDA (2003), the test product is not bioequivalent to the reference product in terms of rate and extent of absorption. However, concerning the wider equivalence criteria for highly variable drug (EMEA, 2008), the test product is bioequivalent to the reference formulation in terms of rate and extent of absorption.

Background Our earlier genome-wide expression study revealed up-regulation of a tryptophan-catabolizing enzyme, indoleamine 2,3-dioxygenase (IDO1), in patients with scrub typhus. This gene has been previously reported to have anti-microbial activity in a variety of infectious diseases; therefore, we aimed to prove whether it is also involved in host defense against Orientia tsutsugamushi (OT) infection. Methodology/Principal Findings Using LC-MS, we observed an increased ratio of serum L-kynurenine to serum L-tryptophan in patients with scrub typhus, which suggests an active catalytic function of this enzyme upon the illness. To evaluate the effect of IDO1 activation on OT infection, a human macrophage-like cell line THP-1 was used as a study model. Although transcription of IDO1 was induced by OT infection, its functional activity was not significantly enhanced unless the cells were pretreated with IFN-γ, a potent inducer of IDO1. When the degree of infection was evaluated by quantitative real-time PCR, the relative number of OT 47 kDa gene per host genes, or infection index, was markedly reduced by IFN-γ treatment as compared to the untreated cultures at five days post-infection. Inhibition of IDO1 activity in IFN-γ treated cultures by 1-methyl-L-tryptophan, a competitive inhibitor of IDO1, resulted in partial restoration of infection index; while excessive supplementation of L-tryptophan in IFN-γ treated cultures raised the index to an even higher level than that of the untreated ones. Altogether, these data implied that IDO1 was partly involved in restriction of OT growth caused by IFN-γ through deprivation of tryptophan. Conclusions/Significance Activation of IDO1 appeared to be a defensive mechanism downstream of IFN-γ that limited intracellular expansion of OT via tryptophan depletion. Our work provided not only the first link of in vivo activation of IDO1 and IFN-γ-mediated protection against OT infection but also highlighted the promise of this multifaceted gene in scrub typhus research., Author Summary Scrub typhus is a potentially life-threatening infectious disease that is a major cause of acute undifferentiated fever in Asia-Pacific region. It is caused by Orientia tsutsugamushi (OT), an obligatory intracellular gram-negative bacterium in family rickettsiaceae. Earlier studies have shown that IFN-γ is essential in protection against OT infection in animals and cell-based models, but molecular mechanisms underlying such phenomenon remain largely unclear. In the present study, we are the first to demonstrate that activation of IDO1, a key enzyme in tryptophan-degrading pathway, is a mechanism downstream to IFN-γ in control of OT infection. IDO1 was found active in patients with acute scrub typhus. Subsequent in vitro experiments suggested that IDO1 restrains OT growth via deprivation of tryptophan, an important material for proliferation of OT, rather than via production of its downstream anti-microbial metabolites. Since IDO1 is a multifaceted gene that also plays a part in several processes of the immune system, including induction of tolerogenic responses; other possible consequences of IDO1 activation deserve further investigation in a more complex experimental model as well as in naturally infected human before subsequent clinical implication of this basic knowledge can be ultimately applied.

To determine the bioequivalence of 10 mg dose of ramipril tablets between the test product (Ramtace 10 mg, Unison Laboratories, Thailand) and the reference product (Tritace 10 mg, Aventis Pharma SPA, Italy).The present study was carried out with a single dose, 2-treatment, 2-period, 2-sequence randomized crossover design under fasting condition with a minimum of 14 days washout period in 24 healthy Thai male and female volunteers. Plasma samples for determination of ramipril and ramiprilat were obtained pre-dose and at frequent intervals for up to 72 h post dose. Ramipril and ramiprilat plasma concentrations were quantified by a validated method employing high performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). All ofthe pharmacokinetic parameters were investigated using non-compartmental analysis.The result demonstrated the 90% confidence interval (90%CI) of the geometric mean ratio (test/reference) of C max, AUC(0-72) and AUC(0-infinity) of ramipril were 97.26% (84.50%-111.93%), 100.70% (89.47%-113.34%) and 100.29% (88.90% 113.15%), respectively. For ramiprilat, the 90% CI for C max, AUC(0-72), and AUC(0-infinity) were 108.87% (103.00%-115.07%), 104.93% (100.50%-109.55%) and 103.30% (98.03%-108.85%), respectively.the 90% confidence intervals for log-transformed geometric mean test/reference formulation ratios of primary parameters were entirely within 80.00%-125.00%. Thus, it can be concluded that the test formulation was bioequivalent to the reference formulation.

Background: The generic product of trimetazidine, an anti-anginal agent, is currently available in Thailand. Bioequivalence study is used to compare rate and extent of absorption between generic and innovator’s products. Objective: To determine the bioavailability of two modified release tablets of 35mg trimetazidine dihydrochloride (Matenol ® MR; generic product and Vastarel ® MR; innovator’s product) Materials and methods: The study was conducted according to a single-dose, two-treatment, two-period, two- sequence randomized crossover design under fasting and fed conditions with a minimum of 7 days washout period. Twenty-four healthy Thai male and female volunteers were enrolled; however, only twenty-two subjects in the fasting group and twenty-three subjects in the fed group were completed the studies. For both conditions, each volunteer received a 35mg trimetazidine modified release tablet of both formulations. Every volunteers were obtained blood samples 16 times over a period of 24 hours after each oral administration.The trimetazidine plasma concentrations were quantified using a validated method employing liquid chromatography with tandem mass spectrometry with the lower limit of quantification of 0.25 ng/mL. All of the pharmacokinetic parameters were investigated using non- compartmental analysis model. Results: The 90% confidence interval of the geometric mean ratio of C max , AUC 0-t and AUC 0-∞ were within the equivalence criteria (80.00-125.00%) which were 105.53% (95.71%-116.36%), 104.28% (96.24%-112.98%, and 105.26% (96.61%-114.67%) under fasting condition and 110.21% (102.72%-118.25%), 101.95% (94.33%- 119.19%), and 99.7% (91.18%-109.02%) under fed condition, respectively. No statistical differences of median T max ( p >0.05) between two formulations in both conditions were observed. Furthermore, both preparations were well tolerated and had a few non-serious adverse events including nausea, dizziness, drowsiness and headache. Conclusion: These two trimetazidine products have comparable bioavailability.

Objective: The purpose of this study was to compare the bioequivalence of 10 mg tablets of olanzapine between a generic drug (Olapin ® -10; Unison Laboratories Co., Ltd., Thailand) and a reference drug (Zyprexa ® ,Eli Lilly, England) in healthy volunteers. Subjects and methods: A single dose, randomized, 2-period, 2-sequence, crossover study was conducted in 24 healthy Thai male and female volunteers. Each volunteer received a 10 mg tablet of the reference or test drug under fasting condition with a washout period of at least 21 days. Blood samples were obtained at pre-dose and at various time points up to 120 hours after dosing. Olanzapine plasma concentrations were quantified by a validated method employing liquid chromatography with tandem mass spectrometry (LC-MS/MS). Results: 24 volunteers completed both treatment periods. The geometric mean ratios (GMR) (test/reference) between the two formulations of olanzapine were 95.76% (90%CI, 88.55-103.55%) for C max ; 103.77% (97.49- 110.46%) for AUC 0-120 ; and 104.39% (98.20-110.98%) for AUC 0-∞(obs) . There was no statistical difference of the Tmax between the two formulations ( p >0.05). One hundred and eight adverse events were reported from both formulations. Most of the adverse events were judged to be mild in intensity and did not require additional medical treatment. Conclusion: No significant difference in the analysed pharmacokinetic parameters was found between the two formulations of 10 mg olanzapine in the healthy Thai volunteers. The 90%CI of GMR of the pharmacokinetic parameters was entirely within the equivalence criteria (80-125%). Therefore, it can be concluded that this two olanzapine tablet formulations were considered bioequivalent.

To determine the bioavailability of 50 mg sertraline tablets between the test product (Zotaline, MH Manufacturing Co., Ltd, Thailand) and the reference product (Zoloft, Pfizer Australia Pty Ltd, Australia).An open-labeled, single dose, 2-treatment, 2-period, 2-sequence, randomized crossover study under fasting conditions with 14 days washout period was conducted in 24 healthy Thai volunteers. Blood samples were collected before dosing and at frequent intervals for up to 96 h post dose. Analysis of sertraline concentrations was performed using a validated liquid chromatography with tandem mass spectrometry (LC-MS/MS) method.Twenty-four volunteers completed both treatment periods. Pharmacokinetic parameters were determined using the non-compartment model. The 90 percent confidence intervals of the geometric mean ratios (test/reference) of C(max) 104.47% (96.64%-112.93%), AUC(0-96) 108.06% (100.71%-115.94%) and AUC(0-infinity) 108.39% (100.93%-116.40%) fell within the equivalence range (80%-125%). There was no significant difference of the T(max) parameter between the two formulations (p0.05). No serious adverse events related to the study drugs were found.The two formulations of sertraline tablets were bio-equivalent in Thai healthy volunteers.

Glucosamine sulfate is widely used to relieve symptoms from osteoarthritis. The present study was conducted in order to determine pharmacokinetic and assess the in-vivo bioequivalence of two different hard capsule formulations of glucosamine sulfate when administered as equal dose of 500 mg. The two formulations contained different salt form where reference product is NaCl and test product is KCl.A randomized, single dose, two-treatment, two-period, two-sequence crossover study was conducted. Twenty-four healthy volunteers were recruited at Siriraj Clinical Research Unit. Each subject received a dose of 500 mg glucosamine sulfate of both formulations with at least one-week washout period. Blood samples were collected over 24 h after the oral administration. The plasma fractions were analyzed for glucosamine using a liquid chromatography-mass spectrometry (LC-MS/MS).Twenty-four volunteers were enrolled in the present study Pharmacokinetic parameters were determined using the non-compartment model. The 90% confidence intervals of the mean ratios (test/reference) of C(max) (93.69%; ranged from 86.68%-113.32%) and AUC(0-t), (97.73; ranged from 87.38%-112.62%) fell within the acceptable range (80-125%) for bioequivalent eligibility. Both preparations were well tolerated and had a few non-serious adverse events.The glucosamine sulfate containing KCl (test product) is bioequivalent to glucosamine sulfate containing NaCl (reference product) in terms of rate and extent of absorption.

Aim: Oseltamivir, an ester prodrug of its active carboxylate metabolite, is an effective neuraminidase inhibitor used to treat influenza A and B virus infections. The purpose of this study was to compare the bioavailability of two 75 mg oral formulations of oseltamivir: a generic drug, GOP-A-Flu™ (test, Government Pharmaceutical Organization, Thailand) and Tamiflu® (reference, Hoffmann-La Roche Ltd., Nutley, NJ, USA) in healthy volunteers. Subjects and methods: A single-dose, randomized, 2-sequence, crossover study was conducted in 24 healthy Thai volunteers. Each volunteer received a 75 mg capsule of the reference or test drugs under fasting conditions. Blood samples were collected before dosing and at various time points up to 48 hours after dosing and analyzed for plasma oseltamivir and oseltamivir carboxylate concentrations. The pharmacokinetic parameters including C max , AUC 0-t , AUC 0-∞ t max and t 1/2 were analyzed using the non-compartmental method. Drug safety was assessed. Results: 23 volunteers completed both treatment periods. The geometric mean ratios (test/reference) between the two formulations of oseltamivir were 96.83% (90% Cl, 76.85 - 123.15%) for C max 103.66% (86.44-113.56%) for AUC 0.-t , and 103.98% (86.44- 113.56%) for AUC 0-∞ . Those of oseltamivir carboxylate were 102.17% (90% Cl, 90.90 - 109.10%) for C max , 103.95% (90.90 - 109.10%) for AUC 0-t, and 103.95% (90.92 - 109.08%) for AUC 0-∞ . No significant difference of the t max of oseltamivir and oseltamivir carboxylate between the two formulations was detected (p > 0.05). Both formulations were well-tolerated. Conclusion: Although the C max of oseltamivir was the only parameter not entirely within the equivalence criteria, the two capsule formulations were considered bioequivalent in terms of rate and extent of absorption regarding its active carboxylate metabolite.

To compare the bioequivalent parameters of 30 mg pioglitazone tablets manufactured locally (Glista) and originally (Actos).A randomized, single dose, two-treatment, two-period, two-sequence crossover study was conducted Twenty-four healthy volunteers were recruited at Siriraj Clinical Research Unit. Each subject received a 30 mg pioglitazone tablet of both formulations with at least a week washout period Blood samples were collected over 48 h after the oral administration. The plasma fractions were analyzed for pioglitazone using a liquid chomatography-mass spectrometry (LC-MS/MS).Twenty-four volunteers enrolled in the present study. Pharmacokinetic parameters were determined using the non-compartment model. The 90 percent confidence intervals of the mean ratios (test/reference) of Cmax (86.2687-113.7313%), A UC0--t(85. 7139-114.2861%) and AUC0--infinity (81.7820-118.2180%) fell within the acceptable range (80-125%) for bioequivalent eligibility. Both preparations were well tolerated and had afew non-serious adverse events.The 2-tablet preparations of pioglitazone were bioequivalent in Thai healthy volunteers.

A new dihydroartemisinin (DHA) tablet formulation has been developed by the Thai Government Pharmaceutical Organization (GPO). In this report, its in vitro dissolution and in vivo pharmacokinetics as well as its safety in healthy volunteers were evaluated, using the DHA tablet made by Dafra Pharma NV as a reference. A two-period crossover clinical study design was utilised. Twenty-four volunteers were randomly allocated to two sequences (12 volunteers in each) to receive a 200mg single oral dose of either the GPO or Dafra formulation with a wash-out period of 5-7 days. In vitro, the GPO formulation dissolved more readily. In vivo, the GPO formulation had a higher maximum plasma concentration and approximately 149% (90% CI 125-179%) greater bioavailability. Both formulations were well tolerated. Interestingly, significant decreases in haemoglobin and haematocrit values (P