Systemic absorption of epinephrine compared between the intranasal and intramuscular routes of administration in healthy adults

BACKGROUND

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.

OBJECTIVE

To investigate the pharmacokinetics and pharmacodynamics of IN and IM epinephrine absorption in a larger group of healthy adults (n = 12).

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Comparative Fasting Bioavailability of 2 Cilostazol Formulations in Healthy Thai Volunteers: An Open-Label, Single-Dose, Randomized, 2-Way Crossover Study

OBJECTIVE

To evaluate the bioequivalence of50 mg cilostazol tablets manufactured locally (Citazol®) and originally (Pletaal®) in healthy Thai volunteers.

MATERIAL AND METHOD

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).

RESULTS

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 (p>0.05). No serious adverse events related to the studied drugs were found.

CONCLUSION

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.

Plasma concentrations of bupivacaine after spinal anesthesia with single shot femoral nerve block in total knee arthroplasty

BACKGROUND

Femoral nerve block is commonly established for postoperative analgesia in total knee arthroplasty but no evidence of plasma bupivacaine level has been reported.

OBJECTIVE

Determine the plasma concentrations of bupivacaine in patients who had single-injection of femoral nerve block.

MATERIAL AND METHOD

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.

RESULTS

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.

CONCLUSION

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.

Prevalence and risk factors for chloroquine maculopathy and role of plasma chloroquine and desethylchloroquine concentrations in predicting chloroquine maculopathy

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.

Association of Nevirapine Levels with Rash or Hepatotoxicity Among HIV-Infected Thai Women

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.

Activation of indoleamine 2,3-dioxygenase in patients with scrub typhus and its role in growth restriction of Orientia tsutsugamushi

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.

Bioequivalence study of 10 mg ramipril tablets in healthy Thai volunteers

OBJECTIVE

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).

MATERIAL AND METHOD

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.

RESULTS

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.

CONCLUSION

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.

Bioequivalence study of 50 mg sertraline tablets in healthy Thai volunteers

OBJECTIVE

To determine the bioavailability of 50 mg sertraline tablets between the test product (Zotaline, M&H Manufacturing Co., Ltd, Thailand) and the reference product (Zoloft, Pfizer Australia Pty Ltd, Australia).

MATERIAL AND METHOD

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.

RESULTS

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 (p > 0.05). No serious adverse events related to the study drugs were found.

CONCLUSION

The two formulations of sertraline tablets were bio-equivalent in Thai healthy volunteers.

Bioequivalence study of 500 mg glucosamine sulfate in Thai healthy volunteers

BACKGROUND AND OBJECTIVE

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.

MATERIAL AND METHOD

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).

RESULTS

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.

CONCLUSION

The glucosamine sulfate containing KCl (test product) is bioequivalent to glucosamine sulfate containing NaCl (reference product) in terms of rate and extent of absorption.

Evaluation of the safety and relative bioavailability of a new dihydroartemisinin tablet formulation in healthy Thai 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<0.001) were noted following administration of one dose of DHA (decrease of 0.73 g/dl haemoglobin and 2.0% haematocrit compared with baseline) or two doses of DHA (decrease of 0.95 g/dl haemoglobin and 3.3% haematocrit compared with baseline). The second dose was associated with additional toxicity compared with one dose with regard to haematocrit (P<0.001) but not haemoglobin. This finding warrants further investigation, since the drug will be used for the treatment of malaria in which anaemia is a consequence.

Bioequivalence study of 30 mg pioglitazone tablets in Thai healthy volunteers

OBJECTIVE

To compare the bioequivalent parameters of 30 mg pioglitazone tablets manufactured locally (Glista) and originally (Actos).

MATERIAL AND METHOD

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).

RESULTS

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.

CONCLUSION

The 2-tablet preparations of pioglitazone were bioequivalent in Thai healthy volunteers.