Development and validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of acrivastine and pseudoephedrine in human plasma and its application in pharmacokinetics.

A specific, sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed for the simultaneous determination of acrivastine and pseudoephedrine in human plasma samples. Plasma samples were processed and analyzed on a Phenomenex Luna 3 µ CN 100A column (150 mm×2.0 mm) eluted with the mobile phase consisting of methanol and 0.01 mol/L ammonium acetate water solution containing 0.1% formic acid (45:55, v/v) at a flow rate of 0.2 mL/min. The analytes were detected by positive ion electrospray ionization in multiple reaction monitoring mode. The transitions of m/z 349→278, m/z 166→148 and m/z 256→167 were monitored for acrivastine, pseudoephedrine and diphenhydramine (IS), respectively. The method was specific and sensitive with a lower limit of quantitation (LLOQ) of 1.52 ng/mL for acrivastine and 8.13 ng/mL for pseudoephedrine. The method showed good linearity in the range of 1.52~606.0 0 ng/mL for acrivastine and 8.13~813.12 ng/mL for pseudoephedrine (r≥0.996). The mean recovery were ranged 91.82% ~ 98.46% for acrivastine and 90.77% ~ 92.05% for pseudoephedrine. Validation results, such as accuracy, precision and repeatability were within the required limits. The method was successfully applied in a pharmacokinetic study of the acrivastine and pseudoephedrine hydrochloride compound capsule in humans.

Simultaneous determination of triprolidine and pseudoephedrine in human plasma by liquid chromatography-ion trap mass spectrometry.

A highly efficient, selective and specific method for simultaneous quantitation of triprolidine and pseudoephedrine in human plasma by liquid chromatography-ion trap-tandem mass spectrometry coupled with electro spray ionization (LC-ESI-ion trap-tandem MS) has been validated and successfully applied to a clinical pharmacokinetic study. Both targeted compounds together with the internal standard (gabapentin) were extracted from the plasma by direct protein precipitation. Chromatographic separation was achieved on a C(18) ACE((R)) column (50.0mmx2.1mm, 5mum, Advance Chromatography Technologies, Aberdeen, UK), using an isocratic mobile phase, consisting of water, methanol and formic acid (55:45:0.5, v/v/v), at a flow-rate of 0.3mL/min. The transition monitored (positive mode) was m/z 279.1-->m/z 208.1 for triprolidine, m/z 165.9-->m/z 148.0 for pseudoephedrine and m/z 172.0-->m/z 154.0 for gabapentin (IS). This method had a chromatographic run time of 5.0min and a linear calibration curves ranged from 0.2 to 20.0ng/mL for triprolidine and 5.0-500.0ng/mL for pseudoephedrine. The within- and between-batch accuracy and precision (expressed as coefficient of variation, %C.V.) evaluated at four quality control levels were within 94.3-106.3% and 1.0-9.6% respectively. The mean recoveries of triprolidine, pseudoephedrine and gabapentin were 93.6, 76.3 and 82.0% respectively. Stability of triprolidine and pseudoephedrine was assessed under different storage conditions. The validated method was successfully employed for the bioequivalence study of triprolidine and pseudoephedrine formulation in twenty six volunteers under fasting conditions.

Quantification of antihistamine acrivastine in plasma by solid-phase extraction and high-performance liquid chromatography.

An automated solid-phase extraction method was developed for the determination of the H1-antihistamine acrivastine in plasma samples. Acrivastine was analyzed at the wavelength of 254 nm using a reversed-phase HPLC assay. Both extraction procedure and analytical condition were optimized and validated for maximum recovery and resolution. The developed method was further applied to plasma samples collected from an in vivo pharmacokinetic study in rabbits. The assay was found to be simple, specific, accurate and reproducible.

Enhanced efficacy of triprolidine by transdermal application of the EVA matrix system in rabbits and rats.

The bioavailability of triprolidine from the ethylene vinyl acetate (EVA) matrix system containing polyoxyethylene-2-oleyl ether was studied to determine the feasibility of enhanced transdermal delivery of triprolidine in rabbits. The antihistamine effects were also confirmed to determine the percutaneous absorption of triprolidine from the EVA matrix system containing a penetration enhancer and plasticizer in rats. The triprolidine-EVA matrix (50mg/kg) was applied to the abdominal skin of rabbits. Blood samples were collected via the femoral artery for 36 h and the plasma concentrations of triprolidine were determined by HPLC. The pharmacokinetic parameters were calculated using the LAGRAN computer program. The area under the curve(AUC) was significantly higher in the enhancer group (4582+/-1456 ng/mL h) than that (2958+/-997 ng/mL h) in the control group (P<0.05), showing an approximate 155% increased bioavailability. The average Cmax in the enhancer group (241+/-46.5 ng/mL) was significantly higher than that in the control group (198+/-28.9 ng/mL), (P<0.05). The mean Tmax in the enhancer group (8.0+/-2.57 h) was higher than that in the control group (6.0+/-2.24 h, but this was not statistically significantly. The relative bioavailability of triprolidine in the transdermal application was 35.9% in the control group and 55.6% in the enhancer group compared comparing with that after oral administration. As the triprolidine-EVA matrix, which contains polyoxyethylene-2-oleyl ether as an enhancer and triethyl citrate as a plasticizer was administered to the rabbits via the transdermal routes, the relative bioavailability increased approximately 1.55 fold compared with that in the control group, showing a relatively constant, sustained blood concentration with minimal fluctuation. The antihistamine effect was determined using the Evans blue dye procedure by comparing the changes in the vascular permeability increase following the transdermal application. The vascular permeability increase was reduced significantly by the transdermal application of the EVA-triprolidine system containing triethyl citrate and polyoxyethylene-2-oleyl ether. These results show that the plasticizer and penetration enhancer increase the skin permeation of triprolidine and the triprolidine-EVA matrix system could be developed as a transdermal delivery system providing the increased constant plasma concentration and antihistamine effects.

Distribution of antihistamines into the CSF following intranasal delivery.

The preferential absorption of certain drug compounds from the nasal cavity into the cerebrospinal fluid (CSF) raises questions regarding the transport processes controlling drug disposition following intranasal delivery. The disposition characteristics of several structurally similar antihistamine compounds, hydroxyzine, chlorpheniramine, triprolidine, and chlorcyclizine, into the CSF following nasal administration were studied using the rat as an animal model. The antihistamines were administered either intranasally or intra-arterially, and serial CSF and plasma samples were collected from the cisterna magna and the femoral artery, respectively. The drug levels in CSF and plasma were assayed by HPLC. Hydroxyzine concentrations in plasma and CSF were found to be significantly greater than most of the other compounds tested. In addition, hydroxyzine also showed the most rapid systemic absorption following nasal administration. Interestingly, the hydroxyzine levels in CSF following intranasal administration were significantly higher than those following intra-arterial administration. The AUC ratios between CSF and plasma for hydroxyzine after intranasal and intra-arterial administration were 4.0 and 0.4, respectively. The AUC ratios for triprolidine, the other antihistamine with measurable CSF concentrations, were 0.5 and 0.7, respectively. The distribution of antihistamines from the nasal membrane into the CSF appears to be controlled by a combination of their molecular properties. It also appears that the intranasal delivery of drugs with optimal physicochemical characteristics can result in an improved CNS bioavailability compared to those achieved from an equivalent parenteral dose.

Acute and subchronic effects of the H1-histamine receptor antagonist ebastine in 10, 20 and 30 mg dose, and triprolidine 10 mg on car driving performance.

1. The effects of a new antihistamine, ebastine (10, 20 and 30 mg), on several parameters of driving performance in actual traffic were studied in 15 healthy male volunteers. Subjects were treated for 5 days, and their driving performance tested on day 1 and day 5. The study was double-blind, placebo controlled and included the antihistamine triprolidine (10 mg sustained release) as an active drug control. 2. General tolerability was good except in one case following the reference compound triprolidine. No significant changes in driving performance were found with the new antihistamine ebastine at any dosage, on day 1 or day 5. Triprolidine (10 mg) significantly increased both the amount of weaving and the delay in following speed manoeuvres of a leading car, compared with placebo. 3. The results suggest that ebastine in doses up to 30 mg may be relatively safe for use by those who drive motor vehicles while under medication. The results do not warrant such a conclusion for triprolidine 10 mg.

Pharmacokinetics of oral and transdermal triprolidine.

In this open, nonrandomized, three-way crossover study, six healthy male volunteers received single doses of triprolidine (TPL) hydrochloride syrup orally (2.5 mg) and wore transdermal TPL patches (5 mg and 10 mg doses) to compare the pharmacokinetic profiles and dose tolerance of the two formulations. A washout period of at least 1 week was scheduled between the three dosing periods. Blood samples were collected at defined times, and plasma concentrations were determined using a radioimmunoassay. Maximum plasma drug concentration (Cmax) decreased from 5.6 +/- 2.9 ng/mL (mean +/- SD) with oral dosing to 2.0 +/- 1.0 ng/mL and 4.2 +/- 2.0 ng/mL following 5 mg and 10 mg transdermal doses, respectively. Time to reach peak concentration (tmax) increased from 2.0 +/- 1.2 hours with oral dosing to 12.0 +/- 5.9 and 14.3 +/- 9.9 hours following 5 mg and 10 mg transdermal doses, respectively. The differences between AUC0-alpha values with the oral syrup and the 5 mg and 10 mg transdermal doses were not significant when normalized to 2.09 mg (TPL base). The bioavailabilities of the 5 mg and 10 mg transdermal doses relative to the oral 2.09 mg doses were 0.89 +/- 0.32 and 1.04 +/- 0.33, respectively. Mild erythema and pruritus were the most common adverse effects secondary to TPL transdermal application. Drowsiness observed following oral TPL, was not evident following either transdermal dose. The results of this study, therefore, indicate that TPL can be absorbed transdermally, providing consistent plasma concentrations.

An investigation of the H1-receptor antagonist triprolidine: pharmacokinetics and antihistaminic effects.

A single oral dose of triprolidine hydrochloride, 0.04 mg/kg (mean dose 2.7 +/- SD 0.4 mg) was administered to seven healthy, fasting adult volunteers who had never been treated previously with H1-receptor antagonists. Blood sampling and intradermal tests with 0.01 ml of histamine phosphate (0.1 mg/ml) were performed at -0.25, 1, 2, 3, 4, 5, 6, 7, 8, and 12 hours after the dose. Wheal-and-flare circumferences were traced, and the areas were measured by planimetry. Pruritus was quantitated by use of a clinical score. Urine was collected in 6-hour pooled aliquots for a total of 24 hours. Serum and urine triprolidine concentrations were measured by high-performance liquid chromatography. Wheal-and-flare areas and pruritus decreased after the triprolidine dose. Suppression of mean flare size was statistically significant at 2, 3, 6 and 8 hours. Suppression of mean wheal size was not statistically significant at any time compared to predose values. The mean triprolidine serum half-life was 2.1 +/- 0.8 hours. The mean peak serum triprolidine concentration of 15.4 +/- 8.3 ng/ml occurred 2 hours after ingestion. No triprolidine was detected in the serum after 12 hours. The mean urinary excretion of unchanged triprolidine during 24 hours was 1.3 +/- 1.0% of the dose administered.

Pseudoephedrine and triprolidine in plasma and breast milk of nursing mothers.

Plasma and milk concentrations of pseudoephedrine and triprolidine were determined (by radioimmunoassay) in three lactating mothers over 12-48 h after ingestion of a combination medication containing 60 mg of pseudoephedrine hydrochloride and 2.5 mg of triprolidine hydrochloride monohydrate. Pseudoephedrine concentrations in milk were consistently higher than those in plasma. The total amount of drug in milk, as judged by areas under the respective curves (AUC), was two to three times greater than in plasma. Triprolidine concentrations in milk and plasma were more variable between subjects than those of pseudoephedrine. AUC values for milk and plasma were similar for one subject, while the plasma value exceeded that for milk in another woman. The fraction of the dose excreted in milk was estimated to be 0.4-0.7% for pseudoephedrine and 0.06-0.2% for triprolidine.

Determination of triprolidine in human plasma by quantitative TLC.

A chromatographic thin-layer fluorescence procedure, with a sensitivity limit of 0.8 ng/ml, is described for the quantitative analysis of triprolidine in human and rat plasma. Following the intravenous administration of 1 mg/kg of triprolidine to rats, the drug distributed rapidly into tissues and was eliminated from plasma with a half-life of 53 min. The method was used to determine the plasma triprolidine levels in 16 normal human volunteers following oral administration of 3.75 mg of triprolidine hydrochloride in 15 ml of a syrup. The drug obtained a mean peak plasma level of 8.2 ng/ml in 2 hr and was eliminated from the plasma with a half-life of 5 hr. Considerable individual variation was observed in the area under the plasma triprolidine level-time curve; values ranged from 19 to 163 ng hr/ml with a mean value of 75 ng hr/ml.