Bioavailability of Triprolidine as a Single Agent or in Combination With Pseudoephedrine: A Randomized, Open-Label Crossover Study in Healthy Volunteers.

Antihistamines have been in clinical use for more than 70 years to treat allergic and nonallergic symptoms including relief from cold and flu symptoms. Despite their widespread use, pharmacokinetic (PK) data are sparse for older, first-generation antihistamines. This phase 1 single-center open-label, randomized, single-dose, 3-way crossover trial evaluated the PK profiles of 2 doses of film-coated triprolidine caplets (2.5 and 5 mg) compared with a reference combination tablet (triprolidine 2.5 mg + pseudoephedrine 60 mg) in 24 healthy adults. Blood samples were collected predose and at specified intervals across a 24-hour period after administration, and triprolidine was quantified using liquid chromatography-tandem mass spectrometry. Maximum plasma concentration of triprolidine for the 2.5 mg and dose-normalized 5 mg single-agent tablets were comparable (8.4 versus 7.1 ng/mL, respectively) and higher for the combination tablet (9.5 ng/mL). PK parameters, including time to maximum plasma concentration (∼1.5 hours) and elimination half-life (∼4 hours), were comparable between the 3 treatment arms. The safety profile of this sedating antihistamine was as expected; however, adverse effects were reported in a markedly higher proportion of women than men. There were no significant sex differences in any of the measured PK parameters.

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.

Transport of hydroxyzine and triprolidine across bovine olfactory mucosa: role of passive diffusion in the direct nose-to-brain uptake of small molecules.

Hydroxyzine and triprolidine have both been reported to reach the CNS following nasal administration. The objective of this study was to investigate their in vitro permeation across bovine olfactory mucosa in order to further characterize the biological and physicochemical parameters that influence direct nose-to-brain transport. In vitro experiments were conducted using Sweetana-Grass (Navicyte) vertical diffusion cells to evaluate the effect of directionality, donor concentration and pH on the permeation of hydroxyzine and triprolidine across excised bovine olfactory mucosa. These studies demonstrated that the Jm-s (mucosal-submucosal flux) and Js-m (submucosal-mucosal flux) of hydroxyzine and triprolidine across the olfactory mucosa were linearly dependent upon the donor concentration without any evidence of saturable transport. Hydroxyzine inhibited the efflux of P-gp substrates like etoposide and chlorpheniramine across the olfactory mucosa. Both hydroxyzine and triprolidine reduced the net flux (Js-m-Jm-s) of etoposide with IC50 values of 39.2 and 130.6 microM, respectively. The lipophilicty of these compounds, coupled with their ability to inhibit P-gp, enable them to freely permeate across the olfactory mucosa. Despite the presence of a number of protective barriers such as efflux transporters and metabolizing enzymes in the olfactory system, lipophilic compounds such as hydroxyzine and triprolidine can access the CNS primarily by passive diffusion when administered via the nasal cavity.

Acrivastine. A review of its pharmacological properties and therapeutic efficacy in allergic rhinitis, urticaria and related disorders.

Acrivastine is a short acting histamine H1-receptor antagonist with a rapid onset of action. Double-blind clinical trials have shown acrivastine (usually 8mg three times daily) to be an effective and well tolerated antihistamine in the treatment of chronic urticaria and allergic rhinitis. Acrivastine was more effective than placebo and similar in efficacy to clemastine or terfenadine in the treatment of seasonal allergic rhinitis. In the treatment of dermatoses in which histamine has a pathogenetic role, the efficacy of acrivastine was superior to that of placebo and similar to that of usual dosages of clemastine, hydroxyzine, chlorpheniramine, cyproheptadine or terfenadine. Acrivastine caused less drowsiness than clemastine, the incidence of adverse effects being indistinguishable from that with placebo or terfenadine. Thus, acrivastine is an effective addition to drugs currently available for the treatment of patients with allergic diseases in whom a histamine H1-receptor antagonist is indicated. Because of its rapid onset of action acrivastine will be particularly useful for 'on demand' therapy in patients with intermittent symptoms.

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.

Pharmacokinetics of acrivastine after oral and colonic administration.

Six healthy male volunteers participated in this randomized, crossover open-label pharmacokinetic study consisting of two dosing segments separated by a washout period of at least 5 days. During each dosing segment, each volunteer received 12 mg of acrivastine, an investigational histamine H1-receptor antagonist, in a syrup form either orally or by colonic administration in random order. After oral and colonic administration, respectively, the following mean +/- SD pharmacokinetic parameters were obtained: Cmax 179 +/- 11 and 13.8 +/- 5.2 ng/ml; tmax, 0.85 +/- 0.13 and 3.60 +/- 0.56 hr; AUC0-12 hr, 576 +/- 57 and 104 +/- 46 hr.ng/ml. Differences between the oral and colonic administration for all three parameters were statistically significant (P less than 0.001). The mean +/- SD relative bioavailability of acrivastine from colonic compared to oral dosing was 0.18 +/- 0.09. It may be concluded, therefore, that appreciable absorption of acrivastine from the colon does not take place. These results suggest that comparison of pharmacokinetic profiles of some drugs after oral and colonic administration may be a useful technique for predicting bioavailability from a sustained release oral formulation.

Enhanced transdermal delivery of triprolidine from the ethylene-vinyl acetate matrix.

Triprolidine-containing matrix was fabricated with ethylene-vinyl acetate (EVA) copolymer to control the release of the drug. The permeation rate of triprolidine in the stripped skin was greatly larger than that in the whole skin. Thus it showed that the stratum corneum acts as a barrier of skin permeation. The effect of penetration enhancer and stripping of skin on the permeation of triprolidine through the excised mouse skin was studied. Penetrating enhancers showed increased flux probably due to the enhancing effect on the skin barrier, the stratum corneum. Among enhancers used such as glycols, fatty acids and non-ionic surfactants, polyoxyethylene-2-oleyl ether showed the best enhancement. The permeability of triprolidine was markedly increased with stripping of the mouse skin to remove the stratum corneum that acts as a barrier of skin permeation. For the controlling transdermal delivery of triprolidine, the application of EVA membrane containing permeation enhancer could be useful in the development of transdermal drug delivery system.

Application of TPX polymer membranes for the controlled release of triprolidine.

Oral administration of triprolidine, antihistamines, may cause many adverse effects such as dry mouth, sedation, dizziness and transdermal drug delivery was considered. Poly(4-methyl-1-pentene) (TPX) membrane, which has good mechanical strength was fabricated by the casting method. TPX membranes was a little brittle and the plasticizers was added for preparing the membranes. The present study was carried out to evaluate the possibility of using the polymer TPX membrane as a controlling membrane and further develop a TPX matrix system for transdermal delivery of triprolidine. The effects of molecular weights of TPX, plasticizers, polyethylene glycol (PEG) 400, drug concentration, and temperature on drug release were studied. The solubility of triprolidine increased exponentially as the increased volume fraction of PEG 400 in saline, and the rate of permeation through TPX membrane was proportional to PEG 400 volume fraction. The release rate of drug from the TPX matrix increased with increased temperature and drug concentration. Among the plasticizers used such as alkyl citrates, phthalates and sebacate, tetra ethyl citrate (TEC) showed the best enhancing effects. Enhancement factor of TEC was 3.76 from TPX matrix at 37 degrees C. The transdermal controlled release of triprolidine system could be developed using the TPX polymer including the plasticizer.

Enhanced bioavailability of triprolidine from the transdermal TPX matrix system in rabbits.

The pharmacokinetics and bioavailability of triprolidine, antihistamines, were studied to determine the feasibility of enhanced transdemal delivery of triprolidine from the poly(4-methyl-1-pentene) (TPX) matrix system containing polyoxyethylene-2-oleyl ether in rabbits. The triprolidine-TPX matrix (50 mg/kg) was applied to abdominal skin of rabbits. Blood samples were collected via femoral artery for 36 h and the plasma concentrations of triprolidine were determined by HPLC. Pharmacokinetic parameters was calculated using the LAGRAN computer program. The area under the curve (AUC) was significantly higher in the enhancer group (4058 +/- 1420 ng/ml h) than that (1902 +/- 857 ng/ml h) in control group (P<0.05), showing about 235% increased bioavailability. The average Cmax was increased significantly in the enhancer group (216 +/- 44.3 ng/ml) compared with control group (130 +/- 25.8 ng/ml) (P<0.05). The mean Tmax was increased in the enhancer group (8.0 +/- 2.55 h) compared with the control (6.0 +/- 2.28 h) but was not significant. The relative bioavailability was 23.1% in the control group and 49.3% in the enhancer group compared to the oral route. As the triprolidine-TPX matrix containing polyoxyethylene-2-oleyl ether as an enhancer and tiethyl citrate as a plasticizer was administered to rabbits via the transdermal routes, the relative bioavailability increased by about 2.13-fold compared to the control group, showing a relatively constant, sustained blood concentration with minimal fluctuation. The results of this study shows that triprolidine-TPX matrix could be developed as a transdermal delivery system providing consistent plasma concentration.

Transdermal delivery of triprolidine using TPX polymer membrane.

Triprolidine-containing matrix was fabricated with poly(4-methyl-1-pentene) (TPX) polymer to control the release of the drug. Effect of penetration enhancer and stripping of skin on the permeation of triprolidine through the excised mouse skin was studied. Penetrating enhancers showed the increased flux probably due to the enhancing effect on the skin barrier, the stratum corneum. Among enhancers used such as glycols, fatty acids and non-ionic surfactants, polyoxyethylene-2-oleyl ether showed the best enhancement. The permeability of triprolidine was markedly increased with stripping the mouse skin to remove the stratum corneum, which acts as a barrier of skin permeation. For the controlling delivery of triprolidine, the TPX matrix containing permeation enhancer could be developed.

Acrivastine: a review of its dermatopharmacology and clinical activity.

The general human and skin pharmacology of acrivastine, its clinical utility and some important concepts of the use of H1-antihistamines in dermatology are discussed. The drug has potent H1-antihistamic activity yet a low sedative profile as compared with first generation agents. Acrivastine is rapidly absorbed with peak inhibition of flare areas occurring at 90 min and peak activity against weals at 120 min after drug administration. No accumulation of the drug following multiple dosing has been demonstrated. Due to these effects the drug has a high level of patient acceptability and a high level of useful activity in a range of histamine-mediated dermatoses.

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.

Disposition and metabolism of triprolidine in mice.

The disposition of the antihistamine, triprolidine, was studied in male and female CD-1 mice after a single oral 50 mg/kg dose of [14C]triprolidine HCl. Urine and feces collected over 72 hr postdosing were analyzed for total radiocarbon, and for parent drug and metabolites by radiochromatography. Structures of metabolites were determined by GC/MS, direct probe MS, FAB/MS, LC/MS, NMR, and IR techniques. More than 80% of the dose was recovered in the urine, with the remainder recovered in the feces. The carboxylic acid analog of triprolidine (219C69) was found to be the major metabolite in urine and feces, accounting for an average of 57.6% of the administered dose. Three minor metabolites were identified as a gamma-aminobutyric acid analog of triprolidine, a pyrrolidinone analog of 219C69, and a pyridine-ring hydroxylated derivative of triprolidine. Parent drug could only be detected in urine and accounted for 0.3% (females) to 1.1% (males) of the dose. The results of this study showed that triprolidine was absorbed well but extensively metabolized when administered orally to mice.

Disposition of triprolidine in the male beagle dog.

Three male beagle dogs were given 2.5 mg/kg doses of [14C]triprolidine HCl monohydrate (2.09 mg/kg of the free base) by intravenous and oral routes, in a nonrandomized cross-over experiment. After either route of administration, approximately 75% of the dose was excreted in the urine, and the remainder was excreted in the feces. Triprolidine was extensively metabolized, with less than 1% of the parent drug recovered in the excreta after either route of administration. Three metabolites were isolated from excreta and identified, including the major metabolite (metabolite 1, 219C69), in which the toluene ring methyl group was oxidized to a carboxylic acid, a metabolite (metabolite 2) in which the pyrrolidine ring was opened with oxidation of the terminal carbon to a carboxylic acid (a gamma-aminobutyric acid), and a metabolite (metabolite 3) that was a pyrrolidinone derivative of 219C69. Other metabolites in urine and feces were present in amounts too small for quantitation or identification. Route of administration had little effect on the metabolic pattern of triprolidine. Thus, after oral administration of triprolidine, a mean of 49.1% of the dose was excreted as 219C69, 12.0% as metabolite 2, 3.4% as metabolite 3, and 0.6% as triprolidine, while after intravenous administration, a mean of 50.8% of the dose was excreted as 219C69, 11.1% as metabolite 2, 4.2% as metabolite 3, and 0.8% as triprolidine. Plasma contained triprolidine, 219C69, and metabolite 2, as well as other apparent metabolites that were present at levels too low for quantitation. Mean pharmacokinetic parameters calculated for triprolidine after intravenous dosing were: CL = 24.4 ml/min/kg, Vdss = 5.8 liters/kg, and Vc = 1.6 liters/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Disposition of acrivastine in the male beagle dog.

Three male beagle dogs were given 10 mg/kg iv and oral doses of [14C]acrivastine, a novel nonsedating antihistaminic agent, in a nonrandomized crossover experiment. Urine and feces were collected for 72 hr after dosing. After iv dosing, a mean of 34% was recovered in the urine, and 63% was recovered in the feces. After po dosing, a mean of 29% of the radiocarbon was recovered in the urine, and 63% was recovered in the feces (dose adjusted for 14% lost in vomitus). Acrivastine and three major metabolites were detected in the excreta. The metabolites were identified as a side-chain-reduced analog of acrivastine (metabolite 3, 270C81), a gamma-aminobutyric acid analog of 270C81 (metabolite 2), and a benzoic acid analog of 270C81 (metabolite 1). After iv dosing, 34% of the dose was excreted as parent drug, 21% as metabolite 3, 15% as metabolite 2, and 6% as metabolite 1, while after po dosing, 35% of the dose was excreted as parent drug, 18% as metabolite 3, 11% as metabolite 2, and 7% as metabolite 1. Pharmacokinetic analysis of acrivastine plasma concentration-time curves after both routes of administration indicated a mean total body clearance of 17.3 ml/min/kg, a Vss of 0.93 liter/kg, a terminal half-life of 0.7 hr, and an oral bioavailability of 40%. The apparent plasma half-life of the metabolite, 270C81, was 1.5 hr. Analysis of AUC values indicated that greater amounts of 270C81 than acrivastine circulated in plasma after both iv and po dosing, and that first-pass metabolism of acrivastine to 270C81 occurred. The results indicated that acrivastine was extensively metabolized in the dog to 270C81 and suggested that 270C81 itself underwent further metabolism to metabolites 1 and 2.

Acrivastine, terfenadine and diphenhydramine effects on driving performance as a function of dose and time after dosing.

The study was conducted according to a nine-way, observer- and subject-blind, cross-over design. Its purpose was to compare the single-dose effects of the following drugs on driving performance: acrivastine (8, 16 and 24 mg); the combination of acrivastine (8 mg) with pseudoephedrine (60 mg); terfenadine (60, 120 and 180 mg); diphenhydramine-HCl (50 mg); and placebo. The subjects were 18 healthy female volunteers. Drug effects were assessed in two repetitions of two driving tests (highway driving and car-following) after each treatment. Acrivastine's impairing effects in both driving tests were similarly dose-related. The 8-mg dose had a small, but significant, effect on highway driving in the first trial. The 16-mg and 24-mg doses significantly impaired driving in both tests during the first trial and the 24-mg dose did so again during the second trial. Neither the combination of acrivastine with pseudoephedrine nor terfenadine caused any significant impairment of performance. Diphenhydramine significantly impaired driving in both tests during every trial. In conclusion, the normal therapeutic dose of acrivastine (8 mg) had little effect on driving performance, and virtually none when that dose was given in combination with pseudoephedrine (60 mg). Higher doses of acrivastine severely impaired driving performance. Terfenadine had no significant effect on driving performance after any dose while diphenhydramine strongly impaired every important driving parameter.