Prediction of Human Disproportionate and Biliary Excreted Metabolites Using Chimeric Mice with Humanized Liver.

The PXB-mouse is potentially a useful in vivo model to predict human hepatic metabolism and clearance. Four model compounds, [14C]desloratadine, [3H]mianserin, cyproheptadine, and [3H]carbazeran, all reported with disproportionate human metabolites, were orally administered to PXB- or control SCID mice to elucidate the biotransformation of each of them. For [14C]desloratadine in PXB-mice, O-glucuronide of 3-hydroxydesloratadine was observed as the predominant metabolite in both the plasma and urine. Both 3-hydroxydesloratadine and its O-glucuronide were detected as major drug-related materials in the bile, whereas only 3-hydroxydesloratadine was detected in the feces, suggesting that a fraction of 3-hydroxydesloratadine in feces was derived from deconjugation of its O-glucuronide by gut microflora. This information can help understand the biliary clearance mechanism of a drug and may fill the gap in a human absorption, distribution, metabolism, and excretion study, in which the bile samples are typically not available. The metabolic profiles in PXB-mice were qualitatively similar to those reported in humans in a clinical study in which 3-hydroxydesloratadine and its O-glucuronide were major and disproportionate metabolites compared with rat, mouse, and monkey. In the control SCID mice, neither of the metabolites was detected in any matrix. Similarly, for the other three compounds, all human specific or disproportionate metabolites were detected at a high level in PXB-mice, but they were either minimally observed or not observed in the control mice. Data from these four compounds indicate that studies in PXB-mice can help predict the potential for the presence of human disproportionate metabolites (relative to preclinical species) prior to conducting clinical studies and understand the biliary clearance mechanism of a drug. SIGNIFICANCE STATEMENT: Studies in PXB-mice have successfully predicted the human major and disproportionate metabolites compared with preclinical safety species for desloratadine, mianserin, cyproheptadine, and carbazeran. In addition, biliary excretion data from PXB-mice can help illustrate the human biliary clearance mechanism of a drug.

Quantification of cyproheptadine in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry in a bioequivalence study.

A rapid, sensitive and specific method to quantify cyproheptadine in human plasma using amitriptyline as the internal standard (IS) is described. The analyte and the IS were extracted from plasma by liquid-liquid extraction using a diethyl-ether/dichloromethane (70/30; v/v) solvent. After removing and drying the organic phase, the extracts were reconstituted with a fixed volume of acetonitrile/water (50/50 v/v)+0.1% of acetic acid. The extracts were analyzed by high performance liquid chromatography coupled to electrospray tandem mass spectrometry (LC-MS/MS). Chromatography was performed isocratically using an Alltech Prevail C18 5 µm analytical column, (150 mm x 4.6 mm I.D.). The method had a chromatographic run time of 4 min and a linear calibration curve ranging from 0.05 to 10 ng/mL (r2 > 0.99). The limit of quantification was 0.05 ng/mL. This HPLC/MS/MS procedure was used to assess the bioequivalence of cyproheptadine in two cyproheptadine + cobamamide (4 mg + 1 mg) tablet formulations (Cobactin® [cyproheptadine + cobamamide] test formulation supplied from Zambon Laboratórios Farmacêuticos Ltda. and Cobavital® from Solvay Farma (standard reference formulation)). A single 4 mg + 1 mg [cyproheptadine + cobamamide] dose of each formulation was administered to healthy volunteers. The study was conducted using an open, randomized, two-period crossover design with a 1-week washout interval. Since the 90% CI for Cmax and AUCs ratios were all within the 80-125% bioequivalence limit proposed by the US Food and Drug Administration, it was concluded that the cyproheptadine test formulation (Cobactin®) is bioequivalent to the Cobavital® formulation for both the rate and the extent of absorption of cyproheptadine.

Efficacy and tolerability of rupatadine at four times the recommended dose against histamine- and platelet-activating factor-induced flare responses and ex vivo platelet aggregation in healthy males.

BACKGROUND: European guidelines recommend increasing H1-antihistamine doses up to fourfold in poorly responding patients with urticaria. OBJECTIVES: To assess the efficacy and tolerability of high-dose rupatadine (40 mg) against platelet-activating factor (PAF)- and histamine-induced flare responses in human skin and to verify its anti-PAF activity by assessing its inhibition of PAF-induced platelet aggregation in the blood of subjects receiving rupatadine 40 mg. METHODS: In the flare study, six male volunteers received a single dose of rupatadine 40 mg. Flares were induced before dosing and up to 96 h afterwards by intradermal PAF and histamine. In the ex vivo study, four male volunteers received an oral dose of rupatadine 40 mg and blood samples were taken 4 h afterwards. Platelet aggregation was assessed in platelet-rich plasma by incubation for 5 min with PAF. RESULTS: Rupatadine 40 mg reached maximal plasma levels of 15·1 ± 4·4 ng mL⁻¹)1 at 1 h and its metabolite, desloratadine, 5·2 ± 0·9 ng mL⁻¹)1 at 2 h. Neither was detectable at 12 h. Inhibition of histamine- and PAF-induced flares was significant within 2 h, maximal at 6 h (87·8 ± 3·1% and 87·1 ± 2·5% inhibition, respectively, P < 0·0001) and still statistically significant at 72 h. Rupatadine 40 mg inhibited PAF-induced platelet aggregation ex vivo by 82 ± 9% (P = 0·023). A single oral dose of rupatadine 40 mg was well tolerated with mild transient somnolence being reported. CONCLUSIONS: A single dose of rupatadine at four times the recommended dose is well tolerated, highly effective for up to 72 h against PAF- and histamine-induced dermal flares and has demonstrable PAF-receptor antagonism ex vivo.

Simultaneous determination of rupatadine and its metabolite desloratadine in human plasma by a sensitive LC-MS/MS method: application to the pharmacokinetic study in healthy Chinese volunteers.

A sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of rupatadine and its metabolite desloratadine in human plasma. After the addition of diphenhydramine, the internal standard (IS), plasma samples were extracted with a mixture of methyl tert-butyl ether and n-hexane (1:1, v/v). The analysis was performed on a Ultimate AQ-C18 (4.6mm x 100mm, 5microm) column using a mobile phase consisting of a 80/20 mixture of methanol/water containing 0.0005% formic acid pumped at 0.3mlmin(-1). The analytes and the IS were detected in positive ionization mode and monitoring their precursor-->product ion combinations of m/z 416-->309, 311-->259, and 256-->167, respectively, in multiple reaction monitoring mode. The linear ranges of the assay were 0.1-50 and 0.1-20ngml(-1) for rupatadine and desloratadine, respectively. The lower limits of reliable quantification for both rupatadine and desloratadine were 0.1ngml(-1), which offered high sensitivity and selectivity. The within- and between-run precision was less than 7.2%. The accuracy ranged from -9.2% to +6.4% and -7.2% to +7.2% for rupatadine and desloratadine in quality control samples at three levels, respectively. The method has been successfully applied to a pharmacokinetic study of rupatadine and its major metabolite after oral administration of 10, 20 and 40mg rupatadine tablets to healthy Chinese volunteers.

Rupatadine in allergic rhinitis and chronic urticaria.

Histamine is the primary mediator involved the pathophysiology of allergic rhinitis and chronic urticaria, and this explains the prominent role that histamine H(1)-receptor antagonists have in the treatment of these disorders. However, histamine is clearly not the only mediator involved in the inflammatory cascade. There is an emerging view that drugs which can inhibit a broader range of inflammatory processes may prove to be more effective in providing symptomatic relief in both allergic rhinitis and chronic urticaria. This is an important consideration of the Allergic Rhinitis and its Impact on Asthma (ARIA) initiative which provides a scientific basis for defining what are the desirable properties of an 'ideal' antihistamine. In this review of rupatadine, a newer dual inhibitor of histamine H(1)- and PAF-receptors, we evaluate the evidence for a mechanism of action which includes anti-inflammatory effects in addition to a powerful inhibition of H(1)- and PAF-receptors. We assess this in relation to the clinical efficacy (particularly the speed of onset of action) and safety of rupatadine, and importantly its longer term utility in everyday life. In clinical trials, rupatadine has been shown to be an effective and well-tolerated treatment for allergic rhinitis and chronic idiopathic urticaria (CIU). It has a fast onset of action, producing rapid symptomatic relief, and it also has an extended duration of clinical activity which allows once-daily administration. In comparative clinical trials rupatadine was shown to be at least as effective as drugs such as loratadine, cetirizine, desloratadine and ebastine in reducing allergic symptoms in adult/adolescent patients with seasonal, perennial or persistent allergic rhinitis. Importantly, rupatadine demonstrated no adverse cardiovascular effects in preclinical or extensive clinical testing, nor negative significant effects on cognition or psychomotor performance (including a practical driving study). It improved the overall well-being of patients with allergic rhinitis or CIU based on findings from quality of life questionnaires and patient global rating scores in clinical trials. Thus, rupatadine is a recently introduced dual inhibitor of histamine H(1)- and PAF-receptors, which has been shown to be an effective and generally well-tolerated treatment for allergic rhinitis and chronic urticaria. It possesses a broader profile of anti-inflammatory properties inhibiting both inflammatory cells and a range of mediators involved in the early- and late-phase inflammatory response, but the clinical relevance of these effects remain to be clarified.

Pharmacokinetic and safety profile of rupatadine when coadministered with azithromycin at steady-state levels: a randomized, open-label, two-way, crossover, Phase I study.

BACKGROUND: Rupatadine is an oral active antihistamine and platelet-activating factor antagonist indicated for the management of allergic rhinitis and chronic urticaria in Europe. OBJECTIVE: The purpose of this study was to describe the effect of the concomitant administration of azithromycin and rupatadine on the pharmacokinetics of rupatadine and its metabolites after repeated doses. METHODS: This was a multiple-dose, randomized, open-label, 2-way, crossover, Phase I study in which healthy male and female volunteers received rupatadine 10 mg once a day for 6 days either alone or with azithromycin 500 mg on day 2 and 250 mg from day 3 to day 6. Treatments were administered after a fasting period of 10 hours with 240 mL of water, and fasting conditions were kept until 3 hours postmedication. A washout period of at least 21 days between the 2 active periods was observed. Blood samples were collected and plasma concentrations of rupatadine and its metabolites desloratadine and 3-hydroxydesloratadine were determined by liquid chromatography tandem mass spectrometry. Tolerability was based on the recording of adverse events (AEs), physical examination, electrocardiograms, and laboratory screen controls at baseline and the final study visit. RESULTS: Twenty-four healthy volunteers (15 males, 9 females; mean [SD] age, 25.67 [5.58] years; weight, 65.96 [8.57] kg) completed the study. Except for maximum observed concentration during a dosing interval (Cmax,ss) of 3-hydroxydesloratadine, on average, there were no statistically significant differences in mean plasma concentrations in any of the main pharmacokinetic parameters of rupatadine, desloratadine, and 3-hydroxydesloratadine when administered in combination with azithromycin or alone. The Cmax,ss ratio was 111 (90% CI, 91-136) and area under the plasma concentration-time curve during a dosing interval (AUC0-tau) ratio had a value of 103 (90% CI, 91-117). The corresponding ratios for the rupatadine metabolites were 109 (90% CI, 100-120) for Cmax,ss and 103 (90% CI, 96-110) for AUC0-tau for desloratadine and 109 (90% CI, 103-115) for Cmax,ss and 104 (90% CI, 100-108) for AUC0-tau for 3-hydroxydesloratadine. Point estimates for Cmax,ss ratios using paired data were 111% for rupatadine, 109% for desloratadine, and 109% for 3-hydroxydesloratadine. The 90% CIs were included in the interval 80% to 125% for desloratadine and 3-hydroxydesloratadine, whereas 90% CI for rupatadine was shifted to the right of the interval used for comparing bioavailability of the drugs. A total of 5 subjects reported 9 AEs; 5 of these were thought to be related to the drug administration and all were categorized as mild or moderate. The reported AEs were somnolence (1/24 in the rupatadine group and 1/24 in the rupatadine plus azithromycin group), diarrhea (1/24 in the rupatadine plus azithromycin group), and gastric discomfort (2/24 in the rupatadine plus azithromycin group). Four AEs were considered not to be related (2 episodes of headache, 1 anemia, 1 cheilitis). All were resolved spontaneously. No serious AEs were reported. CONCLUSIONS: The results of this study in these healthy volunteers found no significant differences in pharmacokinetic parameters other than Cmax,ss of 3-hydroxydesloratadine between rupatadine 10 mg administered alone or with azithromycin 500 mg on day 2 and 250 mg from day 3 to day 6. The administration of rupatadine compared with rupatadine plus azithromycin met the regulatory definition of bioequivalence in terms of exposure and rate parameters; however, Cmax,ss of rupatadine was outside the conventional confidence interval.

High performance liquid chromatography-tandem mass spectrometric determination of rupatadine in human plasma and its pharmacokinetics.

A simple, rapid, sensitive and selective liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method was developed and validated for the quantification of rupatadine in human plasma using estazolam as internal standard (IS). Following liquid-liquid extraction, the analytes were separated using a mobile phase of methanol-ammonium acetate (pH 2.2; 5mM) (50:50, v/v) on a reverse phase C18 column and analyzed by a triple-quadrupole mass spectrometer in the positive ion and multiple reaction monitoring (MRM) mode, m/z 416-->309 for rupatadine and m/z 295-->267 for the IS. The assay exhibited a linear dynamic range of 0.1-100 ng/ml for rupatadine in human plasma. The lower limit of quantification (LLOQ) was 0.1 ng/ml with a relative standard deviation of less than 20%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The validated LC-MS/MS method has been successfully applied to study the pharmacokinetics of rupatadine in healthy volunteers.

Antihistaminic effects of rupatadine and PKPD modelling.

Rupatadine is a new oral antihistaminic agent used for the management of allergic inflammatory conditions, such as rhinitis and chronic urticaria. The aim of the present study was to develop a population pharmacokinetic/pharmacodynamic (PKPD) model for the description of the effect of rupatadine and one of its active metabolites, desloratadine, on the histamine-induced flare reaction and to predict the response to treatment after repeated administrations of rupatadine. Both rupatadine and desloratadine were characterized by two-compartmental kinetics. For both compounds, covariates sex and weight had a significant effect on several parameters. The pharmacodynamics were described by an indirect model for the inhibition of flare formation that accounted for the contribution of both rupatadine and desloratadine to the antihistaminic effect. The final PKPD model adequately described the original data. The simulated response after repeated once-daily administrations of 10 mg rupatadine showed a significant and maintained antihistaminic effect over time, between two consecutive dosing intervals.

Cardiac Safety of Rupatadine in a Single-Ascending-Dose and Multiple-Ascending-Dose Study in Healthy Japanese Subjects, Using Intensive Electrocardiogram Assessments-Comparison With the Previous White Caucasian Thorough QT Study.

A thorough QT/QTc study in healthy white Caucasian subjects demonstrated that rupatadine has no proarrhythmic potential and raised no cardiac safety concerns. The present phase 1 study aimed to confirm the cardiac safety of rupatadine in healthy Japanese subjects. In this randomized, double-blind, placebo-controlled study, 27 healthy Japanese subjects were administered single and multiple escalating rupatadine doses of 10, 20, and 40 mg or placebo. Triplicate electrocardiogram (ECG) recordings were performed on days -1, 1, and 5 at several points, and time-matched pharmacokinetic samples were also collected. Concentration-effect analysis based on the change in the QT interval corrected using Fridericia's formula (QTcF) from average baseline was performed. Data from the formal TQT study in white Caucasian subjects was used for a comparison analysis. The ECG data for rupatadine at doses up to 40 mg did not show an effect on the QTc interval of regulatory concern. The sensitivity of this study to detect small changes in the QTc interval was confirmed by demonstrating a significant shortening of QTcF on days 1 and 5 four hours after a standardized meal. The data from this study exhibited no statistically significant differences in the QTc effect between Japanese and white Caucasian subjects.

Rupatadine: a review of its use in the management of allergic disorders.

Rupatadine (Rupafin, Rinialer, Rupax, Alergoliber) is a selective oral histamine H(1)-receptor antagonist that has also been shown to have platelet-activating factor (PAF) antagonist activity in vitro. It is indicated for use in seasonal allergic rhinitis (SAR), perennial allergic rhinitis (PAR) and chronic idiopathic urticaria (CIU) in patients aged >/=12 years. Clinical trials show that rupatadine is an effective and generally well tolerated treatment for allergic rhinitis and CIU. It has a rapid onset of action and a prolonged duration of activity. Importantly, it has no significant effect on cognition, psychomotor function or the cardiovascular system. Once-daily rupatadine significantly improves allergic rhinitis symptoms in patients with SAR, PAR or persistent allergic rhinitis (PER) compared with placebo, and provides similar symptom control to that of loratadine, desloratadine, cetirizine or ebastine. In patients with CIU, longer-term use of rupatadine improves CIU symptoms to a greater extent than placebo. It is as well tolerated as other commonly used second-generation H(1)-receptor antagonists. Thus, the introduction of rupatadine extends the range of oral agents available for the treatment of allergic disorders, including allergic rhinitis and CIU.

Influence of food on the oral bioavailability of rupatadine tablets in healthy volunteers: a single-dose, randomized, open-label, two-way crossover study.

BACKGROUND: Rupatadine is an oral active antihistamine for the management of diseases with allergic inflammatory conditions, such as perennial and seasonal rhinitis and chronic idiopathic urticaria. Oral rupatadine has been approved for the treatment of allergic rhinitis and chronic urticaria in adults and adolescents in several European countries. OBJECTIVE: The purpose of this study was to describe the effect of the concomitant intake of food on the pharmacokinetic profile and bioavailability of a single dose of rupatadine. METHODS: This was a single-dose, randomized, open-label, 2-way crossover study in which healthy male and female volunteers received a single, 20-mg oral dose of rupatadine under fed and fasting conditions. Blood samples were collected and plasma concentrations of rupatadine and its active metabolites desloratadine and 3-hydroxydesloratadine were determined by liquid chromatography tandem mass spectrometry. Tolerability was based on the recording of adverse events (AEs), physical examinations, electrocardiograms, and laboratory tolerability tests immediately before each treatment period and at the final visit of the study. RESULTS: Twenty-four volunteers (12 males; mean [SD] age, 25.4 [5.3] years [range, 18-34 years]; mean [SD] weight, 71.2 [4.3] kg [range, 64-77 kg]; 12 females; mean [SD] age, 26.8 [6.5] years [range, 18-38 years]; mean [SD] weight, 58.4 [6.8] kg, [range 50-69 kg]) were enrolled and randomized with equal distribution of sex. A significant increase in AUC from drug administration to the final quantifiable sample (AUC(0-t)) and AUC from drug administration to infinity (AUC(0-infinity)) values of rupatadine was seen under fed conditions without affecting C(max). The ratios (90% CI) of the mean log-transformed AUC(0-t) and AUC(0-infinity) for rupatadine revealed a significant increase in AUC(0-t) (ratio 131%; 90% CI, 111%-154%) and AUC(0-infinity) (ratio 133%; 90% CI, 113%-156%), whereas C(max) remained unaltered (ratio 97%; 90% CI, 80%-116%). Plasma concentration-time profiles of desloratadine and 3-hydroxydesloratadine were similar with and without food, and no differences were seen for AUC(0-t), AUC(0-infinity), or C(max). Seven (28%) subjects reported > or =1 AE. All AEs were mild, resolved spontaneously, and did not affect the outcome of the study. CONCLUSIONS: The results of this study indicate that concomitant intake of food with a single 20-mg oral dose of rupatadine exhibits a significant increase in rupatadine bioavailability. Despite the absence of bioequivalence, the drug was well tolerated under fed and fasting conditions, and no major changes in severity and/or prevalence of AEs were reported.

Population pharmacokinetic modelling of rupatadine solution in 6-11 year olds and optimisation of the experimental design in younger children.

AIMS: To optimise a pharmacokinetic (PK) study design of rupatadine for 2-5 year olds by using a population PK model developed with data from a study in 6-11 year olds. The design optimisation was driven by the need to avoid children's discomfort in the study. METHODS: PK data from 6-11 year olds with allergic rhinitis available from a previous study were used to construct a population PK model which we used in simulations to assess the dose to administer in a study in 2-5 year olds. In addition, an optimal design approach was used to determine the most appropriate number of sampling groups, sampling days, total samples and sampling times. RESULTS: A two-compartmental model with first-order absorption and elimination, with clearance dependent on weight adequately described the PK of rupatadine for 6-11 year olds. The dose selected for a trial in 2-5 year olds was 2.5 mg, as it provided a Cmax below the 3 ng/ml threshold. The optimal study design consisted of four groups of children (10 children each), a maximum sampling window of 2 hours in two clinic visits for drawing three samples on day 14 and one on day 28 coinciding with the final examination of the study. CONCLUSIONS: A PK study design was optimised in order to prioritise avoidance of discomfort for enrolled 2-5 year olds by taking only four blood samples from each child and minimising the length of hospital stays.

CYP3A5*3 and MDR1 C3435T are influencing factors of inter-subject variability in rupatadine pharmacokinetics in healthy Chinese volunteers.

Rupatadine (RUP) is an oral antihistamine and platelet-activating factor antagonist and is shown as the substrate of CYP3A5 and P-gp. The significant interindividual differences of CYP3A5 and P-gp often cause bioavailability differences of some clinical drugs. The present study is aimed to evaluate the effect of genetic polymorphisms of CYP3A5 and MDR1 on RUP pharmacokinetics in healthy male Chinese volunteer subjects. Blood samples were collected from 36 subjects before and after a single, oral RUP 10 mg dose. A PCR-RFLP assay was used to genotype CYP3A5*3 and assess MDR1 C3435T variation. A validated LC-MS/MS method quantified plasma RUP concentration. The relationship between RUP plasma concentration, pharmacokinetic parameters, and polymorphic alleles (CYP3A5 and MDR1) were assessed. Plasma RUP concentrations were lower for CYP3A5*1/*1 carriers than for CYP3A5*3/*3 and CYP3A5*1/*3 carriers. Mean C(max), AUC(0-t) and AUC(0-∞) were significantly lower, and the CLz and Vd were significantly higher in the CYP3A5 wild-type group, than in the CYP3A5 mutated group. MDR1 CT and MDR1 TT carriers had lower plasma RUP concentrations than MDR1 CC carriers. The mean C(max), AUC(0-t), AUC(0-∞) and T max were significantly lower in the TT group than in the CC and CT groups. The mean CLz was higher in the TT group than in the CC and CT groups, but not significantly. These results suggest that CYP3A5 and MDR1 may play a key role in the variability of RUP metabolism and transport, respectively. CYP3A5 and MDR1 polymorphisms may be the main explanation for the differences observed in RUP pharmacokinetics, and therefore may provide a rationale for safe and effective clinical use of RUP. Our research lays down a solid theory foundation to guide the safe and effective clinical use of RUP and a route to achieve individualized therapy.

Pharmacokinetics, Safety and Cognitive Function Profile of Rupatadine 10, 20 and 40 mg in Healthy Japanese Subjects: A Randomised Placebo-Controlled Trial.

INTRODUCTION: Rupatadine is a marketed second generation antihistamine, with anti-PAF activity, indicated for symptomatic treatment of allergic rhinitis and urticaria. This study was conducted to evaluate the pharmacokinetics (PK), pharmacodynamics (PD), safety and tolerability of rupatadine in healthy Japanese subjects after single and multiple oral doses. METHODS: In this randomised, double-blind, placebo-controlled study, 27 male and female healthy Japanese subjects were administered single and multiple escalating rupatadine dose of 10, 20 and 40 mg or placebo. Blood samples were collected at different time points for PK measurements and subjects were assessed for safety and tolerability. The effect of rupatadine on cognitive functioning was evaluated by means of computerized cognitive tests: rapid visual information processing (RVP), reaction time (RT), spatial working memory (SWM) and visual analogue scales (VAS). RESULTS: Exposure to rupatadine as measured by Cmax and AUC was found to increase in a dose dependent manner over the dose range of 10-40 mg for both single and multiple dose administration. The safety assessments showed that all treatment related side effects were of mild intensity and there were no serious adverse events (SAEs) or withdrawals due to treatment-emergent adverse events (TEAEs) in this study. The therapeutic dose of rupatadine did not show any CNS impairment in any of the cognitive tests. CONCLUSIONS: This study demonstrated that rupatadine is safe and well tolerated by Japanese healthy subjects. The PK-PD profile confirmed previous experience with rupatadine.

Rupatadine: global safety evaluation in allergic rhinitis and urticaria.

INTRODUCTION: Rupatadine is a second-generation H1-antihistamine with dual affinity for histamine H1 and PAF receptors. Rupatadine is indicated for the treatment of allergic rhinitis and urticaria. AREAS COVERED: A Medline search was conducted to identify preclinical and clinical studies of rupatadine. This was supplemented with additional articles obtained from online sources. The focus of this review is on the safety profile of rupatadine. EXPERT OPINION: The review of these data indicates that rupatadine is highly selective for histamine H1-receptors, exhibits additional PAF antagonism in in vitro and in vivo studies, does not cross the blood-brain barrier, and has similar adverse events comparable with other second-generation antihistamines. Rupatadine is a safe and well tolerated drug in patients over 2 years old, with no central nervous system or cardiovascular effects and it can be taken with or without foods.

Loratadine. A preliminary review of its pharmacodynamic properties and therapeutic efficacy.

Loratadine is a long acting antihistamine which has a high selectivity for peripheral histamine H1-receptors and lacks the central nervous system depressant effects often associated with some of the older antihistamines. Results from controlled clinical trials have shown that loratadine (usually 10mg once daily) is a well-tolerated and effective antihistamine which will be beneficial in patients with allergic rhinitis and chronic urticaria. It was found to be significantly superior to placebo, faster acting than astemizole and as effective as usual dosages of terfenadine, clemastine, mequitazine and azatadine in eliciting relief of symptoms. Importantly, loratadine is associated with a lower incidence of sedation than azatadine, clemastine, chlorpheniramine and mequitazine. Thus, loratadine, with its convenience of once daily administration, will be a useful addition to those drugs currently available for the treatment of patients with allergic diseases in whom a histamine H1-receptor antagonist is indicated. Indeed, it is likely to find a place as one of the newer 'agents of choice' in this setting.

Pharmacokinetics of loratadine in patients with renal insufficiency.

The disposition of loratadine, a new orally active histamine H1 receptor antagonist and its primary metabolite descarboethoxyloratadine were characterized in adult volunteers with normal renal function (group I), patients with chronic renal failure, i.e., creatinine clearance less than 30 mL/min (group II), as well as chronic hemodialysis patients (group III). The effect of hemodialysis on the disposition of loratadine and descarboethoxyloratadine was also assessed. Subjects in groups I and II were given a single oral 40 mg dose of loratadine while the patients in Group III received two single 40 mg doses of loratadine (during an interdialytic period and just prior to hemodialysis). Loratadine was rapidly absorbed and the decline of plasma concentrations after attainment of the Cmax was biexponential in all subjects. No significant differences in t1/2 beta were observed between the three groups (8.7 +/- 5.9, 7.6 +/- 6.9, 8.6 +/- 1.6 hrs: in groups I, II, and III, respectively). The apparent total body clearance and apparent volume of distribution of loratadine also did not differ significantly among the three groups. No significant differences in the Cmax or tmax of the metabolite were observed. The metabolite AUC infinity 0 however was significantly greater in group II subjects: (212.4 +/- 37.8, 469.5 +/- 95.4, 325.2 +/- 114.6 ng.hr/mL; groups I, II, and III, respectively). No significant relationship was observed between the terminal elimination half-life of loratadine or descarboethoxyloratadine and creatinine clearance. Hemodialysis augmented endogenous clearance by less than 1%. The disposition of loratadine is not significantly altered in patients with severe renal insufficiency nor is hemodialysis an effective means of removing loratadine or descarboethoxyloratadine from the body.

Pharmacokinetics and dose proportionality of loratadine.

The dose proportionality and pharmacokinetics of loratadine, a new nonsedating antihistamine, were studied in 12 normal volunteers. In a three-way cross-over, each volunteer received a single 10-, 20-, or 40-mg loratadine capsule. Blood was collected up to 96 hours after dosing. Plasma loratadine concentrations were determined by radioimmunoassay (RIA), and those of a minor, but active metabolite, descarboethoxyloratadine, by high performance liquid chromatography (HPLC). Concentrations in the disposition phase were fitted to a biexponential equation for pharmacokinetic analysis. For dose proportionality, AUC- and Cmax-dose relationships were evaluated by linear regression. Also, pharmacokinetic parameters and dose-adjusted AUCs were compared by analysis of variance. Loratadine was rapidly absorbed, reaching Cmax values (4.7, 10.8, and 26.1 ng/mL) at 1.5, 1.0 and 1.2 hours for the 10-, 20-, and 40-mg doses, respectively. The loratadine t1/2 beta ranged from 7.8 to 11.0 hours. Descarboethoxyloratadine reached Cmax values (4.0, 9.9, and 16.0 ng/mL) at 3.7, 1.5, and 2.0 hours for the 10-, 20-, and 40-mg doses, respectively. Its t1/2 beta ranged from 17 to 24 hours. For both compounds, AUC- and Cmax-dose relationships were linear and there were no differences in the t1/2 beta, CL/F, or dose-adjusted AUC values among the treatments. Loratadine and descarboethoxyloratadine plasma concentrations and pharmacokinetics were not dose dependent.

Loratadine: multiple-dose pharmacokinetics.

The steady-state pharmacokinetics of loratadine (L), a new long-acting antihistamine devoid of CNS activity, was investigated in 12 healthy male volunteers. Each volunteer received 40-mg L capsules q24h for ten days. Blood samples were collected at various times on day 1, 5, 7, and 10 and assayed for L by radioimmunoassay (RIA) and for descarboethoxyloratadine (DCL), a known active metabolite, by high-performance liquid chromatography (HPLC). The plasma L and DCL concentration-time data in the disposition phases were fitted to a biexponential equation for pharmacokinetic analysis. Steady-state plasma L Cmax concentrations were reached at 1.5 hour (Tmax) after each dose. DCL steady-state Cmax values ranged 26 to 29 ng/mL at a Tmax ranging from 1.8 to 3 hours. The AUC at steady state, AUC tau, was 80 to 96 and 349 to 421 h X ng/mL for L and DCL, respectively. The accumulation indexes (Ra) based on AUC tau ratios, did not change for either compound after day 5. Ra values for L and DCL after the fifth dose were 1.4 and 1.9, respectively, indicating that there is little accumulation of either L or DCL after a multiple (once-a-day) dosage regimen. The t1/2 beta at steady state were 14.4 and 18.7 hours for L and DCL, respectively, which were similar to those reported following a single-dose L administration. Observed plasma drug concentrations were in good agreement with predicted values derived for pharmacokinetic parameters.

Excretion of loratadine in human breast milk.

The excretion of loratadine, a new nonsedating antihistamine, into human breast milk was studied in six lactating nonpregnant volunteers. Each volunteer received one 40-mg loratadine capsule. Milk and blood were collected before and at specified times (to 48 hours) after dosing. Plasma and milk loratadine concentrations were determined by a specific radioimmunoassay, and those of an active but minor metabolite, descarboethoxyloratadine, by high performance liquid chromatography (HPLC). Breast milk concentration-time curves of both loratadine and descarboethoxyloratadine paralleled the plasma concentration-time curves. For loratadine, the plasma Cmax was 30.5 ng/mL at 1.0 hour after dosing and the milk Cmax was 29.2 ng/mL in the 0 to 2 hour collection interval. Through 48 hours, the loratadine milk-plasma AUC ratio was 1.2 and 4.2 micrograms of loratadine was excreted in breast milk, which was 0.010% of the administered dose. For descarboethoxyloratadine, the plasma Cmax was 18.6 ng/mL at 2.2 hours after dosing, whereas the milk Cmax was 16.0 ng/mL, which was in the 4 to 8-hour collection interval. Through 48 hours, the mean milk-plasma descarboethoxyloratadine AUC ratio was 0.8 and a mean of 6.0 micrograms of descarboethoxyloratadine (7.5 micrograms loratadine equivalents) were excreted in the breast milk, or 0.019% of the administered loratadine dose. Thus, a total of 11.7 micrograms loratadine equivalents or 0.029% of the administered dose were excreted as loratadine and its active metabolite. A 4-kg infant ingesting the loratadine and descarboethoxyloratadine excreted would receive a dose equivalent to 0.46% of the loratadine dose received by the mother on a mg/kg basis.(ABSTRACT TRUNCATED AT 250 WORDS)