Loratadine - Pharmacokinetics

Absorption: Loratadine was rapidly absorbed following oral administration of 10 mg tablets, once daily for 10 days to healthy adult volunteers with times to maximum concentration (Tmax) of 1.3 hours for loratadine and 2.5 hours for its major active metabolite, descarboethoxyloratadine. Based on a cross-study comparison of single doses of loratadine syrup and tablets given to healthy adult volunteers, the plasma concentration profile of descarboethoxy-loratadine for the two formulations is comparable. The pharmacokinetics of loratadine and descarboethoxyloratadine are independent of dose over the dose range of 10 mg to 40 mg and are not altered by the duration of treatment. In a single-dose study, food increased the systemic bioavailability (AUC) of loratadine and descarboethoxyloratadine by approxi-mately 40% and 15%, respectively. The time to peak plasma concentration (Tmax) of loratadine and descarboethoxyloratadine was delayed by 1 hour. Peak plasma concentrations (Cmax) were not affected by food.

Pharmacokinetic studies showed that CLARITINREDITABS (loratadine rapidly-disintegrating tablets) provide plasma concentrations of loratadine and descarboethoxyloratadine similar to those achieved with CLARITIN Tablets. Following administration of 10 mg loratadine once daily for 10 days with each dosage form in a randomized crossover compari-son in 24 normal adult subjects, similar mean exposures (AUC) and peak plasma concentrations (Cmax) of loratadine were observed. CLARITINREDITABS (loratadine rapidly-disintegrating tablets)mean AUC and Cmax were 11% and 6% greater than that of the CLARITINTablet values, respectively. Descarboethoxyloratadine bioequivalence was demonstrated between the two formulations. After 10 days of dosing, mean peak plasma concentrations were attained at 1.3 hours and 2.3 hours (Tmax) for parent and metabolite, respectively.

In a single-dose study with CLARITIN REDITABS (loratadine rapidly-disintegrating tablets), food increased the AUC of loratadine by approximately 48% and did not appreciably affect the AUC of descarboethoxyloratadine. The times to peak plasma concentration (Tmax) of loratadine and descarboethoxyloratadine were delayed by approximately 2.4 and 3.7 hours, respectively, when food was consumed prior to CLARITIN REDITABS (loratadine rapidly-disintegrating tablets) administration. Parent and metabolite peak concentrations (Cmax) were not affected by food.

In a single-dose study with CLARITIN REDITABS (loratadine rapidly-disintegrating tablets) in 24 subjects, the AUC of loratadine was increased by 26% when administered without water compared to administration with water, while Cmax was not substantially affected. The bioavailability of descarboethoxyloratadine was not different when administered without water.