The pharmacokinetic properties of olopatadine were studied after administration by the nasal, oral, intravenous, and topical ocular routes. Olopatadine exhibited linear pharmacokinetics across the routes studied over a large dose range.

Absorption:

Healthy Subjects: Olopatadine was absorbed with individual peak plasma concentrations observed between 30 minutes and 1 hour after twice daily intranasal administration of Olopatadine Hydrochloride Nasal Spray. The mean ( ± SD) steady-state peak plasma concentration (Cmax) of olopatadine was 16.0 ± 8.99 ng/mL. Systemic exposure as indexed by area under the curve (AUC0-12) averaged 66.0 ± 26.8 ng·h/mL. The average absolute bioavailability of intranasal olopatadine is 57%. The mean accumulation ratio following multiple intranasal administration of Olopatadine Hydrochloride Nasal Spray was about 1.3.

Seasonal Allergic Rhinitis (SAR) Patients: Systemic exposure of olopatadine in SAR patients after twice daily intranasal administration of Olopatadine Hydrochloride Nasal Spray was comparable to that observed in healthy subjects. Olopatadine was absorbed with peak plasma concentrations observed between 15 minutes and 2 hours. The mean steady-state Cmax was 23.3 ± 6.2 ng/mL and AUC0-12 averaged 78.0 ± 13.9 ng·h/mL.

Distribution: The protein binding of olopatadine was moderate at approximately 55% in human serum, and independent of drug concentration over the range of 0.1 to 1000 ng/mL. Olopatadine was bound predominately to human serum albumin.

Metabolism: Olopatadine is not extensively metabolized. Based on plasma metabolite profiles following oral administration of [14C] olopatadine, at least six minor metabolites circulate in human plasma. Olopatadine accounts for 77% of peak plasma total radioactivity and all metabolites amounted to <6% combined. Two of these have been identified as the olopatadine N-oxide and N-desmethyl olopatadine. In in vitro studies with cDNA-expressed human cytochrome P450 isoenzymes (CYP) and flavin-containing monooxygenases (FMO), N-desmethyl olopatadine (Ml) formation was catalyzed mainly by CYP3A4, while olopatadine N-oxide (M3) was primarily catalyzed by FMO1 and FMO3. Olopatadine at concentrations up to 33,900 ng/mL did not inhibit the in vitro metabolism of specific substrates for CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4. The potential for olopatadine and its metabolites to act as inducers of CYP enzymes has not been evaluated.

Elimination: The plasma elimination half-life of olopatadine is 8 to 12 hours. Olopatadine is mainly eliminated through urinary excretion. Approximately 70% of a [14C] olopatadine hydrochloride oral dose was recovered in urine with 17% in the feces. Of the drug-related material recovered within the first 24 hours in the urine, 86% was unchanged olopatadine with the balance comprised of olopatadine N-oxide and N-desmethyl olopatadine.

Special Population:

Hepatic Impairment: No specific pharmacokinetic study examining the effect of hepatic impairment was conducted. Since metabolism of olopatadine is a minor route of elimination, no adjustment of the dosing regimen of Olopatadine Hydrochloride Nasal Spray is warranted in patients with hepatic impairment.

Renal Impairment: The mean Cmax values for olopatadine following single intranasal doses were not markedly different between healthy subjects (18.1 ng/mL) and patients with mild, moderate and severe renal impairment (range 15.5 to 21.6 ng/mL). Mean plasma AUC0-12 was two-fold higher in patients with severe impairment (creatinine clearance <30 mL/min/1.73 m2). In these patients, peak steady-state plasma concentrations of olopatadine are approximately 10-fold lower than those observed after higher 20 mg oral doses, twice daily, which were well-tolerated. These findings indicate that no adjustment of the dosing regimen of Olopatadine Hydrochloride Nasal Spray is warranted in patients with renal impairment.

Gender: The mean systemic exposure (Cmax and AUC0-12) in female SAR patients following multiple administration of olopatadine was 40% and 27% higher, respectively than those values observed in male SAR patients.

Race: The effects of race on olopatadine pharmacokinetics have not been adequately investigated.

Age: Pediatric Patients 6 to 11 Years of Age: The systemic pharmacokinetics of olopatadine, olopatadine N-oxide and Ndesmethyl olopatadine in patients 6 through 11 years of age were characterized using data from 42 pediatric patients administered Olopatadine Hydrochloride Nasal Spray, one spray per nostril twice daily for a minimum of 14 days. The mean Cmax (15.4 ± 7.3 ng/mL) of olopatadine was approximately 2-fold less than was comparable to that observed in adults (78.0 ± 13.9 ng·h/mL). The Cmax and AUC0-12 of olopatadine N-oxide were comparable to that observed in adults. The Cmax and AUC0-12 of N-desmethyl olopatadine are approximately 18% and 37% higher than that observed in adults, respectively.

Pediatric Patients 2 to 5 Years of Age: The systemic pharmacokinetics of olopatadine, olopatadine N-oxide, and N-desmethyl olopatadine were characterized using population pharmacokinetic methods applied to sparse data (approximately 5 samples per patient) obtained from 66 pediatric patients (2 to less than 6 years of age) administered one-half the recommended adult dose (1 spray per nostril) of Olopatadine Hydrochloride Nasal Spray twice daily for a minimum of 14 days. The mean Cmax and AUC0-12 of olopatadine were 13.4 ± 4.6 ng/mL and 75.0± 26.4 ng*hr/mL respectively. The mean Cmax and AUC0-12 of olopatdine N-oxide and N-desmethyl olopatadine were similar to that of patients 6 to 11 years of age.

Drug Interaction Studies

Drug interactions with inhibitors of liver enzymes are not anticipated because olopatadine is eliminated predominantly by renal excretion. Olopatadine did not inhibit the in vitro metabolism of specific substrates for CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4. Based on these data, drug interactions involving P450 inhibition are not expected. Due to the modest protein binding of olopatadine (55%), drug interactions through displacement from plasma proteins are also not expected.