Alvogen

OSELTAMIVIR PHOSPHATE

Post-LOE

ORAL · FOR SUSPENSION

12.1 Mechanism of Action Oseltamivir is an antiviral drug with activity against influenza virus [see ]. 12.3 Pharmacokinetics Absorption and Bioavailability Oseltamivir is absorbed from the gastrointestinal tract after oral administration of oseltamivir phosphate and is extensively converted predominantly by hepatic esterases to oseltamivir carboxylate. At least 75% of an oral dose reaches the systemic circulation as oseltamivir carboxylate and less than 5% of the oral dose reaches the systemic circulation as oseltamivir (see Table 6). Table 6 Mean (% CV) Pharmacokinetic Parameters of Oseltamivir and Oseltamivir Carboxylate Following Multiple Dosing of 75 mg Capsules Twice Daily (n=20) Parameter Oseltamivir Oseltamivir Carboxylate C max (ng/mL) 65 (26) 348 (18) AUC 0‐12h (ng∙h/mL) 112 (25) 2719 (20) Plasma concentrations of oseltamivir carboxylate are proportional to doses up to 500 mg given twice daily (about 6.7 times the maximum recommended oseltamivir phosphate dosage) [see ]. Coadministration with food had no significant effect on the peak plasma concentration (551 ng/mL under fasted conditions and 441 ng/mL under fed conditions) and the area under the plasma concentration time curve (6218 ng∙h/ml under fasted conditions and 6069 ng∙h/mL under fed conditions) of oseltamivir carboxylate. Distribution The volume of distribution (V ss ) of oseltamivir carboxylate, following intravenous administration in 24 subjects (Oseltamivir phosphate is not available as an IV formulation), ranged between 23 and 26 liters. The binding of oseltamivir carboxylate to human plasma protein is low (3%). The binding of oseltamivir to human plasma protein is 42%, which is insufficient to cause significant displacement‐based drug interactions. Elimination Absorbed oseltamivir is primarily (>90%) eliminated by conversion to the active metabolite, oseltamivir carboxylate. Plasma concentrations of oseltamivir declined with a half‐life of 1 to 3 hours in most subjects after oral administration. Oseltamivir carboxylate is not further metabolized and is eliminated unchanged in urine. Plasma concentrations of oseltamivir carboxylate declined with a half‐life of 6 to 10 hours in most subjects after oral administration. Metabolism Oseltamivir is extensively converted to the active metabolite, oseltamivir carboxylate, by esterases located predominantly in the liver. Oseltamivir carboxylate is not further metabolized. Neither oseltamivir nor oseltamivir carboxylate is a substrate for, or inhibitor of, cytochrome P450 isoforms. Excretion Oseltamivir carboxylate is eliminated entirely (>99%) by renal excretion. Renal clearance (18.8 L/h) exceeds glomerular filtration rate (7.5 L/h), indicating that tubular secretion (via organic anion transporter) occurs in addition to glomerular filtration. Less than 20% of an oral radiolabeled dose is eliminated in feces. Specific Populations Renal Impairment Administration of 100 mg of oseltamivir phosphate twice daily (about 1.3 times the maximum recommended dosage) for 5 days to subjects with various degrees of renal impairment showed that exposure to oseltamivir carboxylate is inversely proportional to declining renal function. Population‐derived pharmacokinetic parameters were determined for patients with varying degrees of renal function including ESRD patients on hemodialysis. Median simulated exposures of oseltamivir carboxylate for recommended treatment and prophylaxis regimens are provided in Table 7. The pharmacokinetics of oseltamivir have not been studied in ESRD patients not undergoing dialysis [see , and ]. Table 7 Simulated Median Treatment Exposure Metrics of Oseltamivir Carboxylate in Patients with Normal Renal Function, with Renal Impairment and ESRD Patients on Hemodialysis Renal Function/ Impairment Normal Creatinine Clearance 90‐140 mL/min (n=57) Mild Creatinine Clearance 60‐90 mL/min (n=45) Moderate Creatinine Clearance 30‐60 mL/min (n=13) Severe Creatinine Clearance 10‐30 mL/min (n=11) ESRD Creatinine Clearance <10 mL/min on Hemodialysis (n=24) Recommended Treatment Regimens PK exposure parameter 75 mg twice daily 75 mg twice daily 30 mg twice daily 30 mg once daily 30 mg every HD cycle Cmin (ng/mL) 145 253 180 219 221 Cmax (ng/mL) 298 464 306 477 1170 AUC48 (ng∙h/mL)* 11224 18476 12008 16818 23200 Recommended Prophylaxis Regimens PK exposure parameter 75 mg once daily 75 mg once daily 30 mg once daily 30 mg every other day 30 mg alternate HD cycle Cmin (ng/mL) 39 62 57 70 42 Cmax (ng/mL) 213 311 209 377 903 AUC48 (ng∙h/mL)* 5294 8336 6262 9317 11200 *AUC normalized to 48 hours. In continuous ambulatory peritoneal dialysis (CAPD) patients, the peak concentration of oseltamivir carboxylate following a single 30 mg dose of oseltamivir or once weekly oseltamivir was approximately 3‐fold higher than in patients with normal renal function who received 75 mg twice daily. The plasma concentration of oseltamivir carboxylate on Day 5 (147 ng/mL) following a single 30 mg dose in CAPD patient

2017

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Antiretroviral Pregnancy Registry (APR): Multi-sponsor Registry to Detect Any Major Teratogenic Effe

HIV Infections

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DP-R213

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