A simple extemporaneous oral suspension of aprepitant yields sufficient pharmacokinetic exposure in children

Introduction: Aprepitant is used for the treatment of chemotherapy induced nausea and vomiting. A liquid formulation is needed for treatment of young children. However, the commercial (powder for) suspension was not available worldwide for a prolonged period of time and, therefore, a 10 mg/mL aprepitant oral suspension was extemporarily prepared to prevent suboptimal antiemetic treatment. The current pharmacokinetic study was developed to investigate whether this extemporaneous oral suspension offers an appropriate treatment option. Methods: From 49 pediatric patients (0.7–17.9 years) 235 plasma concentrations were collected. Patients were either treated with our extemporaneous oral suspension (n = 26; 53%), commercially available capsules (n = 18; 37%), or the intravenous prodrug formulation of aprepitant (fosaprepitant, n = 5; 10%). Pharmacokinetic analyses were performed using nonlinear mixed effects modelling. Results: A one-compartment model adequately described the pharmacokinetics of aprepitant in children. The bioavailability of the extemporaneous oral suspension was not significantly different to that of the capsules (P = 0.26). The observed bioavailability throughout the total population was 83% (95% CI 69%-97%). The absorption of the extemporaneous oral suspension was 39.4% (95%CI 19.5–57.4%) faster than that of capsules (mean absorption time of 1.78 h (95%CI 1.32–2.35), but was comparable to that of the commercial oral suspension. The median area under the curve after (fos)aprepitant was 22.2 mg/L*h (range 8.9–50.3 mg/L*h) on day 1. Conclusion: Our extemporaneous oral suspension is an adequate alternative for the commercially (un)available oral suspension in young children. An adequate exposure to aprepitant in children was yielded and the bioavailability of the extemporaneous suspension was comparable to capsules.