Comparison of Oxycodone Pharmacokinetics after Buccal and Sublingual Administration in Children

We evaluated and compared the pharmacokinetics of two oral administration routes of oxycodone parenteral liquid (10 mg/mL) - single buccal and sublingual administration - in 30 generally healthy awake children, aged 6–91 months.

Two groups of children undergoing inpatient surgery were enrolled. In a randomised fashion, children received a single dose of oxycodone 0.2 mg/kg buccally (n = 15) or sublingually (n = 15). Regular blood samples were collected for up to 12 hours, and plasma was analysed for oxycodone, oxymorphone and noroxycodone using gas chromatography-mass spectrometry.

Bioavailability was similar after administration at the two instillation sites. The area under the plasma concentration-time curve from time zero extrapolated to infinity (AUC_∞) was 2400–8000 ng · min/mL (median 4200 ng · min/mL) in the buccal group and 2700-7900 ng · min/mL (median 5500 ng · min/mL) in the sublingual group. After buccal administration, maximum plasma concentration (Cmax) was 5.4–39 ng/mL (16 ng/mL) after buccal and 5.5–42 ng/mL (22 ng/mL) after sublingual administration. Twelve of the 15 children in both groups reached the oxycodone analgesic concentration of 12 ng/mL, which was sustained for 43–209 minutes (median 160 minutes) in the children with buccal oxycodone and for 32–262 minutes (median 175 minutes) in the children with sublingual oxycodone. The terminal elimination half-lives were closely similar in the two groups: 104–251 minutes (median 140 minutes) in the buccal group and 110–190 minutes (150 minutes) in the sublingual group.

The results of this study show that in young children the absorption of oxycodone is similar after buccal and sublingual instillation.