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1. The pharmacokinetics and physiological effects of buprenorphine were studied in 12 newborn premature neonates (27 to 32 weeks gestational age) who were given a loading dose of 3.0 micrograms kg‐1 of buprenorphine followed by an intravenous infusion of 0.72 micrograms kg‐ 1 h‐1 of buprenorphine. Plasma concentrations of buprenorphine were measured during the infusion, at steady‐state and for 24 h after the cessation of the buprenorphine infusion. 2. The mean steady‐state plasma buprenorphine concentration (+/‐ s.d.) for an infusion rate of 0.72 micrograms kg‐1 h‐1 was 4.3 +/‐ 2.6 ng ml‐1. 3. Buprenorphine clearance was 0.23 +/‐ 0.07 l h‐1 kg‐1, the elimination half‐life was 20 +/‐ 8 h and the volume of distribution was 6.2 +/‐ 2.11 l kg‐1. 4. Small but significant falls were noted in systolic blood pressure at 6 h and heart rate at 1, 6 and 12 h after the administration of buprenorphine, but these did not appear to cause any clinical deterioration. 5. Four of the 12 subjects studied required an increase in the infusion rate of buprenorphine to achieve adequate sedation. 6. The results suggest that this dosing regimen of buprenorphine is safe but may not be as effective as other opioids in producing sedation and analgesia in premature newborns.

Ethanol-water systems enhance permeation of ionic solutes through human stratum corneum. Optimum enhancement of salicylate ion permeation has been observed with ethanol volume fractions near 0.63. The mechanism of action of ethanol-water systems enhancing skin permeation was investigated by in vitro skin permeation studies combined with Fourier transform infrared spectroscopy experiments. The increased skin permeation of the ionic permeant by the ethanol-water systems may be associated with alterations involving the polar pathway. Polar pathway alterations may occur in either or both the lipid polar head and proteinaceous regions of the stratum corneum. Ion-pair formation may also contribute to increased permeation. However, the decreased permeation of salicylate ion observed at higher volume fractions of ethanol may be attributed to decreased uptake of permeant into the stratum corneum.

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