Evaluation of the Clearance of a Sublingual Buprenorphine Spray in the Beagle Dog Using Gamma Scintigraphy

Pharmacokinetics and physiologic/behavioral effects of buprenorphine administered sublingually and intravenously to neonatal foals

Buprenorphine is absorbed following sublingual administration, which would be a low-stress delivery route in foals. However, the pharmacokinetics/pharmacodynamics are not described in foals. Six healthy foals <21 days of age participated in a blinded, randomized, 3-period, 5-sequence, 3-treatment crossover prospective study. Foals received 0.01-0.02 mg/kg buprenorphine administered SL or IV with an equivalent volume of saline administered by the opposite route. Blood was collected from the cephalic vein for pharmacokinetic analysis. Physiologic parameters (HR, RR, body temperature, GI sounds), locomotion (pedometer), and behavioral data (activity level, nursing time, response to humans) were recorded. Plasma concentration of buprenorphine exceeded a presumed analgesic level (0.6 ng/ml) in five foals in the IV group and one in the SL group but only for a very brief time. Pharmacokinetic analysis following IV administration demonstrated a short elimination half-life (t_1/2β 1.95 ± 0.7 hr), large volume of distribution (6.46 ± 1.54 L/kg), and a high total clearance (55.83 ± 23.75 ml/kg/min), which differs from adult horses. Following SL administration, maximum concentrations reached were 0.61 ± 0.11 ng/ml and bioavailability was 25.1% ± 10.9%. In both groups, there were minor statistical differences in HR, RR, body temperature, locomotion, and time spent nursing. However, these differences were clinically insignificant in this single dose study, and excitement, sedation, or colic did not occur.

Pharmacokinetics, pharmacodynamics, and metabolism of acepromazine following intravenous, oral, and sublingual administration to exercised Thoroughbred horses

Acepromazine is a tranquilizer used commonly in equine medicine. This study describes serum and urine concentrations and the pharmacokinetics and pharmacodynamics of acepromazine following intravenous, oral, and sublingual (SL) administration. Fifteen exercised adult Thoroughbred horses received a single intravenous, oral, and SL dose of 0.09 mg/kg of acepromazine. Blood and urine samples were collected at time 0 and at various times for up to 72 hr and analyzed for acepromazine and its two major metabolites (2-(1-hydroxyethyl) promazine and 2-(1-hydroxyethyl) promazine sulfoxide) using liquid chromatography-tandem mass spectrometry. Acepromazine was also incubated in vitro with whole equine blood and serum concentrations of the parent drug and metabolites determined. Acepromazine was quantitated for 24 hr following intravenous administration and 72 hr following oral and SL administration. Results of in vitro incubations with whole blood suggest additional metabolism by RBCs. The mean ± SEM elimination half-life was 5.16 ± 0.450, 8.58 ± 2.23, and 6.70 ± 2.62 hr following intravenous, oral, and SL administration, respectively. No adverse effects were noted and horses appeared sedate as noted by a decrease in chin-to-ground distance within 5 (i.v.) or 15 (p.o. and SL) minutes postadministration. The duration of sedation lasted 2 hr. Changes in heart rate were minimal.

Nanovesicles system for rapid-onset sublingual delivery containing sodium tanshinone IIA sulfonate: in vitro and in vivo evaluation

A novel formulation based on nanovesicles system for rapid-onset sublingual delivery of hydrophilic drug (sodium tanshinone IIA sulfonate, STS) was investigated. The nanovesicles system was composed of 1.5% soybean lecithin, 6% propylene glycol, and penetration enhancers (1% sodium dodecyl sulfate and 0.03% hyaluronan acid). The STS-loaded nanovesicles with an average diameter of 133 ± 9.04 nm and high entrapment efficiency of 85.65 ± 3.89% were characterized. The effects of permeation enhancers on the penetration of STS formulations were investigated using Franz diffusion cells in vitro, showing 86.1-235.8 times higher permeation rate than that of normal STS solution. The rapid symptom relief effect of the nanovesicles system on acute myocardial infarction rabbits was evaluated by in vivo study, ST-segment deviation(S and T wave abnormality in electrocardiogram) was attenuated markedly and rapidly within 5 min, infarct size of heart was significantly reduced and the biochemical indicators were substantially decreased, compared with the control groups (p < 0.05). This study provided a promising tool for the future sublingual delivery of hydrophilic compounds with the noninvasive and rapid onset clinical effect.