Rise of testosterone, nortestosterone, and 17ß-estradiol concentrations in peripheral blood plasma of pigs after sublingual application in vivo

Sublingual permeability of model drugs in New Zealand White Rabbits: In Vitro-In vivo correlation

This study investigated sublingual drug permeation and administration using five model drugs with diverse physicochemical properties, employing New Zealand White Rabbit sublingual mucosa for in vitro experiments and New Zealand White Rabbits for in vivo studies. The research aimed to determine key permeation parameters, specifically permeability and lag time. A strong linear correlation (r = 0.93, n = 5) was established between in vitro permeability and the distribution coefficient of the model drugs at pH 6.8. The study revealed no significant difference between in vitro and in vivo permeability, suggesting that in vitro studies can reliably predict in vivo permeability for these drugs. However, the in vivo lag time was significantly shorter than the in vitro lag time due to the presence of capillaries in the sublingual mucosa, which provided direct access to the systemic circulation and the absence of an aqueous boundary layer.

Oral transmucosal drug delivery--current status and future prospects

Oral transmucosal drug delivery (OTDD) dosage forms have been available since the 1980s. In contrast to the number of actives currently delivered locally to the oral cavity, the number delivered as buccal or sublingual formulations remains relatively low. This is surprising in view of the advantages associated with OTDD, compared with conventional oral drug delivery. This review examines a number of aspects related to OTDD including the anatomy of the oral cavity, models currently used to study OTDD, as well as commercially available formulations and emerging technologies. The limitations of current methodologies to study OTDD are considered as well as recent publications and new approaches which have advanced our understanding of this route of drug delivery.