Comparison of the effects of various transmucosal absorption enhancers on buccal insulin delivery: in vitro and in vivo studies

The effects of various transmucosal absorption enhancers on insulin permeation were studied in vitro and in vivo. The penetration of insulin through hamster and rabbit buccal membranes was investigated in vitro. The results showed that there was a statistically significant increase in the permeability of insulin compared with controls after concomitant administration with Brij 78, sodium deoxycholate, sodium lauryl sulfate and lecithin, but aprotinin, bacitracin, 1-menthol and poloxamer were less effective. The buccal delivery of insulin was investigated in vivo, in rats. Insulin absorption vas estimated from the cumulative response of the serum glucose concentration and in comparison to a SC dose/response curve. Buccal insulin efficacy in the absence of co-administration absorption enhancers was very low in relation to the SC administration of insulin. The values all increased significantly following concomitant administration via the buccal route with sodium deoxycholate, sodium lauryl sulfate, lecithin and Brij 78, Fr (relative pharmacological bioavailability) (P < 0.05). From the present studies, it is concluded that with the most effective absorption enhancers, buccal insulin vas one-fifth to one-fourth as effective as SC insulin. For the enhancement of these promoters, the results of in vitro experiments were in agreement with the in vivo results.Pharmacology & PharmacySCI(E)1ARTICLE6415-4191