Absorption characteristics of insulin through the buccal mucosa

The purpose of the study was to investigate absorption characteristics of insulin through the buccal mucosa by studying the influence of application time of the buccal cell on the hypoglycemic response as well as the plasma insulin level. Three application times of the buccal cell (0.5, 1.0 and 1.5 h) were studied. A marked increase in the extent of hypoglycemia was observed when the application time was extended from 0.5 to 1.0 h. Correspondingly, the amount of insulin absorbed increased in the same order. However, a further increase in application time from 1.0 to 1.5 h did not seem to significantly enhance the hypoglycemic response. This finding was also confirmed by the insulin blood levels. It can be suggested that a certain amount of time is required for insulin molecules to be taken up by the buccal mucosa. Tmax of hypoglycemia was observed about 1.0 h after the removal of the cell, irrespective of the application time. Absorption profile of plasma insulin was found to be application time-dependent. These results can be attributed to the reservoir function of the buccal mucosa and time-dependent equilibrium of insulin with the buccal mucosa.