DIFFUSION RATES OF VASOPRESSIN THROUGH HUMAN VAGINAL AND BUCCAL MUCOSA

The permeability to several chemical compounds and the histology of va ginal and buccal mucosa are very similar. Because vaginal mucosa is mo re abundant, it may be used as a model for the latter. To further deve lop the vaginal/buccal mucosa model. the objective of the present stud y was to evaluate the passage of a small polypeptide, vasopressin, acr oss fresh and frozen specimens of these two mucosae. Specimens of fres h buccal and vaginal mucosa were taken from excised tissue obtained fo llowing vaginal hysterectomies and various oral surgical procedures. P ieces of buccal and vaginal tissue specimens obtained were used fresh or were snap-frozen and stored at -85 degrees C for periods of up to 1 0 months. Biopsies from fresh and thawed specimens were mounted in flo w-through diffusion cells and their permeability to tritiated vasopres sin was determined using a continuous flow-through perfusion sytem. Sp ecimens were examined histologically before and after freezing as well as before and after permeability experiments and similarities between vaginal and buccal tissues verified. No statistically significant dif ferences between flux values for fresh and frozen vaginal and buccal m ucosa, respectively, were found. These results demonstrate that the pe rmeation of vasopressin across fresh and frozen human vaginal and bucc al mucosa is for practical purposes similar. These results further sup port the human vaginal/buccal mucosa model for in vitro permeability s tudies on therapeutically active compounds.