Permeation of several drugs through keratinized epithelial-free membrane of hamster cheek pouch

Permeability of Buccal Mucosa

The buccal mucosa provides an alternative route of drug delivery that can be more beneficial compared to other administration routes. Although numerous studies and reviews have been published on buccal drug delivery, an extensive review of the permeability data is not available. Understanding the buccal mucosa barrier could provide insights into the approaches to effective drug delivery and optimization of dosage forms. This paper provides a review on the permeability of the buccal mucosa. The intrinsic permeability coefficients of porcine buccal mucosa were collected. Large variability was observed among the published permeability data. The permeability coefficients were then analyzed using a model involving parallel lipoidal and polar transport pathways. For the lipoidal pathway, a correlation was observed between the permeability coefficients and permeant octanol/water partition coefficients (Kow) and molecular weight (MW) in a subset of the permeability data under specific conditions. The permeability analysis suggested that the buccal permeation barrier was less lipophilic than octanol. For the polar pathway and macromolecules, a correlation was observed between the permeability coefficients and permeant MW. The hindered transport analysis suggested an effective pore radius of 1.5 to 3 nm for the buccal membrane barrier.

Lidocaine loaded gelatin/gelatinized tapioca starch films for buccal delivery and the irritancy evaluation using chick chorioallantoic membrane

The aim of this study was to confirm the feasibility of gelatin/gelatinized tapioca starch (α st) films for buccal delivery and to evaluate their irritancy. Lidocaine (LB) and lidocaine hydrochloride (LH) were used as model drugs and glycerin was used as the plasticizer. The scanning electron microscopy, atomic force electron microscopy, X-ray diffraction and thermogravimetric analysis results confirmed the compatibility of gelatin/α st/glycerin (Gαgly) films. Drug releases of LB- or LH-Gαgly films were evaluated. The drug release profiles of medicated films presented good patterns in both short time and 8 h drug release studies. The permeation study was examined through chick chorioallantoic membrane (CAM) by using modified Franz diffusion cells. Moreover, the irritancy study for buccal films was also examined by a hen's egg test on CAM model (HET-CAM). The results revealed that LB and LH could permeate through CAM, and these Gαgly films created no irritation on HET-CAM. This indicates that the LB- and LH-Gαgly films are possible to use as buccal films.

Evaluation of pig esophageal mucosa as a permeability barrier model for buccal tissue

Porcine buccal mucosa is frequently used for in vitro drug absorption studies as its structure and permeability characteristics are close to those of human tissue. However, this tissue model suffers from practical disadvantages, including a limited surface area, damage caused by mastication, and a fastidious and time-consuming excision procedure. It has been hypothesized that such limitations may be overcome by replacing the buccal tissue with the pig esophageal mucosa. The latter has a very similar structure and is easier to separate from the underlying tissue; furthermore, its surface area is greater and is generally intact. The aims of this work, therefore, were (i) to perform histological studies on the two membranes; (ii) to compare the transport of fentanyl citrate across buccal and esophageal mucosae; and (iii) to evaluate the effects of freezing on the tissue permeability. The results show that their histology is comparable, that the permeability of fentanyl citrate across the two epithelial barriers is similar, and that freezing the tissues did not alter their permeability.

Comparative permeability of various chemical markers through human vaginal and buccal mucosa as well as porcine buccal and mouth floor mucosa

A number of drugs undergo extensive first-pass metabolism after oral administration, necessitating large doses for effective therapeutic responses in the body. Buccal administration of drugs is becoming more popular because the drugs diffuse into the systemic circulation directly, circumventing the first-pass metabolism. Lower concentrations thus need to be administered and side effects may be minimized. In this study, one of the classic models for human buccal permeability, i.e. the porcine buccal mucosal model, is compared with the more recent human vaginal model and both these are in turn further compared to porcine mouth floor mucosa. To determine the permeability of the different markers (arecoline, 17beta-estradiol, water and vasopressin), a continuous flow-through perfusion system was used (20 degrees C, 24h). Mean steady state flux values were compared statistically using a t-test at a significance level of 5%. Porcine buccal mucosa showed a consistently lower permeability towards all the markers than the other mucosae tested. Porcine mouth floor mucosa was found to be more permeable than porcine buccal mucosa. From these studies we concluded that human vaginal and porcine mouth floor mucosae were superior models for human buccal mucosa than porcine buccal mucosa, using in vitro permeability studies with various chemical markers.

Buccal absorption of ergotamine tartrate using the bioadhesive tablet system in guinea-pigs

The buccal administration of ergotamine tartrate (ET) combined with polyvinyl alcohol (PVA) gel brought about higher plasma concentration of ET compared with that of oral administration of capsules in guinea-pigs. T(max) of ET in plasma of buccal administration was significantly smaller than that of oral administration. For the buccal dosage form of ET, the bioadhesive tablet system (BTS) was newly developed. It consisted of a reservoir of drug and an adhesive region. BTS showed better absorption of ET compared with PVA gel in guinea pigs. Among several pharmaceutical bases in the reservoir of BTS, Witepsol W-35 was most effective. It is likely that the high lipophilic property of Witepsol W-35 in which ET was dissolved facilitated the drug release by its relatively low melting point (around 35 degrees C), consequently a rapid absorption. In addition, the enhancing activity of the cod-liver oil extract (CLOE) in hydrophilic ointment on the in vivo buccal ET absorption was clarified to be comparable to that in the in vitro study utilizing the keratinized epithelial-free membrane (KEF-membrane) of the hamster cheek pouch.