Physical methods to promote drug delivery on mucosal tissues of the oral cavity

Abstract

Although physical methods are very promising to promote drug delivery through keratinized epithelial tissues, they are not extensively used on the oral cavity mucosae. The authors feel that, in the near future, these methods could be further developed to provide noninvasive and convenient means for locoregional/systemic delivery of drugs with poor bioavailability profile, short half-life and multiple doses scheduling. This review will help the readers in the selection of a suitable physical method for improving drug delivery in the oral cavity for future chances. The authors imagine that new formulations or devices will be marketed in the coming years.

Polymeric drug delivery systems for intraoral site‐specific chemoprevention of oral cancer

“…The ability of a drug to penetrate the mucosal barrier can be affected by physicochemical properties of the drugs, mucosal properties, and environmental factors within the oral cavity . The epithelial permeation of drugs can be enhanced by numerous approaches, including the development of mucoadhesive formulations, the incorporation of mucosal permeation enhancers in the formulation, or the chemical modification of drugs (e.g., the formation of prodrugs) . A better understanding of the effect of these potential factors on mucosal drug permeation will likely facilitate the development of effective local drug delivery strategies.…”

“…The permeation of drugs across oral mucosae occurs predominantly via intracellular (transcellular) or intercellular (paracellular) diffusion . Lipophilic compounds generally permeate through transcellular diffusion, whereas hydrophilic compounds permeate through intercellular spaces . Some drugs can diffuse via both routes simultaneously .…”

“…The most commonly used permeation enhancers are fatty acids, bile salts, and surfactants . Alternative and/or concurrent methods such as sonophoresis, iontophoresis, and electroporation could be employed or developed for improved drug delivery in the oral cavity …”

Bioavailability Improvement Strategies for Poorly Water-Soluble Drugs Based on the Supersaturation Mechanism: An Update

“…In the early stage of drug dissolution (1 h), this phase separation can promote drug dissolution due to the solubilization effect of TPGS1000. In the late stage of drug dissolution, the phase separation effect will lead, in contrast, to a drug precipitate (12).…”

“…More and more results have shown that the drug could exist in a state of solution at a concentration above their saturation solubility, that is, supersaturation (10). The transmembrane transport effect of the drugs in supersaturation, as discovered by Higuchi, was initially and widely investigated in the field of transdermal drug delivery (11)(12)(13)(14). With further understanding, it was found that the drug concentration of the supersaturable formulations always exceeds the equilibrium solubility when exposed to gastrointestinal fluids (10,15).…”