Sublingual mucosa

Solubilization of poorly water-soluble drugs by complexation with cyclodextrins and then delivery via the buccal or sublingual mucosa has been studied as an additional strategy for increasing drug absorption. Cyclodextrins are able to form inclusion complexes with drugs,... 

The permeability of the oral mucosal epithelium is intermediate between that of the skin epithelium, which is highly specialized for a barrier function (see Section 8.1) and the gut, which is highly specialized for an absorptive function. Within the oral cavity, the buccal mucosa is less permeable than the sublingual mucosa. 

The sublingual mucosa is much thinner, approximately 100- 200 /mi. The thin epithelium of the sublingual mucosa means that extremely rapid absorption is possible via this route. 

A rich blood supply and lymphatic network in the lamina propria serve the oral cavity, thus drag moieties which traverse the oral epithelium are readily absorbed into the systemic circulation. The blood flow in the buccal mucosa is 2.4 mL min 1 cm 2 whereas that to the sublingual mucosa is 0.97 mL min-1 cm 2. 

The buccal mucosa comprises an expanse of smooth and relatively immobile surface and thus is ideally suited to the use of retentive delivery systems. In contrast, the sublingual mucosa is unsuitable for adhesive dosage forms for a number of reasons, including ... 

Pharmacokinetics Isoproterenol can be absorbed systemically by the sublingual mucosa but is more reliably absorbed when given parenterally or as an inhaled aerosol. It is a marginal substrate for COMT and is stable to MAO action. 

Rapid absorption from the sublingual mucosa was also demonstrated through work by Al-Furaih et al., who reported that sublingual administration... 

Fig. 2 Mean plasma isosorbide dinitrate concentrations after application of isosorbide dinitrate (5 mg) to the buccal and sublingual mucosa in six healthy male volunteer subjects. (Redrawn from Ref.. )...

A distinct feature of the sublingual mucosa is its capacity to produce most of the saliva in the oral cavity. Saliva is produced mainly in the sublingual region by the submandibular, parotid, or... 

A single study in humans has been performed by YoKosuka et al. (1977). An insulin solution containing 1 % sodium glycocholate was sprayed on the sublingual mucosa of three healthy subjects, but no increase in serum insulin was observed. 

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