Buccal administration route

Recently, several in vitro experiments substantiated the potential of the human vaginal mucosa as a good administration route relating to the degree of permeation when compared with other mucosal surfaces. In fact, the vagina can be more permeable to some commonly used model substances, such as water, 17[3-cstradiol (Figure 3), arecoline, arecaidine, and vasopressin, than colonic or small intestinal mucosa, or at least as permeable as when compared to human buccal mucosa [46,47],... 

The lack of activity after oral administration for most peptides and proteins resulted in the past besides parenteral application into the utilization of nonoral administration pathways, for example, nasal, buccal, rectal, vaginal, percutaneous, ocular, or pulmonary drug delivery [27]. Drug delivery via these administration routes, however, is also frequently accompanied by presystemic degradation processes. Bioavailability of numerous peptides and proteins is, for example, markedly reduced after subcutaneous or intramuscular administration compared to their intravenous administration. The pharma-cokinetically derived apparent absorption rate constant is thus the combination of absorption into the systemic circulation and presystemic degradation at the absorption... 

Androgens are important for general sexual function and libido, but testosterone supplementation is only effective in patients with documented low serum testosterone levels. In patients with hypogonadism, testosterone replacement is the initial treatment of choice, as it corrects decreased libido, fatigue, muscle loss, sleep disturbances, and depressed mood. Improvements in ED may occur, but they should not be expected to occur in all patients.23 The initial trial should be for 3 months. At that time, re-evaluation and the addition of another ED therapy is warranted. Routes of administration include oral, intramuscular, topical patches or gel, and a buccal tablet. 

An alternative to the oral route is the buccal mucoadhesive system. The Striant buccal system adheres to the inside of the mouth and the testosterone is absorbed through the oral mucosa and delivered to the systemic circulation. There is no first-pass effect, as the liver is bypassed by this route of administration. Patients apply a 30-mg tablet to the upper gum twice daily. The cost is similar to that of the patch or gel. Side effects unique to this dosage form include oral irritation, bitter taste, and gum edema. 

Penetration enhancers are low molecular weight compounds that can increase the absorption of poorly absorbed hydrophilic drugs such as peptides and proteins from the nasal, buccal, oral, rectal, and vaginal routes of administration [186], Chelators, bile salts, surfactants, and fatty acids are some examples of penetration enhancers that have been widely tested [186], The precise mechanisms by which these enhancers increase drug penetration are largely unknown. Bile salts, for instance, have been shown to increase the transport of lipophilic cholesterol [187] as well as the pore size of the epithelium [188], indicating enhancement in both transcellular and paracellular transport. Bile salts are known to break down mucus [189], form micelles [190], extract membrane proteins [191], and chelate ions [192], While breakdown of mucus, formation of micelles, and lipid extraction may have contributed predominantly to the bile salt-induced enhancement of transcellular transport, chelation of ions possibly accounts for their effect on the paracellular pathway. In addition to their lack of specificity in enhancing mem-... 

For routes of administration in which the chemical is given orally or placed into an orifice other than the mouth, clear instructions about the correct administration of the chemical must be provided. Many cases are known of oral pediatric drops for ear infections being placed into the ear, and vice versa (ear drops being swallowed) in humans. Errors in test-article administration are especially prevalent when a chemical form is being used in a nontraditional manner (e.g., suppositories that are given by the buccal route). 

Many technicians may not be famihar with terms such as sublingual (under the tongue), buccal (between the cheek and gingiva), otic, and so on. A clear description of each of these nontraditional routes (i.e., other than gavage routes) should be discussed with technicians, and instructions may also be written down and given to them. Demonstrations are often useftd to illustrate selected techniques of administration (e.g., to use an inhaler or nebulizer). Some chemicals must be placed by technicians into body orifices (e.g., medicated intrauterine devices such as Proges-terset). 

Lamey PJ, Lewis MAO (1990) Buccal and sublingual delivery of drugs. In Florence AT, Salole EG (eds.) Routes of Drug Administration. Butterworth Co. (Publishers) Ltd., Norfolk, pp 30-47... 

At present, despite the advantages offered by the buccal delivery route, such as the bypass of intestinal and hepatic first-pass metabolism for systemic delivery, very few pharmaceutical products employ this route of administration. The reasons that contribute to this situation include (1) high costs associated with development, (2) lack of standardized tests to identify drug candidates suitability for this route, (3) the limited understanding of the impact of metabolism and/or transporters found in the oral cavity mucosa on buccal delivery, and (4) the relatively small number of reports describing the usefulness and safety of excipients/permeation enhancers in humans [82, 83], Therefore, the... 

If disturbances of gastrointestinal function prevent the use of oral sustained-release morphine, the fentanyl transdermal system (fentanyl patch) can be used over long periods. Furthermore, buccal transmucosal fentanyl can be used for short episodes of breakthrough pain (see Alternative Routes of Administration). Administration of strong opioids by nasal insufflation has been shown to be efficacious, and nasal preparations are now available in some countries. Approval of such formulations in the USA is growing. In addition, stimulant drugs such as the amphetamines have been shown to enhance the analgesic actions of the opioids and thus may be very useful adjuncts in the patient with chronic pain. 

ADVANTAGES AND DISADVANTAGES OF BUCCAL AND SUBLINGUAL ROUTES OF ADMINISTRATION... 

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