Buccal adhesive patches

Novel approaches, such as the use of buccal adhesive patches for the systemic delivery of large molecular weight drags, require a huge input of time, effort and money, and are also associated with a large amount of risk. These issues can contribute to significant delay in the development and marketing of a new delivery system and can also make these systems relatively expensive. 

Because of their excellent adhesion and physiological safety, povidone K 30 and povidone K 90 are used as adhesives on the skin or mucous membranes. Examples include transdermal systems, oral adhesive gels, buccal adhesive patches or tablets [511,546,547,559,573,574], contact gels for electrocardiograph or electroencephalograph electrodes and adhesives for colostomy bags. Table 107 shows a formulation for a contact gel developed on a laboratory scale for ultrasonic scanning. 

Korbonits M, Slawik M, Cullen D, Ross RJ, Stalla G, Schneider H, Reincke M, Bouloux P.M, Grossman AB. A comparison of a novel testosterone bioadhesive buccal system, Striant, with a testosterone adhesive patch in hypogonadal males. J Clin Endocrinol Metab 2004 89 2039-43. 

Special formulations are now in development to provide prolonged mucosal adhesion and sustained delivery of drug through the buccal membrane. Such formulations comprise flexible adhesive patches and films. Important features for drug delivery associated with these novel buccal patches include ... 

In an evaluation of adhesive patches for buccal administration, Anders and Merkle [86] compared, among others, several HECs and HPCs varying in their molecular mass (as characterized by the viscosity). The duration of mucosal adhesion of drug-free patches was measured in vivo (Fig. 11). 

Anders R, Merkle HP. Evaluation of laminated muco-adhesive patches for buccal drug delivery. Int J Pharm 1989 49 231-240. 

Buccal dosage forms can be of the tablet, patch, gel, or ointment type and can be employed for local or systemic delivery. For local deliveiy, conventional dosage forms such as solutions and various types of tablets (immediate release, effervescent, etc.) are more suitable. These forms generally have uncontrolled drug release with subsequent variable absorption and short residence times, and may not provide sufficient bioavailability. Novel dosage forms such as adhesive tablets, patches, gels, and... 

Sustained adhesion of the dosage form (tablet, patch) to the mucosa is an important first step to successful buccal delivery. The mucus plays an important role during this mucoadhe-sive process by buccal drug delivery systems. The interaction between the mucus and mucoadhesive polymers generally used in most dosage forms can be explained by theories summarized in Table 9.1. 

Adhesivity of oral dosage forms may be a factor in determining their efficacy (buccal delivery) or in causing adverse events (as in oesophageal injury) adhesion of transdermal patches to the skin is clearly important. 

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