Dmg delivery agents

The study of liposomes as dmg-delivery agents has been ongoing for decades. The lipids for liposome formation are typically harvested by extraction from egg yolks and soybeans, and a number of recipes exist for generating liposomes of various diameters. Because the shell material in liposomes is not polymeric, we will not discuss them in depth, limiting ourselves only to those aspects that are pertinent to synthetic analogues like the copolymer vesicles of the next section. 

Penetration enhancers are substances that can increase the absorption of a co-administered dmg, and include surfactants, bile salts, chelating agents, and fatty acids. Penetration enhancers are widely used in dmg delivery to potentiate absorption across various types of epithelia, including the epithelium of the gastrointestinal tract. However, a major limiting factor in the general acceptance of absorption enhancers for improving oral dmg absorption is the non-specific nature of their effects. 

Clonidine is a potent antihypertensive agent which is well absorbed from the GI tract (95%). The dmg has a relatively long half-life (6-20 h) and a modest clearance (13 L h ). The rationale for the development of transdermal clonidine was to reduce side-effects and to improve patient compliance. Catapres-TTS, a reservoir-type patch, reached the market in 1985 in a form designed to remain in place and to deliver dmg for 7 days. Dose titration was possible via the use of systems of different active areas (3.5, 7.0, and 10.5 cm2). The control of dmg delivery over 7 days is impressive, and avoids the peaks and valleys of conventional (twice-a-day) oral administration (Figure 8.7). However, this system has not achieved as wide a success as first seemed likely because of skin sensitization. Clonidine itself, when administered transdermally on a chronic, repetitive basis, induces in a significant fraction of patients a classic immunologic skin reaction, and this has severely attenuated its use. 

Abiief review is presented of recent progress in antimicrobial dendrimers. Mention is made of how both speeifie interactions and non-specific interactions can be utilised to design multifunctional antimicrobial agents which might be more potent than their monofimctional cormterparts. Uses as novel dmg delivery systems are also mentioned. 24 refs. USA... 

Leone-Bay A, Paton DR, Weidner JJ The development of delivery agents that facilitate the oral absorption of macromolecular dmgs, Med Res Rev 2000, 20, 169—186. 

Coatings may double as dmg delivery vehicles for the delivery of therapeutic agents to the implant-tissue interface... 

Uses Aniislat, emollient in cosmetics mfg. of paints, coatings, emulsifiers, vitamins soaps driers for protective coatings feeds biochemical research dietary supplement, nutrienL flavoring agent, adjuvant in foods, infant formulas food-pkg. adhesives dmg delivery for pharnia-ceutical orals and topicals... 

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