Release mechanisms, multiple

Other drug-delivery systems may include double emulsions, usually W/O/W, for transporting hydrophilic dmgs such as vaccines, vitamins, enzymes, hormones [441], The multiple emulsion also allows for slow release of the delivered drug and the time-release mechanism can be varied by adjusting the emulsion stability. Conversely, in detoxification (overdose) treatments, the active substance migrates from the outside to the inner phase. 

Mechanisms of drug release from multiple emulsion systems include diffusion of the dmg molecules from the internal droplets (1), from the medium of the external droplets (2), or by mass transfer due to the coalescence of the internal droplets (3), as shown in Fig. 7.16(b)... 

Notes Common coating properties or functions are listed above. Applications can potentially incorporate multiple deUvery or release mechanisms to achieve a desired delivery profile. Although controlled-release fluid bed coatings are commonly used in oral pharmaceutical applications, the same release mechanisms can be employed in other appUcations including nutraceutical, nutritional, food, household, agricultural, industrial, and other product areas. 

Release of multiple proteins through combination of mechanisms and rates... 

When applied to multiple emulsions during their destabilization these techniques should lead to a better understanding and control of the destabilization and release mechanisms. 

Grossiord JL, Seiller M. 2001. W/OAV multiple emulsions a review of the release mechanisms by break-up of the oily membrane. STP Pharma Sci 11 331-339. 

This review has focused on the release by breakup of the oily membrane, resulting either from a hypo-osmotic dilution or by shear application among the various release mechanisms of molecules initially entrapped in the internal aqueous phase of W/OAV multiple emulsions. Experimental studies have shown very interesting features that have practical application and allowed us to form some assumptions about the molecular mechanisms. In particular, it has been found that these mechanisms can be controlled by different emulsion formulations and/or application parameters as follows ... 

Fluorides. Most woddwide reductions in dental decay can be ascribed to fluoride incorporation into drinking water, dentifrices, and mouth rinses. Numerous mechanisms have been described by which fluoride exerts a beneficial effect. Fluoride either reacts with tooth enamel to reduce its susceptibihty to dissolution in bacterial acids or interferes with the production of acid by bacterial within dental plaque. The multiple modes of action with fluoride may account for its remarkable effectiveness at concentrations far below those necessary with most therapeutic materials. Fluoride release from restorative dental materials foUow the same basic pattern. Fluoride is released in an initial short burst after placement of the material, and decreases rapidly to a low level of constant release. The constant low level release has been postulated to provide tooth protection by incorporation into tooth mineral. 

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