Emulsion carriers

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. 

The ability to encapsulate active ingredients in emulsions, foams, and suspensions, is leading manufacturers to make personal care products that are also pharmaceutical, termed cosmeceuticals. Examples creams with anti-wrinkle properties, lotions with anti-baldness effects, and sunscreens that treat skin damage (see also Chapter 15). 

Multiple emulsions have been used to deliver active agents with prolonged release in dermatological treatments. For example, O/W/O emulsions have been used to deliver pilocarpine hydrochloride as a myopic agent in eye infections [440]. Here the active agents was placed in the internal oil phase of the O/W/O emulsion to provide an appropriate rate of release. Similar approaches have been used in other treatments, using W/O/W emulsions [440]. 

For example, hydrophobic particles tend to be sequestered in the fiver [22]. Thus, adjustment of the size and wettability of the polymer microcapsules can have a great influence on their ultimate distribution in the body. 

Several types of emulsion can be formulated to be compatible with particular body fluids, solubilize and deliver specific agents such as drugs, and provide 

Multiple emulsions have been used to deliver active agents with prolonged release in dermatological treatments. For example, O/W/O emulsions have been used to deliver pilocarpine hydrochloride as a myopic agent in eye infections 

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JS Lucks, BW Muller, RH Muller. Polymeric and emulsion carriers—interaction with antiflocculants and ionic surfactants. Int J Pharm 63 183-188, 1990. 

Takino, T., Konishi, K., Takadura, Y., and Hashida, M. (1994) Long circulating emulsion carrier systems for highly lipophilic drugs.Biol. Pharm. Bull., 17 121-125. 

Tibell, A., Larsson, M., and Alvestrand, A. (1993) Dissolving intravenous cyclosporin Ain a fat emulsion carrier prevents acute renal side effects in theTalinspl. Int., 6 69-72. 

Tibell, A., Linholm, A., Sawe, J., and Norrlind, B. (1995) Cyclosporin Ain fat emulsion carriers experimental studies on pharmacokinetics and tissue distribuIRtrarmacol. Toxicol., 76 115-121. 

It has been reported in an ocular pharmacokinetic study of cyclosporin A incorporated in deoxycholic acid-based anionic and stearylamine-based cationic emulsions in rabbit that, when compared to anionic emulsion, the cationic emulsion showed a significant drug reservoir effect of more than 8 h in corneal and conjunctival tissues of the rabbit eye following topical application [106], Since cornea and conjunctiva are of anionic nature at physiological pH [107], the cationic emulsion would interact with these tissues electrostatically to implicate the observed cyclosporin A reservoir effect. This hypothesis is supported, in principle, by an ex vivo study which showed that cationic emulsion carrier exhibited better wettability properties on rabbit cornea than either saline or anionic emulsion carrier [108],... 

The length of the dew period usually correlates with success or failure in a majority of the work referenced in this review. Recently, it has been reported that invert (water-in-oil) emulsion carriers composed of paraffin wax, mineral (paraffin) oil, soybean oil, and lecithin retarded water evaporation... 

Jr./ Evans, J. P./ Trask-Morrell, B./ Fulgham, F. E., USDA, ARS, New Orleans, LA, and Stoneville, MS, unpublished results). Therefore, invert emulsions could be both a successful delivery system and water source for A. cassiae. However, the lack of sufficient mortality at reasonable application rates indicates that the invert emulsion carrier needs other adjuvants or a more virulent pathogen strain for commercial success. 

For studies of these complex systems NMR is very well suited, as few other methods exist that can determine such basic properties as the state of water and the size distribution of internal emulsion droplets. In addition, the PFG NMR method is sensitive to the molecular transport from emulsion droplets, a quantity which is relevant in the context of release mechanisms from such emulsion carriers. 

The temporal development of the displacement pro file reflects the presence of restricted motion, which may be studied in detail. Examples are motion inside compartments, between compartments, and motion of the compartment itself We may anticipate progress in the use of PFG NMR methods to study release mechanisms and kinetics from emulsion carriers. 

Eratalay A, Oner F, Ozcengiz E, Alpar R, 2004 Adjuvant effects of niosome and water/oil/water multiple emulsions carrier systems for recombinant hepatitis B surface antigen Hacettepe University, J Eaculty Pharm 24(2) 81-94. 

Uses Gellant, suspending agent, emulsifier, bulking agentforfoods (bakery prods., confectionery, dairy, cheese, canning), pharmaceuticals (slow-release capsules, suppositories, surgical lubricants, emulsions) carrier for topical medicaments ... 

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