Editing Emulsion (section)

==Uses==
===In food===
[[File:Ingredients maonesa.jpg|thumb|right|An example of the ingredients used to make [[mayonnaise]]; [[olive oil]], [[salt|table salt]], an egg (for [[yolk]]) and a [[lemon]] (for lemon juice). The oil and water in the egg yolk do not mix, while the [[lecithin]] in the yolk serves as an emulsifier, allowing the two to be blended together.]]

Oil-in-water emulsions are common in food products:

* [[Mayonnaise]] and [[Hollandaise sauce]]s – these are oil-in-water emulsions stabilized with egg yolk [[lecithin]], or with other types of food additives, such as [[sodium stearoyl lactylate]]
* [[Homogenized milk]] – an emulsion of milk fat in water, with milk proteins as the emulsifier 
* [[Vinaigrette]] – an emulsion of vegetable oil in vinegar, if this is prepared using only oil and vinegar (i.e., without an emulsifier), an unstable emulsion results

Water-in-oil emulsions are less common in food, but still exist:

* [[Butter]] – an emulsion of water in butterfat
* [[Margarine]]

Other foods can be turned into products similar to emulsions, for example [[meat emulsion]] is a suspension of meat in liquid that is similar to true emulsions.

===In health care===
In [[pharmaceutics]], [[Hairstyling product|hairstyling]], [[personal hygiene]], and [[cosmetics]], emulsions are frequently used. These are usually oil and water emulsions but dispersed, and which is continuous depends in many cases on the [[pharmaceutical formulation]]. These emulsions may be called [[cream (pharmaceutical)|cream]]s, [[ointment]]s, [[liniment]]s (balms), [[paste (rheology)|paste]]s, [[Thin film|film]]s, or [[liquid]]s, depending mostly on their oil-to-water ratios, other additives, and their intended [[route of administration]].<ref name="Aulton">{{cite book|editor=Aulton, Michael E.|edition=3rd|title=Aulton's Pharmaceutics: The Design and Manufacture of Medicines|publisher=[[Churchill Livingstone]]|year=2007|isbn=978-0-443-10108-3|pages=92–97, 384, 390–405, 566–69, 573–74, 589–96, 609–10, 611}}</ref><ref name="Remington">{{Cite book|last1=Troy|first1=David A.|last2=Remington|first2=Joseph P.|last3=Beringer|first3=Paul|title=Remington: The Science and Practice of Pharmacy|edition=21st|year=2006|publisher=[[Lippincott Williams & Wilkins]]|location=Philadelphia|isbn=978-0-7817-4673-1|pages=325–336, 886–87}}</ref> The first five are [[topical]] [[dosage form]]s, and may be used on the surface of the [[human skin|skin]], [[transdermal]]ly, [[Eye drop|ophthalmically]], [[rectal]]ly, or [[vagina]]lly. A highly liquid emulsion may also be used [[oral administration|oral]]ly, or may be [[Injection (medicine)|injected]] in some cases.<ref name="Aulton"/>

Microemulsions are used to deliver [[vaccine]]s and kill [[microbe]]s.<ref>{{cite web|url=http://www.nano.med.umich.edu/Platforms/Adjuvant-Vaccine-Development.html|title=Adjuvant Vaccine Development|access-date=2008-07-23|url-status=dead|archive-url=https://web.archive.org/web/20080705134014/http://nano.med.umich.edu/Platforms/Adjuvant-Vaccine-Development.html|archive-date=2008-07-05}}</ref> Typical emulsions used in these techniques are nanoemulsions of [[soybean oil]], with particles that are 400–600&nbsp;nm in diameter.<ref>{{cite web|url=http://www.eurekalert.org/pub_releases/2008-02/uomh-nvs022608.php|title=Nanoemulsion vaccines show increasing promise|access-date=2008-07-22|website=Eurekalert! Public News List|publisher=University of Michigan Health System|date=2008-02-26}}</ref> The process is not chemical, as with other types of [[antimicrobial]] treatments, but mechanical. The smaller the droplet the greater the [[surface tension]] and thus the greater the force required to merge with other [[lipids]]. The oil is emulsified with detergents using a [[high-shear mixer]] to stabilize the emulsion so, when they encounter the lipids in the [[cell membrane]] or envelope of [[Cell envelope|bacteria]] or [[virus]]es, they force the lipids to merge with themselves. On a mass scale, in effect this disintegrates the membrane and kills the pathogen. The soybean oil emulsion does not harm normal human cells, or the cells of most other [[higher organisms]], with the exceptions of [[Spermatozoon|sperm cells]] and [[blood cells]], which are vulnerable to nanoemulsions due to the peculiarities of their membrane structures. For this reason, these nanoemulsions are not currently used [[intravenous]]ly (IV). The most effective application of this type of nanoemulsion is for the [[disinfection]] of surfaces. Some types of nanoemulsions have been shown to effectively destroy [[HIV-1]] and [[tuberculosis]] pathogens on non-[[porous]] surfaces.

==== Applications in pharmaceutical industry ====
* '''Oral drug delivery:''' Emulsions may provide an efficient means of administering drugs that are poorly soluble or have low [[bioavailability]] or dissolution rates, increasing both dissolution rates and absorption to increase bioavailability and improve bioavailability. By increasing surface area provided by an emulsion, dissolution rates and absorption rates of drugs are increased, improving their bioavailability.<ref>{{Cite web |last=Sharma |first=Dr Anubhav |date=2023-04-26 |title=Role of Surfactant in Emulsion Stabilization: A Comprehensive Overview |url=https://thewitfire.in/2023/04/26/role-of-surfactant-in-emulsion-stabilization-a-comprehensive-overview/ |access-date=2023-04-27 |website=Witfire |language=en-US}}</ref>
* '''Topical formulations:''' Emulsions are widely utilized as bases for topical drug delivery formulations such as creams, lotions and ointments. Their incorporation allows lipophilic as well as hydrophilic drugs to be mixed together for maximum skin penetration and permeation of active ingredients.<ref>{{Cite journal |last1=Apostolidis |first1=Eftychios |last2=Stoforos |first2=George N. |last3=Mandala |first3=Ioanna |date=April 2023 |title=Starch physical treatment, emulsion formation, stability, and their applications |url=http://dx.doi.org/10.1016/j.carbpol.2023.120554 |journal=Carbohydrate Polymers |volume=305 |pages=120554 |doi=10.1016/j.carbpol.2023.120554 |pmid=36737219 |s2cid=255739614 |issn=0144-8617}}</ref>
* '''Parenteral drug delivery:''' Emulsions serve as carriers for intravenous or intramuscular administration of drugs, solubilizing lipophilic ones while protecting from degradation and decreasing injection site irritation. Examples include propofol as a widely used anesthetic and lipid-based solutions used for total parenteral nutrition delivery.<ref>{{Cite journal |last1=Hazt |first1=Bianca |last2=Pereira Parchen |first2=Gabriela |last3=Fernanda Martins do Amaral |first3=Lilian |last4=Rondon Gallina |first4=Patrícia |last5=Martin |first5=Sandra |last6=Hess Gonçalves |first6=Odinei |last7=Alves de Freitas |first7=Rilton |date=April 2023 |title=Unconventional and conventional Pickering emulsions: Perspectives and challenges in skin applications |url=http://dx.doi.org/10.1016/j.ijpharm.2023.122817 |journal=International Journal of Pharmaceutics |volume=636 |pages=122817 |doi=10.1016/j.ijpharm.2023.122817 |pmid=36905974 |s2cid=257474428 |issn=0378-5173|hdl=10198/16535 |hdl-access=free }}</ref>
* '''Ocular Drug Delivery:''' Emulsions can be used to formulate eye drops and other ocular drug delivery systems, increasing drug retention time in the eye and permeating through corneal barriers more easily while providing sustained release of active ingredients and thus increasing therapeutic efficacy.<ref>{{Cite journal |last1=Ding |first1=Jingjing |last2=Li |first2=Yunxing |last3=Wang |first3=Qiubo |last4=Chen |first4=Linqian |last5=Mao |first5=Yi |last6=Mei |first6=Jie |last7=Yang |first7=Cheng |last8=Sun |first8=Yajuan |date=April 2023 |title=Pickering high internal phase emulsions with excellent UV protection property stabilized by Spirulina protein isolate nanoparticles |url=http://dx.doi.org/10.1016/j.foodhyd.2022.108369 |journal=Food Hydrocolloids |volume=137 |pages=108369 |doi=10.1016/j.foodhyd.2022.108369 |s2cid=254218797 |issn=0268-005X}}</ref>
* '''Nasal and Pulmonary Drug Delivery:''' Emulsions can be an ideal vehicle for creating nasal sprays and inhalable drug products, enhancing drug absorption through nasal and pulmonary mucosa while providing sustained release with reduced local irritation.<ref>{{Cite journal |last1=Udepurkar |first1=Aniket Pradip |last2=Clasen |first2=Christian |last3=Kuhn |first3=Simon |date=March 2023 |title=Emulsification mechanism in an ultrasonic microreactor: Influence of surface roughness and ultrasound frequency |url=http://dx.doi.org/10.1016/j.ultsonch.2023.106323 |journal=Ultrasonics Sonochemistry |volume=94 |pages=106323 |doi=10.1016/j.ultsonch.2023.106323 |pmid=36774674 |pmc=9945801 |issn=1350-4177}}</ref>
* '''Vaccine Adjuvants:''' Emulsions can serve as vaccine adjuvants by strengthening immune responses against specific antigens. Emulsions can enhance antigen solubility and uptake by immune cells while simultaneously providing controlled release, amplifying an immunological response and thus amplifying its effect.<ref name="Hong 1406–1436">{{Cite journal |last1=Hong |first1=Xin |last2=Zhao |first2=Qiaoli |last3=Liu |first3=Yuanfa |last4=Li |first4=Jinwei |date=2021-08-13 |title=Recent advances on food-grade water-in-oil emulsions: Instability mechanism, fabrication, characterization, application, and research trends |url=http://dx.doi.org/10.1080/10408398.2021.1964063 |journal=Critical Reviews in Food Science and Nutrition |volume=63 |issue=10 |pages=1406–1436 |doi=10.1080/10408398.2021.1964063 |pmid=34387517 |s2cid=236998385 |issn=1040-8398}}</ref>
* '''Taste Masking:''' Emulsions can be used to encase bitter or otherwise unpleasant-tasting drugs, masking their taste and increasing patient compliance - particularly with pediatric formulations.<ref name="Hong 1406–1436"/>
* '''Cosmeceuticals:''' Emulsions are widely utilized in cosmeceuticals products that combine cosmetic and pharmaceutical properties. These emulsions act as carriers for active ingredients like vitamins, antioxidants and skin lightening agents to provide improved skin penetration and increased stability.<ref>{{Cite journal |last1=Xu |first1=Tian |last2=Jiang |first2=Chengchen |last3=Huang |first3=Zehao |last4=Gu |first4=Zhengbiao |last5=Cheng |first5=Li |last6=Hong |first6=Yan |date=January 2023 |title=Formation, stability and the application of Pickering emulsions stabilized with OSA starch/chitosan complexes |url=http://dx.doi.org/10.1016/j.carbpol.2022.120149 |journal=Carbohydrate Polymers |volume=299 |pages=120149 |doi=10.1016/j.carbpol.2022.120149 |pmid=36876777 |s2cid=252553332 |issn=0144-8617}}</ref>

=== In firefighting ===
Emulsifying agents are effective at extinguishing fires on small, thin-layer spills of flammable liquids ([[Fire classes|class B fire]]s). Such agents encapsulate the fuel in a fuel-water emulsion, thereby trapping the flammable vapors in the water phase. This emulsion is achieved by applying an [[Aqueous solution|aqueous]] surfactant solution to the fuel through a high-pressure nozzle. Emulsifiers are not effective at extinguishing large fires involving bulk/deep liquid fuels, because the amount of emulsifier agent needed for extinguishment is a function of the volume of the fuel, whereas other agents such as [[Fire-fighting foam|aqueous film-forming foam]] <!-- (AFFF) --> need cover only the surface of the fuel to achieve vapor mitigation.<ref>{{cite book|title=Principles of Fire Protection Chemistry and Physics |author=Friedman, Raymond |isbn= 978-0-87765-440-7|year=1998|publisher=[[Jones & Bartlett Learning]]}}</ref>

===Chemical synthesis===
{{Main|Emulsion polymerization}}

Emulsions are used to manufacture polymer dispersions – polymer production in an emulsion 'phase' has a number of process advantages, including prevention of coagulation of product. Products produced by such polymerisations may be used as the emulsions – products including primary components for glues and paints. Synthetic [[latex]]es (rubbers) are also produced by this process.