Xanthan gum is used in oral gel formulations to increase the level of diffusion of substances and to mask unpleasant drug flavors (1).

Dry eye disease is a disorder that affects 5-34% of the global adult population with reduced quality of life. Artificial tears or lubricants are the most widely used therapy for the treatment of this disease due to their low profile side effects, which attempt to modify the properties of the tear film. Xanthan gum has shown clinical efficacy in the treatment of this disease (2).

Other studies

Biosynthesis, structure and antioxidant activities of xanthan gum from Xanthomonas campestris with additional furfural.  Kang Y, Li P, Zeng X, Chen X, Xie Y, Zeng Y, Zhang Y, Xie T.  Carbohydr Polym. 2019 Jul 15;216:369-375. doi: 10.1016/j.carbpol.2019.04.018. Epub 2019 Apr 5.

Characterization of Emulsion Stabilization Properties of Gum Tragacanth, Xanthan Gum and Sucrose Monopalmitate: A Comparative Study.  Pocan P, Ilhan E, Oztop MH.  J Food Sci. 2019 May;84(5):1087-1093. doi: 10.1111/1750-3841.14602. Epub 2019 Apr 8.

Changes in conjunctival epithelial cells after treatment with 0.2% xanthan gum eye drops in mild-moderate dry eye.  Postorino EI, Aragona P, Rania L, Spinella R, Puzzolo D, Micali A, Mazza AML, Papa V.  Eur J Ophthalmol. 2019 Mar 11:1120672119833278. doi: 10.1177/1120672119833278

Xanthan Gum Capped ZnO Microstars as a Promising Dietary Zinc Supplementation.  Ebrahiminezhad A, Moeeni F, Taghizadeh SM, Seifan M, Bautista C, Novin D, Ghasemi Y, Berenjian A.  Foods. 2019 Mar 2;8(3). pii: E88. doi: 10.3390/foods8030088.

Effect of xanthan gum on the prevention of intra-abdominal adhesion in rats.  Song Z, Zhang Y, Shao H, Ying Y, Chen X, Mei L, Ma X, Chen L, Ling P, Liu F.  Int J Biol Macromol. 2019 Apr 1;126:531-538. doi: 10.1016/j.ijbiomac.2018.12.233. Epub 2018 Dec 26.

References________________________

(1) Control of Drug Diffusion Behavior of Xanthan and Locust Bean Gum Gel by Agar Gel.
Hishikawa Y, Kakino Y, Tsukamoto H, Tahara K, Onodera R, Takeuchi H.
Chem Pharm Bull (Tokyo). 2016

(2) Efficacy of a fixed combination of 0.09 % xanthan gum/0.1 % chondroitin sulfate preservative free vs polyethylene glycol/propylene glycol in subjects with dry eye disease: a multicenter randomized controlled trial.
Pérez-Balbuena AL, Ochoa-Tabares JC, Belalcazar-Rey S, Urzúa-Salinas C, Saucedo-Rodríguez LR, Velasco-Ramos R, Suárez-Sánchez RG, Rodríguez-Carrizalez AD, Oregón-Miranda AA.
BMC Ophthalmol. 2016 Sep

Xanthan Gum is a heteropolysaccharide, a non-starch polysaccharide obtained from the microbial fermentation of carbohydrates by the bacterium Xanthomonas campestris by fermentation in pure culture with carbohydrates such as maize starch. It consists mainly of glucose, glucuronic acid 6-acetyl mannose. Stable to heat, alkalis, acids. Good solubility in water, insoluble in ethanol.

It consists mainly of glucose, mannose and glucuronic acid (1).

It occurs as a fine white to light yellow powder.

What it is used for and where

It is also known as Hanson's gum.

Medical

Functional component in microcapsules that release medication. Forms a moist membrane to prevent infection of the skin.

Food

Stabiliser, emulsifier, suspending agent, thickener, controls structure, flavour and rheology of products such as: bakery products, salad dressings, bread, dairy products, frozen foods, beverages, brewing, candies, cakes. Improves water retention in meat products.

Labelled with the number E415 in the list of European food additives as a thickener.

Cosmetics

Binder agent. A binding compound that is used in cosmetic, food and pharmaceutical products as an anti-caking agent with the function of making the product in which it is incorporated silky, compact and homogenous. The binder, either natural such as mucilage, gums and starches or chemical, may be in the form of a powder or liquid.

Emulsion stabilizer. Emulsions are thermodynamically unstable. Emulsion stabilisers improve the formation and stability of single and double emulsions. It should be noted that in the structure-function relationship, molar mass plays an important role.

Skin conditioning agent - Miscellaneous.  This ingredient has the task of modifying the condition of the skin when it is damaged or dry by reducing its flakiness and restoring its elasticity.

Surfactant - Emulsifying agent. Emulsions are thermodynamically unstable. Emulsifiers have the property to reduce the oil/water or water/oil interfacial tension, improve emulsion stability and also directly influence the stability, sensory properties and surface tension of sunscreens by modulating their filmometric performance.

Viscosity Enhancing Agent - aqueous. Since viscosity is important for increasing the chemical and physical stability of the product, Viscosity Enhancing Agent acqueous is an important dosage factor in gels, suspensions, emulsions, solutions. Increasing viscosity makes formulations less sedimentary and more homogeneously thickened.

In the context of toothpaste, xanthan gum can be used for several reasons:

Viscosity Enhancement: Xanthan gum can help give the toothpaste a thicker consistency, making it less runny.

Stabilization: It can prevent the separation of different ingredients within the toothpaste.

Gelling Agent: Xanthan gum can give toothpaste a smoother feel, making it more pleasant to use.

Controlled Release: In some formulations, xanthan gum can help control the release of active ingredients during brushing, ensuring they are delivered effectively.

Oil industry

Due to its pseudoplasticity it can maintain the viscosity of drilling fluid and improve the oil recovery rate.

The most relevant studies on the subject have been selected with a summary of their contents:

Xanthan Gum studies

Typical optimal commercial product characteristics Xanthan gum

• Molecular Formula   C₃₅H₄₉O₂₉      C₈H₁₄Cl₂N₂O₂
• Molecular Weight  241.115
• Exact Mass    240.043228
• CAS   98112-77-7    11138-66-2
• UNII    Z5Y843J6KQ
• DSSTox Substance ID  DTXSID3070462
• IUPAC  2-(2,4-diaminophenoxy)ethanol;dihydrochloride
• InChI=1S/C8H12N2O2.2ClH/c9-6-1-2-8(7(10)5-6)12-4-3-11;;/h1-2,5,11H,3-4,9-10H2;2*1H 
• InChl Key      VXYWXJXCQSDNHX-UHFFFAOYSA-N
• SMILES   C1=CC(=C(C=C1N)N)OCCO.Cl.Cl
• EC Number 234-394-2
• MDL number MFCD00131256

Synonyms:

• 2-(2,4-Diaminophenoxy)ethanol dihydrochloride
• Ethanol, 2-(2,4-diaminophenoxy)-, hydrochloride (1:2)

References______________________________________________________________________

(1) Coviello T., Matricardi P., Marianecci C., Alhaique F. Polysaccharide hydrogels for modified release formulations. Journal of Controlled Release. 2007