Isotropic formulations are thermodynamically stable

microemulsion Microemulsions are clear, thermodynamically stable isotropic liquid mixtures of oil, water and surfactant, frequently in combination with a cosurfactant. The aqueous phase may contain salt(s) and/or other ingredients, and the "oil" may actually be ...

s possessing

lyotropic liquid crystal A liquid crystalline mesophase is called lyotropic (a portmanteau of lyo- "dissolve" and -tropic "change" ) if formed by dissolving an amphiphilic mesogen in a suitable solvent, under appropriate conditions of concentration, temperature and pres ...

properties. They inhabit a state of matter and physical behaviour somewhere between conventional

liquids A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, an ...

and that of solid

crystals A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...

. Isotropic formulations are amphiphillic, exhibiting selective synchronicity with both the water and

lipid Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...

phases of the substrate to which they are applied. Most recently, isotropic formulations have been used extensively in

dermatology Dermatology is the branch of medicine dealing with the skin.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. Page 537. . It is a speciality with both medical and surgical aspects. A dermatologist is a specialist medical ...

for drug delivery.

Uses

While it is well established that the skin provides an ideal site for the administration of local and systemic

drugs A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhalat ...

, it presents a formidable barrier to the permeation of most substances. Isotropic formulations have been used to deliver drugs locally and systemically via the skin appendages, intercellular and transcellular routes.Harada K. Murakami T. Yata N et al. “Role of Intercellular Lipids in Stratum Corneum in the Percutaneous Permeation of Drugs.” J Invest Dermatol 1992; 9 99: 278-28

/ref>

References

{{Reflist Phases of matter Routes of administration