Institute of Management, Nirma University - Logo

Surfactants, kind of detergent, in medicinal formulations

Have you ever thought that the component of detergents which clean dirt from the surfaces also helps medicines to clean disease from the body! Surfactants are surface active agent,substance as that of detergent, exhibits the property of spreading, wetting and cleaning. The surface-active molecule consists of partly hydrophilic (water-soluble) and partly hydrophobic (water insoluble) unit. In water, surfactants arranges like cycle spokes in 3D spherical structure called micelles, where the hydrophobic tails form the inner core and the hydrophilic heads forms outer shell part. The hydrophobic materials like drugs and oils get easily solubilised in the core of these micelles. Surfactants accumulate on different surfaces e.g dirt or oil, suck it up in the micelle core, and take it away from the surface thereby cleaning the surface. Surfactants tend to accumulate at the boundary between two phases thereby changing the nature of the interface between two phases and allow them to interact
more closely. So, they are used as wetting, cleaning, emulsifying, dispersing, foaming and anti-foaming agents in many practical applications and products, including: paints, inks, emulsions adhesives, cosmetics, insecticides, shampoos, toothpastes, detergents, and pharmaceuticals. The most general application of these molecules as a detergent is accepted
by the larger portion of society. In current discussion, we highlight their application in relatively different area, i.e. pharmaceutical, which is seldom understood scientifically to general section of the society.

  1. When someone takes medicine (e.g tablet), it is dissolved in body fluid (in stomach) and absorbed in blood while undissolved medicine gets wasted as it is excreted from body. The dissolved drug (medicine) is taken to the diseased site by blood where drug will show its effect and treat the disease. Major challenge with most of the medicine is its poor solubility in body fluid which thus demands for high dose of drug or more frequent administration of drug. To overcome this problem, medicines are given in different forms like micelles,
  2. emulsions, suspensions which utilize surfactant in one or other way. Micelles are useful because they allow a water insoluble product such as lipids or drugs, to be kept in solution by insertion into the core of the micelle. Emulsion comprises of medicated oil stabilized in water media with the help of surfactants. Suspension is formulation of poorly soluble drug particles suspended in water, stabilized by wetting and suspending agent. Commonly known examples such products in cosmetics are garnier micellar solution, cold cream (emulsion) and zinc calamine lotion as suspension. Thus, selection of surfactant is essential for forming stable medicinal formulations which inturn is dependent on their surface properties like wetting, spreading, solubilisation and adsorption.
Author Dr. Vidhi Shah Assistant Professor