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Creative Biolabs offers a variety of solutions to fit your specific research needs in the field of drug delivery. Now we are proud to offer a series of co-surfactant reagents, such as butanol and butyric acid for multiple applications. Along with our products and services, we can work with you to create a timeline and plan for your operation.

Introduction to Co-Surfactant

Co-surfactants are usually short-chain amines and alcohols ranging from C4 to C10, including butanol, pentanol, ethanol, isopropanol, and propylene glycol.

In recent years, Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC) have been the novel medicinal carriers to control drug targeting and release in multiple administrations including topical, oral, ophthalmic, and parenteral. For example, the self-micro emulsifying systems (SMEDDS) in oral drug delivery composed of oil, surfactants, and co-surfactants can form microemulsions after contact with gastrointestinal fluid.

Co-surfactants in Microemulsion

There are three kinds of microemulsion which include bicontinuous, oil-in-water, and water-in-oil. Among them, oil-in-water (o/w) microemulsions are more important for oil-soluble drugs delivery. In general, the components of a microemulsion contain oil, surfactant, and co-surfactant. Fine o/w microemulsions can be formed under gentle agitation following dilution by aqueous phases. Microemulsions are also employed in microemulsion electrokinetic chromatography (MEEKC). The O/W systems in this method are obtained with an anionic surfactant and n-butanol as co-surfactant.

During the recrystallization of solid lipids, surfactant covers the surface of nanoparticles with limited fluidity so that increases the particle size or particle aggregation. In this case, ionic or non-ionic co-surfactants are used to reduce the interfacial tension by the formation of dynamic micelles. What’s more, the co-surfactants can be served as co-solvents for poorly water-soluble active ingredients. And it can also interact with the stratum corneum to promote the penetration of active ingredients through the skin. Commonly used co-surfactants in the pharmaceutical field include ethanol, isopropanol, and propylene glycol.

Roles of Co-surfactant

  • Improve the flexibility of the surfactant film around the microemulsion droplet.
  • Contribute to the formation and stability of micelles and microemulsions.
  • Overcome the repulsive forces of similar phases and fluidity of the oil and water.
  • Increase the permeability of the oil and water phases.

Schematic diagram of (A) types of SLNs and (B) types of NLCs.Fig 1. Schematic diagram of (A) types of SLNs and (B) types of NLCs. (Rawal, 2018)

As an extension of your laboratory, Creative Biolabs provides customized services and solutions to your specific needs. If you are interested in our products or services, please do not hesitate to contact us for more detailed information.


  1. Rawal, S.; Patel, M. Lipid nanoparticulate systems: modern versatile drug carriers. Lipid Nanocarriers for Drug Targeting. William Andrew Publishing. 2018: 49-138.
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