Solvent Diffusion

Online inquiry

The solvent diffusion method is developed through the research of polymer nanoparticles, which prepare drug-loaded nanoemulsion by mixing organic solvents with water phase. This technique is an easy, inexpensive, and stable method to obtain varied molecules loaded lipid nanoparticles (LNPs) without high-energy equipment. Based on our rich experience and profound background knowledge, Creative Biolabs can apply the best solvent and packaging method according to the target drugs characteristics to accelerate your project completion.

Introduction of Solvent Diffusion

Solvent diffusion method is widely used in lipophilic molecules loaded LNPs avoiding high temperature, high pressure, and ultrasonic treatment, especially suitable for the preparation of macromolecules loaded LNPs. After the drug is dissolved in the organic solvent, the water-saturated organic phase is emulsified with a solvent-saturated aqueous phase containing an emulsifier. Finally, LNPs precipitate gradually following the addition of water. The LNPs produced by solvent diffusion method has high encapsulation efficiency, gentle release process, and low burst release risk.

Some researchers branched bovine insulin onto LNPs by solvent diffusion method and obtained particles with uniform shape and good dispersion. The characterization data confirmed the encapsulation efficiency of insulin-loaded LNPs reached about 80% and the degradation rate of insulin was greatly reduced. A recent study further improved solvent diffusion and prepared clobetasol propionate loaded LNPs. The particles showed a quasi-sphere or cylinder shape and uniform size. The encapsulation efficiency reached over 90% and the initial release could be maintained for up to 4 days. These data suggest that LNP-loaded drug delivery is an effective way to improve drug release indicators, providing a wide approach for targeted drug release and extension of drugs' half-life.

Schematic steps of solvent diffusion technique (left) and micrograph of insulin-loaded LNPs (right).Fig.1 Schematic product steps (left) and micrograph (right) of insulin-loaded LNPs. (Trotta, 2003)

Applications of Solvent Diffusion

After years of development, the solvent diffusion method preparing LNPs tends to be stable and widely used in the delivery of small molecules, mRNA, peptides, and protein drugs, such as insulin and vincristine. LNP supported drugs have enhanced stability and extended half-life, providing a novel opportunity for targeted release of drugs. However, hydrophilic molecules are difficult to be directly supported on LNPs, so they can be modified to increase lipid solubility.


  • Suitable for almost all molecule types
  • Free of high temperature, pressure, or ultrasonic
  • Simplicity, inexpensive, and rapidly
  • Lower risk of coagulation

Solvent diffusion method provides a broadly applicable technique to easily produce drug-loaded LNPs by bundling many types of molecules with LNPs. This method has many advantages and thus can be used in sorts of fields including small molecule drug targeted delivery, mRNA vaccine development, polypeptide drugs transport, and protein delivery. If you are interested in our LNPs production services, please feel free to contact us for more information.


  1. Trotta, M.; et al. Preparation of solid lipid nanoparticles by a solvent emulsification-diffusion technique. Int J Pharm. 2003, 257(1-2), 153-160.
For Research Use Only.