Single-step and low-energy method to prepare solid lipid nanoparticles and nanostructured lipid carriers using biocompatible solvents
a Department of Pharmaceutics, Bombay College of Pharmacy, Kalina, Santacruz (E), Mumbai 400098, Maharashtra, India
b Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo 200 W. Kawili Street, Hilo, Hawaii 96720, USA
Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLCs) are widely being explored for improving dermal/transdermal and oral delivery of drugs, neutraceuticals and cosmeceuticals. High-pressure homogenization (HPH) is the most commonly used preparation method for SLN/NLCs. SLN/NLCs preparation by the HPH requires high energy input and longer duration. Here, we describe a simple yet innovative low-energy method to prepare SLN/NLCs in a single-step using biocompatible solvents. We first show that biocompatible solvents such as Transcutol P, Soluphor P, N-methyl pyrrolidone, and glycofurol can solubilize glyceryl monostearate, glyceryl behenate, and glyceryl distearate to a variable degree. Our pre-formulation studies showed that only GMS could be transformed into SLN or NLCs despite high solubility of the lipids investigated indicating the importance of solvent-lipid interaction parameter in our preparation method. Finally, we show that SLN and NLCs of glyceryl monostearate with size < 150 nm and acceptable polydispersity index can be easily developed using Transcutol P as a biocompatible solvent and polyoxyl-40-stearate (MYS-40) as a stabilizer. As the Transcutol P has excellent acceptability for dermal/transdermal and oral route, there is no need to remove the residual Transcutol P (5% v/v) from the prepared glyceryl monostearate SLN/NLCs. Thus, our method offers a simple yet innovative way to prepare GMS SLN/NLCs suitable for dermal/transdermal and oral applications.