The production and characteristics of solid lipid nanoparticles (SLNs)
Introduction
Solid lipid nanoparticles (SLNs), introduced in 1991, for combining the advantages but avoiding the disadvantages of other colloidal carriers [1], [2], [3] have attracted increasing attention in recent years, and are regarded as an alternative carrier system [4], [5] to traditional colloidal systems, such as emulsions, liposomes and polymeric microparticles and nanoparticles.
The predominant production technique till recently was the high-pressure homogenization (HPH) method [6], [7]. However, there were still two other production methods that seemed to be given up by the researchers to produce SLNs. One was the solvent evaporation by precipitation in o/w emulsions [8], [9]. Due to the organic solvents and the large amount of surfactants and other additions introduced, this method has some clear disadvantages. But the other production method of high shear homogenization and ultrasound did not involve organic solvents nor large amount of surfactants nor other additions as the HPH, and both dispersing techniques were initially used for production of SLNs [10], [11]. The above two methods were extensively used and easy to handle. However, these traditional techniques had the disadvantage of low dispersion quality. In order to use these easy and familiar tools that were almost available in every laboratory, the traditional dispersing techniques were modified in this study to produce high quality solid lipid nanodispersion.
The model drug employed here was a lipophilic drug mifepristone [12], an effective abortifacient drug, and its chemical structure is shown in Fig. 1. The drug had a poor water solubility and high lipophilicity like steroid drug mifepristone that made it an excellent candidate for SLNs encapsulation.
Section snippets
Materials
Mifepristone was a gift of Tongji Medical College of Huazhong University of Science and Technology. Sephadex G-25 was obtained from Pharmcia (USA). Glycerol monostearate, Tween-80, glycerol and any other chemicals all bought from Shanghai chemicals and agency factory (China).
Preparation of solid lipid nanoparticles
SLNs were prepared by the modified high shear homogenization and ultrasound method. Lipid matrix was melted at about 80°C and certain amount of mifepristone was added to obtain a clear melting solution. After tristilled
TEM investigation
Fig. 2 shows the shape of the nanoparticles entrapping with the model drug. It was evident that the particles investigated revealed round and homogeneous shading, the particle size ranging approximately from 20 to 50 nm. However, in order to obtain more precise information on the size distribution, more careful analyses including LD were performed as follows.
Particle size analysis
A sufficient high-energy input was necessary to break down the droplets into the nanometer range [14]. A finer dispersion could be obtained
Conclusion
Modified high shear homogenization and ultrasound techniques described here were employed to produce SLNs. The model drug mifepristone had been incorporated in them. The mean particle size was found to be 106 nm with a small polydispersity index, 0.278. Both DSC and X-ray diffraction measurements suggested that the majority of the SLNs were less ordered arrangement of crystals, and this was favorable for increasing the drug loading capacity. The EE% of SLNs was more than 87 percent and showed
References (25)
- et al.
Solid lipid nanoparticles (SLN) for controlled drug delivery—a review of the state or the art
Eur J Pharm Biopharm
(2000) - et al.
Lipophilic drug derivatives in liposomes
Int J Pharm
(1998) - et al.
Preparation of submicron drug particles in lecithin-stabilized o/w emulsions 1 model studies of the precipitation of cholesterylacetate
Int J Pharm
(1992) Mifepristonebioavailability, pharmacokinetics and use-effectiveness
Eur J Obstet Gynecol Reprod Biol
(2002)- et al.
Vesicle-to-micelle transformation in systems containing dimeric surfactants
J Colloid Interface Sci
(1997) - et al.
Influence of high pressure homogenization equipment on nanodispersions characteristics
Int J Pharm
(2000) - et al.
Investigations on the physical state of lipid nanoparticles by synchrotron X-ray diffraction
Int J Pharm
(1993) - et al.
Nanosuspensions as particulate drug formulations in therapy rationale for development and what we can expect for the future
Adv Drug Deliv Rev
(2001) - et al.
Particle size reduction for improvement of oval bioavailability of hydrophobic drugs.1. Absolute oral bioavailability of nanocrystalline danazole in beagle dogs
Int J Pharm
(1995) - et al.
Thermoanalysis of the recrystallization process of melt-homogenized glycerid nanoparticles
Colloids Surf B
(1994)
Cited by (383)
Solid lipid nanoparticles for efficient delivery of capsaicin-rich extract: Potential neuroprotective effects in Parkinson's disease
2024, Journal of Drug Delivery Science and TechnologyFormulation and development of novel lipid-based combinatorial advanced nanoformulation for effective treatment of non-melanoma skin cancer
2023, International Journal of PharmaceuticsIntroduction to nanotechnological utility in the pharmaceutical industry
2023, Nanotechnology for Drug Delivery and PharmaceuticalsStatistically designed dexibuprofen loaded solid lipid nanoparticles for enhanced oral bioavailability
2022, Journal of Drug Delivery Science and Technology