Posted: August 24, 2010

Rheological technique predicts stability of solid lipid nanoparticles

(Nanowerk News) A rheological technique, used by researchers at National Nanotechnology Center (NANOTEC) in Thailand has revealed the instability of y-oryzanol-loaded solid lipid nanoparticles (SLNs) over 60 days storage at three different temperatures of 4, 25, and 40°C.
"Upon storage, gelation was developed in all samples, especially at 40°C" said Dr Uracha Ruktanonchai, Research Leader at Nano Delivery Lab, NANOTEC. "Rheological technique helps us in revealing this instability which is attributed by the increase in storage modulus, critical stress, and the characteristic relaxation time."
SLNs have gained interest as colloidal drug carriers due to their submicron size, potential for industrial production, and their physiological compositions. The carrier has been used for effective controlled-release and prolonged stability of both lipophilic and hydrophilic drugs. One of the lipophilic drugs found applications in cosmetic, pharmaceutical, and food areas is a natural antioxidant y-oryzanol, a main constituent in rice bran oil. Temperature and light exposure during storage have found to affect the stability of the nanoparticle.
The researchers reported their work in a paper published by Micron, the international research and review journal for microscopy. Collaborators on this investigation included National Metal and Materials Technology Center, National Science and Technology Development Agency, Thailand.
Dr Uracha is currently exploring the fabrication of lipid nanoparticles and nanodispersion together with the characteristics of the resulting nanostructures particularly for medical and agricultural applications.