Validation of a titration method to determine chondroitin sulfate loaded to solid lipid nanoparticles in an experimental factorial design

Abstract

Previous efforts at the Faculty of Pharmacy and Food Sciences of the University of Barcelona, have achieved to obtain cationic solid lipid nanoparticles (cSLN), with an average size of less than 200 nm, by the hot microemulsion method, which have been tested as a vehicle for pDNA and siRNA, in the transfection of cell lines. It is of scientific interest to evaluate the capacity of SLN transporting different types of biomolecules with pharmacological potential. Chondroitin sulfate (CHON) is a major component of the extracellular matrix of several connective tissues, including skin, bone, ligaments, tendons and cartilage. For that reason, CHON is a potential therapeutical agent in Osteoarthritis (OA), which is characterized by progressive structural and metabolic changes in joint tissues. Studies recommend topical administration in treating OA as first line therapy, and the development of topical systems with nanotechnology may introduce a new perspective for future treatment of OA. An experimental factorial design, to optimize the production of SLN of CHON, was employed. The variables were defined as Concentration (mg/ml), Stirring rate (rpm) and Reaction time (min). Different properties were tested, including entrapment efficiency of CHON, zeta potential and particle size. A titration method was validated to test entrapment efficiency of CHON. A calibration curve was obtained from 0.10 to 1.20 mg mL-1 (r > 0.9994). Withinday % RSD was 0.7 and between-day % RSD was 1.11. Specificity/ selectivity experiments revealed the absence of important interference from excipients, mean recovery from spiked samples for CHON was 93.6 %.