Quality by design assisted optimization of temozolomide loaded PEGylated lyotropic liquid crystals: Investigating various formulation and process variables along with in-vitro characterization

Abstract

Temozolomide (TMZ) is approved for the treatment of glioblastoma. The objective of the present study was to develop and characterize TMZ loaded lyotropic liquid crystals (LLCs) for intravenous delivery. Various formulation and process variables were studied in detail, following the quality by design principles. A three-level Box Behnken design was used for optimization. The effect of lipid concentration, surfactant concentration, and co-surfactant concentration on response variables like size, size distribution, zeta potential, entrapment efficiency, and drug loading was investigated using the statistical data obtained by Design Expert® software. The results demonstrated that LLCs were obtained in the size range of 53.15–186.50 nm with PDI less than 0.25. The optimized formulation showed particle size of 97.70 ± 0.481 nm and entrapment efficiency of 36.46 ± 1.48%. TMZ loaded LLCs were found to follow Korsmeyer's Peppas model and showed sustained release up to 72 h. The LLCs were further PEGylated to prevent hemolysis and achieve long plasma circulation. PEGylated LLCs showed less than 5% hemolysis. TMZ loaded LLCs demonstrated higher cytotoxicity towards glioma cell lines as compared to native TMZ. The results revealed that the prepared LLCs could be a potential delivery system to enhance the efficacy of TMZ. Additionally, the preparation method involved a minimum number of steps ensuring reproducibility and scalability.