Development and Optimization of Dihydrofolate-Targeted Methotrexate-Loaded Lyotropic Liquid Crystal-Based Gel for Localized Breast Cancer Therapy

Breast cancer needs localized drug delivery strategies to improve therapeutic efficacy while minimizing systemic toxicity. This study aimed to develop and optimize methotrexate-loaded lyotropic liquid crystal nanoparticles (MTX-LLCs) and incorporate them into a topical gel for localized breast cancer therapy. MTX-LLCs were prepared by a top-down approach and optimized using a Box-Behnken design (BBD), with GMO (X1), Poloxamer 407 (X2), and probe sonication cycles (X3) as independent variables and entrapment efficiency (EE; Y1) and Vesicle size (Y2) as responses. The optimised formulation containing 2 mL GMO, 150 mg Poloxamer 407 and 20 cycles of sonication showed 92.14 ± 0.57% EE, 155.31 ± 2.41 nm vesicle size and 0.231 ± 0.07 PDI. The MTX-LLCs gel showed a prolonged release of drug (30.75 ± 4.25% at 48 h) compared to the conventional MTX gel (64.80 ± 3.38%). Ex vivo permeation and improved anti-cancer efficacy, suggesting it was improved to 246.5 ± 5.32 µg/cm² at 8 h, compared to 65.8 ± 5.47 µg/cm² for conventional gel. The optimized gel also showed better cytotoxicity against MCF-7 cells with an IC50 of 19.86 ± 2.18 µg/mL as compared to plain MTX of 42.16 ± 3.92 µg/mL. The formulation was shown to be stable regarding physicochemical properties, especially when kept at refrigeration temperatures. In conclusion, the Box-Behnken design was an effective tool for the optimization of MTX-LLCs, and its formulation into a topical gel offered sustained release, increased permeation and improved anti-cancer efficacy, which suggests its potential for localized breast cancer treatment.