Dual Transdermal Delivery Of Etodolac And Atorvastatin Calcium Via Spanlastic Nanovesicles-Loaded HPMC Hydrogel: Formulation, Characterization, Anti-Inflammatory Activity, And Preliminary In Vitro Cytotoxicity Against MCF-7 Cells.

Combination therapy employing nanotechnology provides augmented efficacy over monotherapy. Spanlastics (SPs) are flexible nanovesicles that facilitate permeation across biological barriers. This study developed etodolac (ETD)-loaded SPs and atorvastatin calcium (ATR)-loaded SPs and evaluated the combined effects of ETD-SPs/ATR-SPs versus monotherapy using MCF-7 cells and a CFA-induced arthritis rat model. SPs were prepared and the effects of edge activator type and Span 60:EA ratio on in vitro characterization were evaluated. SPs were spherical, negatively charged, with particle sizes suitable for transdermal delivery. SPs dispersions showed enhanced skin permeation of ETD and ATR compared with free-drug controls. In vitro cytotoxicity studies against MCF-7 cells demonstrated concentration-dependent cytotoxic activity of ETD- and ATR-loaded SPs under the tested conditions. The combination therapy of ETD-SPs and ATR-SPs showed a lower estimated IC50 compared with the corresponding single-agent SPs formulations, evidenced by combination index lower than 1, indicating synergistic interaction at selected effect levels. In vivo anti-inflammatory assessment demonstrated that ETD-SPs and ATR-SPs combination-loaded hydrogel reduced paw thickness and modulated inflammatory biomarkers more effectively than monotherapy, with improved histological appearance. This research establishes SPs-based combination therapy as a promising delivery approach for improving cytotoxicity against MCF-7 cells and anti-inflammatory activity in CFA-induced arthritis.