Quality by Design-Guided Development of Cynara cardunculus var. scolymus L. Extract-Loaded Liposomes

An integrated Quality by Design (QbD) approach was developed for the systematic optimization of Cynara cardunculus var. scolymus L. extraction and its subsequent incorporation into liposomal formulations. A D-optimal design was initially applied to evaluate the influence of extraction method, plant material-to-solvent ratio, and ethanol concentration on total phenolic and flavonoid contents. The optimization identified ultrasound-assisted extraction using 70% ethanol at a plant material-to-solvent ratio of 1:50 as the optimal extraction condition. Phytochemical profiling of the optimized plant extract by LC–TIMS-HRMS/MS led to the putative annotation of 47 metabolites, predominantly hydroxycinnamic acid derivatives and flavonoids. The second D-optimal design elucidated the combined effects of formulation composition and ultrasonic processing and identified an extract-to-phospholipid ratio of 1:0.84 (w/w), a phospholipid-to-cholesterol ratio of 1:0.42 (w/w), and probe sonication for 16.73 min as the conditions providing the most favorable balance among particle size, polydispersity index (PDI), encapsulation efficiency (EE), and drug loading. The formulation obtained under these conditions was subsequently evaluated for in vitro release, showing distinct release profiles under the two investigated pH conditions over 24 h, with cumulative phenolic release reaching 68.14 ± 3.68% at pH 7.4 and 53.77 ± 2.99% at pH 5.5. The liposomal formulation obtained under optimized conditions, with a particle size of 224.1 ± 1.9 nm, a PDI of 0.206 ± 0.014, and an EE of 75.95 ± 0.24%, was lyophilized with 5% (w/v) mannitol, with its key physicochemical attributes preserved upon reconstitution. Long-term stability assessment over 12 months showed that the reconstituted lyophilized liposomes retained a particle size below 300 nm, a PDI below 0.30, and an EE above 73%, while TEM analysis confirmed preservation of vesicular morphology. Preliminary cytocompatibility assessment in adult human dermal fibroblasts further indicated a more favorable cellular response to the liposomal formulation than to the free extract. These findings demonstrate the applicability of a systematic approach integrating extract optimization with liposomal formulation development for C. cardunculus var. scolymus extract-loaded liposomes.