Weibin Chen, Guojie Lei, Xia Lou, Qi Wang, Fang Yang, Kun Zhang, Tong He, Guangyu Chen, Yang Ling, Shiwei Wang
BACKGROUND: Periorbital rejuvenation presents significant challenges: hyaluronic acid (HA) fillers carry risks of edema and the Tyndall effect, whereas traditional poly-L-lactic acid (PLLA) may lead to nodule formation and delayed inflammatory reactions. To address these limitations, the PLLA-b-poly (ethylene glycol) (PLLA-b-PEG)/HA composite filler is designed to optimize tissue compatibility and minimize these specific adverse reactions. OBJECTIVE: To comprehensively evaluate the physicochemical properties, biocompatibility, and clinical efficacy of this filler for periorbital volume deficiency. METHODS: Physicochemical validation included SEM morphology, extrusion force, osmolality, and mechanical support testing. In vivo safety and collagenogenesis were assessed via histology in a rabbit model. Additionally, a retrospective clinical study of 15 subjects with infraorbital hollowing evaluated efficacy at 1, 3, and 6 months using the Allergan Infraorbital Hollows Scale (AIHS) and Global Aesthetic Improvement Scale (GAIS). All subjects also underwent clinical safety follow-up through 12-14 months; in a subset of subjects, additional 12-14-month photographs were available for descriptive review, but these images were not included in the formal efficacy analysis. RESULTS: The filler exhibited uniform microspheres, physiological osmolality (302 mOsmol/kg), and superior mechanical support. In vivo, it showed mild inflammation with neocollagenesis. In the retrospective clinical analysis (N = 15), the median AIHS score improved significantly from 2.0 at baseline to 1.0 at 6 months (p < 0.0001). At 6 months, 93.3% of subjects achieved ≥ 1-grade improvement. GAIS improvement rates were stable (p > 0.05), with no significant difference between subject and investigator ratings. Adverse events were mild, and no delayed or late-onset adverse events, such as nodules or granulomas, were identified during the extended safety follow-up. CONCLUSIONS: The PLLA-b-PEG/HA filler demonstrates unique physicochemical properties and a dual-action mechanism of immediate filling and long-term regeneration, establishing it as a promising, safe treatment for periorbital rejuvenation.