Cross-Linked Sodium Hyaluronate Filler Containing Poly-L-Lactic Acid-b-Poly (Ethylene Glycol) Microspheres for Periorbital Rejuvenation: A Multimodal Assessment of Physicochemical, Preclinical, and Clinical Performance.

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.