Elucidations on the Performance and Reversibility of Treatment with Hyaluronic Acid Based Dermal Fillers: In vivo and in vitro Approaches.

Purpose: The aim of this study was to investigate the performance and the reversibility of different classes of Hyaluronic Acid (HA) dermal fillers. We analysed 4 HA based fillers, belonging to 3 different chemical classes of products, commonly used in the field of wrinkles correction: linear HA 8 mg/mL (Viscoderm 0.8), thermically stabilized hybrid complexes of high and low molecular weight HA molecules at a concentration of 32 mg/mL and 45 mg/mL respectively (Profhilo and Profhilo Structura) and cross-linked HA 25 mg/mL (Aliaxin GP). Methods: The products were tested by a well-established animal model. The generated implants were analyzed through High-Frequency Ultrasound technology. Then, reversibility of the treatment was evaluated by enzymatic degradation kinetics studies, characterised by a combined approach of Carbazole assay and HP-SEC/TDA method. Results: Implants generated by linear HA 8 mg/mL remained detectable by ultrasound acquisition for 4 weeks, whereas those generated by injection of HA hybrid complex 32 mg/mL were detectable for 10 weeks. HA hybrid complex 45 mg/mL and cross-linked HA 25 mg/mL were detectable for 29 and at least 33 weeks, respectively. Enzymatic degradation kinetics studies demonstrated that the HA content in HA hybrid complex 45 mg/mL was almost completely depolymerized and homogeneous after 3 h of treatment. For cross-linked HA 25 mg/mL, 24 h of incubation are needed to obtain the same degree of depolymerization. Conclusion: The study confirmed the ability of the experimental model to predict the behaviour of HA based dermal fillers in vivo and showed the innovative aspects of HA hybrid complex 45 mg/mL, that combines the high-safety profile, in terms of reversibility of the treatment, of the linear HA-based products with the durability of a high degree cross-linked gels, paving the way to the chance to be used for a wide range of applications in the field of aesthetic medicine.

Evaluation of the Volumizing Performance of a New Volumizer Filler in Volunteers with Age-Related Midfacial Volume Defects.

PURPOSE: The primary aim of this study was to evaluate the performance of the study product, in terms of volumizing activity as well as the duration of the effect, in women with age-related midfacial volume defects. In addition, the study allowed the evaluation of the tolerability of the product by both volunteers and investigators. PATIENTS AND METHODS: Twenty-two female volunteers, aged 42-60 years, participated in this study, which was performed under dermatological control in a single center. After an initial visit at baseline to verify adherence to the protocol criteria, volunteers received an injection of Aliaxin® SV (IBSA Farmaceutici Italia Srl), followed 3-4 weeks later by a second touch-up treatment to treat eventual asymmetries. Four subsequent visits, the last performed 9 months from the first injection, were performed to evaluate clinically and instrumentally the efficacy of the treatment. RESULTS: Clinical and statistically significant improvement in cheek volume was recorded after the first postinjection visit, and the effect was maintained until the end of the study period. A clinically measurable amelioration of wrinkle severity was also observed. By 3D picture recording and subsequent quantitative analysis, it was possible to determine the efficacy in terms of increased facial volume, which was already appreciable at the first visit, was further increased at the second and third visits and was maintained at the fourth and last visits. The injections were very well tolerated by the volunteers, as determined by their self-evaluation questionnaires. CONCLUSION: The results of the study confirm the esthetic performance of the study product on age-related midfacial volume defects. The very strong high-volumizing activity of the study product was not only properly determined by the investigators but also confirmed by self-evaluation by the volunteers. These effects were obtained with no appreciable undesired effects.

DoE-Assisted Development of a Novel Glycosaminoglycan-Based Injectable Formulation for Viscosupplementation.

The aim of the present work was the development of a novel glycosaminoglycan (GAG)-based injectable formulation intended for intra-articular administration that should best mimic the healthy synovial fluid. Hyaluronic acid (HA) was chosen among GAG polymers, since it is the most abundant component of the synovial fluid. A DoE (Design of Experiment) approach was used for the development of a formulation containing two HA (very high (VHMW) and low (LMW) molecular weight) grades. The rationale for this choice is that so far, no commercial product based on a single HA grade or even on binary HA mixture possesses optimal viscoelastic properties in comparison with healthy synovial fluid. A full factorial design was chosen to investigate the influence of concentration and relative fraction of the two polymer grades (retained as factors of the model) on formulation functional (viscosity and viscoelastic) properties, which are considered response variables. Thanks to the DoE approach, the composition of the optimized HA formulation was found. The addition to such formulation of an injectable grade fat-free soy phospholipid, which was rich in phosphatidylcholine (PC), resulted in improved lubrication properties. The final HA + PC formulation, packaged in pre-filled sterile syringes, was stable in long-term and accelerated ICH (International Council for Harmonisation) storage conditions. The overall results pointed out the formulation suitability for further steps of pharmaceutical developments, namely for the passage to pilot scale.

High contrast reflection modulation near 1.55mum in InP 2D photonic crystals on silicon wafer.

We report on reflection modulation results near 1.55 mum in InP-based two-dimensional photonic crystals. The fabrication technology uses a polymeric bonding technique to integrate the InP thin-slab onto a Silicon wafer. Reflectivity modulation greater than 90% is obtained by pumping at 810 nm with optical excitation densities of 15 muJ/cm(2). The resulting optical broadband modulation is based on the saturation of absorption of InGaAs quantum wells at a photonic mode frequency tunable by lithography.