Banca de QUALIFICAÇÃO: JÚLIO ABREU MIRANDA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JÚLIO ABREU MIRANDA
DATE: 27/06/2025
TIME: 10:00
LOCAL: REMOTA - https://meet.google.com/kbu-czrx-rni
TITLE:

DEVELOPMENT, CHARACTERIZATION, AND IN VITRO EVALUATION OF A LINSEED OIL-BASED PHOTOPROTECTIVE NANOEMULSION CONTAINING THE ULTRAVIOLET FILTERS AVOBENZONE AND TRIS-BIPHENYL TRIAZINE

KEY WORDS:

AVOBENZONE; TRIS-BIPHENYL TRIAZINE; LINSEED OIL; PHOTOPROTECTION; NANOEMULSION

PAGES: 31
BIG AREA: Ciências da Saúde
AREA: Farmácia
SUMMARY:

Ultraviolet (UV) radiation is a major risk factor for various skin damages, including skin cancer, making sunscreens a key preventive strategy. Avobenzone (AVO) and tris-biphenyl triazine (TBPT) are commonly used UV filters whose combination provides broad-spectrum protection. However, AVO is highly susceptible to photodegradation, limiting its effectiveness in formulations. Therefore, this study aimed to develop and validate an HPLC method for the simultaneous quantification of AVO and TBPT, and to formulate a linseed oil-based nanoemulsion system for their delivery, aiming to enhance AVO’s photostability and efficacy. The optimized HPLC method employed a mobile phase consisting of acetonitrile, isopropanol, and 2% aqueous phosphoric acid (42:42:16), in isocratic mode, with a flow rate of 1.0 mL/min, injection volume of 20 µL, and column temperature of 30 °C. A C18 column (125 Å, 3.9 mm × 300 mm, 10 µm) was used as the stationary phase, with detection at 310 nm for TBPT and 358 nm for AVO. Validation was conducted according to ICH guidelines, evaluating specificity, linearity (0.5–32 µg/mL), detection and quantification limits, accuracy, precision, and robustness using a Box-Behnken Design. A cosmetic matrix containing excipients and linseed oil was used to confirm method specificity. In parallel, a nanoemulsion was developed containing 10% linseed oil, 10% surfactant mixture (Kolliphor® RH 40:Span® 80 at an 8.7:1.3 ratio), and 80% deionized water. AVO (1%) and TBPT (8%) were incorporated into the final formulation (NEUVMIX), which was later optimized (NEUVMIXopt) for long-term stability. The formulations were physicochemically characterized in terms of droplet sized, polydispersity index (PdI), and zeta potential by dynamic light scattering, pH and FTIR. Moreover, AVO photostability was kinetically evaluated. The final nanoemulsion exhibited a droplet size of 147.48 ± 0.58 nm, polydispersity index of 0.23 ± 0.02, zeta potential of -25.09 ± 0.40 mV, and pH of 6.52 ± 0.10, indicating colloidal stability and topical suitability. Photostability tests demonstrated that AVO’s half-life increased from 39.24 ± 0.52 minutes in linseed oil to 73.55 ± 2.73 minutes in the AVO-loaded nanoemulsion (NEAVO), and to 138.16 ± 9.57 minutes in the optimized NEUVMIXopt formulation, confirming the positive impact of the nanoemulsion and TBPT association. Overall, the validated analytical method proved to be a reliable and robust tool for simultaneous quantification of AVO and TBPT, while the developed nanoemulsion enhanced AVO’s photostability and exhibited favorable physicochemical characteristics. These findings support the potential of nanotechnology combined with natural oils as an innovative strategy for developing safer and more effective sunscreen formulations.

COMMITTEE MEMBERS:
Presidente - 1178187 - ERYVALDO SOCRATES TABOSA DO EGITO
Externo ao Programa - 2276354 - LEANDRO DE SANTIS FERREIRA - nullExterna à Instituição - LORENA RIGO GASPAR CORDEIRO - USP