Development of rice bran oil nanoemulsion used as adjuvant in treatment of atopic dermatitis and psoriasis

Author(s)

Daniela Spuri Bernardi

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC)
• Defense date: 2011-04-08

Examining board members

Pedro Alves da Rocha Filho; Maria Palmira Daflon Gremião; Wanderley Pereira de Oliveira

• Advisor: Pedro Alves da Rocha Filho

Abstract

Nanoemulsions are emulsion with droplet size in the range of 50 to 200 nm, with transparent appearance and kinetically stable. It has been widely studied in topical formulations to increase skin permeation of actives helping to reduce the transepidermal water loss, among others benefits. In diseases such as atopic dermatitis and psoriasis, nanoemulsions help in the skin disease recovery. The rice bran oil, which can form the emulsion oil phase, has antioxidant and moisturizing properties that may help to maintain healthy and recover damage skin. This research aims to develop rice bran oil nanoemulsion to be used as an adjuvant in the treatment of atopic dermatitis and psoriasis. Several pairs of surfactant were investigated to employ one that allows stable nanoemulsion formation. The oil HLB was 6.0. The nanoemulsion formation was in HLB of 8.0 to the surfactant pair sorbitan monooleate/castor oil ethoxylated 30 OE (system 1), and HLB of 9.0 to surfactant pair castor oil ethoxylated 15 OE/40 OE (system 2), with amounts of 10.00 % oil, 10.00% surfactants and 80.00% water for both formulations. The emulsification method by phase inversion with the aqueous phase poured in the oil was the most suitable for the formation of small droplet size, together with the temperature at 75°C. The nanoemulsion composed by the system 1 maintained stable when added to moisturizers/emollients, during 90 days of stability study and freeze/defrost cycles. The value of 0,269 mg/mL of rice bran oil in the reaction medium was able to inhibit 50.00% of DPPH. In the irritation test in the organotypic model, the nanoemulsions were practically non-irritating and the surfactant solutions were slightly irritating. The in vivo tests showed an increase of hydration in volunteers with normal skin as well as in patients with atopic dermatitis and psoriasis. The high performance liquid chromatography (HPLC) showed the presence of one of the gamma-oryzanol constituents, a compound with superior antioxidant properties, at the rice bran oil studied. (AU)

• FAPESP's process: 09/01922-3 - Development of nano-emulsions containing rice bean oil (Oriza sativa) for atopic dermatitis and psoriasis treatment
• Grantee: Daniela Spuri Bernardi
• Support Opportunities: Scholarships in Brazil - Master