title: Optimization of headspace solid-phase microextraction for analysis of β-caryophyllene in a nanoemulsion dosage form prepared with copaiba (Copaifera multijuga Hayne) oil.
abstract: Recent studies have shown the anti-inflammatory activity of Copaiba oils may be addressed to the high content of β-caryophyllene, the most common sesquiterpene detected, especially in the Copaifera multijuga Hayne species. In the present study, nanoemulsions were proposed as a delivery system for copaiba oil in view to treat locally inflamed skin. This article describes the optimization and validation of a stability-indicating SPME-GC method, for β-caryophyllene analysis in the nanoemulsions produced by high pressure homogenization. SPME methods are performed with PDMS (polydimethylsiloxane) fiber (100 μm). Three SPME parameters were evaluated by a three-level-three-factor Box-Behnken factorial design as potentially affecting the technique efficiency. According to the results obtained, the best conditions to extract β-caryophyllene were: (i) sampling temperature of 45°C, (ii) sampling time of 20 min and (iii) no NaCl addition. Results coming from the forced degradation tests showed a reduction of β-caryophyllene peak area when both caryophyllene methanolic solution and nanoemulsions were exposed to acid hydrolysis, UV-A irradiation, oxidative (H(2)O(2)) and thermolitic (60°C) conditions. Such reduction occurred in lower extent in the nanoemulsions, suggesting a protective effect of the formulation to β-caryophyllene content. Since no degradation products were detected in the same retention time of β-caryophyllene, the specificity of the method was demonstrated. The method was linear in the range of 0.14-0.68 μg mL(-1) of β-caryophyllene (r(2)>0.999), and was also validated for precision (R.S.D.≤5.0%), accuracy (97.85-101.87%) and robustness. Finally, the method was applied to quantification of β-caryophyllene content in the developed formulations.
authors.affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, CEP, Brazil.
authors.forename: Daiane de O
authors.initials: Dde O
authors.lastname: Dias
authors.forename: Mariana
authors.initials: M
authors.lastname: Colombo
authors.forename: Regina G
authors.initials: RG
authors.lastname: Kelmann
authors.forename: Tatiane P
authors.initials: TP
authors.lastname: De Souza
authors.forename: Valquiria L
authors.initials: VL
authors.lastname: Bassani
authors.forename: Helder F
authors.initials: HF
authors.lastname: Teixeira
authors.forename: Valdir F
authors.initials: VF
authors.lastname: Veiga
authors.forename: Renata P
authors.initials: RP
authors.lastname: Limberger
authors.forename: Letícia S
authors.initials: LS
authors.lastname: Koester
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004655:Emulsions / Q000737:chemistry*; D007887:Fabaceae / Q000737:chemistry*; D006868:Hydrolysis; D036103:Nanotechnology; D009822:Oils, Volatile / Q000737:chemistry; D010084:Oxidation-Reduction; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes / Q000032:analysis* / Q000302:isolation & purification; D052617:Solid Phase Microextraction; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D004129:Dimethylpolysiloxanes; D004655:Emulsions; D009822:Oils, Volatile; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; C013830:baysilon; C024714:caryophyllene