title: Technological Evaluation of Emulsions Containing The Volatile Oil from Leaves ofPlectranthus AmboinicusLour.
abstract: BACKGROUND
  Plectranthus amboinicusLour is a species which is widespread throughout tropical countries where it is widely used against respiratory tract disorders such as bronchodilator, antitussive, and expectorant conditions.
  
  
  OBJECTIVE
  This study aims to characterize the essential oil ofP. amboinicus(PaEO) and produce and evaluate emulsions containing PaEO.
  
  
  METHODS
  The essential oil was characterized by physical-chemical analyses for density, refractive index, 90% ethanol solubility, color, appearance, and identification by gas chromatography coupled to mass spectrometry detection. The emulsions were prepared following a hydrophile-lipophile balance [HLB] spreadsheet design from two nonionic surfactants (Span 80®and Tween 20®) producing HLB values ranging from 4.3 to 16.7. The products were stored at room temperature at 5°C. The emulsion stabilities were tested both in the long and short-term.
  
  
  RESULTS
  The PaEO was obtained by steam distillation and the total extraction was reached after 3 hours yielding of 0.2% (w/w). This essential oil was characterized by physicochemical analyses for density [1.5 g.ml-1], refraction index [0.9167], ethanol 90% solubility [1:2], color, and appearance (yellow/clear). Nineteen components were identified in the oil, among them the sesquiterpenes: carvacrol [33.50%], p-cymene [28.20%] and γ-terpinene [14.77%]. The emulsions obtained successfully showed, for the first time, HLB values for essential oils fromPlectranthus amboinicus[15.7].
  
  
  CONCLUSIONS
  The experimental data shows a relationship between HLB values of the surfactant mixtures contributing to the emulsified systems production containing phytopharmaceuticals. Such an approach is of great importance to the development of lipid carriers for therapeutic drugs.
  
  
  CONCLUSIONS
  The essential oil from leaves ofPlectranthus amboinicuswas extracted by steam distillation and characterized.The emulsions containing essential oil were produced and the stability was performed in the short and long term.The critical hydrophilic-lipophilic balance (HLB) of the essential oil was 15.7 and was achieved by the combination of surfactants (Tween 80®and Span 20®).Abbreviations used:PaEO: essential oil ofP. amboinicus, HLB: hydrophilic-lipophilic balance, CI: Creaming Index, MET: micro-emultocrit technique.
authors.affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Pernambuco - UFPE, Rua Prof. Artur de Sá s/n, Recife, Pernambuco, Brazil.
authors.forename: Pablo Queiroz
authors.initials: PQ
authors.lastname: Lopes
authors.affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Pernambuco - UFPE, Rua Prof. Artur de Sá s/n, Recife, Pernambuco, Brazil.
authors.forename: Fabíola Bernardo
authors.initials: FB
authors.lastname: Carneiro
authors.affiliation: Departamento de Ciências Farmacêuticas, Universidade Federal da Paraíba - UFPB, Cidade Universitária, João Pessoa, Paraíba, Brazil.
authors.forename: Ana Letícia Braz
authors.initials: AL
authors.lastname: de Sousa
authors.affiliation: Departamento de Ciências Farmacêuticas, Universidade Federal da Paraíba - UFPB, Cidade Universitária, João Pessoa, Paraíba, Brazil.
authors.forename: Sócrates Golziodo
authors.initials: SG
authors.lastname: Santos
authors.affiliation: Centro de Ciências Biológicas e Sociais Aplicadas, Universidade Estadual da Paraíba - UEPB, Rua Horácio Trajano de Oliveira, s/n, João Pessoa, Paraíba, Brazil.
authors.forename: Elquio Eleamen
authors.initials: EE
authors.lastname: Oliveira
authors.affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Pernambuco - UFPE, Rua Prof. Artur de Sá s/n, Recife, Pernambuco, Brazil; Departamento de Ciências Farmacêuticas, Universidade Federal de Pernambuco - UFPE, Rua Prof. Artur de Sá s/n, Recife, Pernambuco, Brazil.
authors.forename: Luiz Alberto Lira
authors.initials: LA
authors.lastname: Soares
keywords: Plectranthus amboinicus; carvacrol; emulsion; essential oil; stability