Phenobarbital loaded microemulsion: development, kinetic release and quality control

ABSTRACT This study aimed to obtain and characterize a microemulsion (ME) containing phenobarbital (PB). The PB was incorporated in the proportion of 5% and 10% in a microemulsion system containing Labrasol(r), ethanol, isopropyl myristate and purified water. The physicochemical characterization was performed and the primary stability of the ME was evaluated. An analytical method was developed using spectrophotometry in UV = 242 nm. The kinetics of the in vitro release (Franz model) of the ME and the emulsion (EM) containing PB was evaluated. The incorporation of PB into ME at concentrations of 5 and 10% did not change pH and resistance to centrifugation. There was an increase in particle size, a decrease of conductivity and a change in the refractive index in relation to placebo ME. The ME remained stable in preliminary stability tests. The analytical method proved to be specific, linear, precise, accurate and robust. Regarding the kinetics of the in vitro release, ME obtained an in vitro release profile greater than the EM containing PB. Thus, the obtained ME has a potential for future transdermal application, being able to compose a drug delivery system for the treatment of epilepsy.

摘要 本研究旨在制备并表征含苯巴比妥（phenobarbital，PB）的微乳（microemulsion，ME）。以Labrasol®、乙醇、肉豆蔻酸异丙酯及纯化水构建微乳体系，按5%与10%的比例掺入苯巴比妥。对该微乳开展理化表征，并评价其初步稳定性。建立了紫外波长242nm处的紫外分光光度分析方法。采用Franz扩散池模型，评价了含苯巴比妥的微乳与普通乳剂（emulsion，EM）的体外释放动力学。结果表明，掺入5%与10%浓度的苯巴比妥后，微乳的pH值与抗离心稳定性未发生改变；与空白微乳相比，其粒径增大、电导率降低、折光率出现变化。初步稳定性试验证实该微乳稳定性良好。该分析方法专属性强、线性范围良好、精密度与准确度俱佳且耐用性优异。体外释放动力学结果显示，含苯巴比妥的微乳的体外释放效果优于普通乳剂。综上，本研究制备的微乳具备潜在的经皮给药应用价值，可作为药物递送系统用于癫痫的治疗。