Palomo M E, Ballesteros M P, Frutos P
Departmento de Farmacia y Tecnologia Farmaceutica, Universidad Complutense de Madrid, Madrid, Spain.
J Microencapsul. 1996 May-Jun;13(3):307-18. doi: 10.3109/02652049609026018.
Variations in microencapsulation processes give rise to different products and it seems there are no firm rules. It is thus difficult to know what kind of product will be obtained before the research is carried out. Changes in temperature, rate, time and type of stirring can cause great modifications in the system, most of which are responsible for variations in standard techniques. In our study, we investigate the solvent influence on ethylcellulose (EC) microcapsule formation. We have selected four different solvents: ethanol as an aqueous solvent and acetone, chloroform and toluene as organic solvents. Diclofenac sodium (DFNa), a non-steroidal anti-inflammatory agent, has been used as an encapsulated substance as it is inactivated in the gastric juices. This polymer and microencapsulation process was selected after an exhaustive study with different polymers and processes. Once the solvent influence was determined, ethylphthalate was incorporated in one type of microcapsule in order to study the influence of this plasticizer on drug release by the modification of film-permeability.
微囊化工艺的变化会产生不同的产品，而且似乎没有固定的规则。因此，在进行研究之前很难知道会得到什么样的产品。温度、速率、时间和搅拌类型的变化会导致体系发生很大的改变，其中大部分是造成标准技术变化的原因。在我们的研究中，我们研究了溶剂对乙基纤维素（EC）微囊形成的影响。我们选择了四种不同的溶剂：作为水性溶剂的乙醇以及作为有机溶剂的丙酮、氯仿和甲苯。双氯芬酸钠（DFNa），一种非甾体抗炎药，因其在胃液中会失活而被用作包封物质。在对不同的聚合物和工艺进行详尽研究之后，选择了这种聚合物和微囊化工艺。一旦确定了溶剂的影响，就将邻苯二甲酸乙酯加入到一种微囊中，以便通过改变膜的渗透性来研究这种增塑剂对药物释放的影响。
