Pharmaceutical films made from the waste material from the preparation of propolis extracts: development and characterization

abstract This study investigated the development and characterized the physicochemical properties of films obtained from by-products (BP) from the preparation of propolis extracts. Films were produced in the presence and absence of a polymeric adjuvant (gelatin or ethylcellulose) and propylene glycol by a solvent casting method. Density, surface topography by scanning electron microscopy, mechanical properties (folding endurance, tensile strength and percentage elongation), water vapour permeability (WVP), moisture uptake capacity, thermogravimetry, differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR) were determined. The films were a transparent, light greenish-yellow colour, with a uniform surface, and were flexible and easy to handle. The thickness and density of the preparations indicated that the compounds were homogeneously dispersed throughout the film. Mechanical properties were influenced by the film composition; films containing gelatin were more resistant to stress, while those containing ethylcellulose were more flexible. Increasing the adjuvant concentration decreased the elasticity and the rupture resistance, but increased the moisture uptake capacity and WVP of the formulations. BP was thermally stable as were the films. FTIR tests suggested interactions between BP and the adjuvants. This work could contribute to the utilization of BP to prepare films for food and pharmaceutical uses

摘要 本研究针对蜂胶提取物制备过程中产生的副产物（by-products，以下简称BP）所制得薄膜的开发及其理化性质表征展开研究。采用溶剂浇铸法，分别在添加或不添加高分子佐剂（明胶或乙基纤维素）以及丙二醇的条件下制备薄膜。对薄膜的多项性能进行了测定，包括密度、扫描电子显微镜观测的表面形貌、力学性能（耐折度、拉伸强度及伸长率）、水蒸气透过率（water vapour permeability，简称WVP）、吸湿能力、热重分析、差示扫描量热法，以及傅里叶变换红外光谱（Fourier transform infrared spectroscopy，简称FTIR）。所制备的薄膜呈透明淡绿黄色，表面均匀平整，柔韧性良好且易于操作。薄膜厚度与密度的测定结果表明，各组分在薄膜中均匀分散。力学性能受薄膜组成影响显著：添加明胶的薄膜抗应力性能更优，而添加乙基纤维素的薄膜柔韧性更佳。提高佐剂浓度会降低薄膜的弹性与抗断裂性能，但会提升配方的吸湿能力与WVP。BP及所制备的薄膜均具有热稳定性。FTIR测试结果显示，BP与高分子佐剂之间存在相互作用。本研究可为利用BP制备食品及医药领域用薄膜提供参考依据。