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（BP）所制备的薄膜，开展了开发工作并对其理化性质进行了表征。研究采用溶剂浇铸法（solvent casting method），在添加或不添加聚合物助剂（polymeric adjuvant，即明胶（gelatin）或乙基纤维素（ethylcellulose））以及丙二醇（propylene glycol）的条件下制备薄膜。随后对薄膜的多项性能进行了测定：密度、扫描电子显微镜（scanning electron microscopy）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（WVP）、吸湿容量、热重分析、差示扫描量热法以及傅里叶变换红外光谱（FTIR）。所制备的薄膜呈透明淡黄绿色，表面均匀平整，兼具柔韧性且易于操作。制备所得薄膜的厚度与密度结果表明，各组分在薄膜基质中均匀分散。薄膜的力学性能受配方组成影响显著：添加明胶的薄膜抗应力性能更佳，而添加乙基纤维素的薄膜柔韧性更优。提升助剂浓度会降低薄膜的弹性与抗断裂性能，但会提高其吸湿容量与水蒸气透过率（WVP）。副产物（BP）与所制薄膜均具备良好的热稳定性。傅里叶变换红外光谱（FTIR）检测结果表明，BP与聚合物助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技术参考。