Foglio Bonda Andrea, Candiani Alessandro, Pertile Martina, Giovannelli Lorella, Segale Lorena
Department of Pharmaceutical Sciences, Università del Piemonte Orientale, 28100 Novara, Italy.
Gels. 2021 Oct 3;7(4):162. doi: 10.3390/gels7040162.
Peppermint essential oil is encapsulated by inverse ionotropic gelation in core-shell systems, composed of alginate (ALG) alone or alginate with shellac gum (SHL) and/or carrageenan (CRG). A mixture design approach is used to evaluate the correlation between the formulation composition and some properties of the final products. Immediately after the preparation, capsules appear rounded with a smooth and homogeneous surface, having a similar particle size ranging from 3.8 mm to 4.5 mm. The drying process, carried out at 40 °C in an oven for 3 h, reduces capsules' diameters by at least 50% and has a negative impact on the shape of the systems because they lose their regular shape and their external membrane partially collapses. The peppermint essential oil content of dried capsules is between 14.84% and 33.75%. The swelling behaviour of the systems is affected by the composition of their outer shell. When the external membrane is composed of alginate and shellac gum, the capsule ability to swell is lower than that of the systems containing alginate alone. The swelling ratio reaches 31% for alginate capsules but does not exceed 21% if shellac is present. Differently, when the second polymer of the shell is carrageenan, the swelling ability increases as a function of polymer concentration and the swelling ratio reaches 360%. In the case of systems whose outer membrane is a polymeric ternary mixture, the swelling capacity increases or decreases according to the concentrations of the individual polymers. The obtained results suggest that carrageenan could be a useful excipient to increase the swelling behaviour of the systems, while shellac gum makes the system shell more hydrophobic. The use of a mixture design (i.e., the use of ternary diagrams and related calculations), in which each single component is chosen to provide specific properties to the final mixture, could be the right approach to develop improved formulations with a tailored essential oil release profile.
薄荷精油通过反相离子凝胶法包裹在核壳体系中，该体系由单独的海藻酸盐（ALG）或海藻酸盐与紫胶（SHL）和/或卡拉胶（CRG）组成。采用混合设计方法来评估配方组成与最终产品某些性质之间的相关性。制备后，胶囊立即呈现圆形，表面光滑且均匀，粒径范围相似，为3.8毫米至4.5毫米。在40℃的烘箱中干燥3小时的干燥过程使胶囊直径至少减小50%，并对体系形状产生负面影响，因为它们失去了规则形状且外膜部分塌陷。干燥胶囊中薄荷精油的含量在14.84%至33.75%之间。体系的溶胀行为受其外壳组成的影响。当外膜由海藻酸盐和紫胶组成时，胶囊的溶胀能力低于仅含海藻酸盐的体系。海藻酸盐胶囊的溶胀率达到31%，但如果存在紫胶则不超过21%。不同的是，当外壳的第二种聚合物是卡拉胶时，溶胀能力随聚合物浓度增加，溶胀率达到360%。对于外膜为聚合物三元混合物的体系，溶胀能力根据各聚合物的浓度增加或降低。所得结果表明，卡拉胶可能是一种有用的辅料，可增加体系的溶胀行为，而紫胶使体系外壳更疏水。使用混合设计（即使用三元相图和相关计算），其中选择每个单一成分以赋予最终混合物特定性质，可能是开发具有定制精油释放曲线的改良配方的正确方法。
