Recent Advances in the Preparation of Delivery Systems for the Controlled Release of Scents

Abstract

Scents are volatile compounds highly employed in a wide range of manufactured items, such as fine perfumery, household products, and functional foods. One of the main directions of the research in this area aims to enhance the longevity of scents by designing efficient delivery systems to control the release rate of these volatile molecules and also increase their stability. Several approaches to release scents in a controlled manner have been developed in recent years. Thus, different controlled release systems have been prepared, including polymers, metal–organic frameworks and mechanically interlocked systems, among others. This review is focused on the preparation of different scaffolds to accomplish a slow release of scents, by pointing out examples reported in the last five years. In addition to discuss selected examples, a critical perspective on the state of the art of this research field is provided, comparing the different types of scent delivery systems.

Fixative effect of 2‐oxo‐2‐phenylacetates in fine fragrance and eau‐de‐toilette applications

“…Repetitive column chromatography (SiO 22.0 (q), 20.7 (q), 16.2 (q). EI-MS: 139 (18), 138 (34), 124 (3), 123 (25), 109 (6), 106 (4), 105 (40), 97 (12), 96 (19), 95 (100), 94 (10), 93 (8), 91 (8), 84 (4), 83 (63), 82 (24), 81 (78), 80 (7), 79 (19), 78 (4), 77 (34), 71 (3), 70 (3), 69 (27), 68 (13), 67 (46), 65 (5), 57 (17), 56 (5), 55 (45), 54 (5), 53 (11), 52 (3), 51 (10), 50 (3), 44 (4), 43 (11), 42 (3), 41 (28), 39 (13), 29 (6), 27 (7).…”

“…Because highly volatile compounds in perfumes evaporate more rapidly than less volatile compounds do, the olfactive impression of perfumes evolves over time. 2 Both the encapsulation of fragrances into core-shell microcapsules [3][4][5][6][7] and the release of individual fragrances from precursors (profragrances or properfumes) by covalent bond cleavage [7][8][9][10] improve the long-lastingness of perfume perception in application, but do not or only partially prevent the olfactive evolution of a perfume. For about a century, attempts have been made to balance the evaporation of a complex perfume mixture by slowing the evaporation of the volatile part of the perfume through the addition of so-called fixatives.…”

Controlled Release of Volatile Enones from Monomeric and Dimeric Thioether, Sulfoxide and Sulfone Profragrances

“…Both the tendency to readily undergo retro‐1,4‐addition (1,4‐elimination) under mild environmental conditions and the compatibility of the reaction with biological systems led to the investigation of thioether conjugates as profragrances for the controlled release of enones in functional perfumery applications [7–13] . Profragrances or properfumes are designed to release fragrances or fragrance mixtures from a suitable precursor by cleavage of a covalent bond during application of perfumed consumer articles [14–17] . The generation of fragrances by covalent bond cleavage is an efficient way to prolong the long‐lastingness of fragrance perception.…”

Effects of molecular interactions on the release of small molecules from silicone rubber

“…Polymeric materials have been widely used in the delivery/release of small molecules in such applications as drugs, [1][2][3][4] scents/fragrances, [5][6][7] and semiochemicals. [8][9][10][11] Among the polymer carriers used, silicone rubber has been the focus of much research attention recently, especially in applications requiring low toxicity, chemical inertness, and biocompatibility.…”