Animal studies and Crystallization process of TRILAURIN

TRILAURIN is a triglyceride formed from glycerol and lauric acid (dodecanoic acid). In experimental settings, it is commonly used as an emulsifier, thickening agent, and solvent. Trilaurin can also be employed in the construction of nanoliposomes. In addition, it has been shown to inhibit the formation of tumors initiated by dimethylbenzanthracene (DMBA) and promoted by croton oil. The most important physiological function of glyceryl trilaurate (Trilaurin) is to supply the body with energy and essential fatty acids. It is formed by the dehydration esterification of one molecule of glycerol with three molecules of fatty acids. The fats in food are all triglycerides, and after ingestion, 90% of them are absorbed by the intestinal tract.

Figure1: Picture of TRILAURIN

Basic Introduction

TRILAURIN, along with other glyceryl triesters, belongs to a broad class of compounds known as triglycerides, which are formed by esterifying glycerin with aliphatic acids. In cosmetic formulations, these triesters—including TRILAURIN—function primarily as occlusive skin-conditioning agents and/or nonaqueous viscosity-increasing agents. Hundreds of such triglycerides are incorporated into a wide variety of cosmetic products, with use concentrations spanning from as low as a few tenths of a percent up to 46%. Although commonly referred to as triglycerides, these compounds are metabolized following oral ingestion into monoglycerides, free fatty acids, and glycerol, all of which are absorbed through the intestinal mucosa and subsequently undergo further metabolic processing. Regarding dermal penetration, TRILAURIN shares a key property with other glyceryl triesters: for instance, dermal absorption of triolein in mice was found to be negligible, with the oil remaining entirely at the application site, and only minimal absorption was observed in guinea pig skin. Importantly, certain glyceryl triesters, such as tricaprylin, have been demonstrated to enhance the percutaneous penetration of co-administered drugs—a penetration-enhancing effect that must be considered when formulating products containing TRILAURIN or related triglycerides for topical application.[1]

Animal studies

TRILAURIN was shown to suppress the development of neoplasms initiated by dimethylbenzanthracene (DMBA) and promoted by croton oil. In contrast, tricaprylin exhibited no teratogenic effects in mice or rats, although certain reproductive effects were observed in rabbits. When trioctanoin was used as a vehicle control in mice, it was associated with a low incidence of fetal eye abnormalities and a small percentage of abnormal sperm. In clinical safety evaluations, TRILAURIN demonstrated an excellent dermal tolerability profile: a commercial product containing 36.3% Trilaurin applied to human skin produced no irritation reactions whatsoever. Furthermore, TRILAURIN—along with tristearin and tribehenin—was evaluated in repeated-insult patch tests at concentrations of 40%, 1.68%, and 0.38%, respectively, in commercial formulations, and all three produced negative results, indicating no sensitization potential. By contrast, tristearin at 0.32% in a commercial product did induce transient, mild-to-moderate ocular irritation following instillation into the eyes of human subjects. Given that glyceryl triesters have been shown to enhance the percutaneous penetration of other chemicals, TRILAURIN and related triglycerides should be used with caution in cosmetic products, and formulators are advised to exercise care when incorporating them into topical applications.[1]

Crystallization

TRILAURIN was systematically investigated for its crystal growth behavior, along with the influence of various partial laurates on this process, using a combination of temperature gradient microscopy, differential scanning calorimetry, and X-ray diffraction. Through these analyses, TRILAURIN was found to exhibit a complex crystallization pattern that is highly sensitive to the presence of related laurate compounds. Specifically, the addition of monolaurin and lauric acid accelerated the crystal growth rate of TRILAURIN; however, this acceleration came at the cost of reduced facet development and smaller crystal dimensions. In contrast, when dilaurin isomers were introduced, TRILAURIN displayed a marked decrease in growth rate, indicating a strong inhibitory effect from these additives. Moreover, TRILAURIN crystals underwent noticeable morphological changes under different additive conditions, and the metastable phases became relatively more stable. Notably, the growth rate of TRILAURIN was lower in samples containing 1,3-dilaurin compared to those containing 1,2-dilaurin. It is hypothesized that these divergent effects on TRILAURIN crystallization arise primarily from differences in the molecular size and geometry of the additive molecules employed.[2]

Reference

[1] Johnson Jr W. International Journal of Toxicology, 2001, 20: 61-94.

[2] Smith P R, Cebula D J, Povey M J W. The effect of lauric-based molecules on trilaurin crystallization[J]. Journal of the American Oil Chemists’ Society, 1994, 71(12): 1367-1372.