Eutectic mixtures in personal care compositions

[0081]Mixtures of L-menthol, L-menthyl lactate and 12-HSA where prepared as follows, using the ingredients as in Table 1 and the amounts mentioned in Tables 2A and 2B.

[0082]The three components L-menthol, L-menthyl lactate and 12-HSA were weighed and then mixed by grinding in a mortar and pestle until a homogenous mixture was obtained. Mixtures that started to melt at room temperature were mixed by grinding until a transparent liquid was formed.

TABLE 1Ingredients of ternary eutectic mixturesIngredientPurityCAS#Supplier12-HSA95%106-14-9Alfa AesarL-menthol99.5% 2216-51-5Damas-betaL-menthyl lactate99%69-72-7Sigma

[0083]The melting point of these mixtures was measured and the results are shown in Tables 2A and 2B. It is clearly shown that specific mixtures have a lower melting temperature. The lowest melting point of about −52 degrees Celsius was determined for a eutectic composition of L-menthol and L-menthyl lactate in a weight ratio of 4:6 and a 12-HSA concentration of 1 wt % with res...

[0084]A personal care composition (PCC 1) according to Table 3A comprising a pre-formed mixture of L-menthol, L-menthyl lactate and 12-HSA was prepared using the following protocol.[0085]1. Phase A was prepared by mixing the ingredients and heating the mixture to 70 degrees Celsius to dissolve the ingredients.[0086]2. Phase B was prepared by mixing sodium polyacrylate and 1,3-butylene glycol and adding them to Phase A. Glycerin was used to flush the beaker and decanted into phase A. The same was repeated with water.[0087]3. Phase C was prepared by mixing the ingredients at 75 degrees Celsius under manual stirring until the phase was transparent.[0088]4. Phase D was prepared by mixing the ingredients in a mortar and pestle until a transparent liquid was obtained. This liquid was added to Phase C.[0089]5. The ingredients of phase E and F were mixed separately and added at 75 degrees Celsius to the mixture obtained after step 4) and stirred manually.[0090]6. Phase G was added to the mi...

[0095]Personal care compositions according to Table 3B comprising were prepared using the following protocol. PCC 2 comprises 12-HSA, but no L-menthol and L-menthyl lactate. In PCC 3, L-menthol, L-menthyl lactate and 12-HSA were added separately (i.e. not added as a pre-formed eutectic mixture).[0096]1. Phase A was prepared by mixing the ingredients and heating the mixture to 70 degrees Celsius to dissolve the ingredients.[0097]2. Phase B was prepared by mixing sodium polyacrylate and 1,3-butylene glycol and adding them to Phase A. Glycerine was used to flush the beaker and decanted into phase A. The same was repeated with water.[0098]3. Phase C was prepared by was prepared by mixing the ingredients at 75 degrees Celsius under manual stirring until the phase was transparent. For PCC 3, 12-HSA, L-menthol and L-menthyl lactate were added to the dispersion one by one as the last ingredients.[0099]4. The ingredients of phase D and E were mixed separately and then added to the mixture ob...