Microemulsion and sub-micron emulsion process and compositions

Abstract

There is provided a process for the preparation of an oil in water (O / W) microemulsion or sub-micron emulsion composition for dermal delivery of at least one pharmaceutically active ingredient, the method including the steps of a) Admixing a first part including at least one of the group consisting of animal, mineral or vegetable oils, silanes, siloxanes, esters, fatty acids, fats, halogen compounds or alkoxylated alcohols; and one or more lipophilic surfactants, and a second part including water and at least one hydrophilic surfactant to achieve homogeneity, b) heating the mix of step a) to a phase assembly temperature in the range of 40 - 99 DEG C, preferably 45 - 95 DEG C, more preferably 65 - 85 DEG C with continuous mixing to obtain a microemulsion or sub-micron emulsion, c) allowing said microemulsion or sub-micron emulsion to cool, and d) adding a third part to said microemulsion or sub-micron emulsion at a temperature between 2 DEG C and said phase assembly temperature, said third part if necessary being premixed and heated until the components are dissolved and including at least one component selected from the group consisting of non-surfactant amphiphilic type compound, surfactant and water with the proviso that when the third part includes water it also includes a non-surfactant amphiphilic type compound and / or surfactant. The phase assembly temperature can be determined visually by the achievement of translucence in the composition or by measures such as conductivity which peaks and then is maintained at a plateau whilst phase assembly occurs. It has been found that whilst if a non-surfactant amphiphilic type compound such as the polyol is added together with the second part as would conventionally be the case, a microemulsion or sub-micron emulsion is not formed, by adding the so called third part, phase assembly occurs at a lower temperature than would be expected and moreover.

Description

technical field [0001] The present invention relates to a method of formulating microemulsions and submicron emulsions for cosmetic and therapeutic applications in the field of dermatology. In particular, it relates to methods of formulating stable microemulsions and submicron emulsions comprising components known to be degradable in the physical state of the formulation. The present invention also relates to cosmetic and therapeutic microemulsion and submicron emulsion compositions resulting from these methods. The present invention includes cosmetic and therapeutic methods of treatment using microemulsions and submicron emulsions, as the use of compositions resulting from said formulations in appropriate treatments. Background technique [0002] The size of the particle is critical to its ability to cross the skin barrier and release the pharmaceutically active ingredient for the treatment of the local or systemic condition of the patient concerned. As the particles beco...

AI Technical Summary

Problems solved by technology

In the case of poorly soluble pharmaceutical actives, the need for additives such as propylene glycol that can aid in penetration is evident, but conversely, reduce the ease of preparation of microemulsions

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