Nanodispersions

Abstract

The invention provides process for making contra-soluble nano-dispersions of at most sparingly-soluble materials in a soluble carrier material comprising the steps of: (i) providing a single phase mixture of: a) a solvent or a mixture of miscible solvents, b) at least one carrier material soluble in solvent (a), said carrier material being also contra-soluble to payload material (c) and solid at ambient temperature, c) at least one a payload material which is soluble in solvent (a), and, (ii) drying the mixture to remove solvent (a) and thereby obtain the carrier material (b) in solid form with payload (c) dispersed therein as nanoparticles.

Description

TECHNICAL FIELD[0001]The present invention relates to dried compositions which form so-called ‘nano dispersions’ when placed in water or other solvents and deliver a material which is not normally soluble in water or said other solvent.BACKGROUND TO THE INVENTION[0002]Many potentially useful materials are insoluble or at best only sparingly soluble in water. This places significant limits on their usefulness or requires that they are used in combination with solvents which almost always more expensive than water and which may have physiological incompatibilities or environmental negatives.[0003]Our co-pending applications including GB 0501835.3 relate to the use of emulsions of immiscible solvents to prepare a poorly soluble material in a form that is rapidly dispersible. In the above-mentioned applications a ‘carrier’ material (such as a surfactant or a polymer) is dissolved in an aqueous solvent (typically water) and a water-insoluble ‘payload’ material is dissolved in a non-aqueo...

AI Technical Summary

Benefits of technology

[0021]By using the process as described herein, and an appropriate choice of carrier, it is possible to form a solid matrix that is soluble in a particular aqueous or non-aqueous solvent and which releases the payload (which is insoluble in the particular solvent dissolving the matrix) to form a liquid nano-dispersion of the payload material in the solvent.

[0032]As noted above, typical particle sizes for the dispersed form of the payload material after delivery may be determined by use, for example, of a Malvern™‘Nano-S’ apparatus. Results generally fall into the range from 500-2 nm (expressed as a diameter) and this particle size range is preferred, with 300-4 nm being particularly preferred. For comparative purposes, the range is analogous to the size of a virus particle (which typically range from 450-20 nm). The size distribution may show more than one peak. Thus, as noted above, the “solutions” obtained are not true solutions comprising a material dispersed on a molecular scale but are nano-scale dispersions in which the ‘soluble’ material retains some organized structure but on such a small scale that it has many of the properties of a true solution. For example, dispersing a water-insoluble bleach from products of the present invention results in the bleach being more finely dispersed and reduces the spot damage seen when larger water-insoluble particles of the bleach contact a fabric.

[0079]In the type I and type II process the carrier material can also be a water-soluble inorganic material which is neither a surfactant not a polymer. Simple organic salts have been found suitable, particularly in admixture with polymeric and / or surfactant carrier materials as described above. Suitable salts include carbonate, bicarbonates, halides, sulphates, nitrates and acetates, particularly soluble salts of sodium, potassium and magnesium. Preferred materials include, sodium carbonate, sodium bicarbonate and sodium sulphate. These materials have the advantage that they are cheap and physiologically acceptable. They are also relatively inert as well as compatible with many materials found in household and pharmaceutical products.Preferred Combinations of Carrier Materials:

Problems solved by technology

This places significant limits on their usefulness or requires that they are used in combination with solvents which almost always more expensive than water and which may have physiological incompatibilities or environmental negatives.

Solid solutions are believed to form only at particular component ratios and there is therefore little formulation flexibility with these systems.