Successfully formulating active ingredients with low water solubility into aqueous formulations is challenging due to the need to control crystal nucleation and growth.  Often formulated as aqueous dispersions in the form of suspension concentrates, these compounds can increase in particle size over time, limiting shelf-life.<br/> <br/>We report the development of novel polyalkoxylated amino alcohols that provide control of crystal nucleation and growth upon dilution in water from water miscible solvents.  Specifically, we demonstrate the inhibition of crystal nucleation and growth of two actives (pyraclostrobin and difenoconazole) upon dilution in water at concentrations 30 – 50X greater than their water solubility limit.  The inhibition of crystal growth is maintained for &gt;24 hours at room temperature when the polymer, solvent, and active are combined prior to dilution in water.  Synthesized using a high throughput parallel pressure reactor, the produced new polyalkoxylated amino alcohol polymers featured systematic variation in the initiator, hydrophobic block length, and hydrophilic block length.  Combined with variations in polymer-to-active ratio in the formulation, the experiments were designed to develop an initial understanding of the structure/property relationships necessary to inhibit nucleation of actives in aqueous solution using polymers that associate with the actives.  The formulations containing a water-miscible solvent, active, and polymer were diluted into water before being continuously analyzed for the onset of turbidity as a function of the height of the solution and time elapsed.<br/><br/>Multiple polymers inhibited nucleation and growth for each active tested, as determined by the solution maintaining an optically clear appearance for the duration of the test.  Initial observations suggest that besides the polymer:active ratio, there is a strong dependence on the functional groups present in the initiator in determining the polyalkoxylated amino alcohol polymer’s ability to inhibit crystal growth.

Crystal nucleation inhibition of poorly water soluble actives using novel alkoxylated amino alcohol polymers

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