Stable Oxadiazole Crystal Forms for Suspension Fungicide Stability
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Solution Overview
Problem
Existing formulations of oxadiazole derivatives used in agrochemicals are unstable, leading to unwanted crystal growth and equipment blockages due to polymorphic conversion, affecting the stability and efficacy of suspension concentrate formulations.
Innovation Solution
Development of stable crystalline forms of oxadiazole derivatives, characterized by specific X-ray diffraction patterns and unit cell parameters, which are incorporated into agrochemical compositions to maintain formulation stability and prevent equipment blockages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing oxadiazole derivative formulations are used, then fungicidal activity is achieved, but formulation stability deteriorates due to polymorphic conversion and crystal growth
Solution Approach 1:
The patent applies parameter changes by identifying and characterizing specific polymorphic forms (Polymorph A, B, C, D, E) with distinct X-ray diffraction patterns, unit cell parameters, and melting points. By selecting specific polymorphic forms with superior stability characteristics and controlling crystallization conditions, the formulation maintains consistent crystal structure without unwanted polymorphic conversion, thereby resolving the contradiction between reliability and compositional stability.
Solution Approach 2:
The patent employs preliminary action by pre-characterizing and selecting stable polymorphic forms before formulation development. The detailed characterization of polymorphic forms including XRD patterns, DSC thermograms, and unit cell parameters allows the selection of thermodynamically stable forms that resist conversion during storage and application, preventing crystal growth issues before they occur.
2Reliability
If stable crystalline forms are used, then formulation stability is improved, but manufacturing complexity increases due to precise crystallization control requirements
Solution Approach 1:
The patent resolves the manufacturing complexity issue by establishing specific parameter ranges for crystallization including temperature zones, solvent types, and cooling rates that reliably produce the desired stable polymorphic forms. By defining these parameters, the process becomes more controllable and reproducible despite the need for precise crystallization control.
Solution Approach 2:
The patent uses solvent selection as an intermediary to control polymorphic form generation. Specific solvents and solvent combinations are identified as mediators that guide crystallization toward desired stable polymorphic forms, simplifying the control process by using the solvent as a controllable variable rather than requiring direct manipulation of multiple crystallization parameters simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The stable crystalline forms ensure formulation stability, reduce impurities, and enhance the efficacy of agrochemicals, preventing blockages and maintaining effective pest control in agricultural applications.
Implementation Method 1
New solid forms of this compound and its isomers, their compositions and methods of their preparation and use have now been discovered
Implementation Method 2
a polymorph of a compound of formula (I-A) and a polymorph of a compound of formula (I-B) is disclosed
Implementation Method 3
powder X-ray diffraction (pXRD) techniques are often used
Implementation Method 4
characterized by an X-ray diffraction pattern comprising four or more 2-theta angle values
Data Source
AI summary
The invention relates to crystalline forms of compounds of formula (I-A) and (I-B)(I-A)(I-B) compositions comprising said crystalline forms and methods of their use as fungicides.