TY706 Crystal Form A Stability via Controlled Crystallization

The patent applies parameter changes by controlling crystallization conditions including solvent type, temperature, pH value, and addition rate to obtain a stable crystal form (Form A) of TY706. This resolves the contradiction by transforming the amorphous or fluctuating solid obtained by simple evaporation into a well-defined crystal structure with consistent appearance and properties across batches.

The patent utilizes phase transitions through controlled crystallization from solution to transform the compound from an amorphous or unstable solid state into a stable crystal form. The crystallization process involves nucleation and crystal growth phases that produce consistent physical form and appearance, resolving the batch-to-batch variability issue.

The patent applies preliminary action by performing crystallization before final product isolation. The crystallization step pre-purifies the compound by incorporating impurities into the mother liquor rather than having them co-evaporate with the product. This preliminary purification action ensures high and consistent purity while maintaining efficient production.

The crystallization process exploits phase transitions to separate the pure compound from impurities. As the solution cools or solvent evaporates during controlled crystallization, the pure compound crystallizes out while impurities remain in solution, achieving both high purity and consistent quality across batches.

The patent merges the purification and form stabilization steps into a single crystallization operation. The controlled crystallization process simultaneously achieves impurity removal, consistent appearance, and stable physical form, eliminating the need for separate purification and drying steps that would otherwise be required.

The patent optimizes crystallization parameters (solvent selection, temperature profile, pH control, addition rate) to achieve stable crystal formation in a single step. By carefully controlling these parameters, the process achieves both purification and form stabilization without requiring multiple sequential operations, thus limiting the increase in process complexity.