A process for the preparation of crystalline form of tafamidis

A process for the preparation of Tafamidis, comprising the steps of:

• a. dissolving Tafamidis meglumine (2) in water;
• b. adjusting pH of the reaction mass with a suitable acid;
• c. adding polar aprotic solvent to the reaction mixture;
• d. separating organic layers and adding polar aprotic solvent or mixture of solvents to the organic layer;
• e. adding the reaction mixture to suitable solvent;
• f. filtering the solid and washing with suitable solvent;
• g. milling the wet material at suitable temperature;
• and
• h. drying and isolating Tafamidis

A process for the preparation of Tafamidis, comprising the steps of:

• a. providing a mixture of Tafamidis in an organic solvent;
• b. heating the reaction mass at suitable temperature;
• c. adding suitable polar aprotic solvent to the reaction mixture;
• d. adding the reaction mixture to suitable solvent;
• e. filtering the solid and washing with suitable solvents;
• f. milling the wet material at suitable temperature;
• and
• g. drying and isolating Tafamidis.

A process for the preparation of Tafamidis, comprising the steps of:

• a) milling wet material of Tafamidis solvate at suitable temperature;
• b) drying the material to remove residual solvent;
• wherein the Tafamidis obtained in step b) consists of at least one of the properties selected from a group consisting of:
• i. moisture content less than 1% (w/w);
• ii. d90 particle size of less than 100 microns;
• iii. specific surface area of less than 30 sq·m/g;
• and
• iv. total residual solvents less than 3000 ppm.