Compound crystal, preparation method and application

[0031] After mixing Favipiravir and p-aminobenzoic acid uniformly at a molar ratio of 1:1, take about 2 g of solid, add about 0.5 ml of ethyl acetate, and grind manually in a mortar for 30 minutes. The samples were dried in a forced air oven at 30°C. The resulting product is analyzed by XRD and is a co-crystal of Favipiravir-p-aminobenzoic acid.

[0033] After mixing Favipiravir and p-aminobenzoic acid uniformly at a molar ratio of 1:1, take about 2g of solid, add 10ml of methyl tert-butyl ether, and suspend and stir with magnetic stirring at room temperature for 72h-96h. After the sample was filtered, the obtained solid was dried in a blast drying oven at 60°C. Gained solid shows through XRD analysis, is the eutectic of favipiravir-p-aminobenzoic acid.

[0035] Take 0.6g of p-aminobenzoic acid, add 50ml of ethyl acetate, dissolve after heating. Then add 0.456g of Favipiravir and stir for 2h. After the solid was filtered, it was air-dried at 40°C. XRD analysis showed that it was a co-crystal of favipiravir-para-aminobenzoic acid.