Patent ID: 8039631

Claim:
A process for preparing Crystalline Form A of Lansoprazole, which comprises dissolving Lansoprazole obtained by oxidation of 2-([3-methyl-4-(2,2,2-trifluoroethoxy) -2-pyridinyl]-methy)thio-1H-benzimidazole in ethanol, adding water, stirring the mixture at the temperature range of from 15 to 40° C. for 0.5 to 4 hours, filtering, and drying, said Crystalline Form A of Lansoprazole having the following X-ray powder diffraction peaks: No. 2Theta d I (cps) I/lo FWHM 1: 5.6400 15.6569 9945 1000 0.2200 2: 11.3200 7.8101 2384 226 0.2200 3: 12.6800 6.9755 1174 98 0.2200 4: 13.2200 6.6917 759 55 0.1800 5: 13.5000 6.5536 678 46 0.1400 6: 14.1400 6.2583 4008 391 0.2200 7: 14.8600 5.9567 468 27 0.2000 8: 16.8000 5.2729 9148 920 0.2200 9: 17.4400 5.0808 97 892 0.2200 10: 18.5200 4.7870 3420 329 0.2600 11: 19.1600 4.6284 161 57 0.4000 12: 22.2400 3.9940 5738 569 0.2200 13: 22.8000 3.8972 2883 273 0.2000 14: 23.3800 3.8018 2369 221 0.2200 15: 24.8600 3.5786 3762 356 0.2400 16: 25.4600 3.4957 2871 259 0.2600 17: 25.8200 3.4477 3309 303 0.2200 18: 26.6600 3.3410 655 270 0.2000 19: 27.3000 3.2641 1043 68 0.1400 20: 27.6800 3.2201 2700 240 0.2400 21: 28.6400 3.1143 1849 158 0.4000 22: 29.2900 3.0559 503 23 0.2000 23: 30.1800 2.9588 1543 134 0.2200 24: 30.5600 2.9229 1166 96 0.1800 25: 31.1400 2.8698 2145 199 0.2200 26: 31.5600 2.8325 500 31 0.1600 27: 32.9800 2.7138 944 77 0.2400 28: 33.4400 2.6775 944 76 0.2200 29: 33.8600 2.6452 407 20 0.1600 30: 34.5400 2.5947 1151 97 0.2200 31: 34.9800 2.5630 745 55 0.2800 32: 35.9400 2.4967 706 50 0.3600 33: 36.7200 2.4455 527 30 0.2200 34: 37.5000 2.3964 649 42 0.2200 35: 37.9400 2.3696 526 30 0.2200 36: 38.5200 2.3352 513 28 0.2600 37: 39.3800 2.2862 975 75 0.2400.