Pill Identification by Imprints: S 521 Home Pill Identification by Imprints: S 521 2 results CETIRIZINE HCL 10 MG TABLET Side 1: S 521 Color: White Side 2: Shape: Rectangular (Rounded End) CETIRIZINE HCL 10 MG TABLET Side 1: S 521 Color: White Side 2: Shape: Rectangular (Rounded End) Other Popular Drug Imprint logo 272 44 69 PAD 0107 AN 521 P 50 A CG I 136 BRX 3 TR100 Relagesic L837 MYLAN AC I 13 logo and 100 logo and 5307 WATSON 151 ML 1 logo and 21 CIPRO T31 U 129 AN 351 L 65 ED UB 2172 93 5512 SANKYO L181 353 F 75 U-S 250 F 27 HYD 60 SZ 465 ATON 705 F SG 1328 VGC RI6 FL 28/10