I think you can try method that recommend by Dr. Delattre above, but doing quantitative analysis (by HPLC) you must have (authentic ) standard of sucralfate, without reference standard it is not possible to do quantitative analysis by HPLC. As far as I know you can do quantitative without any specific standard (in this case sucralfate), if you do it by Q NMR (You can use general IS)