RESUMEN
Objective: To determine the water content and water phase distribution of Xiancao prescription effervescent granules by a more rapid, accurate and non-destructive low-field NMR instrument. Methods: The standard curve equation of water content and FID signal amplitude was fitted by calibrating the FID signal amplitude of four different mass of manganese chloride solutions. Three parts of Xiancao prescription effervescent granules were obtained by dry and wet granulation to test their FID signals and calculated the water content of dry and wet granulation by the fitting standard curve equation; Then the results were compared according to decompression drying of pharmacopeia standard. Results: The water content of effervescent tablets was convenient and rapid, and the result was stable and accurate. Compared with the standard decompression drying method, the water content measured by low field NMR instrument was less than 0.3%. Conclusion: Due to the decompression drying method can’t be Xiancao prescription effervescent granules within the bound water completely dry, sum of effervescent granules particles inside bound water and free water instrument is measured by low-field NMR, which can clearly show an effective method for the study of physical properties of three different phase water molecules in the process of drug manufacturing.