Determination of the Molecular Weight and Its Distribution of Low Molecular Weight Hypromellose

OBJECTIVE To determine the molecular weight and its distribution of low molecular weight hypromellose. METHODS High performance size exclusion chromatograghy in conjunction with refractive index detector and eighteen-angle laser light scatter detector(HPSEC-RID-MALLS), was performed on the Shodex OHpak SB-804HQ(8.0 mm×300 mm) column, using 0.1 mol·L^-1 sodium nitrate-methanol(95：5) as mobile phase. RESULTS The error of the weight-average molecular weight of low molecular weight hypromellose was ≤2%, and the error of number-average molecular weight and molecular weight distribution of low molecular weight hypromellose were ≤5%. The results were accurate and reliable. CONCLUSION It can be used to determine the molecular weight and its distribution of low molecular weight hypromellose by HPSEC-RID-MALLS．