Study on the cross-linking degree of PVPP by NMR technology and its powder compressibility

In this paper, the low-field nuclear magnetic resonance technology CPMG (Carr-Purcell-Meiboom-Gill) echo method was used to determine the cross-linking degree and cross-linking density of crospovidone (PVPP) from different manufacturers. Based on the seven physical properties of PVPP, a fingerprint spectrum (radar chart) of twenty secondary quality indicators were obtained, and three compressibility evaluation indicators, index of the parameter (IP), index of parametric profile (IPP), index of good compression (IGC) were calculated by the fingerprint spectrum. It was found that the cross-linking degree and compressibility index IP of PVPP showed a strong correlation (r=0.816) by the correlation analysis, indicating that the cross-linking degree is one of the key quality attributes for evaluating the compressibility of PVPP.