Pharma | Determination of the K-value of Povidone
This report highlights the ability of Lovis to produce consistent and reliable data for quality control of povidone when combined with a DMA density meter and an optional Xsample module in accordance with the European Pharmacopeia.
Povidone (polyvinylpyrrolidone, PVP) is a water-soluble synthetic polymer obtained by polymerization of N-vinylpyrrolidone. It is widely used in pharmaceutical formulations due to its excellent binding, film-forming, stabilizing, and solubilizing properties. Depending on its molecular weight, Povidone grades exhibit different viscosities, which directly influence tablet hardness, disintegration behavior, solution stability, and dissolution rate. Since these functional characteristics depend on polymer chain length, the K-value serves as a critical quality control parameter for ensuring consistent excipient performance.
Requirements according to Ph. Eur.
The European Pharmacopoeia monograph 0685 Povidone defines the K-value as a mandatory identifier for characterizing polymer chain length and consequently, the performance of the material. The monograph prescribes the determination of relative viscosity, from which the K-value is calculated according to the equation for the K-value as described in the monograph. To ensure reproducible and compliant results, precise temperature control, accurate runtime measurement, and stable hydrodynamic conditions are essential.
Dilute solution viscometry using Lovis
The rolling-ball principle of Lovis 2001 enables precise, low-volume viscosity measurements with excellent temperature stability and high repeatability.
This combined with the integrated polymer software allows for determining the relative viscosity and K-value of Povidone solutions as described in Ph. Eur. monograph 0685 for Povidone.
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