Crospovidone Impurity – A

1-ethenylpyrrolidin-2-one (1-vinylpyrrolidin-2-one). ◊FUNCTIONALITY-RELATED CHARACTERISTICS This section provides information on characteristics that are recognised as being relevant control parameters for one or more functions of the substance when used as an excipient (see chapter 5.15). Some of the characteristics described in the Functionality-related characteristics section may also be present in the mandatory part of the monograph since they also represent mandatory quality criteria. In such cases, a cross-reference to the tests described in the mandatory part is included in the Functionality-related characteristics section. Control of the characteristics can contribute to the quality of a medicinal product by improving the consistency of the manufacturing process and the performance of the medicinal product during use. Where control methods are cited, they are recognised as being suitable for the purpose, but other methods can also be used. Wherever results for a particular characteristic are reported, the control method must be indicated. The following characteristics may be relevant for crospovidone used as disintegrant. Hydration capacity. Introduce 2.0 g into a 100 mL centrifuge tube and add 40 mL of water R. Shake vigorously until a suspension is obtained. Shake again 5 min and 10 min later, then centrifuge for 15 min at 750 g. Decant the supernatant and weigh the residue. The hydration capacity is the ratio of the mass of the residue to the initial mass of the sample. It is typically 3 to 9. Particle-size distribution (2.9.31). Powder flow (2.9.36). The following characteristic may be relevant for crospovidone used as suspension stabiliser. Settling volume. Introduce 10 g into a 100 mL graduated cylinder and add 90 mL of water R. Shake vigorously. Dilute to 100 mL with water R, washing the powder residues from the walls of the cylinder. Allow to stand for 24 h, then read the volume of the sediment. It is typically greater than 60 mL.◊