Rare earth compound, obtained by preparing a rare earth compound with a known contamination, determining the purity by Roentgen diffraction pattern and purifying the compound, useful for treating hyperphosphatemia

摘要

Rare earth compound, obtained by a procedure comprising: (i) preparing a raw rare earth compound with a known contamination that dissociates in aqueous media; (ii) determining the purity of rare earth compound, which comprises (a) creating a Roentgen diffraction pattern, (b) providing a set of reference samples, which contain the contamination, (c) creating a set of Roentgen diffraction patterns, and (d) Rietveld analyzing of the Roentgen diffraction pattern; (iii) purifying the rare earth compound and repeating the step (ii). Rare earth compound, obtained by a procedure comprising: (i) preparing a raw rare earth compound with at least a known impurities that dissociates in aqueous media; (ii) determining the purity of the raw rare earth compound, which comprises (a) creating a Roentgen diffraction pattern of the impurities, (b) providing a set of reference samples, which contain the impurities, (c) creating a set of Roentgen diffraction patterns of the reference samples, and (d) carrying out a Rietveld analysis of the Roentgen diffraction patterns, in order to obtain the detection limit, minimum quantitation limit (MQL) and/or the analytic upper limit from the reference samples and the value of the precalculated concentration of impurities from the sample of the rare earth compound; (iii) purifying the rare earth compound and repeating the step (ii) when the rare earth compound contains the contamination or the impurities in a quantity, which is larger than the MQL. Independent claims are included for: (1) a lanthanum carbonate, obtained by the above method using raw lanthanum carbonate; and (2) a medicament comprising lanthanum hydroxycarbonate form (I) that has a Roentgen powder diffraction pattern with peaks of 17.7[deg], 24.4[deg] and 30.3[deg] 2-theta, where the lanthanum hydroxycarbonate content of the composition is at least 96% of lanthanum hydroxycarbonate form (I). ACTIVITY : Metabolic. MECHANISM OF ACTION : None given.