EVALUATION OF POLYMORPHS IN CEPHALEXIN MEDICINES BY C SOLID STATE NMR

摘要

In.this.study.the.presence.of.cephalexin.polymorphs.in.four.commercial.medicines.was.evaluated..The.samples.were.analyzed.using.X‐ray.powder.diffraction.(XRPD),.Fourier.transform. infrared.spectroscopy. (FTIR).and.solid.state.13C.NMR. spectroscopy.(CPMAS. NMR)..The. crystalline. pattern.obtained.by.XRPD.analyses.for.two.medicines.are.very.similar.to.the.cephalexin.monohydrate.reference.sample..FTIR.was.not.capable.to.distinguish.between. the. medicine.samples,.although.one.was.showed. to.be. amorphous.by.XRPD..In.contrast,.1 3C. solid. state.NMR. evidenced. the. differences.between.the.samples.studied.and.confirmed.that.in.those.medicines.the.cephalexin.monohydrate.is.the.polymorph.present.in.higher.amount