title: [Comparison between colorimetry and HPLC on the stability test of roxithromycin].
abstract: OBJECTIVE
  To compare the stability of roxithromycin in solutions of different pH.
  
  
  METHODS
  Roxithromycin solutions of different pH were prepared with water, simulate intestinal fluid (SIF) and simulate gastric fluid (SGF) shown to be the stability of these solutions were tested by colorimetry and HPLC.
  
  
  RESULTS
  Roxithromycin was stable in water, SGF and SIF determined by colorimetry. However, it was found to be stable only in water and SIF but unstable in SGF as determined by HPLC.
  
  
  CONCLUSIONS
  Roxithromycin is unstable in acidic medium like SGF. The metabolite of roxithromycin showed unfavorable interference on the assay of roxithromycin when colorimetry was used. Colorimetry can not be used for the determination and assay of roxithromycin in acidic solution like SGF.
authors.affiliation: Division of Pharmaceutics, Shenyang Pharmaceutical University, Shenyang 110015, China.
authors.forename: Z P
authors.initials: ZP
authors.lastname: Wei
authors.forename: S R
authors.initials: SR
authors.lastname: Mao
authors.forename: D Z
authors.initials: DZ
authors.lastname: Bi
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003124:Colorimetry / Q000379:methods*; D004355:Drug Stability; D015575:Roxithromycin / Q000032:analysis* / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D015575:Roxithromycin