title: Long-term stability of extemporaneously prepared captopril oral liquids in glass bottles.
abstract: OBJECTIVE
  The long-term stability of captopril in extemporaneously prepared oral liquids was studied.
  
  
  METHODS
  Captopril solutions of 1 and 5 mg/mL were prepared in sterile water for irrigation with sorbitol, disodium edetate, and sodium benzoate. The samples were stored in 100-mL amber glass bottles with a headspace of air at 22 degrees C for 12 months. The captopril concentration was determined by high-performance liquid chromatography at 0, 3, 6, 9, and 12 months. The pH of the solutions was also measured, and the physical appearance was recorded. The stability of the 1-mg/mL captopril preparation during 1 month of simulated use when stored at 2-8 degrees C was tested at the start and the end of the 12-month study period. Chemical stability was defined as retention of at least 90% of the initial captopril concentration. The microbiological quality of the preparations was tested at 0, 6, and 12 months (1 mg/mL) and 0 and 12 months (5 mg/mL).
  
  
  RESULTS
  Throughout the 12-month study period, the captopril concentration in the oral liquids exceeded 90% of the initial concentration. The lowest concentration (98.5%) was detected in the 5-mg/mL preparation after 3 months of storage. The 1-mg/mL preparation was stable during 1 month of simulated use, both at the start and the end of the 12-month study period. No microbiological growth was observed in any of the samples tested.
  
  
  CONCLUSIONS
  Extemporaneously prepared oral liquid formulations of captopril 1 and 5 mg/mL were chemically stable when stored in glass bottles at room temperature for 12 months when stabilized with 0.1 mg/ mL disodium edetate at a low pH.
authors.affiliation: Rikshospitalet University Hospital, Oslo, Norway. jorgen.brustugun@sykehusapotekene.no
authors.forename: Jørgen
authors.initials: J
authors.lastname: Brustugun
authors.forename: Yvonne Elisabeth
authors.initials: YE
authors.lastname: Lao
authors.forename: Charlotte
authors.initials: C
authors.lastname: Fagernaes
authors.forename: Jorunn
authors.initials: J
authors.lastname: Braenden
authors.forename: Solveig
authors.initials: S
authors.lastname: Kristensen
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry*; D002216:Captopril / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004304:Dosage Forms; D004339:Drug Compounding; D004355:Drug Stability; D004356:Drug Storage; D004864:Equipment and Supplies; D005079:Excipients; D005898:Glass; D006801:Humans; D006863:Hydrogen-Ion Concentration
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004304:Dosage Forms; D005079:Excipients; D002216:Captopril