title: Effects of compounding and storage conditions on stability of pergolide mesylate.
abstract: OBJECTIVE
  To determine the effects of temperature and light over a 35-day period on stability of pergolide mesylate after compounding in an aqueous vehicle.
  
  
  METHODS
  Evaluation study.
  
  
  METHODS
  Pergolide was compounded into a formulation with a final target concentration of 1 mg/mL. Aliquots of the formulation were then stored at -20 degrees, 8 degrees, 25 degrees, or 37 degrees C without exposure to light or at 25 degrees C with exposure to light for 35 days. Samples were assayed in triplicate by means of high-pressure liquid chromatography immediately after compounding and after 1, 7, 14, 21, and 35 days of storage.
  
  
  RESULTS
  Mean+/-SD concentration of pergolide in the formulation immediately after compounding was 1.05+/-0.086 mg/mL. Samples exposed to light while stored at 25 degrees C had undergone excessive degradation by day 14, samples stored at 37 degrees C had undergone excessive degradation by day 21, and samples stored at 25 degrees C without exposure to light had undergone excessive degradation by day 35. The decrease in expected concentration corresponded with the appearance of degradation peaks in chromatograms and with a change in color of the formulation.
  
  
  CONCLUSIONS
  Results indicated that pergolide mesylate was unstable after compounding in an aqueous vehicle and that storage conditions had an effect on stability of the compounded formulation. Compounded pergolide formulations in aqueous vehicles should be stored in a dark container, protected from light, and refrigerated and should not be used >30 days after produced. Formulations that have undergone a color change should be considered unstable and discarded.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Davis
authors.forename: Loren Madden
authors.initials: LM
authors.lastname: Kirk
authors.forename: Gigi S
authors.initials: GS
authors.lastname: Davidson
authors.forename: Mark G
authors.initials: MG
authors.lastname: Papich
mesh_terms: D000284:Administration, Oral; D000818:Animals; D018491:Dopamine Agonists / Q000737:chemistry / Q000592:standards* / Q000627:therapeutic use; D004339:Drug Compounding / Q000379:methods / Q000592:standards / Q000662:veterinary*; D004355:Drug Stability; D004356:Drug Storage / Q000592:standards*; D006734:Horse Diseases / Q000188:drug therapy; D006736:Horses; D008027:Light; D010479:Pergolide / Q000737:chemistry / Q000592:standards* / Q000627:therapeutic use; D019999:Pharmaceutical Solutions / Q000737:chemistry / Q000592:standards* / Q000627:therapeutic use; D047748:Pituitary ACTH Hypersecretion / Q000188:drug therapy / Q000662:veterinary; D013696:Temperature; D013997:Time Factors
chemical_list: D018491:Dopamine Agonists; D019999:Pharmaceutical Solutions; D010479:Pergolide