In vitro method for detecting precipitation of parenteral formulations after injection

Samuel H Yalkowsky, S. C. Valvani, B. W. Johnson

Research output: Contribution to journalArticle

47 Scopus citations


Many injectable formulations currently on the market, including diazepam and alprazolam, utilize one or more cosolvents to solubilize the active constituents. On injection into an aqueous medium, some of these components tend to precipitate. A simple procedure is described for measuring the degree of precipitation that occurs when a solubilized drug is injected. This in vitro technique was used to show that alprazolam injection shows less precipitation than diazepam injection under all tested conditions, and that the precipitation observed with diazepam can be controlled by ensuring that the formulation is injected very slowly. This simple technique also can be used during preformulation development to evaluate the relative potential for precipitation of various formulations.

Original languageEnglish (US)
Pages (from-to)1014-1017
Number of pages4
JournalJournal of Pharmaceutical Sciences
Issue number9
Publication statusPublished - 1983


ASJC Scopus subject areas

  • Molecular Medicine
  • Chemistry(all)
  • Organic Chemistry
  • Drug Discovery
  • Pharmaceutical Science
  • Pharmacology

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