Effect of pharmaceutical excipients on aqueous stability of rabeprazole sodium

Shan Ren, Mi Jin Park, Hongkee Sah, Beom Jin Lee

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


The chemical stability of a proton-pump inhibitor, rabeprazole sodium, was evaluated in simulated intestinal fluid (pH 6.8) containing various 'Generally Recognized As Safe (GRAS)'-listed excipients, including Brij® 58, Poloxamer 188, Cremophor RH40, Gelucire 44/14 and PEG 6000. After incubation at 37 and 60 °C, the amounts of rabeprazole and its degradation product, thioether-rabeprazole, were quantitated by HPLC analysis. The main degradation product was separated and characterized by LC/MS. The degradation of rabeprazole followed first-order kinetics. In the absence of any excipients, the rate constants (k) obtained at 37 and 60 °C were 0.75 and 2.78 h-1, respectively. In contrast, the addition of excipients improved its stability. Among several excipients tested in this study, Brij® 58 displayed the greatest stabilizing effect. For instance, at 37 and 60 °C, Brij® 58 reduced the k values to 0.22 and 0.53 h-1, respectively. The stabilizing mechanisms of these hydrophilic polymeric excipients with optimal HLB values could be partially explained in terms of their solubilizing efficiency and micellar formation for thioether-rabeprazole. In conclusion, rabeprazole formulations that contain suitable excipients would improve its stability in the intestinal tract, thereby maximizing bioavailability.

Original languageEnglish
Pages (from-to)197-204
Number of pages8
JournalInternational Journal of Pharmaceutics
Issue number1-2
StatePublished - 28 Feb 2008


  • Aqueous stability
  • Pharmaceutical excipients
  • Rabeprazole
  • Stabilizing mechanism
  • Thioether-rabeprazole


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