Effect of water activity and temperature on the stability of creatine during storage Effect of water activity on creatine stability

Michael Uzzan, Jacob Nechrebeki, Peng Zhou, Theodore P. Labuza

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Creatine degradation to creatinine, which has no biological activity, in combinations of glycerol and pH 4.0 buffer solutions followed first-order kinetics up to a point where degradation started to level off, generally beyond the first half-life. Practical data are reported for a wide range of water activity (aw) values (0.310.983) at 4°C, 23°C, and 35°C. Creatine degradation did not exhibit a dilution effect, that is a decrease in rate about an aw of 0.7, as is found for both microbiological growth and chemical reactions in semisolid food matrix systems. The temperature dependence obeyed the Arrhenius relationship with an energy of activation of about 20 kcalmol at aw ≥ 0.68 increasing to 23 kcalmole below that aw. In addition, a semilog plot of half-life as a function of aw at each temperature follows a predicted straight line. The pH and assumed liquid viscosity increase through increased glycerol concentration were not able to completely explain the decrease in rate of degradation as a function of aw. Furthermore, we confirmed that creatine stability in the crystal form is very high as long as it does not reach the deliquescence state.

Original languageEnglish (US)
Pages (from-to)1003-1008
Number of pages6
JournalDrug Development and Industrial Pharmacy
Volume35
Issue number8
DOIs
StatePublished - Nov 9 2009

Keywords

  • Creatine
  • First-order kinetics
  • Glycerol
  • Storage stability
  • Water activity

Fingerprint Dive into the research topics of 'Effect of water activity and temperature on the stability of creatine during storage Effect of water activity on creatine stability'. Together they form a unique fingerprint.

Cite this