RT Journal Article
SR Electronic
T1 Identification and Characterization of the Sulfate Precipitate in GI147211C IV Formulation
JF PDA Journal of Pharmaceutical Science and Technology
JO PDA J Pharm Sci Technol
FD Parenteral Drug Association (PDA)
SP 326
OP 329
VO 50
IS 5
A1 Tong, Wei-Qin
A1 Clark, Jerry
A1 Franklin, Michael L.
A1 Jozwiakowski, Jill P.
A1 Lemmo, Joanne B.
A1 Sisco, Jay M.
A1 Whight, Sheila R.
YR 1996
UL http://journal.pda.org/content/50/5/326.abstract
AB GI147211, a water soluble analog of camptothecin, is currently being investigated for the treatment of cancer as a topoisomerase I inhibitor. Precipitate was observed in some samples of a stability lot of the IV clinical formulation after being stored at 5°Cfor one month. The precipitate was identified as the sulfate salt of GI147211 by various techniques including Environmental Scanning Electron Microscope / Energy Dispersive X-ray (ESEM/EDX) and Ion Chromatography (IC). The cause of the precipitation was proven to be from the presence of residual sulfate ions in ammonium sulfate treated glass vials that were suspected to be improperly washed. The solubility product (Ksp) of the sulfate salt was determined in 5% dextrose solution adjusted to pH 3.5 at 5°C to mimic the clinical formulation and refrigerated storage conditions. The Ksp was also determined at 15 and 33°C to determine the temperature effect on the constant. The stoichiometry of the sulfate salt was determined by solubility experiments using HPLC and IC to be 2:1 (base/salt). Based on the stoichiometry, the Ksp was calculated to be 3.04 x 10–12, 9.27 x 1O–12 and 9.96 x 10–11 M3 at 5°C, 15°Cand33°C, respectively. Using the Ksp values, the sulfate threshold in GI147211 Injection when GI147211 sulfate precipitates was determined to be 1.3, 3.8 and 41 ppm at 5, 15 and 33°C, respectively. Further experiments demonstrated that using the proper cleaning techniques the sulfate level in the treated vials was reduced to < 1.3 ppm. The washing cycles for the vials used for clinical supplies were thereafter modified so that the sulfate precipitate would no longer be an issue.