1: Antimicrob Agents Chemother  2002 Aug;46(8):2327-32 

Comparative stability studies of antipseudomonal beta-lactams for potential
administration through portable elastomeric pumps (home therapy for cystic
fibrosis patients) and motor-operated syringes (intensive care units).

Viaene E, Chanteux H, Servais H, Mingeot-Leclercq MP, Tulkens PM.

Unite de Pharmacologie Cellulaire et Moleculaire, Universite Catholique de
Louvain UCL 73.70, Avenue E. Mounier 73, B-1200 Brussels, Belgium.

The stability of antipseudomonal beta-lactams in concentrated solutions was
examined in view of their potential administration by continuous infusion with
external pumps (for intensive care patients) or with portable pumps carried
under clothing (for cystic fibrosis patients). Aztreonam (100 g/liter),
piperacillin (128 g/liter, with tazobactam), and azlocillin (128 g/liter)
remained 90% stable for up to more than 24 h at 37 degrees C (mezlocillin [128
g/liter] was stable at 25 degrees C but not at 37 degrees C). Ceftazidime (120
g/liter), cefpirome (32 g/liter), and cefepime (50 g/liter) remained 90% stable
for up to 24, 23.7, and 20.5 h at 25 degrees C but only for 8, 7.25, and 13 h at
37 degrees C, respectively. The control of temperature therefore appears to be
critical for all three cephalosporins that cannot be recommended for use in
portable pumps carried under clothes for prolonged periods for reasons of
stability. Cefpirome and cefepime solutions developed an important color change
(from light yellow to dark red) upon exposure when stored at 30 degrees C or
higher. Degradation of ceftazidime was accompanied by the liberation of pyridine
which, at 37 degrees C, was in excess of what is allowed by the U.S.
Pharmacopeia, i.e., 1.1 mg/liter, after 8 and 12 h for drug concentrations of 12
and 8.3%, respectively. Imipenem and meropenem are too unstable (10% degradation
at 25 degrees C after 3.5 and 5.15 h, respectively) to be recommended for use by
continuous infusion. Faropenem, examined in comparison with imipenem and
meropenem, proved as stable as aztreonam or piperacillin.

PMID: 12121900 [PubMed - indexed for MEDLINE]