Pharmacopsychiatry 2005; 38 - 73
DOI: 10.1055/s-2005-862686

Storage and Transport Stability of New Antidepressant and Antipsychotic Drugs

A Rieger-Gies 1, S Heller 1, G Stroba 1, E Daum-Kreysch 1, J Sachse 1, S Härtter 1, C Hiemke 1
  • 1Department of Psychiatry, University of Mainz, Germany

Information on the stability of drugs in human serum or plasma is scarce and drug decomposition during transport without any additional cooling or preservatives cannot be ruled out.

We analysed the stability of plasma samples under three different conditions:

Storage at room temperature (RT): All samples were left at RT for 14 days and concentration were analysed at baseline and after 1, 3, 7 and 14 days.

Storage at –20°C with repeated thawing and freezing: Sames were thawed, quantitatively analysed at baseline and after 1, 3, 6, and 12 months and refrozen after each analysis.

Storage at –20°C without repeated thawing and freezing: Samples were divided into aliquots (1ml plasma) and frozen at –20°C. The aliquots were thawed and analysed at baseline, after 2 weeks and after 1, 3, 6 and 12 months.

Drug concentrations in plasma were analysed by established HPLC methods with on-line sample pretreatment and either UV/vis (amisulpride, clozapine, olanzapine, quetiapine, reboxetine, and sertraline) or fluorescence (venlafaxine) detection. Single determinations were conducted to imitate the conditions for the analysis of patients' serum samples.

With the exception of olanzapine, all drugs investigated were stable even at RT. Repeated thawing and freezing had no effect. Without preservation storage at RT for one week did not affect drug concentrations in blood. Olanzapine in serum, however, was degraded after 7 days at RT. Using control samples which were stored frozen (–20°C), the analyses of external controls over 12 months were within the±1 within-laboratory standard deviations from the consensus mean. In case of olanzapine, the decomposition was observed at RT

Since no effect on the concentration was observed for the antipsychotics and antidepressants assessed, transport by regular mail lasting up to 7 days seems possible without freezing. One should be aware of lowered olanzapine concentrations if the transport at RT lasts longer than 3 days.