-80 °C in five different aliquots. The busulfan concentra- tion in one aliquot was measured within 48 h of storage (IS). The other four aliquots were analyzed after 3 months, 6 months, 1 year, and 2 years of storage at -80 °C, respectively. The AUC was calculated as mentioned ear- lier. Good correlation was found between busulfan con- centrations obtained for the IS and for the other aliquots after storage with a maximum decrease of 7.8% at 2 years (Table 1B). The decrease in AUC values was 4.7%, 6.9%, and 7.3% at 6, 12, and 24 months, respectively. These data suggest that plasma samples collected for busulfan assay can be stored at -80 °C for up to 6 months with a 5% reduction in concentration and AUC and a 10% reduc- tion in these values for up to 2 years. Henner et al (13 ) reported that plasma samples supplemented with 0.5–20 mol/L busulfan and stored at -20 °C for 0, 16, and 57 days showed values identical to that of the plasma sample analyzed immediately after the addition of busulfan ( 5%). Our data show that busulfan concentrations in plasma samples stored at -80 °C are stable for up to 2 years. In conclusion, we have shown that busulfan concentra- tions are stable in whole blood for 24 h at 4 °C and in plasma for 2 years at -80 °C. There is a 5% variation in concentration and AUC if plasma is isolated within 6 h of blood collection and analyzed within 6 months of storage. These data will be very useful for evaluation of busulfan kinetics in situations where sample analysis cannot be undertaken immediately. This study was supported by an Indian Council of Med- ical Research Grant for the project “Advanced Center for Bone Marrow Transplantation for Thalassaemia in India” (56/2/93-BMS II). References 1. Santos GW, Tutschka PJ, Brookmeyer R, Saral R, Beschorner WE, Bias WB, et al. Marrow transplantation for acute non-lymphocytic leukemia after treatment with busulfan and cyclophosphamide. N Engl J Med 1983;309: 1347–53. 2. Hobbs JR, Hugh Jones K, Shaw PJ, Downie CJ, Williamson S. Engraftment rates related to busulfan/cyclophosphamide dosages for displacement marrow transplantation in 50 children. Bone Marrow Transplant 1986;1: 201– 8. 3. Lucarelli G, Galimberti M, Polchi P, Angelucci E, Baronciani D, Giardini C, et al. Bone marrow transplantation in patients with thalassemia. N Engl J Med 1990;322:417–21. 4. Nespoli L, Locatelli F, Zecca M. Busulfan as part of conditioning regimen for bone marrow transplantation in children. Bone Marrow Transplant 1991; 8(Suppl 1):30 –2. 5. Copelan EA, Biggs JC, Thompson JM, Crilley P, Szer J, Klein JP, et al. Treatment of acute myelocytic leukemia with allogeneic bone marrow transplantation following preparation with BU-CY2. Blood 1991;78:838 – 43. 6. Dix SP, Wingard JR, Mullins RE, Jerkunica I, Davidson TG, Gilmore CE, et al. Association of busulfan area under the curve with veno-occlusive disease following BMT. Bone Marrow Transplant 1996;17:225–30. 7. Grochow LB, Jones RJ, Brundrett RB, Braine HG, Chen TL, Saral R, et al. Pharmacokinetics of busulfan: correlation with veno-occlusive disease in patients undergoing bone marrow transplantation. Cancer Chemother Phar- macol 1989;25:55– 61. 8. Vassal G, Koscielny S, Challine D, Valteau-Couanet D, Boland I, Deroussent A, et al. Busulfan disposition and hepatic veno-occlusive disease in children undergoing bone marrow transplantation. Cancer Chemother Pharmacol 1996;37:247–53. 9. Vassal G, Deroussent A, Challine D, Hartmann O, Koscielny S, Valteau- Couanet D, et al. Is 600 mg/m 2 the appropriate dosage of busulfan in children undergoing bone marrow transplantation? Blood 1992;79:2475–9. 10. Chattergoon DS, Saunders EF, Klein J, Calderwood S, Doyle J, Freedman MH, Koren G. An improved limited sampling method for individualised busulfan dosing in bone marrow transplantation in children. Bone Marrow Transplant 1997;20:347–54. 11. Schuler U, Schroer S, Kuhnle A, Blanz J, Mewes K, Kumbier I, et al. Busulfan pharmacokinetics in bone marrow transplant patients: is therapeutic drug monitoring warranted? Bone Marrow Transplant 1994;14:759 – 65. 12. Quernin MH, Poonkuzhali B, Medard Y, Dennison D, Srivastava A, Krish- namoorthy R, et al. High-performance liquid chromatographic method for quantification of busulfan in plasma after derivatization by tetrafluorothio- phenol. J Chromatogr B 1999;721:147–52. 13. Quernin MH, Poonkuzhali B, Montes C, Krishnamoorthy R, Dennison D, Srivastava A, et al. Quantification of busulfan in plasma by gas chromatog- raphy-mass spectrometry following derivatization with tetrafluorothiophenol. J Chromatogr B 1998;709:47–56. 14. Heinzel G, Woloszezak R, Thoman P. Pharmacokinetic pharmacodynamic data analysis system for the PC. Sturtgart, Germany: Gustav Fischer, 1993. 15. Henner WD, Furlong EA, Flaherty MD, Shea TC, Peters WP. Measurement of busulfan in plasma by HPLC. J Chromatogr 1987;416:426 –32. Gas Chromatographic–Mass Spectrometric Measure- ment of 15-Deoxy- 12,14 -prostaglandin J 2 , the Peroxi- some Proliferator-activated Receptor  Ligand, in Urine, Chantal The ´venon, Michel Guichardant, and Michel Lagarde * (INSERM U352, Biochimie and Pharmacologie INSA- Lyon, Bldg. Louis Pasteur, 20 Avenue A. Einstein, 69621 Villeurbanne, France; * author for correspondence: fax 33-4-72-43-85-24, e-mail michel.lagarde@insa-lyon.fr) Prostaglandin D 2 (PGD 2 ) together with its positional isomer PGE 2 is a direct metabolite of PGH 2 arising from the dioxygenation of arachidonic acid (1). More than 15 years ago, PGJ 2 , the 9-deoxy derivative of PGD 2 via dehydration, was identified and described as a mitogen (2). Later, the  12 isomer of PGJ 2 was found in human urine (3). A new dehydration product of PGJ 2 , 15-deoxy- 12,14 - PGJ 2 (15dPGJ 2 ), has been described as a specific ligand of peroxisome proliferator-activated receptor , which is associated with adipocyte differentiation (4, 5). Consider- able interest has arisen in cyclopentenone derivatives of prostaglandins (6), particularly 15dPGJ 2 , which has been described as an active compound in cancer (7, 8) and in cell apoptosis (9, 10), in addition to adipogenesis (11 ). 15dPGJ 2 has recently been reported to have antiinflam- matory activity (12 ). Indeed, it prevents cytokine- and endotoxin-stimulated activation of peripheral and resi- dent tissue macrophages and cytokine-induced inducible nitric oxide synthase expression in B cells by inhibition of transcriptional activation and induction of the heat-shock response. Despite the growing interest in this prostaglandin me- tabolite, no reliable assay has been reported, especially by gas chromatography–mass spectrometry (GC-MS), a ref- erence method for prostanoids (13 ). The lack of such an assay presumably reflects the difficulty in derivatizing this peculiar prostaglandin, which has three conjugated double bonds with the ketone group. We report here a 768 Technical Briefs Downloaded from https://academic.oup.com/clinchem/article/47/4/768/5639130 by guest on 06 April 2022