Determination of 8-Methoxypsoralen, A Photoactive Compound, in Blood by High Pressure Liquid Chromatography

Abstract

KEY WORDS: 8-Methoxypsoralen; analysis; biological fluids; high p r e s s u r e liquid c h r o m a t o g r a p h y ; vitiligo; psoriasis. C a r l V. Puglisi, J. A r t h u r F. d e Silva, a n d J o h n C. M e y e r D e p a r t m e n t of Biochemistry a n d D r u g Metabolism H o f f m a n n -L a R o c h e Inc. Nutley, N e w J e r s e y 07110 A B S T R A C T A r a p i d , s e n s i t i v e , a n d s p e c i f i c high p r e s s u r e liquid c h r o m a t og r a p h i c ( H P L C ) a s s a y w a s d e v e l o p e d f o r t h e d e t e r m i n a t i o n of 8-m e t h o x y p s o r a l e n (8-MOP) f r o m blood. T h e a s s a y involves e x t r a c t i o n of 8-methoxypsoralen i n t o n-hexane: 2-propanol (95:5) f r o m blood b u f f e r e d to pH 9. T h e o v e r a l l r e c o v e r y is 7 5 f 5.0% (S.D.), a n d t h e s e n s i t i v i t y l i m i t of d e t e c t i o n is 10-15 n g / m l of blood, using a 1 rnl s p e c i m e n . T h e a s s a y w a s used in t h e d e t e r m i n a t i o n of blood l e v e l s of 8 -m e t h o x y p s o r a l e n in a dog following i n t r a v e n o u s a n d o r a l a d m i n i s t r a t i o n of a 5 m g / k g d o s e , a n d in m a n following s i n g l e o r a l 0.56 m g / k g d o s e s of 8-MOP, t o t a l l i n g 40 mg.

Photopheresis at onset of type 1 diabetes: a randomised, double blind, placebo controlled trial

“…If needed, the individual dosage was adjusted to achieve a peak 8-MOP plasma concentration of >100 ng/ml at the start of apheresis and a concentration of >50 ng/ml in the cell solution. 8-MOP concentration was determined by a standard high pressure liquid chromatography technique 32. Mean plasma concentration at the start of apheresis was 324 ng/ml (range 50–878) and mean 8-MOP concentration of the cell solution during irradiation was 105 ng/ml (range 10–273).…”

Treatment of rheumatoid arthritis by extracorporeal photochemotherapy. A pilot study

“…The total volume is then passed as a 1-mm film through a 6-chambered disposable sterile cassette, in order to expose it to ultraviolet A energy, delivered by a fluorescent source. Lethal damage to lymphocytes requires a methoxsalen concentration of 50 ng/ml (this minimum level is confirmed in each patient's serum [8] before the initial treatment) in the presence of 1-2 J of ultraviolet A energy per square centimeter of surface area (9). After exposure, the irradiated cells are reinfused into the patient.…”

Automated liquid–liquid extraction based on 96-well plate format in conjunction with ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) for the quantitation of methoxsalen in human plasma

“…Several methods are reported in literature for the determination of 8-methoxsalen in biological matrices based on HPLC [7][8][9][10][11][12] and GC [13][14][15]. These published methods either involve cumbersome sample preparation steps or are insufficiently sensitive or precise to perform 8-MOP analysis during photochemotherapy.…”