NSAIDs and Analgesic Drugs

Diclofenac and six metabolites (e.g., hydroxydiclofenac, dihydroxydiclofenac sul te, 4-amino-3,5-dichlorobenzene sulfonic acid) were isolated fi om urine and separated on a C, column ( = 282 nm). A 95/5 40/60 (at 20min) - 0/100 (at 22 min hold 4 min) water (10 mM ammonium formate at pH 7.0)/methanol gradient gave excellent separation. Time-of-flight MS was used to confirm peak identity [496]. 

Clonixin was extracted fiom plasma and urine and quantitated on a C g column (A = 290nm) using a 36/28/36 methanol/acetonitrile/water (0.3% acetic acid) mobile phase [497]. It is interesting to note that the elution time for a urine extract was 7.1 min, whereas that for the plasma sample was 9.8 min. No change in mobile 

Ibuprofen and its hydroxy and carboxy metabolites were extracted from plasma and urine and separated on a Cjg column (A - 220 nm) using a mobile phase consisting of 65/35 methanol/water (1 mL H3PO4/L). Separation was complete in 15 min [499]. Recoveries from spiked samples were found to be greater than 95% for plasma (1 to 500pg/mL) and greater than 85% for urine (50 to 500pg/mL). 

Acetaminophen, acetylsalicylic acid (aspirin), caffeine, and propoxyphene hydrochloride were well resolved on a C,g column (A = 254mn) using a 15/85 methanol/water (lOmM sodium acetate buffer at pH 4.1) mobile phase. Elution was complete in 12min and 500ng injections were easily detected [501]. 

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