HPLC‐Determination of some Antiinflammatory, Weak Analgesic and Uricosuric Drugs in Human Blood Plasma and its Application to Pharmacokinetics

Abstract

HPLC-determination of naproxen, indomethacin, ketoprofen, fenoprofen, ibuprofen, diclofenac sodium, tolfenamic acid, phenylbutazone, mofebutazone, salicylic acid, acetylsalicylic acid, phenacetin, paracetamol, sulfinpyrazone and probenecid by means of an adjustable, rapid, accurate and specific method is described. Plasma samples of 0.2 ml were deproteinised and the drugs extracted simultaneously with pure acetonitrile. Aliquots of 25 p1 of this primary extract were directly injected on the column. As elution solvent for drug screening was basically used 55% methanol in 50 mMphosphate buffer at pH 4.0. Optimal separation of some drugs or reasonable elution times for others were obtained by varying the methanol concentration of the elution solvent or possibly its pH. The method used for individual drug determinations is very applicable for therapeutic monitoring purposes as well as for use in pharmacokinetic investigations. As an example, the practical detection limit for naproxen in plasma was about 0.2 pg ml-'. By concentrating the extract this could be lowered to about 0.04 pg ml-'. The method was applied in a study of the pharmacokinetics of naproxen in a person, who ingested a single oral dose of 2.5 mg kg-'. Pronounced two-compartment kinetics were found. V, was 0.038 1 kg-', Vdrs 0.138 1 kg-l, t % (p) 21.3 hrs, ty2 (a) 0.99 hr and ty2 (k.) 0.67 hr.

Ibuprofen, Pharmacokinetics and Pharmacodynamics in the Isolated Rabbit Heart

“…each. Ibuprofen concentrations in the samples of perfusate were determined by a HPCL method modified from a previously described method (Nielsen-Kudsk 1980). The chromatographic equipment used included a Waters" p Bondapack CIS column (180 x 3.9 mm), a U6K loopinjector, a model 6000A pump system and an extended wavelength absorbance detector operating at 214 nm.…”

Development and Validation of Liquid Chromatography- Mass Spectroscopy/Mass Spectroscopy Method for Quantitative Analysis of Naproxen in Human Plasma after Liquid-Liquid Extraction

“…Most of its therapeutic activity is probably mediated through prostaglandin synthesis inhibition [6][7][8]. Several chromatographic methods have been reported for determination of naproxen in raw material [9], tablets [10][11][12], plasma [13][14][15], urine [16], intestinal perfusion samples [17] and pharmaceutical preparations [18][19][20].…”

A Validated Stability-Indicating UHPLC Method for Determination of Naproxen and Its Related Compounds in Bulk Drug Samples

“…Naproxen is cited in the European Pharmacopoeia to have contamination by compounds A, B, D, E [5,6] and Imp-C is likely to be present in the preparation of Naproxen by using asymmetric hydrogenation step process [7]. A survey on literature reveals that many chromatographic methods have been reported for the determination of Naproxen in raw material [8], tablets [9,10], plasma [11][12][13], urine [14], intestinal perfusion samples [15] and pharmaceutical preparations [16]. However, no stability indicating UHPLC method is reported for estimation of related compounds and assay of naproxen from bulk drug samples.…”