Sample preparation by salts precipitation and quantitation by high-performance liquid chromatography with uv detection of selected drugs in biological fluids

Ng, Linda

doi:10.1016/s0021-9673(01)88190-5

Cited by 23 publications

(4 citation statements)

References 18 publications

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“…Laboratory methods. Total serum naproxen and serum 6-desmethyl naproxen levels were measured using a high pressure liquid chromatography (HPLC) modification of a previously published method (19). Serum samples (0.3 ml) were first treated with 0.1 ml of 15% ZnS04, followed by 0.2 ml of saturated barium hydroxide.…”

Section: Methodsmentioning

confidence: 99%

A controlled study of concurrent therapy with a nonacetylated salicylate and naproxen in rheumatoid arthritis

Fürst

Blocka

Cassell

et al. 1987

Arthritis & Rheumatism

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Previous studies of combinations of nonsteroidal drugs used in the treatment of rheumatoid arthritis (RA) have yielded conflicting results. We used standard methods to measure disease activity and high pressure liquid chromatography to measure plasma drug concentrations. We used doses of choline magnesium trisalicylate, adjusted to achieve therapeutic serum salicylate concentrations, and naproxen in a randomized, double‐blind, placebo‐controlled cross‐over study of full dose trisalicylate (CMT), full dose naproxen (N), full dose of both (CMT‐N), and half dose of both (cmt‐n) to examine their relative efficacy and toxicity in treating RA. CMT‐N was statistically superior to all other treatments in only 1 of 12 efficacy variables, but was equal to N and better than CMT or cmt‐n for 7 variables. There were minimal differences among treatments for the other 4 efficacy variables. The mean percentage difference for the efficacy variables between CMT‐N and N was 3%, between CMT‐N and CMT was 10.6%, and between CMT‐N and cmt‐n was 10.5%. Thirteen percent of patients manifested toxic reactions during the initial open dose‐adjustment salicylate run‐in phase. During the double‐blind phases of the study, CMT‐N was more toxic than N, CMT, or cmt‐n (7.5% versus 3.4%, 1.8%, and 3.7%, respectively). Tinnitus was more common when full‐dose CMT was used; N (N or CMT‐N) was associated with increased skin toxicity. Gastrointestinal complaints were equally common with all regimens. CMT‐N, although sometimes statistically superior to CMT, N, or cmt‐n, showed no clinically important additive or synergistic effect versus N or CMT alone.

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Section: Methodsmentioning

confidence: 99%

A controlled study of concurrent therapy with a nonacetylated salicylate and naproxen in rheumatoid arthritis

Fürst

Blocka

Cassell

et al. 1987

Arthritis & Rheumatism

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“…Precipitation of serum protein. Serum protein was removed with barium sulphate (12,13) in preparation for glucose assay, i.e. the serum specimen (0.2 mL), barium sulphate solution (1 g/dL, 0.9 mL) and sodium hydroxide (1 g/dL, 0.9 mL) were added and vortex-mixed, followed by centrifugation (3000 r.p.m.)…”

Section: Determination Of Serum Glucosementioning

confidence: 99%

Determination of serum glucose by horseradish peroxidase‐catalysed imidazole chemiluminescence coupled to a micro‐flow‐injection system

Nozaki

Munesue²,

Kawamoto

2007

Luminescence

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The reactivity of flow-injection (FI)-horseradish peroxidase (HRP)-catalysed imidazole chemiluminescence (CL) was studied for continuous determination of hydrogen peroxide (H(2)O(2)) and serum glucose with immobilized glucose oxidase. Light emission by the HRP-catalysed imidazole CL was obtained when immobilized HRP, alkaline imidazole (in Tricine solution, pH 9.3) and H(2)O(2) were reacted at room temperature. The optimal pH for the CL reaction was 9.3 and the optimal concentration of imidazole was 100 micromol/L. When no imidazole was added, the light intensity of the same H(2)O(2) specimen decreased to a level that could not be quantitatively determined. The spectrum of the light emitted by imidazole CL was in the range 400-600 nm with a peak at 500 nm. The calibration equation for determination of H(2)O(2) was y = 9860x(2) + 3830x + 11,700, where y = light intensity (RLU) and x = concentration of H(2)O(2) (micromol/L). The detection limit of H(2)O(2) was 5 pmol, and the reproducibility of the H(2)O(2) assay was 2.3% of the coefficient of variation (H(2)O(2) 48 micromol/L, n = 13). The CL method was successfully applied to assay glucose after on-line generation of H(2)O(2) with the immobilized glucose oxidase column, resulting in good reproducibility (CV = 3.3% and 1.0% for the standard glucose and the control serum, respectively).

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“…Laboratory methods. Total serum naproxen and serum 6-desmethyl naproxen were measured using an Altex (San Ramon, CA) high pressure liquid chromatograph (HPLC), by a modification of a previously published method (10). Serum samples (0.3 ml) were treated with 0.1 ml of 15% zinc sulfate, followed by 0.2 ml of saturated barium hydroxide.…”

Section: Eval T Tmentioning

confidence: 99%

Serum concentrations of salicylate and naproxen during concurrent therapy in patients with rheumatoid arthritis

Fürst

Sarkissian

Blocka

et al. 1987

Arthritis & Rheumatism

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The kinetic interaction between salicylate and naproxen was investigated in 25 rheumatoid arthritis patients. Kinetic interactions were tested in serum after patients had been on each drug regimen for 1 month. Salicylate decreased serum naproxen concentration from 89.5 mg/liter to 65.9 mg/liter (P < 0.001) and increased serum naproxen clearance by 56%. Naproxen had minimal effect on serum salicylate concentrations.The pharmacokinetic interaction between salicylates (usually aspirin) and nonsteroidal antiinflammatory drugs (NSAIDs) has been investigated in single or short-term studies using normal volunteers (1-6). Salicylates decreased the area under the time-versusconcentration curve (AUC) of ketoprofen, isoxicam, ibuprofen, indomethacin, fenoprofen, and diclofenac by 8 4 8 % . In the only study of the kinetic interaction between naproxen and salicylate, 8 normal subjects were given single doses, and the AUC of naproxen was decreased by 16% (7). The majority of these drug-drug interaction studies are conducted using healthy subjects. The only study of NSAID-salicylate kinetic interaction in rheumatoid arthritis (RA) patients was an investigation of the interaction between

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Sample preparation by salts precipitation and quantitation by high-performance liquid chromatography with uv detection of selected drugs in biological fluids

Cited by 23 publications

References 18 publications

A controlled study of concurrent therapy with a nonacetylated salicylate and naproxen in rheumatoid arthritis

A controlled study of concurrent therapy with a nonacetylated salicylate and naproxen in rheumatoid arthritis

Determination of serum glucose by horseradish peroxidase‐catalysed imidazole chemiluminescence coupled to a micro‐flow‐injection system

Serum concentrations of salicylate and naproxen during concurrent therapy in patients with rheumatoid arthritis

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