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Development and validation of HPLC/DAD method for simultaneously determination of six prohibited substances in model matrices

Zaharieva Zdravka, Tanev Dimitar, Danalev Dancho

Acta Chromatographica

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2020

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Vol. 32, no. 4

276--280

EN

The authorities have identified an emerging trend where over-the-counter products, represented as dietary supplements, contain hidden active ingredients that could be harmful. Consumers may unknowingly take products laced with varying quantities of approved prescription drug ingredients, controlled substances, and untested and unstudied pharmaceutically active ingredients. Hidden ingredients are increasingly becoming a problem in products promoted for sexual enhancement, weight loss, or bodybuilding. The tests have revealed the presence of some undesired substances like sildenafil, tadalafil, vardenafil, and their analogues in tainted sexual enhancement products. The content of these substances is usually around the daily curative dose. A simple high-performance liquid chromatography (HPLC) method for simultaneously determination of sildenafil, vardenafil, tadalafil, dapoxetine, yohimbine, and sibutramine was developed and validated. InfinityLab Poroshell 120 EC-C18 (150 '4.6 mm '4 μm particles) was used, as well as a diode-array detector (DAD) at 230 nm, and a gradient flow with 0.030 М ammonium acetate buffer and acetonitrile. The method is linear in the following range: 2.5–37.5 μg/mL for yohimbine, 2.06–30.9 μg/mL for vardenafil, 2.0–30.0 μg/mL for sildenafil, 3.1–46.5 μg/mL for tadalafil, 1.98–29.7 μg/mL for dapoxetine, and 2.2–66.0 μg/mL for sibutramine. The linearity coefficient is R2 = 1 for all substances. Model matrices were spiked, and the analytical recoveries for all substances are in the range 97.5%–99.5%. The method exhibited an upper hand compared with previously reported methods in terms of speed and simplicity. Additionally, the mobile phase (also used as extracting, column washing, and diluting solvent) was composed of only buffer and acetonitrile, which rendered the method much cheaper than others.

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Electrochemical determination of carvedilol, sildenafil and paracetamol using glassy carbon electrode

Baranowska I., Koper M., Markowski P.

Chemia Analityczna

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2008

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Vol. 53, No. 6

967-981

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Simultaneous determination of sildenafil, its N-desmethyl metabolite and other drugs in human urine by gradient RP-HPLC method

Baranowska I., Markowski P., Baranowski J., Rycaj J.

Chemia Analityczna

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2007

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Vol. 52, No. 4

645-671

EN

A new, rapid, sensitive and accurate gradient reversed-phase high-performance liquid chroma-tography technique for simultaneous separation and analysis of sildenafil citrate (SC), its N-desmethy! active metabolite - N-desmethylsildenafil (UK-103,320) in the presence of different drugs in human urine was developed. The analysed drugs were extracted from urine by liquid-liquid extraction. Effective RP-HPLC separation of the examined drugs was performed using a Merck LiChroCART* analytical column (Purospher*STARRP-I8 endcapped, 125 x 3 mm, particle size 5 μrn) with a gradient mobile phase system and diode array or fluorescence detector. Linear ranges of detection for SC and UK-103,320 were found to be 0.03-8.5 μgmL-1 (r2 = 0.9994) for both compounds. Linear ranges for other drugs (analgesic, antibiotic, diuretic and demulcent), which could exist in urine from patients treated with SC were also detennined. Complete separation of all analytes was achieved below 25 min. The retention times for all studied analytes ranged from 4.76 to 18.84 min. The limits of detection and limits of quantification for both analysed compounds were calculated and recovery studies were also performed. The mean absolute recoveries of SC and UK-103,320 were > 94%. The new procedure was suitably validated and successfully applied for the analysis of SC, its active metabolite and other drugs in urine samples of patients with pulmonary hypertension.

PL

Opracowano nową, szybką, czułą i dokładną gradientową technikę wysokosprawnej chro- •., matografn cieczowej w odwróconym układzie faz do jednoczesnego rozdzielania i oznaczania cytrynianu sildenafilu (SC) i jego N-desmetylo aktywnego metabolitu -N-desmetyio-sildenafilu (UK-103,320) w obecności różnych leków w ludzkim moczu. Badane leki ekstra-howano z próbek moczu przy użyciu ekstrakcji ciecz-ciecz. Efektywne rozdzielanie badanych leków metodą RP-HPLC wykonywano z zastosowaniem kolumny analitycznej Merck LiChroC ART* (Purospher*- STAR RP-18 endcapped, i 25 x 3 mm, średnica ziarna 5μm) z gradientowym przepływem fazy ruchomej i detektorem z matrycą fotodiodową lub detektorem fluorescencyjnym. Liniowe zakresy detekcji SC i UK-!03,32Q mieściły się w przedziale 0.03-8.5 μg mL-1 (r2 = 0.9994) dla obu związków. Wyznaczono również zakresy liniowości dla pozostałych ieków (przeciwbólowe, antybiotyki, diuretyk i przeciwzapalne), które mogą współistnieć w moczu pacjentów leczonych SC. Całkowity rozdział wszystkich analitów osiągnięto w czasie poniżej 25 rnin. Czasy retencji dla wszystkich badanych analitów mieściły się w przedziale od 4.76 do 18.84 min. Wyznaczono granice wykrywalności i oznaczalności oraz odzyski wszystkich analizowanych związków. Wartości całkowitych odzysków dla SC i UK-103,320 były większe niż 94%. Nowa procedura została zwalidowana oraz z powodzeniem zastosowana do analizy SC, jego aktywnego metabolitu oraz innych leków w próbkach moczu pacjentów z nadciśnieniem płucnym.

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Nowy, oryginalny sposób wytwarzania sildenafilu

Balicki R., Chmielowiec U.

Przemysł Chemiczny

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2006

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T. 85, nr 5

351-353

PL

Opisano nowy, oryginalny sposób wytwarzania sildenafilu (Viagra) opracowany w Instytucie Farmaceutycznym. Podano też ogólne dane dotyczące substancji czynnej, mechanizm działania leku oraz poprzednią metodę jego otrzymywania w firmie Pfizer.

EN

2-Ethoxy-5-(4-methylpiperazinyl-1-sulfonyl)benzaldehyde was prepd. from salicylaldehyde and directly cyclocondensed (1:1 by moles) with 4-amino-1-methyl-3-n-propylpirazolo-5-carboxyamide (9) in dimethylamide as solvent and with Na2S2O5 as condensing agent at 110°C for 3 hrs. to yield sildenafil in >80%. Pfizer’s (EP 0463 756 (1990)) route to, and the mode and mechanism of action of sildenafil are reviewed.