Thin-layer chromatographic analysis of some beta-blocking drugs in plasma.

beta-receptor blockers--atenolol, celiprolol, metoprolol, propafenone, propranolol and talinolol--extracted from plasma, were separated by TLC method on silica gel by ascending technique. Isolation of drugs was performed by using liquid-liquid extraction after alkalization of blood plasma. Suitable conditions for separation were established using ethyl acetate-acetone-ammonia (5:4:1) as the mobile phase. The substances were identified by UV irradiation (254 nm) or by reactions with a variety of reagents. The visual limits of determination of named beta-blockers, after reaction with indicators, are between 100-300 ng; celiprolol and talinolol are the most sensitively detectable of investigated substances.

High-performance liquid chromatographic assay of dilazep in plasma after solid-phase extraction.

A new, simple and accurate high-performance liquid chromatography method is presented for measuring dilazep in plasma, using a reversed-phase technique and UV absorption at 267 nm. Dilazep and papaverine (the internal standard) added to plasma were successfully isolated using a solid-phase extraction procedure (CN cartridges). The method was linear between 2.5-12.5 micrograms ml-1. Over the tested concentration range the intra-day coefficient of variation for replicate analyses of plasma ranged from 2.38 to 5.27% (the day-to-day CV ranged from 2.52 to 7.99%). The detection limit for the analysis of dilazep in plasma was 50 ng with 20 microliters injection.

Chromatographic (TLC) analysis of diltiazem in pharmaceutical form in presence of other antiarrhythmics.

Diltiazem was identified by TLC method on silica gel by ascending technique, in presence of five another antiarrhythmic drugs (disopyramide, flecainide, lidocaine, lorcainide, procainamide). Suitable conditions for separation of diltiazem were established using ethanol-benzene-dioxane-ammonia (2:20:16:3) as the mobile phase. When using acidified iodoplatinate solution or Dragendorff reagent as indicators, the amount of diltiazem as small as 100 ng can be identified. The TLC method is simple and sensitive and it was used to identify diltiazem in tablets.

Determination of aprindine in human plasma using reversed phase HPLC.

A rapid, simple, accurate method is presented for the determination of aprindine in human plasma. Liquid-liquid extraction of aprindine was carried out using diethyl ether. Amiodarone was applied as an internal standard. The samples were chromatographed on LiChrosorb RP-18 (10 microns) column and the mobile phase was methanol/acetonitrile/phosphate buffer pH 2.5 (80:15:5). The detection was carried at 254 nm. The method was tested for linearity (range from 0.5 to 2.5 micrograms/ml), recovery (ca. 90%) and precision (CV = 3.7%).

Identification of flecainide and lorcainide in blood by means of TLC.

New antiarrhythmics-flecainide and lorcainide-extracted from plasma were separated by TLC method on silica gel by ascending development, using suitable mobile phases. The substances were identified by reaction with indicators: Dragendorff reagent for lorcainide (up to the amount 50 ng) and acidified 15% FeCl3, followed by 15% KI and water for flecainide (up to the amount 500 ng).

Determination of nadoxolol in human plasma using reversed-phase high-performance liquid chromatography.

A rapid, simple and accurate HPLC method is presented for the determination of nadoxolol in human plasma. Nadoxolol from plasma was successfully purified using an Adsorbex column. The samples were chromatographed on a LiChrosorb RP-18 (10 microns) column with methanol-acetonitrile-phosphate buffer (pH 3.3) (70:20:10) as the mobile phase. Detection was carried out at 254 nm. The method was tested for linearity (from 5 to 25 micrograms/ml), recovery (85%) and precision (C.V. = 4.5%).

Determination of amiodarone in tablets and plasma by high-performance liquid chromatography.

A method is described for measuring amiodarone in human plasma and tablets using a LiChrosorb RP-18 column, a mobile phase methanol-acetonitrile-phosphate buffer pH 2.6 (80:15:5, v/v) and UV detection at 254 nm. Another antiarrhythmic drug - aprindine was used as an internal standard (i.s.).

Thin-layer chromatographic analysis of some benzofuran derivatives in human plasma.

Benzofuran derivatives: amiodarone, benziodarone, benzbromarone and benzarone, extracted from plasma, were separated by TLC method on silica gel by ascending and horizontal developments, using suitable mobile phases. The substances were identified by reaction with potassium permanganate solution, either by Dragendorff (modified after Amelink) or Sonnenschein reagents (up to the amounts of 250 ng of amiodarone and benzarone and 500 ng of benziodarone and benzbromarone).

[High-performance liquid chromatographic determination of propanidid and etomidate]. / Oznaczenie propanidydu i etomidatu we krwi metoda wysokosprawnej chromatografii cieczowej.

High-performance reversed-phase liquid chromatographic determination of propanidid and etomidate was performed on ODS silica, after precipitation of the proteins in plasma with methanol, extraction of the drugs with diethyl ether, evaporation and dissolving in a mobile phase: acetonitrile-phosphate buffer pH 4.44 (7:3, v/v); UV detection at 254 nm. Dionine hydrochloride was used as an internal standard. Propanidid was determined in a range 5-25 microg/cm3 of plasma and etomidate in 0.1-0.5 microg/cm3 of plasma, thus enables the analysis of therapeutic levels of the drugs.

[Propanidid and etomidate identification from the blood by thin-layer chromatography]. / Identyfikacja propanidydu i etomidatu we krwi za pomoca chromatografii cienkowarstwowej.

Propanidid and etomidate were extracted from blood with diethyl ether at pH ca. 8 (phosphate buffer), then separated and identified by thin-layer chromatography on silica gel, using diethyl ether-acetone (3:1, v/v) for propanidid or dioxane-acetic acid (47:3, v/v) for etomidate as the mobile phase. Both compounds can be revealed on dried chromatograms using sodium carbonate solution up to the amount 1 microg/cm3 of plasma, and it is sufficient sensivity for propanidid adhibited in therapeutic doses, whereas this limits the detection of etomidate for overdosed patients only.

High-performance liquid chromatographic determination of ethosuximide in plasma.

A HPLC method for a rapid determination of ethosuximide in plasma is described. A sample is extracted with ethyl ether from acidic medium with glutethimide as internal standard and injected onto analytical RP-18 column with spectrophotometric monitoring at 244 nm.

[Determination of methadone in plasma using high pressure liquid chromatography methods]. / Oznaczanie metadonu w osoczu metoda wysokosprawnej chromatografii cieczowej.

High-performance liquid chromatography on the column of LiChrosorb RP-18 was applied to the determination of methadone in plasma, after previous precipitation of proteins with methanol and extraction from alkalized plasma with diethyl ether. Methadone, ion-paired with pentane-1-sulphonic acid added in a mobile phase acetonitrile-methanol-ammonium acetate solution (20:58:22), was monitored at 254 nm. Piritramide was used as an internal standard. The determination range was 0.25-1.25 micrograms/cm3 of plasma and recovery was 88-93%.

[Testing of some dibenzoazepines and dibenzocycloheptadiene derivatives with high pressure thin layer chromatography]. / Badania niektórych pochodnych dibenzoazepiny i dibenzocykloheptadienu metoda chromatografii cienkowarstwoweji wysokosprawnej cieczowej.

An influence of several adsorbents and the composition of the eluent mixtures on the separation of dibenzoazepine and dibenzocycloheptadiene derivatives was examined by thin-layer chromatography. The best system (RP-18 and methanol-buffer solution pH 8.5 19:1) was employed for the separation of amitryptiline and doxepine by HPLC. Both compounds were determined in ng amounts in pharmaceutical preparations and in blood by addition and in patients blood. Doxepine was used as internal standard for the determination of amitryptiline.

[Extraction of glutethimide and methyprylon from blood using thin layer chromatography]. / Wykrywanie glutetimidu i metyprylonu we krwi metoda chromatografii cienkowarstwowej.

Glutethimide and methyprylone were extracted from blood and plasma at pH ca. 4 (acetate buffer) thrice with chloroform, using 2.5 solvent volume ratio to that of aqueous phase. Phenobarbital was used as an internal standard in thin-layer chromatography experiments on silica gel--to obtain of comparable ratios of Rf values of glutethimide and/or methyprylone to that of phenobarbital. Suitable conditions of the separation of three substances were established using one of following mobile phases: benzene-dioxane-aq.ammonia (15:4:1), chloroform-acetone-aq.ammonia (25:25:1), chloroform-acetone-diaethylamine (5:4:1) and chloroform-diethyl ether-acetone (5:3:2); on 7.5 x 2.5 cm plates; development time (at 5 cm distance) was up to 10 minutes. The concentrations as small as 0.1 microg of examined substances in 1 cm3 of plasma may be identified on chromatograms using 20% Na2CO3 solution.

[Chromatographic identification and analysis of dextromoramide in the plasma by the method of high performance liquid chromatography]. / Identyfikacja chromatograficzna i oznaczanie dekstromoramidu w osoczu metoda wysokosprawnej chromatograffii cieczowej.

Dextromoramide and pethidine were separated and identified by thin-layer chromatography on silica gel, using ammonia and methanol (1.5:100) as the mobile phase, after previous extraction with dicthyl ether or with a mixture of n-hexane and isoamyl alcohol (98.5:1.5) from blood alkalized to pH 10.3 Dextromoramide can be revealed on the chromatograms in the amount of 0.5 micrograms and pethidine in the amount of 1 micrograms using the Dragendorff reagent. Reversed-phase TLC proved less sensitive. High-performance liquid chromatography on the column of LiChrosorb RP-18 was applied to the determination of dextromoramide in blood after extraction with diethyl ether, using methanol--phosphate buffer pH 4.5 (95:5) as the mobile phase. The determination range was of 0.5-5.0 micrograms per 2 cm3 of blood plasma (1.26.10(-8)-1.26.10(-7) mole/dm3).

Determination of drugs containing fluorine with ion-selective electrode. Part 1: Synthetic glucocorticosteroids.

Synthethic glucocorticosteroids (fludrocortisone acetate, fluocinolone acetate, flumethasone pivalate, triamcinolone acetonide and dexamethasone acetate) were determined on the basis of their fluoride content, when deflagrated after Schöniger, in three ways: by potentiometric titration or by direct potential measurement of ion-selective fluoride electrode or by spectrophotometry with lanthanum alizarin complexan.