Comparison of two extraction methods for determination of propranolol and furosemide in human plasma by mixed-mode chromatography

Propranolol

Propranolol is a noncardioselective β-blocker. It is reported to have membrane-stabilizing properties, but it does not own intrinsic sympathomimetic activity. Propranolol hydrochloride is used to control hypertension, pheochromocytoma, myocardial infarction, cardiac arrhythmias, angina pectoris, and hypertrophic cardiomyopathy. It is also used to control symptoms of sympathetic overactivity in the management of hyperthyroidism, anxiety disorders, and tremor. Other indications cover the prophylaxis of migraine and of upper gastrointestinal bleeding in patients with portal hypertension. This study provides a detailed, comprehensive profile of propranolol, including formulas, elemental analysis, and the appearance of the drug. In addition, the synthesis of the drug is described. The chapter covers the physicochemical properties, including X-ray powder diffraction, pK, solubility, melting point, and procedures of analysis (spectroscopic, electrochemical, and chromatographic). In-depth pharmacology is also presented (pharmacological actions, therapeutic dosing, uses, Interactions, and adverse effects and precautions). More than 60 references are given as a proof of the abovementioned studies.

Mixed-mode chromatography in pharmaceutical and biopharmaceutical applications

Mixed-mode chromatography (MMC) is a fast growing area in recent years, thanks to the new generation of mixed-mode stationary phases and better understanding of multimode interactions. MMC has superior applications in the separation of compounds that are not retained or not well resolved by typical reversed-phase LC methods, especially for polar and charged molecules. Due to the multiple retention modes that a single MMC column can offer, often MMC provides additional dimension to a separation method by adjusting the mobile phase conditions. Mixed-mode media is also an effective way to clean up complex sample matrices for purification purposes or for sensitive detection of trace amounts of analytes. In this article, we discuss mixed-mode stationary phases and separation mechanisms and review recent advances in pharmaceutical and biopharmaceutical applications including the analysis and/or purification of counterions, small molecule drugs, impurities, formulation excipients, peptides and proteins.

Ion-exchange vs reversed-phase chromatography for separation and determination of basic psychotropic drugs

Ion exchange chromatography, an alternative to reversed-phase (RP) chromatography, is described in this paper. We aimed to obtain optimal conditions for the separation of basic drugs because silica-based RP stationary phases show silanol effect and make the analysis of basic analytes hardly possible. The retention, separation selectivity, symmetry of peaks and system efficiency were examined in different eluent systems containing different types of buffers at acidic pH and with the addition of organic modifiers: methanol and acetonitrile. The obtained results reveal a large influence of the salt cation used for buffer preparation and the type of organic modifier on the retention behavior of the analytes. These results were also compared with those obtained on an XBridge C18 column. The obtained results demonstrated that SCX stationary phases can be successfully used as alternatives to C18 stationary phases in the separation of basic compounds. The most selective and efficient chromatographic systems were applied for the quantification of some psychotropic drugs in fortified human serum samples.

RP-HPLC Method for Simultaneous Estimation of Frusemide and Amiloride Hydrochloride in Tablet Formulation

A new reverse phase high performance liquid chromatography method for the simultaneous estimation of frusemide and amiloride hydrochloride in tablet formulation is developed. The determination was carried out on a HIQ SIL, C18 (250×4.6 mm, 5 µm) column using a mobile phase of 50 mM phosphate buffer solution:acetonitrile (50:50 v/v, pH 3.0). The flow rate was 1.0 ml/min with detection at 283 nm. The retention time for frusemide was 3.038 min and for amiloride hydrochloride 10.002 min. Frusemide and amiloride hydrochloride showed a linear response in the concentration range of 20-200 µg/ml and 10-100 µg/ml, respectively. The results of analysis have been validated statistically and by recovery studies. The mean recoveries found for frusemide was 99.98% and for amiloride hydrochloride was 100.09%. Developed method was found to be simple, accurate, precise and selective for simultaneous estimation of frusemide and amiloride hydrochloride in tablets.

Analytical issues in HPLC/MS/MS simultaneous assay of furosemide, spironolactone and canrenone in human plasma samples

A new sensitive HPLC/MS/MS method for simultaneous determination of furosemide, spironolactone and canrenone in human plasma samples is presented. Electrospray ionization source (ESI) has been used. The tandem MS detection was performed under MRM conditions, in the negative ion mode for furosemide and indapamide (internal standard 1) and in the positive ion mode for spironolactone, canrenone and nitrazepam (internal standard 2). A simple plasma protein precipitation with acetonitrile was used as sample preparation technique. The chromatographic separation was carried out under the reversed phase mechanism, on a 250 mm length column packed with octadecyl modified silicagel and thermostated at 35 degrees C. The column was operated under isocratic conditions (3:7 aqueous 0.1% formic acid and methanol, v/v) at a flow rate of 0.8 mL/min. Quantitation intervals of 20-1600 ng/mL for furosemide and 2-100 ng/mL for spironolactone and canrenone have been concluded through validation. Precision and accuracy were situated within the accepted thresholds (maximum 15% relative standard deviation and +/-15% percentage bias). The most sensitive aspects relating to the analytical method development and validation were highlighted and critically assessed in order to reach an objective opinion about the real performances and inherent applicability of the method in bioanalysis.

Direct determination of propranolol in urine by spectrofluorimetry with the aid of second order advantage

This work presented an application of the second-order advantage provided by parallel factor analysis (PARAFAC) aiming at direct determination of propranolol, a beta-blocker also used as doping agent, in human urine by spectrofluorimetry. The adopted strategy combined the use of PARAFAC, for extraction of the pure analyte signal, with the standard addition method, for a determination in the presence of an individual matrix effect caused by the quenching action of the proteins present in the urine. The urine samples were previously 100 times diluted. For each sample, four standard additions were performed, in triplicates. A specific PARAFAC model was built for each triplicate of each sample, from three-way arrays formed by 231 emission wavelengths, 8 excitation wavelengths and 5 measurements (sample plus 4 additions). The models were built with three factors and always explained more than 99.87% of the total variance. The obtained loadings were related to PRO and two background interferences. The scores related to PRO were used for a linear regression in the standard addition method. The obtained determinations in the PRO concentration range from 5.0 to 20.0 microg ml(-1) provided recoveries between 91.1 and 108.4%.

High operationally stable sol-gel diglycidyloxycalix[4]arene fiber for solid-phase microextraction of propranolol in human urine

A simple, sensitive, and accurate method for the determination of propranolol in human urine has been developed based on solid-phase microextraction (SPME) followed by GC-flame ionization detection (FID). The sol-gel 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-diglycidyloxycalix[4]arene/hydroxy-terminated silicone oil (diglycidyloxy-C[4]/OH-TSO) fiber was prepared to accommodate to the harsh extraction conditions. It possesses excellent alkali-proof ability and retains its extraction characteristics intact even after treatment with highly alkaline (4 mol/L) NaOH solution. Direct chemical bonding of the coating to the fiber surface provides it with excellent solvent resistance and the introduction of calixarene enhances its thermal stability. The newly developed sol-gel calixarene coating was effectively used for the extraction of propranolol in human urine. No interference with the determination of propranolol was observed from the urine components. Standard curves were linear in the range 50-5000 microg/L for headspace-SPME (HS-SPME) and 25-25000 microg/L for direct-SPME (Dir-SPME) with correlation coefficients better than 0.9999. The detection limit was 0.275 microg/L for HS-SPME and 0.193 microg/L for Dir-SPME. The method was validated using standard addition methodology and recovery values were between 91.4 and 117% for both the sampling modes with the RSDs less than 6% at different concentration levels in the linear ranges. The results obtained by both the sampling modes were feasible, and no significant differences between them regarding accuracy, precision, and detection limits were seen.

Sequential injection extraction based on restricted access material for determination of furosemide in serum

Restricted access material (RAM) column containing 25 microm C18 alkyl-diol support was integrated into the sequential injection analysis (SIA) manifold and the SIA-RAM system was tested for direct determination of furosemide in serum. LiChrospher ADS column based on restricted access material is proposed to direct injection of biofluids. The integration of RAM material into SIA enabled creation of a comprehensive on-line sample clean-up technique combined with fluorescence quantitation of analyte. Centrifuged and diluted serum sample was aspirated into the system and loaded onto the column using acetonitrile-water (2:98), pH 2.7. The analyte was retained on the column while proteins contained in the sample were removed to the waste without precipitation and clogging the column. Interfering substances complicating the detection were washed out by acetonitrile-water (15:85), pH 2.7 in the next step. The extracted analyte was eluted by means of acetonitrile-water (25:75), pH 2.3 to the fluorescence detector (emission filter 385 nm). The whole procedure comprising sample pre-treatment, analyte detection and column reconditioning took 20 min. The recoveries of furosemide from serum lay between 101.4 and 103.4% for three concentrations of analyte.

Simultaneous high-performance liquid chromatographic assay of furosemide and propranolol HCL and its application in a pharmacokinetic study

A practical, sensitive, selective and efficient reversed-phase high-performance liquid chromatographic (HPLC) method is reported for the determination of two commonly used antihypertensive drugs, furosemide and propranolol hydrochloride. The drugs were eluted through a Nucleosil C(18) column with a mobile phase composed of 0.02 M potassium dihydrogen phosphate and acetonitrile (80:20, v/v) adjusted to pH 4.5 and the effluent from the column was monitored at 235 nm. The present method enabled simple and isocratic HPLC with UV detection of these drugs in raw materials and in pharmaceutical formulations. These procedures were also applied for the assay of furosemide in rabbits' plasma, using propranolol hydrochloride as an internal standard. The linear concentration range of the assay was 0.1-200 and 5-200 microg ml(-1) for furosemide and propranolol hydrochloride, respectively. The inter and intra-day assay precision and accuracy showed reproducibility and good linearity (r(2)>0.99). The method retained its accuracy and precision when applying the standard addition technique. The results obtained by applying the proposed method was statistically analysed and compared with those obtained by the reported methods.

AAS and spectrophotometric determination of propranolol HCl and metoprolol tartrate

Two simple and accurate spectrophotometric methods are described for the determination of propranolol hydrochloride (I) and metoprolol tartrate (II). The methods are based on the reaction of each drug as a secondary amine: (a) with carbon disulphide, the formed complex extracted into iso-butyl methyl ketone (IBMK) after chelation with Cu(II) ions at pH 7.5, followed by measuring the absorbance at 435.4 nm or indirectly for the drug by flame atomic absorption spectrophotometry (AAS). The calibration graph is linear up to 40 and 60 microg ml(-1) with apparent molar absorptivities of 6.89 x 10(3) and 1.08 x 104 l mol(-1) cm(-1) and correlation coefficients of 0.9994 and 0.9995 for propranolol and metoprolol, respectively; (b) with pi-acceptors, tetracyanoethylene (TCNE), or chloranilic acid (CLA) to give highly coloured complex species. The coloured products are quantitated spectrophotometrically at 415 or 510 nm for the two drugs with TCNE and CLA, respectively, and obey Beer's Law with RSD less than 2.0. The methods were applied to the determination of these drugs in pharmaceutical preparation without interferences.

Two reproducible and sensitive liquid chromatographic methods to quantify atenolol and propranolol in human plasma and determination of their associated analytical error functions

Two liquid chromatography (LC) methods with fluorimetric detection have been developed to measure atenolol and propranolol in human plasma. The same 5 microm Nucleosil RP-18 column, extraction procedure and mobile phase (containing acetonitrile, water, triethylamine and phosphoric acid, pH 3) were used. The linearity ranges were 25-800 ng/ml for atenolol and 3.13-100 ng/ml for propranolol. The coefficients of variation for validation assays were lower than 15% at the concentration assayed. The functions of the analytical error were linear: SD (ng/ml)=7.698+0.037C for atenolol and SD (ng/ml)=0.126+0.036C for propranolol.