Flow injection-chemiluminescence determination of propranolol in pharmaceutical preparations

A Novel Voltametric Measurements of Beta Blocker Drug Propranolol on Glassy Carbon Electrode Modified with Carbon Black Nanoparticles

A new voltametric method for highly sensitive propranolol (PROP) determination was developed. A glassy carbon electrode modified with a hybrid material made of carbon black (CB) and Nafion was used as the working electrode. The preconcentration potential and time were optimized (550 mV and 15 s), as well as the supporting electrolyte (0.1 mol L⁻¹ H₂SO₄). For 15 s preconcentration time, linearity was achieved in the range 0.5–3.5 μmol L⁻¹ and for 120 s in 0.02–0.14 μmol L⁻¹. Based on the conducted calibration (120 s preconcentration time) limit of detection (LOD) was calculated and was equal to 7 nmol L⁻¹. To verify the usefulness of the developed method, propranolol determination was carried out in real samples (tablets and freeze-dried urine). Recoveries were calculated and were in the range 92–102%, suggesting that the method might be considered as accurate. The repeatability of the signal expressed as relative standard deviation (RSD) was equal to 1.5% (n = 9, PROP concentration 2.5 µmol L⁻¹). The obtained results proved that the developed method for propranolol determination might be successfully applied in routine laboratory practice.

Flow-injection post-chemiluminescence method for the determination of palmatine

A post-chemiluminescence (PCL) phenomenon was observed when palmatine was injected in a mixture of N-bromosuccinimide (NBS) and alkaline dichlorofluorescein (DCF) after the chemiluminescence (CL) reaction of NBS-alkaline DCF had finished. Based on the PCL reaction, a rapid and sensitive method for the determination of palmatine was established. Under optimum conditions, the CL intensity was linear, with the concentration of palmatine in the range of 5.0 × 10(-9) to 1.0 × 10(-6) M. The detection limit was 6.0 × 10(-10) M for palmatine. The relative standard deviation for 11 parallel measurements of 1.0 × 10(-7) M palmatine was 1.5%. This method was applied to the determination of palmatine in pharmaceutical samples and biological fluids, with satisfactory results. The possible reaction mechanism is discussed briefly.

Determination of sulpiride in pharmaceutical preparations and biological fluids using a Cr (III) enhanced chemiluminescence method

A highly sensitive and simple method for identifying sulpiride in pharmaceutical formulations and biological fluids is presented. The method is based on increased chemiluminescence (CL) intensity of a luminol-H2O2 system in response to the addition of Cr (III) under alkaline conditions. The CL intensity of the luminol-H2O2-Cr (III) system was greatly enhanced by the addition of sulpiride and the CL intensity was proportional to the concentration of sulpiride in a sample solution. Various parameters affecting the CL intensity were systematically investigated and optimized for determination of the sulpiride in a sample. Under the optimum conditions, the CL intensity was proportional to the concentration of sulpiride in the range of 0.068-4.0 µg/mL, with a good correlation coefficient of 0.997. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 8.50 × 10(-6) µg/mL and 2.83 × 10(-5) µg/mL, respectively. The method presented here produced good reproducibility with a relative standard deviation (RSD) of 2.70% (n = 7). The effects of common excipients and metal ions were studied for their interference effect. The method was validated statistically through recovery studies and successfully applied for the determination of sulpiride in pure form, pharmaceutical preparations and spiked human plasma samples. The percentage recoveries were found to range from 99.10 to 100.05% for pure form, 98.12 to 100.18% for pharmaceutical preparations and 97.9 to 101.4% for spiked human plasma.

Electrogenerated chemiluminescence sensor for the determination of

An electrogenerated chemiluminescence (ECL) sensor for the determination of propranolol hydrochloride was fabricated by employing tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)32+) as an ECL signal producer and graphene as a modified material. The ECL sensor was fabricated by adsorbing Ru(bpy)32+ onto a mixture of graphene and Nafion. The introduction of conductive graphene into Nafion was found to greatly enhance the ECL intensity of Ru(bpy)32+ and the ECL intensity of Ru(bpy)32+ decreased in the presence of propranolol hydrochloride. Based on this phenomenon, a sensitive and stable ECL method was developed for the determination of propranolol hydrochloride by employing a Ru(bpy)32+-graphene-Nafion modified electrode. Under the optimized conditions, the ECL intensity was linear with the concentration of propranolol hydrochloride over a range of 1.0 × 10-10 to 5.0 × 10-9 mol L-1 with a detection limit of 3 × 10-11 mol L-1. The ECL sensor exhibited long-term stability with a relative standard deviation of 4.1% for sixteen continuous determinations of 2.0 × 10-9 mol L-1 propranolol hydrochloride. The developed method has been successfully applied to the determination of propranolol hydrochloride in pharmaceutical samples.

Conductometric determination of propranolol hydrochloride in pharmaceuticals

In this paper the conductometric titration of propranolol hydrochloride in pharmaceutical formulations using silver nitrate as titrant is proposed. The method was based on the formation of an insoluble salt (AgCl(s)) between the chloride of propranolol hydrochloride molecule and Ag(I) ions of the titrant AgNO3. The effect of the PROP-AgNO3 concentrations and the interval of time between the successive additions of the titrant on the shape of the titration curve were studied. The obtained recoveries for four samples ranged from 96.8 to 105%. The proposed method was successfully applied in the determination of propranolol hydrochloride in several pharmaceutical formulations, with results in close agreement at a 95 % confidence level with those obtained using official spectrophotometric method.

Involvement of serotoninergic 5-HT1A/2A, alpha-adrenergic and dopaminergic D1 receptors in St. John's wort-induced prepulse inhibition deficit: a possible role of hyperforin

Prepulse inhibition (PPI) of acoustic startle response is a valuable paradigm for sensorimotor gating processes. Previous research showed that acute administration of St. John's wort extract (500 mg/kg, p.o.) to rats caused significant disruption of PPI while elevating monoamines levels in some brain areas. The cause-effect relationship between extract-induced PPI disruption and augmented monoaminergic transmission was studied using different serotoninergic, adrenergic and dopaminergic antagonists. The effects of hypericin and hyperforin, as the main active constituents of the extract, on PPI response were also tested. PPI disruption was prevented after blocking the serotoninergic 5-HT1A and 5-HT2A, alpha-adrenergic and dopaminergic D1 receptors. Results also demonstrated a significant PPI deficit after acute treatment of rats with hyperforin, and not hypericin. In some conditions manifesting disrupted PPI response, apoptosis coexists. Electrophoresis of DNA isolated from brains of hyperforin-treated animals revealed absence of any abnormal DNA fragmentation patterns. It is concluded that serotoninergic 5-HT1A and 5-HT2A, alpha-adrenergic and dopaminergic D1 receptors are involved in the disruptive effect of St. John's wort extract on PPI response in rats. We can also conclude that hyperforin, and not hypericin, is one of the active ingredients responsible for St. John's wort-induced PPI disruption with no relation to apoptotic processes.

Detection of propranolol in pharmaceutical formulations by diffuse reflectance spectroscopy

This paper describes an analytical reflectometric method that has an objective not only the industrial quality control but also to detect possible falsifications and/or adulterations of propranolol in pharmaceutical formulations. The method is based on the diffuse reflectance measurements of the colored product (III) of the spot test reaction between propranolol hydrochloride (I) and 2,6-dichloroquinone-4-chloroimide (II) using filter paper as solid support. Spot test conditions have been investigated using experimental design in order to identify and optimize the critical factors. The factors evaluated were DCQ concentration, propranolol solvent and DCQ solvent. The best reaction conditions were achieved with the addition of 30 microL of propranolol solution in ethanol 35% (v/v) and 30 microL of DCQ solution at 70 mg mL(-1) in acetone, in this order. All reflectance measurements were carried out at 500 nm and the linear range was from 8.45x10(-4) to 8.45x10(-2)mol L(-1) (r=0.998). The limit of detection was 1.01x10(-4)mol L(-1). No interference was observed from the assessed excipients and drugs. The method was applied to determine propranolol in commercial brands of pharmaceuticals. The results obtained by the proposed method were favorably compared with those given by the British Pharmacopoeia procedure.

Determination of hydroxycamptothecinum by flow injection analysis with chemiluminescence detection

An novel analytical method consisting of flow-injection sampling and chemiluminescence (CL) detection for determination of anticancer drug hydroxycamptothecinum (HCPT) is described. It is based on the CL reaction of potassium permanganate-formaldehyde-HCPT system. The formaldehyde-sensitized CL emission mechanism was proposed for HCPT-potassium permanganate (KMnO(4))-HCOH systems by comparing the fluorescence emission with CL spectra. Illuminant was the single-state bimolecular oxygen, (1)O(2) (1)O(2)((1)Delta(g) (1)Delta(g)), which was from (1)O(2)((1)Delta(g)) produced in the reaction system, and emits CL spectra at 639 nm. The presence of formaldehyde can sensitized CL emission, because it may be to accelerate the generation of (1)O(2) ((1)Delta(g)). The optimum conditions for CL emission were investigated and optimized. The CL intensity was correlated linearly with concentration of HCPT in the range of 0.010-60.0 mg L(-1). The determination limit is 0.006 mg L(-1). The relative standard deviation is 1.6% for 11 parallel measurements of 0.20 mg L(-1) HCPT standard solution. The proposed method has been applied for the determination of HCPT in pharmaceutical preparations, serum, and urine. The results of the quantitative analysis for HCPT studied using the developed method showed a good agreement with provided by using an official method.

Recent applications of flow-injection and sequential-injection analysis techniques to chemiluminescence determination of pharmaceuticals

A review is presented on the state of the art of the chemiluminescence analysis of pharmaceuticals by the two most relevant automated controlled-flow methodologies--flow-injection analysis (FIA) and sequential-injection analysis (SIA). The current chemiluminometric applications of FIA and SIA in pharmaceutical analysis are discussed with special emphasis on the analytical figures of merit and sample matrix characteristics. The review involving 211 references and covering papers published between 2001 and 2006 is divided into several sections according to the fundamental types of chemiluminescence systems employed.

Acidic potassium permanganate as a chemiluminescence reagent—A review

A critical and comprehensive review of acidic potassium permanganate chemiluminescence is presented. This includes discussion on reaction conditions, the influence of enhancers such as polyphosphates, formaldehyde and sulfite, the relationship between analyte structure and chemiluminescence intensity, and the application of this chemistry to determine a wide variety of compounds, such as pharmaceuticals, biomolecules, antioxidants, illicit drugs, pesticides and pollutants. Previous proposals for the nature of the emitting species are re-evaluated in light of recent evidence.

Sensitized chemiluminescence determination of fluorouracil in pharmaceutical and biological fluids based on potassium permanganate oxidation in the presence of formaldehyde

A novel chemiluminescence (CL) reaction system was established for the anticancer drug fluorouracil (5-FU). We developed a formaldehyde-sensitized CL emission mechanism for 5-FU-KMnO(4)-HCl systems by comparing the fluorescence emission with CL spectra. The illuminant was the singlet-state bimolecular oxygen (1)O(2) (1)O(2)((1)Delta(g) (1)Delta(g)), which is from (1)O(2)((1)Delta(g)) produced in the reaction system, and emits CL spectra at 639 nm. The presence of formaldehyde can sensitize CL emission by accelerating the generation of (1)O(2)((1)Delta(g)). The optimum conditions for CL emission were investigated. The relationship between the relative CL intensity and the concentration of the analyte showed good linearity. The determination limit was 3 x 10(-8) g mL(-1). The relative standard deviation (SD) was 1.8%. The proposed method was applied to the determination of fluorouracil in pharmaceutical preparations and biological fluids, and satisfactory results were obtained.

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%.

Determination of metoprolol tartrate in tablets and human urine using flow-injection chemiluminescence method

In this paper, a simple, rapid and sensitive flow-injection chemiluminescence method has been developed for the determination of metoprolol tartrate, which acts as a kind of sensitizer in the chemiluminescence emission from the redox of SO(3)(2-) with Ce(IV) in acidic medium. Under the optimized conditions, the proposed method allows the measurement of metoprolol tartrate over the range of 1.5 x 10(-8) to 7.3 x 10(-6)mol/L with a detection limit of 4.7 x 10(-9)mol/L (3sigma), and the relative standard deviation for 7.3 x 10(-7)mol/L metoprolol tartrate (n=11) is 2.20%. The utility of this method was demonstrated by determining metoprolol tartrate in tablets and human urine sample.

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.

Development of time-resolved chemiluminescence for the determination of antu in river water, wheat, barley, and oat grain samples

A novel chemiluminescence method for the determination of antu has been developed based on the reaction between potassium permanganate in acid medium with this rat-poison in the presence of formaldehyde as an emission enhancer. The main feature of the system used is that the recording of the whole chemiluminescence intensity-vs-time profiles can be obtained, using the stopped-flow technique in a continuous-flow system. This enables the use of three quantitative parameters adjustable via software settings, one of them a typically kinetic parameter, such as rate of the light-decay reaction, and the others conventional parameters, such as maximum emission intensity and total emission area, which are proportional to the analyte concentration. The optimum chemical conditions for the chemiluminescence emission were investigated. The effect of common emission enhancers, such as formic acid, formaldehyde, glutaraldehyde, acetaldehyde, quinine, fluorescein, rhodamine B, and rhodamine 6G, was studied. The parameters selected were sulfuric acid 4.0 mol L(-)(1), permanganate 0.1 mmol L(-)(1), and formaldehyde 1.0 mol L(-)(1). The calibration graphs obtained with each one of the measurement parameters were linear for the concentration range from 0.05 to 3.00 microg mL(-)(1). The detection limits ranged from 0.005 to 0.010 microg mL(-)(1), and RSD values (n = 10) of 0.99-1.79% at a 0.30 microg mL(-)(1) concentration level and 1.71-2.22% at a 1.0 microg mL(-)(1) concentration level were obtained. The present chemiluminescence procedures were applied to the determination of antu in different kinds of samples, such as river water, wheat, barley, and oat grain samples. Recovery values not significantly different from the spiked amount were found for these determinations.

Flow injection-chemiluminescence determination of puerarin in pharmaceutical preparations

Strong chemiluminescence was observed when cerium(IV) reacted with rhodamine 6G in sulfuric acid medium in the presence of puerarin. This phenomenon has been utilized to design a sensitive and selective flow injection-chemiluminescence method for the determination of puerarin. Under the optimum conditions, the proposed procedure has a linear range between 1.3 x 10(-9) and 8.0 x 10(-7)g/mL, with a detection limit of 8.4 x 10(-10)g/mL puerarin and a relative standard deviation of 1.86% (n = 11) at 5.0 x 10(-8)g/mL puerarin. The method was successfully applied to the determination of puerarin in pharmaceutical preparations. The mechanism of this chemiluminescence reaction has been proposed.

Flow injection chemiluminescence determination of naftopidil based on potassium permanganate oxidation in the presence of formaldehyde or formic acid

A flow injection method is proposed for the determination of naftopidil based upon the oxidation by potassium permanganate in a sulfuric acid medium and sensitized by formaldehyde and formic acid. The optimum chemical conditions for the chemiluminescence emission were 0.25 mM potassium permanganate and 4.0 M sulfuric acid. Two manifolds were tested and instrumental parameters such as the length of the reactor, injection volume and flow rate were compared. When using the selected manifold in the presence of 0.4 M formaldehyde, naftopidil gives a second-order calibration graph over the concentration range 0.1-40.0 mg L(-1) with a detection limit calculated (as proposed by IUPAC) of 92.5 ng mL(-1) and a standard deviation of 0.12 mg mL(-1) for ten samples of 10.0 mg L(-1) naftopidil. In the presence of 1.15 M formic acid, naftopidil gives a second-order calibration graph over the concentration range 0.05-40.0 mg L(-1) with a detection limit of 14.2 ng mL(-1) and a standard deviation of 0.37 mg mL(-1) for ten samples of 10.0 mg L(-1) naftopidil. In both cases, the determination is free from interferences from common excipients such as sucrose, glucose, lactose, starch and citric acid.

Flow Injection Chemiluminescence Analysis of Some Penicillins by Their Sensitizing Effect on the Potassium Permanganate-Glyoxal Reaction

A new chemiluminescence method using flow injection is described for the determination of four penicillins, namely: phenoxymethylpenicillin potassium, amoxicillin, ampicillin, and ampicillin sodium. The method is based on sensitizing effect of these drugs on the chemiluminescence reaction of potassium permanganate in sulfuric acid with glyoxal. The different experimental parameters affecting the chemiluminescence intensity were carefully studied and incorporated into the procedure. The method allows the determination of 0.1-1.0 microg/ml phenoxymethylpenicillin potassium, 0.1-1.0 microg/ml amoxicillin, 0.1-1.0 microg/ml ampicillin, and 0.1-1.0 microg/ml ampicillin sodium. The method was successfully applied to the determination of four penicillin antibiotics in pharmaceutical preparations.