HPLC determination of guaifenesin with selected medications on underivatized silica with an aqueous-organic mobile phase

Green highly sensitive and selective spectroscopic detection of guaifenesin in multiple dosage forms and spiked human plasma

Guaifenesin (GUA) is determined in dosage forms and plasma using two methods. The spectrofluorimetric technique relies on the measurement of native fluorescence intensity at 302 nm upon excitation wavelength "223 nm". The method was validated according to ICH and FDA guidelines. A concentration range of 0.1-1.1 μg/mL was used, with limit of detection (LOD) and quantification (LOQ) values 0.03 and 0.08 µg/mL, respectively. This method was used to measure GUA in tablets and plasma, with %recovery of 100.44% ± 0.037 and 101.03% ± 0.751. Furthermore, multivariate chemometric-assisted spectrophotometric methods are used for the determination of GUA, paracetamol (PARA), oxomemazine (OXO), and sodium benzoate (SB) in their lab mixtures. The concentration ranges of 2.0-10.0, 4.0-16.0, 2.0-10.0, and 3.0-10.0 µg/mL for OXO, GUA, PARA, and SB; respectively, were used. LOD and LOQ were 0.33, 0.68, 0.28, and 0.29 µg/mL, and 1.00, 2.06, 0.84, and 0.87 µg/mL for PARA, GUA, OXO, and SB. For the suppository application, the partial least square (PLS) model was used with %recovery 98.49% ± 0.5, 98.51% ± 0.64, 100.21% ± 0.36 & 98.13% ± 0.51, although the multivariate curve resolution alternating least-squares (MCR-ALS) model was used with %recovery 101.39 ± 0.45, 99.19 ± 0.2, 100.24 ± 0.12, and 98.61 ± 0.32 for OXO, GUA, PARA, and SB. Analytical Eco-scale and Analytical Greenness Assessment were used to assess the greenness level of our techniques.

Fast concurrent determination of guaifenesin and pholcodine in formulations and spiked plasma using first derivative synchronous spectrofluorimetric approach

Guaifenesin and pholcodine are frequently co-formulated in certain dosage forms. A new fast first derivative synchronous spectrofluorometric method has been used for their simultaneous analysis in mixtures. Here, first derivative synchronous spectrofluorometry enabled the successful simultaneous estimation of guaifenesin at 283 nm and pholcodine at 275 nm using a wavelength difference (Δλ) of 40 nm. The method was fully validated following International Council of Harmonization guidelines. For guaifenesin and pholcodine, linearity was determined within the corresponding ranges of 0.05-0.30 and 0.10-6.0 μg/ml. The two drugs were effectively analyzed using the developed approach in their respective formulations, and the results showed good agreement with those attained using reference methods. The method demonstrated excellent sensitivity, with detection limits down to 0.007 and 0.030 μg/ml and quantitation limits of 0.020 and 0.010 μg/ml for guaifenesin and pholcodine, respectively. Therefore, the procedure was successful in determining these drugs simultaneously in vitro in spiked plasma samples and syrup dosage form. The developed methodology also offered an environmentally friendly advantage by utilizing water as the optimal diluting solvent throughout the whole work. Different greenness approaches were investigated to ensure the method's ecofriendly properties.

A Chemometric Strategy in the Development of a RP-UPLC Method for the Quantitative Resolution of a Two-Component Syrup Formulation

A novel chemometric strategy was implemented in the development of a new ultraperformance liquid chromatography method for the quantitative estimation of guaifenesin and pseudoephedrine hydrochloride in a two-component syrup formulation with minimal experimental effort, time and reagent. A full factorial design with three factors was investigated to find optimal working conditions of chromatographic factors (column temperature, flow rate, and 0.1 M H3PO4% in mobile phase) that affect the chromatographic separation. Then, optimum experimental conditions providing adequate separation of the analyzed drug substances within the short runtime were determined. Under optimal experimental conditions, the retention times for guaifenesin and pseudoephedrine hydrochloride were obtained as 0.817 and 1.430 min, respectively. In the optimized RP-UPLC method, chromatographic response was reported as a linear function of concentration between 5.0 and 80.0 μg/mL for guaifenesin and 10.0-90.0 μg/mL for pseudoephedrine hydrochloride. The proposed method was carefully validated and successfully applied to quality control and analysis of a cough syrup preparation containing guaifenesin and pseudoephedrine hydrochloride. Consequently, the proposed reversed-phase ultraperformance liquid chromatography method provided an opportunity to quantify relevant drugs with small amount of reagents and short runtime.

Electroanalytical Analysis of Guaifenesin on Poly(Acridine Orange) Modified Glassy Carbon Electrode and its Determination in Pharmaceuticals and Serum Samples

BACKGROUND

Electroanalytical methods are very functional to detect drugs in pharmaceuticals (tablets, syrups, suppositories, creams, and ointments) and biological samples.

OBJECTIVE

This study is aimed to make selective, sensitive, simple, fast, and low cost electrochemical analysis of expectorant drug guaifenesin in pharmaceuticals and serum samples.

METHODS

Differential pulse adsorptive stripping voltammetric method for determination of guaifenesin on a poly(acridine orange) modified glassy carbon electrode has been developed. Glassy carbon electrode was modified with electropolymerization of the acridine orange monomer for the sensitive determination of guaifenesin. Guaifenesin provided highly reproducible and welldefined irreversible oxidation peaks at +1.125 V and +1.128 V (vs. Ag/AgCl) in the selected supporting electrolyte and human serum samples, respectively.

RESULTS

Under optimized conditions, linear response of peak current on the concentration of guaifenesin has been obtained in the ranges of 2.00×10-7 to 1.00×10-4 M in Britton Robinson buffer solution at pH 7.0 and 4.00×10-7 to 1.00×10-4 M in serum samples. The precision of the method was detected by intraday and inter-day repeatability studies in the supporting electrolyte and serum samples media.

CONCLUSION

The analytical applicability of the proposed method exhibited satisfying determination results for guaifenesin from pharmaceutical dosage forms (syrup) and human serum samples without any pre-separation procedures.

Voltammetric Determination of Guaifenesin in Pharmaceuticals and Urine Samples Based on Poly(Bromocresol Purple) Modified Glassy Carbon Electrode

Introduction:

The electro-oxidation behavior of expectorant drug Guaifenesin (GUF) was studied on poly(bromocresol purple) modified Glassy Carbon Electrode (GCE) by Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) methods.

Materials and Methods:

GCE was modified with electropolymerization of Bromocresol Purple (BP) monomer for sensitive determination of GUF with voltammetric methods. The oxidation process of GUF showed irreversible and diffusion controlled behavior. The linearity has been obtained in the range from 1.00 × 10-7 to 2.00 × 10-5 M with the limit of detection 3.658 × 10-9 M for DPV in 0.1 M phosphate buffer solution (PBS) at pH 3.0.

Results and Conclusion:

Fully validated differential pulse voltammetry was successfully applied for the determination of GUF in pharmaceutical dosage forms and urine samples obtained satisfying results.

Fabrication of graphene nanosheet–multiwalled carbon nanotube–polyaniline modified carbon paste electrode for the simultaneous electrochemical determination of terbutaline sulphate and guaifenesin

A sensitive electrochemical method is developed for the simultaneous determination of terbutaline sulphate (TBS) and guaifenesin (GF) at a carbon paste electrode modified with graphene nanosheet–multiwalled carbon nanotube–polyaniline composite (GNS–MWCNT–PANI).

A New UPLC Approach for the Simultaneous Quantitative Estimation of Four Compounds in a Cough Syrup Formulation

A new ultra-performance liquid chromatographic (UPLC) method was developed for the simultaneous estimation of potassium guaiacolsulfonate (PGS), guaifenesin (GUA), diphenhydramine HCl (DIP) and carbepentane citrate (CAR) in a commercial cough syrup. The chromatographic separation of four compounds PGS, GUA, DIP and CAR was performed on a BEH phenyl column (100 × 2.1 mm, 1.7 µm i.d.) using a mobile phase consisting of acetonitrile and 0.1 M HCl (50 : 50, v/v). In addition, the optimized conditions of the chromatographic analysis were found with the flow rate of 0.38 mL/min, the column temperature of 30°C and the injection volume of 1.2 µL with the photodiode array detection of 220 nm. Calibration curves in the concentration ranges of 10-98 µg/mL for PGS, 5-80 µg/mL for GUA, 5-25 µg/mL for DIP and CAR were computed by the regression of the analyte concentration on the chromatographic peak area. The newly developed UPLC method was validated by analyzing the quaternary mixtures of the related compounds, intraday and interday experiment and standard addition samples. After method validation, the proposed UPLC approach was successfully applied for the analysis of the commercial syrup formulation containing PGS, GUA, DIP and CAR compounds.

Stability-indicating HPLC Method for Simultaneous Determination of Terbutaline Sulphate, Bromhexine Hydrochloride and Guaifenesin

The aim of the present study was the development and subsequent validation of a simple, precise and stability-indicating reversed phase HPLC method for the simultaneous determination of guaifenesin, terbutaline sulphate and bromhexine hydrochloride in the presence of their potential impurities in a single run. The photolytic as well as hydrolytic impurities were detected as 3,5-dihydroxybenzoic acid, 3,5-dihydroxybenzaldehyde, 1-(3,5-dihydroxyphenyl)-2-[(1,1-dimethylethyl) amino]-ethanone from terbutaline, 2-methoxyphenol and an unknown impurity identified as (2RS)-3-(2-hydroxyphenoxy)-propane-1,2-diol from guaifenesin. The chromatographic separation of all the three active components and their impurities was achieved on Wakosil II column, using phosphate buffer (pH 3.0) and acetonitrile as mobile phase which was delivered initially in the ratio of 80:20 (v/v) for 18 min, then changed to 60:40 (v/v) for next 12 min, and finally equilibrated back to 80:20 (v/v) for 10 min. Other HPLC parameters were: Flow rate at 1.0 ml/min, detection wavelengths 248 and 280 nm, injection volume 10 μl. The calibration graphs plotted with five concentrations of each component were linear with a regression coefficient R(2) >0.9999. The limit of detection and limit of quantitation were estimated for all the five impurities. The established method was then validated for linearity, precision, accuracy, and specificity and demonstrated to be applicable to the determination of the active ingredients in commercial and model cough syrup. No interference from the formulation excipients was observed. These results suggest that this LC method can be used for the determination of multiple active ingredients and their impurities in a cough and cold syrup.

Development and validation of stability indicating the RP-HPLC method for the estimation of related compounds of guaifenesin in pharmaceutical dosage forms

Aim and background:

A stability-indicating gradient reverse phase liquid chromatographic (RP-LC) method was developed for the quantitative determination of related substances of guaifenesin in pharmaceutical formulations.

Materials and methods:

The baseline separation for guaifenesin and all impurities was achieved by utilizing a Water Symmetry C18 (150 mm × 4.6 mm) 5 μm column particle size and a gradient elution method. The mobile phase A contains a mixture of 0.02 M KH₂PO₄ (pH 3.2) and methanol in the ratio of 90:10 v/v, while the mobile phase B contains 0.02 M KH₂PO₄ (pH 3.2) and methanol in the ratio of 10:90 v/v, respectively. The flow rate of the mobile phase was 0.8 ml/min with a column temperature of 25°C and detection wavelength at 273 nm.

Results:

Guaifenesin was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal, and photolytic degradation.

Conclusion:

The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness.

A new technique for spectrophotometric determination of pseudoephedrine and guaifenesin in syrup and synthetic mixture

The accuracy in predicting different chemometric methods was compared when applied on ordinary UV spectra and first order derivative spectra. Principal component regression (PCR) and partial least squares with one dependent variable (PLS1) and two dependent variables (PLS2) were applied on spectral data of pharmaceutical formula containing pseudoephedrine (PDP) and guaifenesin (GFN). The ability to derivative in resolved overlapping spectra chloropheniramine maleate was evaluated when multivariate methods are adopted for analysis of two component mixtures without using any chemical pretreatment. The chemometrics models were tested on an external validation dataset and finally applied to the analysis of pharmaceuticals. Significant advantages were found in analysis of the real samples when the calibration models from derivative spectra were used. It should also be mentioned that the proposed method is a simple and rapid way requiring no preliminary separation steps and can be used easily for the analysis of these compounds, especially in quality control laboratories.

Sensitive spectrophotometric method for quantitation of guaifenesin and dropropizine in their dosage forms

Guaifenesin and dropropizine were analyzed through oxidation with periodic acid to give formaldehyde which was allowed to condense with 4-Amino-5-hydrazino-4H [1,2,4]-triazole-3-thiol (AHTT). The condensation product was further oxidized to yield a purple colored compound with maximum absorption at 550 nm. Beer's law was obeyed in the range of 5–45 μg mL⁻¹ for guaifenesin and 10–80 μg mL⁻¹ for dropropizine. Both drugs were also successfully determined in their dosage forms.

Simultaneous HPLC analysis of pseudophedrine hydrochloride, codeine phosphate, and triprolidine hydrochloride in liquid dosage forms

An HPLC method using UV detection is proposed for the simultaneous determination of pseudophedrine hydrochloride, codeine phosphate, and triprolidine hydrochloride in liquid formulation. C18 column (250mmx4.0mm) is used as the stationary phase with a mixture of methanol:acetate buffer:acetonitrile (85:5:10, v/v) as the mobile phase. The factors affecting column separation of the analytes were studied. The calibration graphs exhibited a linear concentration range of 0.06-1.0mg/ml for pseudophedrine hydrochloride, 0.02-1.0mg/ml for codeine phosphate, and 0.0025-1.0mg/ml for triprolidine hydrochloride for a sample size of 5microl with correlation coefficients of better than 0.999 for all active ingredients studied. The results demonstrate that this method is reliable, reproducible and suitable for routine use with analysis time of less than 4min.

Spectrophotometric determination of pipazethate HCl, dextromethorphan HBr and drotaverine HCl in their pharmaceutical preparations

A simple, accurate and highly sensitive spectrophotometric method is proposed for the rapid determination of pipazethate hydrochloride, dextromethorphan hydrobromide and drotaverine hydrochloride using chromotrope 2B (C2B) and chromotrope 2R (C2R). The method consists of extracting the formed ion-associates into chloroform in the case of pipazethate HCl and dextromethorphan HBr or into methylene chloride in the case of drotaverine HCl. The ion-associates exhibit absorption maxima at 528, 540 and 532 nm with C2B and at 526, 517 and 522 nm with C2R for pipazethate HCl, dextromethorphan HBr and drotaverine HCl, respectively. The calibration curves resulting from the measurements of absorbance-concentration relations (at the optimum reaction conditions) of the extracted ion-pairs are linear over the concentration range 4.36-52.32 microg mL(-1) for pipazethate, 3.7-48.15 microg mL(-1) for dextromethorphan and 4.34-60.76 microg mL(-1) for drotaverine, respectively. The effect of acidity, reagent concentration, time, solvent and stoichiometric ratio of the ion-associates were estimated. The molar absorptivity and Sandell sensitivity of the reaction products were calculated. Statistical treatment of the results reflects that the procedure is precise, accurate and easily applied for the determination of the drugs under investigation in pure form and in their pharmaceutical preparations.

A new hydrophilic interaction liquid chromatographic (HILIC) procedure for the simultaneous determination of pseudoephedrine hydrochloride (PSH), diphenhydramine hydrochloride (DPH) and dextromethorphan hydrobromide (DXH) in cough-cold formulations

A new HILIC method has been developed for the simultaneous determination of pseudoephedrine hydrochloride (PSH), diphenhydramine hydrochloride (DPH) and dextromethorphan hydrobromide (DXH) in cough-cold syrup. Mobile phase consists of methanol:water (containing 6.0 g of ammonium acetate and 10 mL of triethylamine per liter, pH adjusted to 5.2 with orthophosphoric acid), 95:5 (v/v). Column containing porous silica particles (Supelcosil LC-Si, 25 cm x 4.6 mm, 5 microm) is used as stationary phase. Detection is carried out using a variable wavelength UV-vis detector at 254 nm for PSH and DPH, and at 280 nm for DXH. Solutions are injected into the chromatograph under isocratic condition at constant flow rate of 1.2 mL/min. Linearity range and percent recoveries for PSH, DPH and DXH were 150-600, 62.5-250, 75-300 microg/mL and 100.7%, 100.1% and 100.8%, respectively. Method is stability indicating and excipients like saccharin sodium, sodium citrate, flavour and sodium benzoate did not interfere in the analysis. Compounds elute in order of increasing ionization degree caused by cation-exchange mechanism in a run time of less than 15 min. Mobile phase pH is manipulated to regulate ionization and ion-exchange interaction and thereby retention of compounds.

Simultaneous, stability indicating, HPLC-DAD determination of guaifenesin and methyl and propyl-parabens in cough syrup

A stability indicating high performance liquid chromatography procedure has been developed for the simultaneous determination of guaifenesin (GUA), methyl p-hydroxybenzoate (MHB) and propyl p-hydroxybenzoate (PHB) in a commercial cough syrup dosage form. The method was specific and stability indicating as chromatographic conditions were selected to provide adequate separation of GUA, MHB and PHB from the putative degradation products guaiacol (GUAI) and p-hydroxybenzoic acid (HBA) as well as from excipients. The isocratic separation and quantitation were achieved within 17 min on a 150-mm column with an ether-linked phenyl stationary phase and a hydrophilic endcapping. The mobile phase was constituted of eluant A: aqueous phosphate buffer (pH 3.0, 10 mM)/acetonitrile 25/75 (v/v) and eluant B:methanol; the A:B ratio was 85:15 (v/v) with a flow rate 1 ml min-1 and detection of analytes at 254 and 276 nm. The method showed good linearity for the GUA-MHB-PHB mixture in the 95-285, 4-12, and 1-3 microg ml-1 ranges, respectively, being all the square of the correlation coefficients greater than 0.999. The interday R.S.D.s were 1.17, 1.14, and 0.91%, for GUA, MHB, and PHP, respectively. The method demonstrated also to be accurate; indeed the average recoveries, at 100% of the target assay concentration, were 100.5, 100.3, and 100.7% with relative standard deviations of 0.8, 0.7, and 0.4% for GUA, MHB, and PHB, respectively, from laboratory prepared samples. The applicability of the method was evaluated in commercial dosage form analysis as well as in stability studies.

Voltammetric assay of Guaifenesin in pharmaceutical formulation

The electrochemical oxidation of Guaifenesin in a pharmaceutical formulation containing Guaifenesin has been carried out in Britton-Robinson buffer (BRB) (0.04 mol L-1) on platinum electrode. Guaifenesin exhibits a well-defined irreversible oxidation peak at 0.924 V/ref. The influence of pH on the oxidation of Guaifenesin was studied in BRB (pH range 2-5). A method for the analysis of Guaifenesin in BRB (0.04 mol L-1, pH 2), which allows quantification over the range 20-60 microg mL-1, was proposed and successfully applied to the determination of Guaifenesin in syrup with mean recovery and relative standard deviation of 103.3% and 1.32%, respectively.

Quantitative and structural determination of pseudoephedrine sulfate and its related compounds in pharmaceutical preparations using high-performance liquid chromatography

A simple isocratic reversed-phase high performance liquid chromatograghic method for the separation of pseudoephedrine and its related compounds in pharmaceutical formulations is described. The separation is achieved in less than 35 min on a C-18 column (4.6 mm I.D. x 25 cm length, 5-micrometer particle size) using a mobile phase consisting of a mixture of ammonium acetate and methanol. The results described in this report demonstrate that the method is sensitive and selective. Structural elucidation of two new pseudoephedrine degradation products is described. On the basis of structural analysis by liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-nuclear magnetic resonance spectroscopy (LC-NMR), the two newly elucidated degradation products were identified to be 2-(carboxyamino)propiophenone (molecular ion of m/z=194) and 2-formyl-2-(methylamino)-acetophenone (molecular ion of m/z=178).

Stability-indicating HPLC assays for the determination of prilocaine and procaine drug combinations

Stability-indicating, reversed phase high-performance liquid chromatographic (HPLC) methods have been developed for the determination of several procaine hydrochloride and prilocaine hydrochloride combinations. The separation and quantitation of epinephrine-prilocaine and epinephrine-procaine drug combinations were achieved on a phenyl column using a mobile phase of 80:20% v/v 25 mM phosphate buffer (pH 3.0) containing 50 mM heptanesulfonic acid sodium salt-acetonitrile at a flow rate of 1 ml x min(-1) and UV detection at 254 nm. The method showed linearity for the epinephrine and prilocaine hydrochloride mixture in the 0.25-2.5 and 8-200 micro g ml(-1) ranges, respectively. The intra- and inter-day relative standard deviations (RSDs) ranged from 0.26 to 2.05% and 0.04 to 0.61% for epinephrine and prilocaine hydrochloride, respectively. The epinephrine and procaine hydrochloride mixture yielded linear ranges of 0.25-2.0 and 5-100 micro g ml(-1) and intra- and inter-day RSDs ranged from 0.23 to 1.88% and 0.07 to 0.26% for epinephrine and procaine hydrochloride, respectively. The assays were shown to be suitable for measuring epinephrine-prilocaine and epinephrine-procaine combinations in their respective injection dosage forms. Stability-indicating HPLC assays were also developed for several other procaine drug combinations since their monographs are present in the USP 24; however, quantitation was not investigated since these combinations are not commercially available. A mobile phase consisting of 80:20% v/v 25 mM phosphate buffer (pH 3.0) containing 50 mM heptanesulfonic acid-acetonitrile was utilized for the levonordefrin-tetracaine-procaine drug combination, while a mobile phase consisting of 70:30% v/v 25 mM phosphate buffer (pH 3.0) containing 50 mM heptanesulfonic acid sodium salt-acetonitrile was utilized for the separation of levonordefrin-procaine-propoxycaine and norepinephrine-procaine-propoxycaine. All separations were achieved on a phenyl column at a flow rate of 1 ml x min(-1) and UV detection at 254 nm.