Assay of ambroxol in human plasma by high-performance liquid chromatography with amperometric detection

A brief review on critical analytical aspects for quantification of ambroxol in biological samples

Ambroxol (AMB) is a member of the expectorant class, widely used as a secreolytic agent in patients to break up secretions. AMB is rapidly and effectively distributed from blood to tissue. The lungs have the highest concentration of AMB; accumulation of AMB in human lung tissue was detected at concentrations 15- to 20-fold greater than those reported in the circulation. Because of its wide range of actions and therapeutic applications may be worth looking into, particularly for respiratory symptoms, antioxidant, anti-inflammatory, influenza, and rhinovirus infections. Though several analytical methodologies have been established and confirmed for the AMB analysis in matrices of pharmaceutical and biological origins, novel sustainable, and economical methods are still to be choice of protocol to increase its sensitivity, reliability, and repeatability. Therefore, the present review offers an overview of critical analytical aspects regarding the HPLC, LC-MS/MS, HPTLC, capillary electrophoresis, spectrophotometry, and electrochemical methods for quantifying AMB in pharmaceutical and biological samples. Furthermore, this review will thoroughly discuss the physicochemical properties, stability, extraction conditions, instrumentation, and operational parameters of the targeted analyte. As a result, for the first time, this review complies with vital background information and an up-to-date interpretation of research undertaken by anticipated methodologies examined and implemented for the pharmaceutical analysis AMB.

Isolation, Identification, and Characterization of One Degradation Product in Ambroxol by HPLC-Hyphenated Techniques

This study details the isolation, identification, and characterization of ambroxol’s unknown impurity. One unknown impurity of ambroxol was formed in the formulated drug under stress conditions [40°C /75% relative humidity (RH) for 6 months] with the relative retention time (RRT) 0.68 in RP-HPLC. The impurity was enriched by exposing it to heat and it was isolated by using preparative HPLC. The enriched impurity was purified and characterized using the following sophisticated techniques: 2D NMR (gDQ-COSY, gHSQC, and gHMBC), FTIR, and LC-MS/MS. On the basis of the spectral data, the impurity was characterized as trans-4-(6,8-dibromoquinazolin-3(4H)-yl)cyclohexanol.

Micellar liquid chromatographic method for the simultaneous determination of Levofloxacin and Ambroxol in combined tablets: Application to biological fluids

BACKGROUND

Levofloxacin hemihydrate (LEV) and ambroxol HCl (AMB) are available for the treatment of upper and lower respiratory tract infections. A survey of the literature reveals that two reversed phase HPLC methods were e reported for the simultaneous determination of LEV and AMB in pharmaceutical preparations. However the reported methods suffers from the low sensitivity, no application of the method in the combined tablets and no application to biological fluids. Also the toxic effects of the used solvents which are harmful to human beings. For this reason, our target was to develop a simple sensitive, less hazardous micellar HPLC method for the simultaneous determination of LEV and AMB in their combined dosage forms and plasma.

RESULTS

The method showed good linearity over the ranges of 1-44 μg/mL and 1-20 μg/mL with limits of detection 0.26 and 0.07 μg/mL and limits of quantification 0.80 and 0.20 μg/mL for LEV and AMB, respectively. The method was further extended to the determination of LEV in spiked human plasma with mean percentage recoveries of 100.10% ± 1.14 as well as determination of LEV in real human plasma without prior extraction. Statistical evaluation of the data was performed according to ICH Guidelines.

CONCLUSION

The suggested method was successfully applied for the simultaneous analysis of the studied drugs in their co-formulated tablets and human plasma. The mean percentage recoveries in combined tablets were 100.20 ± 1.64 and 100.72 ± 1.11 for LEV and AMB, respectively and 100.10 ± 1.14 for LEV in spiked human plasma. Statistical comparison of the results with those of the comparison method revealed good agreement and proved that there were no significant difference in the accuracy and precision between the two methods respectively.

Development and Validation of a Reversed-Phase HPLC Method for the Estimation of Zolpidem in Bulk Drug and Tablets

In the present study an isocratic reversed-phase high-performance liquid chromatography method was developed for the estimation of zolpidem in bulk drug and pharmaceutical dosage forms. The quantification was carried out on C18columns. A mixture of acetonitrile-ammonium acetate (pH=8.0, 0.02 M) (60 : 40 v/v) was used as the mobile phase, at flow rate of 1.0 mL/min and the determination wavelength at 245 nm. The retention time of zolpidem was found to be 3–5 min. The validation of the proposed method was carried out for specificity, linearity, accuracy, precision, limit of detection, limit of quantification, and robustness. The linear dynamic range was from 2.5 to 30 μg mL−1. Regression equation was found to bey=0.1416x+0.0183with correlation coefficientr=0.9996. The percentage recovery obtained for zolpidem was greater than 96.5%. Limit of quantification and limit of detection were found to be 2.5 μg mL−1and 0.83 μg mL−1, respectively. The developed method can be used for routine quality control analysis of zolpidem in tablet formulations.

Ambroxol lozenge bioavailability : an open-label, two-way crossover study of the comparative bioavailability of ambroxol lozenges and commercial tablets in healthy thai volunteers

OBJECTIVE

To compare the bioavailability of two 15mg ambroxol lozenges with a commercial 30mg ambroxol tablet.

DESIGN

Open-label, two-way crossover study.

METHOD

Each formulation was randomly administered to 20 healthy Thai volunteers (ten male and ten female) with a 1-week washout period between formulations. After administration, serial blood samples were collected over a 24-hour period and the plasma concentration of ambroxol was subsequently measured using high performance liquid chromatography with ultraviolet detection after liquid-liquid extraction. Pharmacokinetic parameters were analysed by a noncompartmental pharmacokinetic model and compared between formulations using analysis of variance with a significance level of 0.05.

RESULTS

The point estimates (90% CI) of the area under the plasma concentration-time curve (AUC) and peak plasma concentration (C(max)) ratios between lozenge and commercial tablet were 1.07 (0.89 to 1.28) and 1.20 (1.04 to 1.40), respectively. The point estimate (90% CI) of the difference between formulations for time to C(max) was 0.40 (-0.20 to 1.00).

CONCLUSION

The two formulations under test were not bioequivalent based on the stipulated bioequivalence criteria. The bioavailability from the ambroxol lozenge might be better, since the 90% CI of the AUC(0-infinity) fell outside the bioequivalence range, and its range was narrower. The difference in rate of absorption was not conclusive because ambroxol was delivered from the lozenge by two parallel processes, namely absorption via oral and gastrointestinal mucosa. The additional oral mucosal absorption might not only contribute more absorption but also introduce variability compared with that of tablet administration. The relative importance of oral versus gastrointestinal mucosal absorption of ambroxol from the lozenge formulation, and the clinical significance of this, requires further study.

A Rapid, Stability Indicating RP-UPLC Method for Simultaneous Determination of Ambroxol Hydrochloride, Cetirizine Hydrochloride and Antimicrobial Preservatives in Liquid Pharmaceutical Formulation

A stability indicating reversed phase ultra performance liquid chromatography (RP-UPLC) method was developed for simultaneous determination of ambroxol hydrochloride (AMB), cetirizine hydrochloride (CTZ), methylparaben (MP) and propylparaben (PP) in liquid pharmaceutical formulation. The desired chromatographic separation was achieved on an Agilent Eclipse plus C18, 1.8 μm (50 × 2.1 mm) column using gradient elution at 237 nm detector wavelength. The optimized mobile phase consists of a mixture of 0.01 M phosphate buffer and 0.1 % triethylamine as a solvent-A and acetonitrile as a solvent-B. The developed method separates AMB, CTZ, MP and PP in presence of twelve known impurities/degradation products and one unknown degradation product within 3.5 min. Stability indicating capability was established by forced degradation experiments and seperation of known and unknown degradation products. The lower limit of quantification was established for AMB, CTZ, MP and PP. The developed RP-UPLC method was validated according to the International Conference on Harmonization (ICH) guidelines. This validated method is applied for simultaneous estimation of AMB, CTZ, MP and PP in commercially available syrup samples. Further, the method can be extended for estimation of AMB, CTZ, MP, PP and levo-cetirizine (LCTZ) in various commercially available dosage forms.

RP-HPLC and Spectrophotometric Estimation of Ambroxol Hydrochloride and Cetirizine Hydrochloride in Combined Dosage Form

Rapid, precise, accurate, specific and sensitive reverse phase liquid chromatographic and absorbance ratio spectrophotometric methods have been developed for the simultaneous analysis of ambroxol hydrochloride and cetirizine hydrochloride in their tablet formulation. The chromatographic methods were standardized using a HIQ SIL-C(18) column (250×4.6 mm i.d., 10 μm particle size) with UV detection at 229 nm and mobile phase consisting of methanol-acetonitrile-water (40:40:20, v/v/v). Ambroxol hydrochloride and cetirizine hydrochloride have absorbance maxima at 243 nm and 229 nm, respectively. The isoabsorptive wavelength for both the drugs was 236 nm. For absorbance ratio method developed, wavelengths selected were 243 nm and 236 nm. The proposed methods were successfully applied to the determination of ambroxol hydrochloride and cetirizine hydrochloride in tablets, with high percentage of recovery, good accuracy and acceptable precision. Different analytical performance parameters such as linearity, precision, accuracy, limit of detection, limit of quantitation and robustness were determined according to International Conference on Harmonization ICH Q2B guidelines. Results of analysis of the developed method were compared by performing ANOVA.

Determination of ambroxol in human plasma by high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-MS/ESI)

A rapid, sensitive and specific method to determination of ambroxol in human plasma using high performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-MS/ESI) was described. Ambroxol and the internal standard (I.S.), fentanyl, were extracted from plasma by N-hexane-diethyl ether (1:1, v/v) after alkalinized with ammonia water. A centrifuged upper layer was then evaporated and reconstituted with 100 microl mobile phase. Chromatographic separation was performed on a BDS HYPERSIL C18 column (250 mmx4.6 mm, 5.0 microm, Thermo electron corporation, USA) with the mobile phase consisting of 30 mM ammonium acetate (0.4% formic acid)-acetonitrile (64:36, v/v) at a flow-rate of 1.2 mL min(-1). The total run time was 5.8 min for each sample. Detection and quantitation was performed by the mass spectrometer using selected ion monitoring at m/z 261.9, 263.8 and 265.9 for ambroxol and m/z 337.3 for fentanyl. The calibration curve was linear within the concentration range of 1.0-100.0 ng mL(-1) (r=0.9996). The limit of quantification was 1.0 ng mL(-1). The extraction recovery was above 83.3%. The methodology recovery was higher than 93.8%. The intra- and inter-day precisions were less than 6.0%. The method is accurate, sensitive and simple for the study of the pharmacokinetics and metabolism of ambroxol.

Simultaneous high-throughput determination of clenbuterol, ambroxol and bromhexine in pharmaceutical formulations by HPLC with potentiometric detection

Potentiometric detection of clenbuterol, ambroxol and bromhexine in marketed pharmaceuticals was described in six isocratic HPLC systems. The podant- and macrocyclic-type neutral ionophores, N,N,N',N'-tetracyclohexyl-oxybis(o-phenyleneoxy)diacetamide (TOPA) and hexakis(2,3,6-tri-O-octyl)-alpha-cyclodextrin (OCD), were applied in poly(vinyl)chloride (PVC)-based liquid membrane electrodes. Both types of neutral ionophores improve the sensitivity for all mentioned drugs when compared with a tetrakis(p-chlorophenyl)borate (BOR)-based electrode as well as with single wavelength UV detection. Detection limits (S/N=3) of 2.6 x 10(-10) mol l(-1) (injected concentration) for the highly hydrophobic bromhexine were achieved with the TOPA-based electrode and a cyano reversed-phase (RP)-HPLC with Uptisphere UP5CN-25QS silica column (250 x 4.6 mm i.d.) eluted with acetonitrile (AcN)-ethanol-perchloric acid (1.66 mM) (60:2:38, v/v/v) (pH* 2.45). Comparable result was obtained with OCD-based electrodes and an XTerra RP18 hybrid silica-polymer column eluted with AcN-phosphoric acid (20 mM) (25:75, v/v) (pH* 2.60). In the mobile phases containing 60-75% v/v AcN or methanol, stable and reproducible response of both types of neutral ionophore-based electrodes was observed for at least 3 days. The results of the validated procedure for reliable simultaneous determination of the drugs in fortified representative samples of pharmaceuticals were also presented.

Determination of ambroxol in human plasma using LC-MS/MS

A sensitive and selective liquid chromatographic method coupled with tandem mass spectrometry (LC-MS/MS) was developed for the quantification of ambroxol in human plasma. Domperidone was used as internal standard, with plasma samples extracted using diethyl ether under basic condition. A centrifuged upper layer was then evaporated and reconstituted with 200 microl methanol. The reconstituted samples were injected into a C(18) XTerra MS column (2.1 x 30 mm) with 3.5 microm particle size. The analytical column lasted for at least 600 injections. The mobile phase was composed of 20 mM ammonium acetate in 90% acetonitrile (pH 8.8), with flow rate at 250 microl/min. The mass spectrometer was operated in positive ion mode using turbo electrospray ionization. Nitrogen was used as the nebulizer, curtain, collision, and auxiliary gases. Using MS/MS with multiple reaction monitoring (MRM) mode, ambroxol was detected without severe interferences from plasma matrix. Ambroxol produced a protonated precursor ion ([M+H](+)) at m/z 379 and a corresponding product ion at m/z 264. And internal standard (domperidone) produced a protonated precursor ion ([M+H](+)) at m/z 426 and a corresponding product ion at m/z 174. Detection of ambroxol in human plasma was accurate and precise, with quantification limit at 0.2 ng/ml. This method has been successfully applied to a study of ambroxol in human specimens.

Quantitative determination of ambroxol in tablets by derivative UV spectrophotometric method and HPLC

A derivative UV spectrophotometric method for the determination of ambroxol in tablets was developed. Determination of ambroxol in tablets was conducted by using first-order derivative UV spectrophotometric method at 255 nm (n = 5). Standards for the calibration graph ranging from 5.0 to 35.0 microg/ml were prepared from stock solution. The proposed method was accurate with 98.6+/-0.4% recovery value and precise with coefficient of variation (CV) of 1.22. These results were compared with those obtained by reference methods, zero-order UV spectrophotometric method and reversed-phase high-performance liquid chromatography (HPLC) method. A reversed-phase C(18) column with aqueous phosphate (0.01 M)-acetonitrile-glacial acetic acid (59:40:1, v/v/v) (pH 3.12) mobile phase was used and UV detector was set to 252 nm. Calibration solutions used in HPLC were ranging from 5.0 to 20.0 microg/ml. Results obtained by derivative UV spectrophotometric method was comparable to those obtained by reference methods, zero-order UV spectrophotometric method and HPLC, as far as ANOVA test, F(calculated) = 0.762 and F(theoretical) = 3.89, was concerned.

Determination of ambroxol or bromhexine in pharmaceuticals by capillary isotachophoresis

Expectorant drugs ambroxol (AX) and bromhexine (BX) were determined by capillary isotachophoresis (ITP) with conductimetric detection. The leading electrolyte (LE) was a buffer solution that contained 5 mM picolinic acid and 5 mM potassium picolinate (pH 5.2). The terminating electrolyte (TE) was 10 mM formic acid. The driving current was 80 microA (for approximately 200 s) or 50 microA (for approximately 350 s) and the detection current was 20 microA (a single analysis took about 8 min). The effective mobilities of AX and BX (evaluated with tetraethylammonium as the mobility standard) were 18.8 x 10(-9) m2 V(-1) s(-1) and 14.3 x 10(-9) m2 V(-1) s(-1) respectively. The calibration graphs relating the ITP zone length to the concentration of the analytes were rectilinear (r = 0.9993-0.9999) in the range 10 mg L(-1) (20 mg L(-1) for BX) to 200 mg l(-1) of the drug standard. The relative standard deviations (RSD) were 1.2 1.6% (n = 6) when determining 100 mg l(-1) of the analytes in pure test solutions. The method has been applied to the assay of AX or BX in seven commercial mass-produced pharmaceutical preparations. According to the validation procedure based on the standard addition technique the recoveries were 97.5-102.7% of the drug and the RSD values were 0.11-2.20% (n = 6).

High performance liquid chromatographic determination of ambroxol in the presence of different preservatives in pharmaceutical formulations

A high-performance chromatographic method is described for simultaneous determination of ambroxol in the presence of different preservatives in syrups. The method separates ambroxol from methyl- ethyl-, propyl- and butyl paraben and from other multi-component mixtures. The retention behaviour of ambroxol and parabens as a function of both pH and mobile phase composition was investigated. The eluents were monitored with a UV detector at 247 nm. Linear relationships between the amount of pharmaceutical compounds and peak heights were confirmed at the concentrations of 0.74-14.08 microg ml(-1). The high recovery (no extraction of the samples is required) and the low %RSD confirm the suitability of the proposed method for the determination of ambroxol in different pharmaceutical preparations.

Sensitive method for the determination of ambroxol in body fluids by capillary electrophoresis and fluorescence detection

A sensitive and rapid capillary electrophoretic method combined with laser-induced fluorescence detection has been developed for the determination of ambroxol. Samples were derivatized with 5 x 10(-4) M fluorescein isothiocyanate. A linear relationship between concentration and peak area was obtained in the concentration range 0.008-42 microg ml(-1) with a correlation coefficient of 0.9999. The applicability of the method to serum and urine samples was demonstrated. The method is also useful for the determination of ambroxol in pharmaceutical preparations.

High-performance liquid chromatographic determination of ambroxol in human plasma

Ambroxol has been determined in biological fluids using a rapid and sensitive high-performance liquid chromatographic method. The samples prepared from plasma by liquid-liquid extraction were analysed on reversed-phase silica gel by competing-ion chromatography with ultraviolet detection. The method was applied to the determination of ambroxol levels in twelve healthy volunteers after oral administration of 90 mg of ambroxol in tablets of Mucosolvan and Ambrosan.