Quantitative capillary column gas chromatographic method for the determination of glycopyrronium in human plasma

Development and Validation of a Stability-Indicating Chromatographic Method for the Determination of Indacaterol Maleate with Glycopyrronium Bromide in Mixture

Introduction:

(COPD) Chronic Obstructive Pulmonary Disease is a partially reversible and treatable lung disease, characterized by progressive limitation of airflow. It is one of the main causes of mortality and morbidity worldwide.

Methods:

An easy, precise and selective reversed-phase liquid chromatographic method, with stabilityindicating assay was established and validated for the determination of indacaterol maleate and glycopyrronium bromide in the mixture. In addition, a forced degradation study was performed for indacaterol maleate, comprised of hydrolysis by acid and base, degradation by oxidation and heat, and photo-degradation. Separation and forced degradation were done by isocratic elution using a reversed phase phenyl column and (methanol: phosphate buffer) at ratio (65:35, v/v) with 3.5 pH buffer as an eluent at 1 mL min-1 as a flow rate. Quantitation was accomplished using a UV detector at 210 nm.

Results:

The method showed good separation of glycopyrronium bromide, indacaterol maleate and its degradation products. Accuracy, linearity, and precision were acceptable over 10-160 µg mL-1 and 10- 80 µg mL-1 concentration range for indacaterol maleate and glycopyrronium bromide, respectively.

Conclusion:

The proposed method does not require any previously done separation steps, making it applicable for the analysis of the drugs under investigation in their pharmaceutically marketed preparations.

Multiple analytical methods for determination of formoterol and glycopyrronium simultaneously in their novel combined metered dose inhaler

One of the major causes of mortality all over the world is chronic obstructive pulmonary disease (COPD). Recently approved combined inhaler of formoterol fumarate (FF) and glycopyrronium bromide (GLY) has been used in very low concentrations (µg level/actuation) doses in COPD patients. The first spectrophotometric and advanced highly sensitive liquid chromatography has been achieved successfully throughout this study, permitting validated analysis of dual combined inhaler in raw material as well as pharmaceutical inhaled dosage form. Three sensitive analytical methods were carried out for the simultaneous assay of FF and GLY in their novel combined Metered dose inhaler (MDI). The first method depends on measuring the first derivative amplitudes at 208.27 nm for FF and at 213.27 nm and 239.86 nm for GLY, respectively. The second method depends on measurement of the first derivative of the ratio spectra at 214 or 229 nm for FF and 240 or 259 nm for GLY, respectively. For the spectrophotometric methods, the linearity ranges were 0.48-9.6 µg/mL for FF and 0.9-18 µg/mL for GLY. For the third method, valid ion-pairing chromatographic method was carried out applying C₁₈ column and isocratic mobile phase of 60% v/v acetonitrile and 40% v/v deionized waster (pH 3.0) enclosing 0.025% sodium dodecyl sulfate, using UV detection adjusted to 210 nm and flow rate of 1.2 mL/min. For the ion-pairing chromatographic method, the linearity ranges were 0.048-4.8 µg/mL for FF and 0.09-9.0 µg/mL for GLY. The developed methods are reproducible, valid and offer efficient resolution between formoterol and glycopyrronium using spectrophotometric methods and highly sensitive and precise chromatographic method. The percent recoveries of the inhaled drugs in their MDI were good. The method was successfully established for the quantitative analysis of FF and GLY in their combined pharmaceutical inhaler capsules to validate the therapeutic efficiency of the combined drugs in quality control labs.

Validated ion pair chromatographic method for simultaneous determination and in vitro dissolution studies of indacaterol and glycopyrronium from inhaled capsule dosage form

A rapid, and highly sensitive analytical method were developed for the simultaneous determination of indacaterol maleate (IND) and glycopyrronium bromide (GLY) in their inhaler capsules. Valid ion-pairing chromatographic (IPC) method was performed for separation of GLY in presence of IND using C₁₈ column and mobile phase consisting of acetonitrile: acidified deionized water (60:40% v/v) containing 0.02% sodium dodecyl sulfate (SDS) adjusted to pH 3.0 using OPA (orthophosphoric acid) isocratically eluted at 2.0 mL/min. Quantitation was achieved with UV detection at 210 nm. Cyproheptadine was used as an internal standard. The retention times were 1.9 and 2.5 min for IND, and GLY, respectively. For the IPC method, the calibration graphs were linear in the range of 0.66-66.0 μg/mL for IND and 0.3-30.0 μg/mL for GLY. The proposed method are rapid, reproducible (R.S.D. <2.0%) and achieves satisfactory resolution between IND and GLY (resolution factor = 4.23). The mean recoveries of the analytes in their inhaler capsule were satisfactory. It was applied successfully to in vitro dissolution testing using Franz diffusion cell and extended to a content uniformity test consistent with the United States Pharmacopoeia (USP) guidelines and were found to be precise and accurate for the capsules studied with acceptance value of 4.53 and 1.39 for IND and GLY, respectively.

Dispersive micro-solid-phase extraction combined with online preconcentration by capillary electrophoresis for the determination of glycopyrrolate stereoisomers in rat plasma

A simple and sensitive analytical method for four isomers of glycopyrrolate in rat plasma was developed using cation-selective exhaustive injection-sweeping cyclodextrin-modified electrokinetic chromatography (CSEI-Sweeping-CDEKC) for online enrichment combined with dispersive micro-solid-phase extraction pretreatment. The CSEI-Sweeping-CDEKC was conducted on an uncoated fused silica capillary (40.2 cm × 75 μm) with an applied voltage of -20 kV. The electrophoretic analysis was carried out in 30 mM phosphate solution at pH 2.0 containing 20 mg/mL sulfated-β-cyclodextrin and 5% acetonitrile. Under these optimized conditions, the detection limit for racemic glycopyrrolate was found to be 2.0 ng/mL and this method could increase 495-fold detection sensitivity compared with the traditional injection method. Additionally, the parameters that affected the extraction efficiency of dispersive micro-solid-phase extraction were also examined systematically. The glycopyrrolate isomers in rat plasma samples as low as 0.0625 μg/mL were able to be separated and detected by capillary electrophoresis with the aid of CSEI-sweeping. The findings of this study show that the dispersive micro-solid-phase extraction pretreatment coupled with CSEI-Sweeping-CDEKC is a rapid and convenient method for analyzing glycopyrrolate isomers in rat plasma.

Rapid simultaneous determination of indacaterol maleate and glycopyrronium bromide in inhaler capsules using a validated stability-indicating monolithic LC method

Background

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. A combination of indacaterol maleate with glycopyrronium bromide has recently been approved as a once-daily maintenance therapy in patients with COPD. The very low dose (μg level/capsule) renders the analysis of such products challenges. This study reports for the first time about HPLC method for the quality control of such combination and it is a stability indicating at the same time.

Results

A rapid, simple, precise and reproducible HPLC method was developed and validated for simultaneous determination of indacaterol maleate and glycopyrronium bromide using tenoxicam as an internal standard. The chromatographic separation was achieved on an onyx monolithic C18 column (100 × 4.6 mm) using a mobile phase consisting of acetonitrile and 30 mM phosphate buffer (pH 3.5) (30:70, v/v), run at a flow rate of 2 mL/min with UV detection at 210 nm. The total analysis time was less than 3 min. The HPLC method was validated for linearity, limits of detection and quantitation, precision, accuracy, system suitability and robustness. Calibration curves were obtained in the concentration ranges of 1–44 µg/mL for indacaterol maleate and 0.5–20 µg/mL for glycopyrronium bromide. Stability tests were done through exposure of the analyte solution for different stress conditions and the results indicate no interference of degradants with HPLC method.

Conclusions

The method was successfully applied for the quantitative analysis of indacaterol maleate and glycopyrronium bromide both individually and in a combined pharmaceutical inhaler capsules to support the quality control and to assure the therapeutic efficacy of the two drugs. The simple procedure involved in sample preparation and the short run-time added the important property of high throughput to the method. Graphical abstract

Simultaneous spectrophotometric determination of indacaterol and glycopyrronium in a newly approved pharmaceutical formulation using different signal processing techniques of ratio spectra

Three spectrophotometric methods have been developed and validated for determination of indacaterol (IND) and glycopyrronium (GLY) in their binary mixtures and novel pharmaceutical dosage form. The proposed methods are considered to be the first methods to determine the investigated drugs simultaneously. The developed methods are based on different signal processing techniques of ratio spectra namely; Numerical Differentiation (ND), Savitsky-Golay (SG) and Fourier Transform (FT). The developed methods showed linearity over concentration range 1-30 and 10-35 (μg/mL) for IND and GLY, respectively. The accuracy calculated as percentage recoveries were in the range of 99.00%-100.49% with low value of RSD% (<1.5%) demonstrating an excellent accuracy of the proposed methods. The developed methods were proved to be specific, sensitive and precise for quality control of the investigated drugs in their pharmaceutical dosage form without the need for any separation process.

Pharmacokinetics and related pharmacodynamics of anticholinergic drugs

The pharmacokinetics and some pharmacodynamic properties of atropine, glycopyrrolate and scopolamine are reviewed. With the development of new analytical methods for drug determination, it is now possible to measure relatively low concentrations of these drugs in biological fluids and, consequently, some new kinetic data have been collected. Following intravenous administration, a fast disappearance from the circulation is observed and due to a high total clearance value their elimination phase half-lives vary from 1 to 4 h. All these agents are nonselective muscarinic receptor antagonists, but their actions on various organ systems with cholinergic innervation show considerable diversity. The cardiovascular effects are of short duration; other peripheral muscarinic effects and CNS effects can last up to 8 h or even longer. Differing from atropine and scopolamine, glycopyrrolate as a quaternary amine penetrates the biological membranes (blood-CNS, placental barriers) slowly and incompletely, making it the drug of choice for elderly patients with coexisting diseases and for obstetric use. Similarly, its oral absorption is slow and erratic, and hence it cannot be used as an oral premedicant. Atropine, scopolamine and glycopyrrolate have a definitely faster absorption rate, when injected into the deltoid muscle compared with administration into the gluteal or vastus lateralis muscles. There appear to be significant differences in the metabolism and renal excretion of these agents. Scopolamine is apparently excreted into the urine mainly as inactive metabolites, nearly half of the atropine dose administered is recovered in the urine as the parent drug or as active metabolites and about 80% of glycopyrrolate is excreted as unchanged drug or active metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)

Solid-phase extraction techniques for the determination of glycopyrrolate from equine urine by liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry

Glycopyrrolate (Robinul) is a quaternary ammonium salt which serves as a respiratory enhancing drug. It is reportedly used in horse racing to improve breathing. Extraction of glycopyrrolate from equine urine employing unique solid-phase extraction techniques gave a residue suitable for liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-mass spectrometry (GC-MS). LC-MS-MS analysis employed an extract derived from 5 ml of urine subjected to cation-exchange chromatography. The daughter ion of m/z 318 monitored in the positive-ion mode was m/z 116. Recovery of glycopyrrolate was 99.5% and the within-run coefficient of variation of two quality control samples (1.0 and 10 ng/ml) was less than 5%. The between-run coefficient of variation for the same two quality control samples was less than 6.5%. The minimal detectable concentration for the assay was 250 pg/ml. Due to the extremely low concentration of glycopyrrolate in urine, qualitative detection via full-scan GC-MS required XAD-2 extraction of 50 ml of urine, cation-exchange chromatography clean-up and a tandem hydrolysis-derivatization procedure. The target analyte for GC-MS qualitative analysis was the methyl ester of hydrolyzed glycopyrrolate. Glycopyrrolate could be detected in post-administration (1 mg intravenously) urine samples for up to 9 h by both LC-MS-MS and GC-MS. The success of the method was due to a combination of the extreme sensitivity of the LC-MS-MS method and the very selective extraction process for quaternary ammonium salts.

Radioreceptor assay for pharmacokinetic studies of glycopyrrolate

A sensitive radioreceptor assay for the determination of glycopyrrolate concentrations in human plasma, urine and cerebrospinal fluid (CSF) is described. The applicability of the assay for kinetic studies in human was studied by determining the plasma concentrations and the renal excretion in three gynaecological surgical patients, who received 8 micrograms/kg of glycopyrrolate as a premedication intramuscularly. Tritiated N-methyl scopolamine was used to label the muscarinic cholinergic receptors in the membrane preparation obtained from the rat brain. The limit of detection of the assay was 70 ng/l in plasma, 2 micrograms/l in urine and 140 ng/l in CSF. There was no evidence of cross-reactivity of glycopyrrolate derivatives in clinical concentrations. A very rapid absorption was found with a mean maximum plasma concentration (Cmax) of 14.26 (range 12.02-16.97) micrograms/l and mean Tmax (time to Cmax) of 13.3 (range 10-15) min. and almost 50% of the dose administered was excreted into the urine within 3 hr. The CSF levels of glycopyrrolate were under detection limit. It is concluded that the sensitivity of the method is sufficient for pharmacokinetic studies of glycopyrrolate after therapeutic dosing.

Pharmacokinetics of glycopyrronium in parturients

A sensitive radioreceptor assay was used to determine the pharmacokinetics of glycopyrronium 6 micrograms/kg after intramuscular (deltoid muscle) administration in eight Caesarean section patients. A fast absorption rate was found with a mean maximum plasma concentration (Cmax) of 6.3 (SD 1.5) ng/ml, a mean time to Cmax (Tmax) of 10.0 (3.8) minutes and the elimination half-life (t1) of 33.4 (1.92). The respective AUC0-8 h value was 5.61 (1.27) hours ng/ml. This dose produced a significant increase in the maternal heart rate after 10 minutes (p less than 0.05) and an antisialogogue effect after 30 minutes (p less than 0.05) of the drug injection. Almost half of drug (48.3%) was excreted into the urine within 3 hours. There were no measurable levels of glycopyrronium in the lumbar cerebrospinal fluid (CSF) after 60 minutes of drug injection. The concentrations of glycopyrronium in the umbilical venous (0.28 (0.25) ng/ml) and in the umbilical arterial (0.18 (0.11) ng/ml) plasma after 86 minutes of drug injection were low and clinically insignificant, as was the case in the amniotic fluid (0.15 (0.08) ng/ml).

Glycopyrrolate: pharmacokinetics and some pharmacodynamic findings

In the present study, a sensitive and reproducible radioreceptor assay (RRA) was used to evaluate the basic pharmacokinetic properties of glycopyrrolate, a quaternary amine with peripheral antimuscarinic activity. Based on the plasma levels after a single intravenous injection, 6 micrograms/kg (n = 6), the distribution phase half-life (2.22 +/- 1.26 s.d. min) and the elimination phase half-life (0.83 +/- 0.29 h) of glycopyrrolate were short due to the low distribution volume during the elimination phase (0.64 +/- 0.29 l/kg) and to the respectively high total plasma clearance value (0.54 +/- 0.14 l/kg/h). An intramuscular injection, 8 micrograms/kg (n = 6), was followed by a fast and predictable systemic drug absorption and clinical effects (heart rate increase, dry mouth). In this group the time to maximum plasma concentration (tmax) was 27.48 +/- 6.12 min and the maximum plasma concentration (Cmax) was 3.47 +/- 1.48 micrograms/l. After oral drug intake, 4 mg (n = 6), an apparently low and variable gastrointestinal absorption was found (tmax = 300.0 +/- 197.2 min, Cmax = 0.76 +/- 0.35 microgram/l), thus indicating that the oral route of drug administration is of no value as a routine premedication. The correlation between the plasma concentration of glycopyrrolate and the drug effects appears to be variable. Because of its sensitivity, the RRA method proved to be quite useful in evaluating the kinetics of glycopyrrolate and its relationship to various clinical effects.

Pharmacokinetic implications for the clinical use of atropine, scopolamine and glycopyrrolate

Several specific and sensitive new methods for determining atropine and its metabolites in biological fluids have increased the possibility to characterise the pharmacokinetic properties of this antimuscarinic agent. Following i.v. injection, atropine disappears very quickly from the circulation, resembling its fast onset of action. Age, but not sex, appears to have a clear effect on its kinetics, explaining at least partly the higher sensitivity of very young and very old patients to this anticholinergic agent. Following i.m. or oral atropine administration, typical anticholinergic effects coincide quite well with the absorption rate of the drug, indicating that the premedication should be given about 1 and 2 h before induction of anaesthesia. A sufficient absorption after rectal administration offers an alternative treatment, especially in children. Differing from its placental transfer, atropine has a delayed and incomplete lumbar cerebrospinal fluid penetration, indicating a fundamental difference between these two biological membranes. Oropharyngeally administered atropine has a very variable absorption, but inhaled or intratracheally given drug has produced interesting new results, e.g. pulmonary atropine administration appears to have clinical significance in special situations, such as cardiac arrest and organophosphate poisoning (military personnel). Depending on the method used, different data on the metabolism and excretion for atropine have been reported and therefore further studies are needed in this respect. The pharmacokinetics of scopolamine and glycopyrrolate and their relation to clinical response are poorly understood.