Development of a Stability-Indicating Purity Method for Ubrogepant Through Stress Degradation Analysis, Extraction, and Characterization of Unidentified Degradation Products Using Flash Chromatography, NMR, IR, and LC-MS

BACKGROUND

Ubrogepant is a prescription medication used to prevent migraine headaches. It is currently available in tablet form.

OBJECTIVE

The goal of this work is to investigate the drug degradation profile of ubrogepant, as well as to isolate and characterize undiscovered ubrogepant degradation products by utilizing LC-MS, NMR, and IR spectroscopic analytical techniques and, furthermore, to develop a high-resolution, sensitive, stability-indicating analytical approach for detecting and quantifying ubrogepant degradation products in its pharmaceutical formulation.

METHODS

To identify and quantify the degradation products of ubrogepant in pharmaceutical products, a novel gradient reverse-phase HPLC (RP-HPLC) technique with a photo diode array (PDA) detector was developed by utilizing a C18 stationary phase column. The eluent comprised a mixture of acetonitrile and water with 0.1% (v/v) ortho-phosphoric acid. To establish the intrinsic stability of the ubrogepant pharmaceutical product, it was stress-tested under various degradation conditions, including water, alkaline, acid hydrolysis, photolytic, oxidative, and thermal. Flash chromatography was used to isolate the two major degradants, and the structures were determined using NMR (1H, 13C, distortionless enhancement by polarisation transfer-DEPT-135), IR, and LC-MS methods.

RESULTS

The ubrogepant medication was relatively more degradable in alkaline and acidic conditions, and two unique degradation products were discovered. Based on spectroscopic and chromatographic evidence, it was conclusively demonstrated that these unique compounds were ubrogepant hydrolysis products. All degradation products were separated with a resolution greater than 2.0. The peak purity data showed that the ubrogepant peak in all of the stress samples examined was pure. Under all stress environments, ubrogepant achieved a minimum mass balance of 95%. The validated approach developed was sensitive enough to quantify ubrogepant degradation products at 0.03% of the ubrogepant test concentration.

CONCLUSION

The proposed method was found to be stability-indicating since it fits all of the regulatory authorities' typical requirements. This method is highly efficient for detecting and quantifying impurities in ubrogepant drug substances and drug products in QC laboratories.

HIGHLIGHTS

Two new degradation products of ubrogepant were successfully extracted and characterized using NMR, IR, and LC-MS spectroscopic methods. The proposed HPLC method can accurately quantify the degradation products of ubrogepant in pharmaceutical products and is sensitive enough to detect degradation products of ubrogepant as low as 0.17 µg/mL.

Facile Access to Solifenacin Impurity K: One-Step Synthesis and an HPLC-MS Method for Its Determination

Solifenacin (SFC) is a potent muscarinic antagonist that effectively reduces bladder muscle contraction, thereby alleviating symptoms such as frequency of micturition and urgency. Oxidation of SFC leads to the formation of impurities like Impurity K. Effective analysis and control of this impurity is crucial for ensuring compliance with regulatory standards and safeguarding patient health. To address these challenges, we propose a novel one-step synthesis of Impurity K from SFC. Impurity K was synthesized using cerium(IV) ammonium nitrate (CAN) in water/acetonitrile as the solvent. Additionally, we describe a new HPLC-MS method for the detection of Impurity K in solifenacin succinate tablets.

Micro/nanofluidic device for tamsulosin therapeutic drug monitoring in patients with benign prostatic hyperplasia at point of care

Discovering the balance between toxicity and efficacy for many drugs requires therapeutic drug monitoring (TDM) of their concentrations in the blood. Here, a hot-embossed microfluidic device with a new design integrated to a nanofracture is presented for purification of blood samples from numerous proteins and cells, allowing to the separation of small molecules from blood matrix. The device was used to separate and quantitatively detect tamsulosin drug after derivatization with fluorescamine reagent, allowing converting it from a neutral molecule into a charged fluorescent complex under the experimental conditions, and thus its separation by electrophoresis. The device is portable and easy operated, and the presented method showed good linearity (R2 = 0.9948) over a concentration range of 0.1-1 μg/mL. The relative standard deviation (RSD%) was below 10% (n = 3), indicating good precisions, and the limit of detection (LOD) and limit of quantitation (LOQ) values were estimated to be 0.1 and 0.55 μg/mL, respectively. Whole blood samples from 10 patients with benign prostatic hyperplasia (BPH) were analyzed, showing good percentage recoveries of tamsulosin in whole blood. This point-of-care (POC), low-cost method could increase the convenience of patients and doctors, make therapies safer, and make TDM available in different regions and places.

Expeditive Chromatographic Methods for Quantification of Solifenacin Succinate along with its Official Impurity as the Possible Acid Degradation Product

Two selective stability-indicating procedures were adopted for the quantification of Solifenacin succinate (SOL) along with its acid degradant, in its powder form or in pharmaceutical tablet. Under stress conditions, the acid degradation pathway of SOL was investigated, its official impurity (SOL imp-A) was obtained as the possible acid degradation product, also. A densitometric technique based on the separation of SOL from SOL imp-A employing HPTLC plates prelaminated with silica gel 60 F254 as the stationary phase and a developing solution containing methanol:chloroform:ammonia (8:1:1, v/v/v) and UV scanning of the developed bands at 220 nm. Linear regression analysis data for the calibration plot of SOL showed perfect linear relationships throughout the range of concentration 10-60 μg/band. A reversed phase C18 analytical column (4.6 × 250 mm, 5 μm) was also used to separate the mixture at a flow rate of 1 mL/min, using acetonitrile:0.05 M phosphate buffer (70:30, v/v) as the mobile phase and phosphoric acid to set pH = 3.5. Quantification was obtained at 220 nm using peak area and linear calibration curve across a concentration range of 10-70 μg/mL. The recommended procedures were applied to the existing dosage form, and they generated satisfactory results.

Comparative Study of Continuous Wavelet Transform and Multivariate Calibration for the Simultaneous Spectrophotometric Determination of Tamsulosin and Solifenacin in Pharmaceutical Formulation and Biological Sample

BACKGROUND

Spectrophotometry alone is not applicable for the simultaneous determination of drugs in a multicomponent pharmaceutical formulation owing to their overlap.

OBJECTIVE

In this study, the combination of UV-Vis spectrophotometry and chemometric methods, including continuous wavelet transform (CWT) and partial least-squares (PLS) was presented for the simultaneous estimation of tamsulosin (TAM) and solifenacin (SOL) in synthetic mixtures, commercial formulations, and a biological sample.

METHODS

The simultaneous spectrophotometric determination of TAM and SOL in binary mixtures, a real sample, and a biological sample was performed by applying CWT and PLS approaches.

RESULTS

In the CWT method, two various wavelet families named Daubechies (db2) at wavelength 223 nm and Biorthogonal (bior1.3) at wavelength 227 nm based on the appropriate zero-crossing point were selected for TAM and SOL, respectively. The linear ranges of TAM and SOL were 0.25-4 μg/mL and 10-30 μg/mL, respectively. The LODs were 0.0459 μg/mL and 0.2085 μg/mL, while the LOQs were 0.3208 μg/mL and 0.6495 μg/mL for TAM and SOL, respectively. The average recovery values of 18 mixtures were 98.28% and 97.79% for TAM and SOL, respectively. Also, the root mean square error (RMSE) of both components was lower than 2.3. Based on the k-fold cross-validation in the PLS approach, the optimum number of components related to TAM and SOL were 9 and 5 with a mean square error prediction (MSEP) of 0.0153 and 0.0370, respectively. The mean recovery values of the test set were found to be 100.09% for TAM and 99.95% for SOL where RMSE values were 0.0064 and 0.0169 for TAM and SOL, respectively.

CONCLUSION

Analysis of variance (ANOVA) was applied to the results of the real sample and there was no significant difference between the proposed methods and HPLC as a reference technique. The result obtained revealed that the proposed methods were found to be fast, facile, economical, and precise, and provide a suitable alternative to the HPLC technique for the concurrent determination of TAM and SOL in QC laboratories.

HIGHLIGHTS

UV-Vis spectrophotometry combined with CWT and PLS was developed. Simultaneous analysis of TAM and SOL was performed using the proposed approaches. These methods were implemented on synthetic mixtures, commercial formulations, and a biological sample. ANOVA test was used to compare the suggested methods and the HPLC technique.

Simultaneous ultra-sensitive analysis of tamsulosin hydrochloride and tolterodine tartrate binary mixture in their dosage form via high-performance thin-layer chromatography with fluorimetric detection

A simple, sensitive, selective, and stability-indicating high-performance thin-layer chromatography method with fluorescence detection was developed for the analysis of a mixture of tamsulosin hydrochloride and tolterodine tartrate, used in the management of benign prostatic hyperplasia in their laboratory-prepared binary mixture and dosage form. The separation was employed on thin-layer chromatography silica gel 60 aluminum sheets. As developing system, ethyl acetate–n-hexane–diethylamine (9:3:1, V/V) was used. Tamsulosin and tolterodine had retention factors (RF) of 0.40 ± 0.03 and 0.85 ± 0.03, respectively. A 225 nm excitation wavelength was used for the fluorescence detection. Linearity was in the range of 10.0–200.0 and 100.0–900.0 ng/band for tamsulosin and tolterodine, respectively. The method was validated successfully according to the International Council for Harmonisation guidelines. Our suggested method for determining tamsulosin and tolterodine in their dosage forms and in the presence of their degradation products could be conveniently applied in quality-control laboratories.

Innovative electrochemical electrode modified with Al2O3 nanoparticle decorated MWCNTs for ultra-trace determination of tamsulosin and solifenacin in human plasma and urine samples and their pharmaceutical dosage form

A simple, cheap, sensitive, and time-saving square wave voltammetric (SWV) procedure using a carbon paste electrode modified with aluminum oxide nanoparticle decorated multi-walled carbon nanoparticles (Al2O3-NPs/MWCNTs/CPE) is presented for the ultra-sensitive determination of tamsulosin (TAM) and solifenacin (SOL), one of the most prescribed pharmaceutical combinations in urology. Characterization of the developed electrode was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD) patterns, energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM) and FT-IR spectrophotometry. The voltammetric behavior of TAM/SOL was evaluated using Al2O3-NPs in different content and electrode compositions. The use of Al2O3 functionalized MWCNTs as a CPE modifier increased the process of electron transfer as well as improved the electrode active surface area therefore, ultra-sensitive results were acquired with a linear range of 10-100 and 12-125 ng ml-1 for TAM and SOL respectively, and a limit of the detection value of 2.69 and 3.25 ng ml-1 for TAM and SOL, respectively. Interestingly, the proposed method succeeded in quantifying TAM and SOL with acceptable percentage recoveries in dosage forms having diverged concentration ranges and in the biological fluids with very low peak plasma concentration (C max). Furthermore, the proposed method was validated, according to the ICH criteria, and shown to be accurate and reproducible.

Two green chromatographic methods for the quantification of tamsulosin and solifenacin along with four of their impurities

Modern analytical procedures often include impurity profiling to verify the potency, safety, and effectiveness of new formulations. We had to develop techniques based on green analysis since the detrimental influence of solvents and chemicals on the environment has now become a serious concern. Two selective, sensitive and green LC methods were established and fully validated for quantitation of tamsulosin hydrochloride and solifenacin succinate along with four of their official and/or related impurities namely; tamsulosin sulfonic acid, tamsulosin impurity H, solifenacin impurity A and solifenacin impurity C. The first used High Performance Thin Layer Chromatography with silica gel 60 F254 plates as the stationary phase and an elution system of ethyl acetate:butanol:glacial acetic acid (10.0:0.4:0.1, by volume) and a scanning wavelength of 225.0 nm. The second method depended on HPLC with diode array detection. Chromatographic separation was accomplished on a Zorbax^® SB C₁₈ (250 × 4.6 mm² , 5 μm) column utilizing a mixture of 10.0 mM sodium dihydrogen phosphate (pH 3.0, adjusted by o-phosphoric acid) and methanol, at a flow rate of 0.8 mL/min in a gradient elution mode and then the separated peaks were scanned at a wavelength of 225.0 nm. To assess the greenness profile, three distinct methodologies were applied. This article is protected by copyright. All rights reserved.

Green & Sensitive pH-dependent Spectrofluorimetric Assay of Tamsulosin Hydrochloride and Tadalafil in their New Combined Formulation for Benign Prostatic Hyperplasia: Application to Spiked Human Plasma

Sensitive and green spectrofluorimetric methods were utilized for Tamsulosin Hydrochloride (TAM) and Tadalafil (TDL) assessment in bulk and their newly available combined mixture for benign prostatic hyperplasia and erectile dysfunction. The technique relies on measuring native fluorescence of TAM in 0.1 N HCl at 324 nm and TDL in 0.1 N NaOH at 348 nm due to their different fluorimetric behavior in acidic and basic media where TAM has no fluorescence in basic medium and vice versa. To achieve better regression, the spectra were derivatized allowing determination of TAM at 314 nm and TDL at 320 and 380 nm (peak to peak) by applying third and first derivative, respectively. In addition, pH-dependent "constant-wavelength synchronous" spectrofluorimetry was applied where TAM and TDL were determined at 218 nm in acidic medium and at 268 nm in basic medium, respectively. Finally, derivatizing the latter emission spectra allowed determination of TAM and TDL at 232 nm and at 262 and 278 nm (peak to peak), respectively. Acidic and basic emission spectra where scanned at λ_exc = 225 nm (for TAM assay) and at λ_exc = 247 nm (for TDL assay), respectively. Fluorescence-concentration plots were linear and the proposed methods were used for analysis of TAM and TDL combined laboratory prepared formulation. These procedures are green, sensitive and of low cost which make them suitable for quality control analysis of the two drugs. In addition, the high selectivity of the proposed methods was tested by successfully applying them for TAM and TDL assay in plasma samples.

Smart UV spectrophotometric methods based on simple mathematical filtration and classical methods for the simultaneous determination of tamsulosin and solifenacin: A comparative study of efficacy and spectral resolution

Treatment protocols combining tamsulosin and solifenacin proved better management of the complicated urinary tract symptoms. The pharmaceutical preparations of tamsulosin and solifenacin suffered from the high difference in their ratio, 0.4 mg tamsulosin and 6 mg solifenacin, and strong spectral overlap. Here, we developed four simple, accurate and selective spectrophotometric methods based on simple mathematical manipulations. These methods require the simplest mathematical filtration using short steps performed using built-in functions of the spectrophotometer operating software utilizing zero-order or derivative spectra. These methods are namely absorption correction method (ACM), induced dual-wavelength (IDW), absorptivity factor method (AFM) and first derivative method (D1). The linear ranges were 15-70 µg/ml and 100-1200 µg/ml for TAM and SFN, respectively. The limits of quantitation were in the range of 3.8-4.05 µg/ml and 23.34-59.05 µg/ml, while the limits of detection were in the range of 1.25-1.34 µg/ml and 7.7-24.6 µg/ml for TAM and SFN, respectively. All validation parameters investigated as per ICH guidelines. A statistical comparison executed for the proposed methods with each other and with the reported methods showed no significant difference between the proposed and the reported methods.

Stability assessment of tamsulosin and tadalafil co-formulated in capsules by two validated chromatographic methods

The advent of a new pharmaceutical formulation evokes the need for examining the chemical stability of their constituents and establishing proper stability-indicating methods. Herein, the stability of the newly co-formulated Tamsulosin and Tadalafil were examined under different stress conditions. The acidic degradation of Tamsulosin yielded its sulfonated derivative, while Tadalafil was susceptible to both acidic and basic degradation. Two stability-indicating chromatographic methods, namely; high-performance thin-layer chromatography and high-performance liquid chromatography, have been developed. Significant high-performance thin-layer chromatography-fractionation could be achieved by utilizing a stationary phase of silica gel 60 F₂₅₄ and a mobile phase composed of ethyl acetate/toluene/methanol/ammonia (4:2:4:0.6, by volumes) with densitometric recording at 280 nm over a concentration range of 0.5-25 μg/band for both drugs. The HPLC-separation could be reached on XBridge^® C₁₈ column isocraticaly by using a mobile phase having acetonitrile/phosphate buffer, pH 6.0 (45:55, v/v) pumped at a flow rate of 1.7 mL/min and applying diode array ultraviolet-detection at 210 nm over a linearity range of 3-70 μg/mL for each drug. Specificity of the two methods was additionally assured via peak purity assessment. Moreover, the methods were distinctly exploited for evaluating the drugs' stability in accelerated stability-studied samples of Tamplus^® capsules.

A novel HPLC-DAD method for simultaneous determination of alfuzosin and solifenacin along with their official impurities induced via a stress stability study; investigation of their degradation kinetics

Stability and impurity profiling are in high demand to guarantee the potency, safety and efficacy of new formulations along with their shelf-life. In this study, stability testing of alfuzosin (ALF) and solifenacin (SOL) in their newly co-formulated capsules was conducted under different stress conditions. The obtained degradation products were structurally elucidated and found to be their official impurities, namely; ALF impurity-D and SOL impurities-A, E & I. A selective and reliable stability-indicating HPLC method was developed for assaying the cited drugs along with three of those official impurities. Chromatographic separation was accomplished within 8 minutes using a XBridge® C18 column as the stationary phase and acetonitrile : phosphate buffer (pH 8) : triethylamine (60 : 40 : 0.02, by volume) as the mobile phase at a flow rate of 1.3 mL min-1. Quantification of the analytes was performed at 210 nm using a diode array detector through which peak purity was assessed. The proposed method was validated as per ICH guidelines and it was successfully applied for the determination of the cited drugs in their combined pharmaceutical formulation with percent recoveries of 100.47 and 100.15 for ALF and SOL, respectively. Moreover, the proposed method was exploited for the assessment of the two drugs' stability in Solitral® capsules under accelerated storage conditions. The method was further extended for studying the degradation kinetics of the two drugs.