Structural characterization of alkaline and oxidative stressed degradation products of lurasidone using LC/ESI/QTOF/MS/MS

Advanced stability-indicating RP-HPLC method for the quantification of lurasidone hydrochloride in bulk and PLGA-based in situ implant formulation

OBJECTIVES

The aims of the present investigation was to develop and validate stability-indicating RP-HPLC method for the estimation of Lurasidone hydrochloride (LURA-H) followed by its drug product, LURA-H encapsulated poly-D,L lactic-glycolic acid (PLGA) based in situ depot forming implant (LURA-H-PLGA-ISI).

METHODS

The LURA-H-PLGA-ISI formulation was developed by simple mixing method. According to international conference on harmonization guidelines, RP-HPLC method was developed and validated using Waters 2695 and discovery C18, 5μ, 250×4.6mm ID column. Force degradation studied were performed by various degradation techniques.

RESULTS

The chromatographic separations of LURA-H as well as LURA-H-PLGA-ISI with good resolutions have been achieved using the mobile phase 0.1% orthophosphoric acid and acetonitrile (50:50). The linearity in the range of 25-150 μg/mL of developed method. LOD and LOQ limits for LURA-H were found to be 0.07μg/mL and 0.22μg/mL, respectively. The % RSD was found to be<2% showing the precision of developed method. The accuracy of developed method was demonstrated which is close to 100±2%. Little modifications in the chromatographic conditions indicated robustness of the developed method. Further, solution stability of LURA-H and LURA-H-PLGA-ISI was stable at room temperature. Furthermore, force degradation studies demonstrated LURA-H was unaffected and stable under thermal, photodegradation and neutral (hydrolytic) stress conditions. AGREE and GAPI assessment demonstrated the developed method is environmentally sustainable.

CONCLUSION

The developed method is simple, robust, precise, accurate and sensitive which can be utilized for the regular analysis of LURA-H in quality control laboratories of bulk drug substance and PLGA containing formulations of LURA-H.

Separation and characterization of related substances of Lurasidone hydrochloride by LC-QTOF-MS techniques

In the present study, a reliable LC-QTOF-MS method was developed and employed for the separation and characterization of process-related substances and forced degradation products of Lurasidone hydrochloride. The chromatographic separation was carried out using an Agilent Poroshell 120 Bonus-RP C18 column (100 mm × 4.6 mm, 2.7 µm) and a mobile phase consisting of a gradient elution of 10 mM ammonium formate solution and methanol. The degradation studies followed the guidelines outlined in ICH Q1A (R2). It was observed that Lurasidone hydrochloride exhibited instability under photolytic, alkaline, and oxidative stress conditions, while remaining relatively stable under acidic and thermal stresses. Through positive ESI-QTOF mass spectrometric analysis, fourteen related compounds in total, including both process-related and stress degradation products, were identified based on the accurate masses of parent and product ions and calculated elemental compositions. Amongst these substances, nine had not been previously reported, and their formation mechanisms were speculated. The process-related substances were further confirmed by NMR spectra determination, and suggestions were proposed to eliminate them. This study highlights the potential for monitoring and controlling related substances during the manufacturing processes, providing valuable insights for process optimization and quality control of Lurasidone hydrochloride.

Microbial degradation products of lurasidone and their significance in postmortem toxicology

Recent research reported that lurasidone degrades in unpreserved ante-mortem human whole blood inoculated with microorganisms known to dominate postmortem blood specimens. In vitro degradation occurred at a similar rate to risperidone, known to degrade in authentic postmortem specimens until below analytical detection limits. To identify the lurasidone degradation products formed, an Agilent 6520 liquid chromatograph quadrupole-time-of-flight mass spectrometer (LC-QTOF-MS) operating in auto-MS/MS mode was used. Numerous degradation products not previously reported in prior in vitro or in vivo pharmacokinetic studies or forced degradation studies were detected. Accurate mass data, mass fragmentation data, acetylation experiments, and a proposed mechanism of degradation analogous to risperidone supports initial identification of the major degradation product as N-debenzisothiazole-lurasidone (calculated m/z [M + H]⁺  = 360.2646). A standard was unavailable to conclusively confirm this identification. Retrospective data analysis of postmortem cases involving lurasidone identified the presence of the major degradation product in four of six cases where lurasidone was also detected. This finding is significant for toxicology laboratories screening for this drug in postmortem casework. The major postmortem lurasidone degradation product has consequently been added to the LC-QTOF-MS drug screen at Forensic Science SA (FSSA) to indicate postmortem lurasidone degradation in authentic postmortem blood specimens and as a marker of lurasidone administration in the event lurasidone is degraded to concentrations below detection limits.

Improving Lurasidone Hydrochloride's Solubility and Stability by Higher-Order Complex Formation with Hydroxypropyl-β-cyclodextrin

The biopharmaceutical classification system groups low-solubility drugs into two groups: II and IV, with high and low permeability, respectively. Most of the new drugs developed for common pathologies present solubility issues. This is the case of lurasidone hydrochloride-a drug used for the treatment of schizophrenia and bipolar depression. Likewise, the stability problems of some drugs limit the possibility of preparing them in liquid pharmaceutical forms where hydrolysis and oxidation reactions can be favored. Lurasidone hydrochloride presents the isoindole-1,3-dione ring, which is highly susceptible to alkaline hydrolysis, and the benzisothiazole ring, which is susceptible to a lesser extent to oxidation. Herein, we propose to study the increase in the solubility and stability of lurasidone hydrochloride by the formation of higher-order inclusion complexes with hydroxypropyl-β-cyclodextrin. Several stoichiometric relationships were studied at between 0.5 and 3 hydroxypropyl-β-cyclodextrin molecules per drug molecule. The obtained products were characterized, and their solubility and stability were assessed. According to the obtained results, the formation of inclusion complexes dramatically increased the solubility of the drug, and this increased with the increase in the inclusion ratio. This was associated with the loss of crystalline state of the drug, which was in an amorphous state according to infrared spectroscopy, calorimetry, and X-ray analysis. This was also correlated with the stabilization of lurasidone by the cyclodextrin inhibiting its recrystallization. Phase solubility,¹H-NMR, and docking computational characterization suggested that the main stoichiometric ratio was 1:1; however, we cannot rule out a 1:2 ratio, where a second cyclodextrin molecule could bind through the isoindole-1,3-dione ring, improving its stability as well. Finally, we can conclude that the formation of higher-order inclusion complexes of lurasidone with hydroxypropyl-β-cyclodextrin is a successful strategy to increase the solubility and stability of the drug.

Structural elucidation of two novel degradants of lurasidone and their formation mechanisms under free radical-mediated oxidative and photolytic conditions via liquid chromatography-photodiode array/ultraviolet-tandem mass spectrometry and one-dimensional/two-dimensional nuclear magnetic resonance spectroscopy

Lurasidone is an antipsychotic drug clinically used for the treatment of schizophrenia and bipolar disorder. During a mechanism-based forced degradation study of lurasidone, two novel degradation products were observed under free radical-mediated oxidative (via AIBN) and solution photolytic conditions. The structures of the two novel degradants were identified through an approach combining HPLC, LC-MSⁿ (n = 1, 2), preparative HPLC purification and NMR spectroscopy. The degradant formed under the free radical-mediated condition is an oxidative degradant with half of the piperazine ring cleaved to form two formamides; a mechanism is proposed for the formation of the novel N,N'-diformyl degradant, which should be readily applicable to other drugs that contain a piperazine moiety that is widely present in drug molecules. The degradant observed under the solution photolytic condition is identified as the photo-induced isomer of lurasidone with the benzisothiazole ring altered into a benzothiazole ring.

Characterization of stress degradation products of nintedanib by UPLC, UHPLC-Q-TOF/MS/MS and NMR: Evidence of a degradation product with a structure alert for mutagenicity

Nintedanib is an anti-cancer drug used for the treatment of idiopathic pulmonary fibrosis and non-small cell lung cancer. The purpose of this study was to explore its degradation chemistry under various stress conditions recommended in ICH guidelines Q1A R(2). The drug was subjected to hydrolytic, photolytic, thermal and oxidative (H₂O₂, AIBN, FeCl₃ and FeSO₄) stress conditions. The degradation products formed in stressed solutions were successfully separated on an ACQUITY UPLC CSH C18 (2.1 × 100 mm, 1.7 μm) column, using a gradient UPLC-PDA method, developed with acetonitrile:methanol (90:10) and 0.1 % formic acid (pH 3.0) as the mobile phase. The drug proved to be labile to acidic, neutral and alkaline hydrolytic, and H₂O₂/AIBN oxidative conditions. It was stable to photolytic and thermal stress conditions, and even in oxidative reaction solutions containing FeCl₃ or FeSO₄. Additionally, the drug exhibited instability when its powder with added sodium bicarbonate was stored at 40 °C/75 % RH for 3 months. In total, nine degradation products (DPs 1-9) were formed. To characterize them, a comprehensive mass fragmentation pathway of the drug was first established using UHPLC-Q-TOF/MS/MS data. Similarly, the mass studies were then carried out on the stressed samples using the developed UPLC method. All the degradation products were primarily characterized through comparison of their mass fragmentation profiles with that of the drug. To confirm the structure in one case (DP 3), additional nuclear magnetic resonance (NMR) studies were carried out on the isolated product. Subsequently, mechanisms for their formation were laid down. A significant finding was the formation of a degradation product upon acid hydrolysis having a free aromatic amine moiety, which is considered as a structural alert for mutagenicity. Furthermore, the physicochemical and ADMET properties of the drug and its degradation products were predicted using ADMET predictor™ software.

Study on forced degradation behaviour of dofetilide by LC-PDA and Q-TOF/MS/MS: Mechanistic explanations of hydrolytic, oxidative and photocatalytic rearrangement of degradation products

A solution and solid state forced decomposition study was carried on dofetilide under diverse stress conditions of hydrolysis, oxidation, photolysis and thermal as per International Council for Harmonisation guidelines (ICH) Q1A(R2) to understand its degradation behaviour. A total of eight degradation products (DPs) were identified and separated on reversed phase kromasil 100 C8 column (4.6 mm x 250 mm x5 μm) using gradient elution with ammonium acetate (10 mM, pH 6.2) and acetonitrile as mobile phase. The detection wavelength was selected as 230 nm. The high performance liquid chromatography (HPLC) study found that the drug was susceptible to hydrolytic stress condition, but it was highly unstable to photolytic and oxidative conditions. The solid drug was stable in thermal and photolytic conditions. Initially comprehensive mass fragmentation pattern of the drug was accomplished with the LC/ESI/QTOF/MS/MS studies in positive ionization mode. The same was followed for all the eight degradation products to characterise their structure. The DP4 was N-oxide and the structure was confirmed by LC/APCI/QTOF/MS/MS in positive ionization mode. The complete mass fragmentation pattern of the drug and its DPs were established which in turn helped the characterisation of their structures. The mechanistic pathway for the formation of all the DPs was explained.

Identification and characterization of unknown degradation impurities in beclomethasone dipropionate cream formulation using HPLC, ESI-MS and NMR

The present study focuses on identifying the degradation profile and pathways of unknown impurities from beclomethasone dipropionate (BDP) topical cream formulation reported under accelerated stability conditions. Six degradation impurities were observed during the accelerated stability testing of BDP topical cream formulation, and these thermally labile degradation impurities were primarily identified using a simple, effective and mass compatible isocratic reversed-phase high-performance liquid chromatography with ultraviolet detection method. The degradation impurities found in this sample were of very low concentration levels, thus the concentration of these impurities in the sample was enriched by mimicking the thermal degradation conditions to structurally elucidate the unknown impurities. These BDP thermal degradation impurities were isolated using preparative liquid chromatography and followed by pre-concentration using rota-vapour. Further, the collected thermal degradation impurities were characterized using ESI-MS, and the major impurity was identified using ¹H and C¹³ NMR spectroscopy, and DEPT technique. Plausible degradation pathway and mechanism of each impurity from BDP has been proposed based on the obtained mass and NMR spectral data. Thus, the present method is simple and suitable to be applied towards BDP assay in various formulations, and also to investigate the thermal stability and degradation kinetics of the final drug product.

Studies on photodegradation process of psychotropic drugs: a review

Consumption of psychotropic drugs is still increasing, especially in high-income countries. One of the most crucial consequences of this fact is significant release of them to the environment. Considerable amounts of atypical antipsychotics, benzodiazepines, antidepressants, and their metabolites were detected in river, lake, and sea water, as well as in tissues of aquatic organisms. Their ecotoxicity was proved by numerous studies. It should be noticed that interaction between psychotropic pharmaceuticals and radiation may lead to formation of potentially more toxic intermediates. On the other hand, photo-assisted wastewater treatment methods can be used as an efficient way to eliminate them from the environment. Many methods based on photolysis and photocatalysis were proposed and developed recently; nevertheless, the problem is still unsolved. However, according to recent studies, photocatalysis could be considered as the most promising and far more effective than regular photolysis. An overview on photolytic as well as homogenous and heterogeneous photocatalytic degradation methods with the use of various catalysts is presented. The photostability and phototoxicity of pharmaceuticals were also discussed. Various analytical methods were used for the photodegradation research, and this issue was also compared and summarized. Use of high-resolution multistage mass spectrometry (Q-TOF, ion trap, Orbitrap) was suggested. The combined techniques such as LC-MS, GC-MS, and LC-NMR, which enable qualitative and quantitative analyses in one run, proved to be the most valuable in this case. Assembling of MS/MS spectra libraries of drug molecules and their phototransformation products was identified as the future challenge.

Characterization of stress degradation products of blonanserin by UPLC-QTOF-tandem mass spectrometry

Forced degradation study of blonanserin and structural elucidation of its degradation products was performed using high resolution tandem mass spectrometry.

Characterization of stress degradation products of mirabegron using UPLC-QTOF-MS/MS and in silico toxicity predictions of its degradation products

Mirabegron is a novel beta-3 adrenergic receptor agonist in the treatment of overactive bladder disorder.