Tablet Samples Research Articles

Development of a new magnetic solid-phase extraction method prior to HPLC determination of naproxen in pharmaceutical products and water samples

In this study, a new magnetic solid phase extraction based on magnetic composite modified with biochar obtained from pumpkin peel was developed for the enrichment and extraction of Naproxen in lake water, tablet and urine samples. The effects of main parameters such as pH, extraction time, amount of adsorbent and sample volume, which affect magnetic solid phase extraction, were investigated. Under optimal conditions, intraday and interday precision values for naproxen were below 5.9, with accuracy (relative error) better than 7.0 %. The detection limit and preliminary concentration factor were 12 ng/mL and 10, respectively. The method proposed here can be used for routine analysis of naproxen in lake water, urine and tablets.

Quality of Essential Medicines from Different Sources in Enugu and Anambra, Nigeria.

This study investigated the quality of 13 essential medicines in the states of Enugu and Anambra, Nigeria. A total of 260 samples were purchased from licensed pharmaceutical manufacturers and wholesalers and from vendors in pharmaceutical markets with unclear licensing status. Samples were analyzed for identity, content, and dissolution according to the United States Pharmacopeia (USP) 42 monographs. Forty-five samples of this study could be examined for authenticity with the Mobile Authentication Service scheme of the Nigerian National Agency for Food and Drug Administration and Control. Out of all samples, 25.4% did not comply with the USP 42 specifications. Strikingly, 21 out of 22 dexamethasone tablet samples (95%) were out of specification (OOS). Nine out of 19 glibenclamide samples (47%) failed dissolution testing, and 7 out of 17 cotrimoxazole samples (41%) failed assay testing. Medicines against noncommunicable diseases showed a slightly higher percentage of OOS samples than anti-infectives (21.2% versus 17.6%). The rates of OOS samples were similar in medicines stated to be produced in Nigeria, India, and China but were very different between individual manufacturers from each of these countries of origin. Therefore, prequalification of products, manufacturers, and suppliers are very important for quality assurance in medicine procurement. Unexpectedly, the total proportions of OOS samples were similar from licensed vendors (25.2%) and from markets (25.5%). Four samples (1.5%), all collected in markets, were clearly falsified and did not contain the declared active pharmaceutical ingredients. The proportion of falsified medicines was found to be lower than frequently reported in the media for Nigeria.

Firefly Interval Selection Combined With Extreme Learning Machine for Spectral Quantification of Complex Samples

ABSTRACTFirefly algorithm (FA) combined with extreme learning machine (ELM) is developed for spectral interval selection and quantitative analysis of complex samples. The method firstly segments the spectra into a certain number of intervals. Vectors with 1 and 0, which represent the interval selected or not, are used as the inputs of the FA. The RMSEP value predicted by ELM model is used as the fitness function of the FA. The activation function and number of hidden layer nodes of ELM, number of spectral intervals, population number, environmental absorbance, and constant of FA are optimized. The predictive performance of FA‐ELM is compared with full‐spectrum PLS, ELM, genetic algorithm‐ELM (GA‐ELM), and particle swarm optimization‐ELM (PSO‐ELM) by one ultraviolet (UV) spectrum dataset of gasoil and three near‐infrared (NIR) spectral datasets of corn, wheat, and tablet samples. The results show that FA‐ELM has a better performance compared with its competitors in predicting monoaromatics, water, wheat kernel texture, and active pharmaceutical ingredients (APIs) in gasoil, corn, wheat, and tablet samples.

Pharmacological and technological studies in the development of tablet composition with acorus calamus leaf extract

The aim: To determine the optimal qualitative and quantitative composition of auxiliary substances for tablets containing dry extract of Acorus calamus leaves and the solid dispersion of quercetin, their relatively therapeutic dose and antiexudative activity. Materials and methods: This study determined a relatively therapeutic dose of dry extract of Acorus calamus leaves, investigated the impact of various auxiliary substances on the properties of tablets formulated with active ingredients - dry extract of Acorus calamus leaves and solid dispersion of quercetin, and assessed antiexudative activity these tablets. The comprehensive analysis entailed the utilization of standardized pharmacopoeial methods to evaluate the quality of the tablet samples. These methods encompassed a range of assessments designed to ensure that the tablets met the requisite pharmacological standards, focusing on key characteristics such as dissolution rate and stability. Determination of the relatively therapeutic dose and antiexudative activity made using standard pharmacological methods in laboratory rats. Results: In-depth exploration during the study led to identifying Ac-Di-Sol and Lubripharm SSF as the most suitable auxiliary substances for the tablet composition. Detailed analysis revealed that Ac-Di-Sol, when utilized at a 10 % concentration, markedly improved the tablets' disintegration rate without adversely affecting their structural integrity. Concurrently, Lubripharm SSF was observed to significantly enhance the tablets' mechanical stability by reducing their friability. Conclusions: As a result of the study, the relatively therapeutic dose of dry extract of Acorus calamus leaves, and the solid dispersion of quercetin, optimal auxiliary substances for the tablet formulation - Ac-Di-Sol and Lubripharm SSF - were established. The conducted research enabled the development of a tablet composition that aligns with the requisite pharmacotechnological specifications and conditions of the modern pharmaceutical industry and demonstrates high antiexudative activity relative to monocomponent substances and famous drugs

Hydrogen peroxide enhanced glow-type chemiluminescence of hydrazine hydrate modified carbon quantum dots-potassium persulfate system

Most known chemiluminescence (CL) systems are flash-type that generate weak luminescence and decline quickly after dozens of seconds, while the glow-type CL systems have stable emission for an extended period to achieve accurate quantitation. In this work, a long-term CL system based on hydrazine-hydrate (N2H4·H2O) modified carbon quantum dots (N-CQDs) as a luminescent probe, with K2S2O8 and H2O2 as co-reactants, was proposed. The CL emission enhanced by H2O2 increased 18-fold more than that of N-CQDs and K2S2O8 direct reaction, and decayed by 5% of the maximum intensity over 700 s. In the reaction system, K2S2O8 and H2O2 co-reactants can promote each other to continuously generate corresponding radicals (•OH, O2•−, 1O2), which in turn trigger the CL emission of N-CQDs. This phenomenon was identified as the primary cause for the production of persistent CL. In addition, a stable and selective CL sensor based on the N-CQDs-K2S2O8-H2O2 CL enhancing system was developed for ascorbic acid quantitation in the linear range from 0.1 to 10.0 mM with a detection limit of 0.036 mM. The method has been applied to the analysis of tablet samples and holds potential in pharmaceutical analysis field.

Binder-free and efficient voltammetric sensor based on Zn-Ca2CuO3 nanoparticles for simultaneous determination of amlodipine, acetaminophen, and ascorbic acid in hypertension patients.

Amlodipine (AM) is a long active calcium channel blocker used to relax blood vessels by preventing calcium ion transport into the vascular walls and its supporting molecules acetaminophen (AP) and ascorbic acid (AA) are recommended for hypertension control and prevention. Considering their therapeutic importance and potential side effects due to over dosage, we have fabricated a sensor for individual and simultaneous determination of AA, AP, and AM in pharmaceuticals and human urine using novel Zn-doped Ca2CuO3 nanoparticles modified glassy carbon electrode (GCE). Optimally doped Ca2CuO3 (2.5 wt% Zn at Cu site) enhanced the detection of target molecules over much wider concentration ranges of 50 to 3130 µM for AA, 0.25 to 417 µM for AP, and 0.8 to 354 µM for AM with the corresponding lowest detection limits of 14 µM, 0.05 µM, and 0.07 µM, respectively. Furthermore, the Zn-Ca2CuO3/GCE exhibited excellent selectivity and high sensitivity even in the presence of several potential interfering agents. The usefulness of the developed electrode was tested using an amlodipine besylate tablet and urine samples of seven hypertension patients under medication. The results confirmed the presence of a significant amount of AP and AM in six patients' urine samples indicating that the personalized medication is essential and the quantum of medication need to be fixed by knowing the excess medicines excreted through urine. Thus, the Zn-Ca2CuO3/GCE with a high recovery percentage and good sensitivity shall be useful in the pharmaceutical and biomedical sectors.

Hybrid Paper/Polyester‐Based Laser‐Induced Graphene Electrodes for Electrochemical Detection of Tadalafil

Here, we describe for the first time the fabrication of laser‐induced graphene (LIG) electrodes on a hybrid substrate composed of sandpaper and polyester. As a proof of concept, the proposed device was used as a voltammetric sensor for tadalafil (TAD) quantification in authentic tablet samples. . The electrochemical TAD sensing based on differential pulse voltammetry (DPV) revealed a linear behavior in the concentration range from 25 to 250 μmol L‐1 (R2 = 0.99), a limit of detection of ~ 9.6 μmol L‐1, sensitivity of ~ 0.0048 µA(µmol L‐1)‐1 and acceptable reproducibility values (RSD ≤ 5.8%). The DPV responses involving the standard addition method in pharmaceutical samples presented recovery results of TAD ranging from 93 to 108%. Also, the proposed analytical method offered a suitable green analytical chemistry profile. We successfully demonstrated the fabrication of graphene‐like sites and nanoparticles composed of alumina upon a hybrid substrate.

A molecularly imprinted electrochemical aptasensor-based dual recognition elements for selective detection of dexamethasone

In this work, a novel molecularly imprinted electrochemical aptasensor (MIEAS) was developed for highly selective detection of dexamethasone (Dex) in natural water environment. Gold nanoparticles (AuNPs) modified by nitrogen doped molybdenum carbide-graphene (N–Mo2C-Gr) were employed as the supports, where N–Mo2C-Gr improved the conductivity of the electrode and provided a larger specific surface area to polymerize more active substances. Using Dex as template molecule, o-phenylenediamine (o-PD) as the chemical functional monomer and aptamer as the biofunctional monomer, a molecularly imprinted polymer (MIP) membrane with Dex specific recognition sites was formed by electropolymerization. Due to the synergistic effect of MIP and aptamers, the as-prepared MIEAS exhibited a decent linear relationship to Dex detection within a relatively wide range of 10−13 – 10−5 M, and the detection limit was 1.79 × 10−14 M. The recovery in actual water and tablet samples is satisfactory, which confirms the potential application prospects of this sensor in the determination of Dex.

Quality assessment of oxytocin injection and misoprostol tablets in Côte d’Ivoire and Senegal

Objective : To assess the quality of oxytocin and misoprostol products available in Côte d’Ivoire and Senegal. Methods : Samples of oxytocin injections and misoprostol tablets were collected from three different levels of the supply chain in Côte d’Ivoire and Senegal from August to December 2021. The sampling process was done by personnel from the National Medicines Regulatory Authorities, employing a methodology and sampling plan aligned with WHO guidelines

Stability indicating for Quality Control Assessment of three antidiabetic molecules using HPLC technique: Stability Assessment of three antidiabetic molecules

Diabetes mellitus responds better to co-formulated tablet dosages of dapagliflozin (DFZN), metformin (MFMN), and vildagliptin (VDGN). For the purpose of studying stability and quantifying DFZN, VDGN, and MFMN in bulk forms and in dosage forms, an efficient and fast HPLC method of analysis is currently developed. The mobile phase featured 80:20 (v/v) 0.2 M, pH 3.0, ammonium acetate buffer and acetonitrile mixed together and Luna's HPLC C-18 column, named Phenyl hexyl, was utilised for DFZN, VDGN, and MFMN separation and its quantification. The PDA type detector operating at 235 nm wavelength was deployed. The “International Conference on Harmonisation” recommendations were strictly adhered throughout the validation process. A strong linear association between response and quantity in the range of 2.5–15 µg/ml (DFZN), 25–150 µg/ml (VDGN), and 125–750 µg/ml (MFMN) is supported by the regression information for the DFZN, VDGN, and MFMN calibration plots. The precision, selectivity, accuracy, sensitivity, ruggedness and robustness were satisfactory for the method. The tablet sample of DFZN, VDGN, and MFMN was subjected to acid, water, base, sodium bisulfite, light, dry heat and peroxide degradations. Significant differences in retention times were observed between the well-resolved peaks of the degradants and the primary peaks (DFZN, VDGN, and MFMN). Thus, the assay might be characterised as stability indicating. The contents of DFZN, VDGN, and MFMN in dosage forms were assessed precisely and accurately by currently developed HPLC technique. This technique may be applied to ensure the quality of formulation doses for DFZN, VDGN, and MFMN contents.

Performance assessment of portable Raman spectroscopy in determining ecstasy tablets

AbstractEcstasy tablets, a type of common street drug originally consisting of 3,4‐methylenedioxymethamphetamine (MDMA), provide stimulant and hallucinogen psychoactive effects. They are frequently found in nightclubs, musical festivals or other recreational events believed to create a relaxing experience for the users. From a forensic perspective, when the drug of abuse is suspected in such scenarios, the law enforcement personnel would then require an easy‐to‐perform, quick and accurate method to detect the existence of such controlled substance prior to the seizure and subsequent forensic examination. In this study, we assessed the performance of a portable Raman spectroscopy as the primary aid in determining ecstasy tablets at the point of use. A total of 130 ecstasy tablet samples were analysed by Raman spectroscopy and characterised by gas chromatography–mass spectrometry (GC–MS). Active chemical substances and cutting agents detected by the two instrumentations were then compared. The performance of Raman spectroscopy was further assessed in terms of its accuracy, sensitivity and specificity, corresponding to the analysis results obtained from GC–MS analysis. Overall, portable Raman Spectroscopy used in this study shows an accuracy of 85.4% in analysing ecstasy tablets obtained from case samples, while the sensitivity and specificity were determined as 85.2% and 100%, respectively. No false positives for MDMA or other drugs were reported. Our results show that portable Raman spectroscopy is a suitable technique for targeted determination of the presence of ecstasy tablets, especially in forensic cases that require non‐destructive, rapid and mass screening during on‐site testing by law enforcement personnel.

Sensitive and selective electrochemical sensor for palbociclib, a highly selective CDK4/6 inhibitor, based on molecularly imprinted polymer

In this research, a molecularly imprinted polymer (MIP)-based electrochemical sensor was developed for the first time to determine palbociclib (PLB), an oral, selective Cyclin Dependent Kinase (CDK4 and CDK6) inhibitor used in the treatment of breast cancer. Acrylamide (ACR) was selected as the functional monomer to fabricate the proposed sensor (ACR-PLB-MIP/GCE), and polymerization was performed by photopolymerization. To improve the efficiency of the MIP-based electrode for PLB measurement, several factors, including monomer ratio, removal time, removal agent, and rebinding time, were carefully optimized. Under optimal conditions and using the differential pulse voltammetry (DPV) technique, the limit of detection (LOD) of 1.35 × 10−12 M and the limit of quantification (LOQ) of 4.48 × 10−12 M were calculated for PLB analysis using ACR-PLB-MIP/GCE in standard solution. Application of the ACR-PLB-MIP/GCE sensor to commercial serum samples resulted in LOD and LOQ values of 3.33 × 10−12 M and 1.11 × 10−11 M, respectively. The sensor was also applied to the tablet sample for the detection of PLB and a satisfactory RSD% (0.95) was obtained. The results of interference studies confirmed the high selectivity of the electrode for PLB analysis. These results clearly demonstrated that the molecular imprinting approach for the detection of PLB in the novel sensor system is a highly efficient approach.

Synthesis of oxygen vacancies rich CeO2-xNx/GCN hybrid nanostructure with great active interfaces for electrochemical detection of antiviral levofloxacin in pharmaceutical samples

COVID-19 is an emerging viral infectious disease. Severe respiratory problems are considered an important syndrome of COVID-19 in humans. Levofloxacin (LEV), a promising fluoroquinolone antibacterial agent/therapeutic agent for influenza virus (H1N1)-induced pneumonia drug. These have been used as a potent antidote for acute respiratory tract infections. Owing to its excellent pharmacokinetic properties such as potential antiviral and scavenging activity, LEV has been used in controlling and treating COVID-19 during infectious emergencies. Even taking over the dosage of LEV and disposing of the embryonic toxic nature of LEV residues in the pharmaceutical research industry can cause adverse effects on the public health and environment. For this purpose, the development of great analytical tools is important to the detection of antiviral LEV for human health safety and environmental protection. In this work, we report a nitrogen (N) doped strategy to construct the enriched oxygen vacancies (OVs) on CeO2-xNx/GCN-2 hybrid nanostructure as an efficient electrocatalyst for the ultrasensitive detection of antiviral LEV. The effect of the N doping into the CeO2 (CeO2-xNx) lattice with increasing the large amount of OVs and boosted their redox properties (Ce4+→Ce3+), thus provided that a great electrochemically active site. Although the abundant OVs were conformed on the CeO2-xNx/GCN-2 from the peak-area ratio of Ce3+/Ce4+ and O2/O1 by X-ray photoelectron spectroscopy (XPS) assay. Owing to the strong electronic coupling between the OV-rich CeO2-xNx and the conductive GCN surface, thus CeO2-xNx/GCN-2 heterojunction achieved superior analytical performance for LEV oxidation with a good linear range from 0.01 μM to 710 μM, and detection limits of 5.6 nM (S/N = 3), and sensitivity 24.711 μA μM−1 cm−2 at a very low working potential (0.7 V). The proposed hybrid sensor also exploited to the analysis of the pharmaceutical industry wastewater, pharmaceutical tablet and human urine samples with a satisfactory recovery rate.

Qualitative transformations of street-seized ecstasy over a decade: A case study in Rio de Janeiro (Brazil).

The illegal drug market is constantly evolving, with new drugs being created and existing ones being modified. Adulterants are often added to the mix, and the primary substance may be secretly replaced by a new one. Once-known tablets can now be vastly different from what they are sold as, all due to the pursuit of profit and evasion of current drug regulations. These alterations in drug composition pose a threat to society, as their effects are still not well understood. Therefore, it is crucial for police intelligence and public health development to obtain the chemical profiles of illicit drugs. This study presents the chemical fingerprinting of ecstasy tablets seized in the state of Rio de Janeiro (Brazil) between 2012 and 2021. The tablet samples were weighed, extracted, diluted with methanol, and acidified before analysis using gas chromatography high-resolution mass spectrometry and attenuated total reflection Fourier transform infrared spectroscopy. The major constituents found were MDMA and clobenzorex, with fewer occurrences of MDA, MDEA, and 2C-B. The results also indicate that the occurrence of mega-events in the study location impacted the chemical fingerprints of ecstasy. A total of 27 combinations of cutting agents, including caffeine, ephedrine, and anesthetics, were identified. Samples composed of clobenzorex were observed throughout the evaluated period in areas near highways, suggesting that this product is mainly used by truck drivers. These findings can help police intelligence units anticipate the behavior of the illicit market during major events, identify traffic routes, and support public health initiatives.

Sustainable synthesis of praseodymium tungstate: An electrochemical probe for detection of Ronidazole

Profligate consumption of antibiotics in animal and livestock husbandry indulged in antibiotic pollution. This collapses the natural balance of the ecosystem and results in various environmental health crises. Herein, we have developed an ultra-sensitive praseodymium tungstate (PWO) based electrochemical sensor to detect one such serious antibiotic, Ronidazole (RD). A facile synthesis strategy was applied to prepare PWO nanomaterial and their structural, functional, and elemental details were thoroughly examined with a wide range of spectroscopic measurements. The electrochemical properties were determined by performing impedance and voltammetry experiments. The high catalytic efficiency of the designed sensor was achieved by optimizing its performance under different parameters. Based on the outcomes, the designed PWO-based sensor offered an extremely low level of detection (0.3 nM) and exhibited a wide range of linearity (0.001 µM to 20.4 µM), high sensitivity (7.72 µA µM−1 cm−2), and good selectivity. Further, the performance of the electrochemical sensor was validated with good repeatability, reproducibility, and stability results. The practical applicability of the sensor was investigated by monitoring the RD in aquatic, biological, and pharmaceutical samples. The obtained results affirmed that the PWO sensor is an efficient platform for the real-time monitoring of RD.

Portable wireless electrochemical sensing of breviscapine using core-shell ZIFs-derived Co nanoparticles embedded in N-doped carbon nanotube polyhedra-modified electrode.

Acore-shell ZIF-67@ZIF-8-derived Co nanoparticles embedded in N-doped carbon nanotube polyhedra (Co/C-NCNP) hybrid nanostructure was preparedby a pyrolysis method. The synthesized Co/C-NCNP was modified on the screen-printed carbon electrode and used for the portable wireless sensitive determination of breviscapine (BVC) by differential pulse voltammetry. The Co/C-NCNP had a large surface area and excellent catalytic activity with increasing Co sites to combine with BVC for selective determination, which led to the improvement of the sensitivity of the electrochemical sensor. Under optimized conditions, the constructed sensor had linear ranges from 0.15 to 20.0µmol/L and 20.0 to 100.0µmol/L with the limit of detection of 0.014µmol/L (3S0/S). The sensor was successfully applied to BVC tablet sample analysis with satisfactory results. This work provided the potential applications of zeolitic imidazolate framework-derived nanomaterials in the fabrication of electrochemical sensors for the sensitive detection of drug samples.

Design of smart temperature-sensitive terpolymeric hydrogel for multi-applications in liquid chromatography

Hydrogels with a unique three-dimensional network structure have been widely used in a variety of fields. However, hydrogels are prone to swelling under water-rich conditions, which severely limits their application in liquid chromatography. Therefore, producing a hydrogel with reliable performance and good mechanical property is essential. Smart temperature-sensitive chromatographic packings have attracted extensive attentions in recent years. In this work, sodium 4-styrenesulfonate and 1-octadecene were introduced into the poly(N-isopropylacrylamide) hydrogel to improve mechanical property and separation performance. As a consequence, a smart temperature-sensitive terpolymeric hydrogel modified silica stationary phase (ION-hydrogel@SiO2) was synthesized for multimode liquid chromatographic separation. It was found that this new ION-hydrogel@SiO2 column exhibited excellent chromatographic separation ability for a wide range of analytes. To a certain extent, this new column has a higher chromatographic separation efficiency compared to the commercial C18 column and XAmide column. Moreover, the use of low proportion of organic phase in chromatographic separation is conducive to the realization of green chromatography. By investigating the chromatographic separation mechanism, it has been demonstrated that the hydrogen bonding interaction is primarily responsible for the temperature-sensitive behavior of the hydrogel. Finally, the ION-hydrogel@SiO2 column was used for the determination of pyridoxine in the commercially available tablet samples. In conclusion, this study presents a feasible idea for the development of novel copolymer hydrogels as liquid chromatographic stationary phases.

Investigating the Presence of Falsified and Poor-Quality Fixed-Dose Combination Artemether-Lumefantrine Pharmaceutical Dosage Forms in Kumasi, Ghana.

Artemether-lumefantrine (AL) is a highly effective and commonly used Artemisinin-based Combination Therapy (ACT) for treating uncomplicated malaria caused by Plasmodium falciparum, including drug-resistant strains. However, ineffective regulatory systems in resource-limited settings can lead to the infiltration of poor-quality and counterfeit antimalarial medicines into the pharmaceutical supply chain, causing treatment failures, prolonged illness, and disease progression. The objective of the study was to assess the quality of selected brands of fixed-dose combination (FDC) AL tablets and suspensions marketed in Kumasi, Ghana. A total of fourteen brands of FDC AL medicines, comprising eight tablets and six suspensions were purchased from various retail pharmacy outlets in Kumasi, Ghana. All samples were subjected to thorough visual inspection as a quick means of checking quality through meticulous observation of the packaging or dosage form. The quality parameters of the tablets were determined using uniformity of weight, hardness, friability, and disintegration tests. Suspensions were assessed based on pH and compared with the British Pharmacopeia (BP) standard. The samples were then analyzed for drug content (assay) using reverse-phase high-performance liquid chromatography (RP-HPLC). All the tablet samples conformed to BP specification limits for uniformity of weight (deviation of less than ± 5%), hardness (4.0-10 kg/mm2), friability (<1%), and disintegration time (<15 minutes). The active pharmaceutical ingredients' quantitative assay demonstrated that all the tablets met the BP specifications (90-110%). The results of the pH studies showed that out of the six brands of suspension investigated, five (83.3%) were compliant with the official specification for pH, while one (16.7%) failed the requirement. Unlike the tablet brands, drug content analysis of the six suspensions showed that two (33.3%) were substandard. The artemether and lumefantrine contents in these failed suspensions were variable (artemether: 81.31%-116.76%; lumefantrine: 80.35%-99.71%). The study results indicate that most of the tested products met the required quality standards, demonstrating satisfactory drug content and other quality specifications. The presence of substandard drugs underscores the necessity for robust pharmacovigilance and surveillance systems to eliminate counterfeit and substandard drugs from the Ghanaian market.

Electrochemical Determination of Anti-Cancer Drug Pazopanib with High Selectivity and Sensitivity Using Molecularly Imprinted Polymer-Modified Glassy Carbon Electrode

Pazopanib (PZB) is a multiple kinase inhibitor used for the treatment of advanced renal cell carcinoma and soft tissue sarcoma. This work focuses on achieving high selectivity and sensitivity for the determination of PZB using a molecularly imprinted polymer (MIP)-based electrochemical sensor. The MIP-based sensor was fabricated by thermal polymerization (TP) directly on a glassy carbon electrode (GCE). The electrochemical response of the 4-ABA/PZB@MIP/GCE sensor was investigated using differential pulse voltammetry (DPV). The characterization of the sensor in terms of morphology and electrochemistry was performed using scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The 4-ABA/PZB@MIP/GCE sensor exhibited a linear response ranging from 1.0 × 10–13 M to 1.0 × 10–12 M with a limit of detection (LOD) and limit of quantification (LOQ) of 1.04 × 10–14 M and 3.48 × 10–14 M, respectively. The applicability of the sensor was evaluated by determining commercial samples of human serum and tablets, and good recoveries were obtained. The results showed that the sensor could identify PZB, compared to structurally analogous drugs such as axitinib, nilotinib, and erlotinib. The interfering substances commonly found in biological fluids were investigated. Finally, the sensor design was validated using a non-imprinted polymer-based GCE.

Trace level quantification of N-nitrosorasagiline in rasagiline tablets by LC-TQ-MS/MS

Parkinson's disease is a chronic, progressive neurological disease that currently affects about more than 10 million population worldwide. Rasagiline is a selective, irreversible monoamine oxidase type B inhibitor used as monotherapy in early Parkinson's disease. Rasagiline tablets have been recalled from market due to the presence of unacceptable levels of nitrosamine impurity. European Medical Agency has set up very stringent limit 100ng/day of N-nitrosorasagiline (NSRG) in drug product based on its mutagenicity. The analytical methods need to be sufficiently sensitive in order to adequately detect and quantify trace levels of NSRG. A highly sensitive LC-MS/MS method for determination of NSRG in rasagiline tablet formulation was developed by effectively separating on zorbax eclipse XDB C18 column using 0.1% formic acid in mixture of water and acetonitrile (35:65 v/v) in an isocratic mode at 0.5mL/min flow rate. The measurement of NSRG was performed using triple quadrupole mass detection accompanied by electrospray ionization in the multiple reaction monitoring mode. The validation of the method was comprehensive, demonstrating strong linearity across the concentration spectrum of 2 to 200ng/mL for NSRG. The obtained correlation coefficient exceeded 0.998, signifying a robust relationship. Recoveries spanning from 80.0% to 120.0% for NSRG were deemed satisfactory. The developed method was able to detect and quantitate NSRG at a concentration level of 1 to 2ng/mL respectively (1 to 2ppm with respect to 1mg/mL of rasagiline tablet sample concentration). The developed and validated method can be employed for routine quality control testing of rasagiline tablets.