Stability‐Indicating HPLC Method for the Determination of Quetiapine: Application to Tablets and Human Plasma

Green and inventive fluorescence approach for levodropropizine determination in human plasma

A green, rapid and sensitive fluorimetric method to quantify levodropropizine (LVP) in human plasma was exploited for the first time. The proposed method adopts LVP's intrinsic fluorescence in distilled water at a detecting emission of 345 nm following excitation at 240 nm. LVP displayed linearity across concentrations ranging from 50 to 1000 ng mL-1, with a detection limit of 0.77 ng mL-1 and a quantification limit of 2.33 ng mL-1. Thorough validation confirmed its reliability, successfully determining LVP in tablets with an average recovery of 98.64 ± 1.07 %. Furthermore, the method's applicability extended to estimate the studied drug in spiked human plasma with excellent obtained percentage recoveries (98.68 ± 1.28-100.14 ± 1.23).

Quetiapine Fumarate: A Review of Analytical Methods

Atypical antipsychotics are newer second-generation antipsychotics with weak dopamine type 2 blocking but potent 5-HT2 antagonistic activity. They are considered first-line treatments for schizophrenia and gradually replace typical antipsychotics. Extrapyramidal side effects are minimal, and they tend to improve impaired cognitive function in psychotics. Quetiapine fumarate is an atypical antipsychotic drug used to treat schizophrenia, mania and depression in people with bipolar disorder combined with other drugs or alone. Quetiapine was developed in 1985 and approved for medical use in the USA in 1997. Thorough computer-aided literature, surveys revealed that numerous analytical methods were reported over the years. The present study reviews analytical methods with their validation parameters published during the last 22 years (1999-2021) either as a single entity or combination in dosage form, and determination from biological samples. Novel strategies for increasing separation quality, such as QbD analysis and green spectroscopy, were discovered during the evaluation, and this review can be utilized for further research reference.

Central Composite Optimization of Glycerosomes for the Enhanced Oral Bioavailability and Brain Delivery of Quetiapine Fumarate

This study aimed to formulate and statistically optimize glycerosomal formulations of Quetiapine fumarate (QTF) to increase its oral bioavailability and enhance its brain delivery. The study was designed using a Central composite rotatable design using Design-Expert^® software. The independent variables in the study were glycerol % w/v and cholesterol % w/v, while the dependent variables were vesicle size (VS), zeta potential (ZP), and entrapment efficiency percent (EE%). The numerical optimization process resulted in an optimum formula composed of 29.645 (w/v%) glycerol, 0.8 (w/v%) cholesterol, and 5 (w/v%) lecithin. It showed a vesicle size of 290.4 nm, zeta potential of −34.58, and entrapment efficiency of 80.85%. The optimum formula was further characterized for DSC, XRD, TEM, in-vitro release, the effect of aging, and pharmacokinetic study. DSC thermogram confirmed the compatibility of the drug with the ingredients. XRD revealed the encapsulation of the drug in the glycerosomal nanovesicles. TEM image revealed spherical vesicles with no aggregates. Additionally, it showed enhanced drug release when compared to a drug suspension and also exhibited good stability for one month. Moreover, it showed higher brain C_max, AUC_0–24, and AUC_0–∞ and plasma AUC_0–24 and AUC_0–∞ in comparison to drug suspension. It showed brain and plasma bioavailability enhancement of 153.15 and 179.85%, respectively, compared to the drug suspension. So, the optimum glycerosomal formula may be regarded as a promising carrier to enhance the oral bioavailability and brain delivery of Quetiapine fumarate.

A Comprehensive Review on Importance and Quantitation of Atypical Antipsychotic Drugs and their Active Metabolites in Commercial Dosage Forms

Background:

Schizophrenia is a severe mental illness that affects more than twenty-one million people throughout the world. Schizophrenia also causes early death. Schizophrenia and other related psychotic ailments are controlled by the prescription of antipsychotic drugs, which act by blocking certain chemical receptors in the brain and thus relieves the symptoms of psychotic disorder. These drugs are present in the different dosage forms in the market and provided in a certain amount as per the need of the patients.

Objective:

Since such medications treat mental disorders, it is very important to have a perfect and accurate dose so that the risk factor is not affected by a higher or lower dose, which is not sufficient for the treatment. For accurate assay of these kinds of drugs, different analytical methods were developed ranging from older spectrophotometric techniques to latest hyphenated methods.

Results:

The current review highlights the role of different analytical techniques that were employed in the determination and identification of antipsychotic drugs and their metabolites. Techniques such as spectrophotometry, fluorimetry, liquid chromatography, liquid chromatography-mass spectrometry, gas chromatography, and gas chromatography-mass spectrometry employed in the method development of such antipsychotic drugs were reported in the review. Different metabolites, identified using the hyphenated techniques, were also mentioned in the review. The synthesis pathways of few of the metabolites were mentioned.

Conclusion:

The review summarizes the analyses of different antipsychotic drugs and their metabolites. A brief introduction of illnesses and their symptoms and possible medications were highlighted. Synthesis pathways of the associated metabolites were also mentioned.

Innovative spectrofluorometric protocol based on micro-environment improvement for determination of Quetiapine in dosage forms and rat plasma

Quetiapine (QUT) is an atypical antipsychotic drug indicated for the treatment of schizophrenia and acute manic episodes associated with bipolar disorders. A simple, rapid, and highly sensitive micellar spectrofluorometric method has been developed and validated for quantitation of QUT in its pharmaceutical formulations with application to content uniformity test, in presence of its degradation product and in rat plasma. The proposed method was based on the enhancement of the fluorescence intensity of QUT in 2% v/v tween 80 micellar solution. The fluorescence intensity was measured at 372 nm after excitation at 261 nm. A linear relationship was achieved between the fluorescence intensity and the drug concentration in the range of 20-1000 ng/mL with 18.5 and 6.3 ng/mL as limits of quantitation and detection, respectively. The proposed method was extended to study the stability of QUT after its exposure to different forced degradation conditions such as; acidic, alkaline, oxidative, photolytic and thermal conditions according to ICH guidelines. The study revealed that QUT is stable under all the of these conditions except the oxidative one. Furthermore, the high sensitivity of the micellar method permits its application for determination of QUT in rat plasma with good percentage recovery as well as determination of C_max.

Successive Stability Indicating Spectrophotometric Technique for Simultaneous Determination of Quetiapine Fumarate and its Three Major Related Compounds

Background:

Quetiapine Fumarate (QTF) is an atypical antipsychotic drug used to treat mental disorders as depression and schizophrenia. The analysis of the dug in the presence of its precursors, degradants and impurities without interference represents a challenge for the analysts. The regulatory requirements recommended by ICH stated that the impurities above or equal to 0.1% must be identified, characterized and determined. The aim of this work was to introduce three smart and selective spectrophotometric methods that could resolve the complete overlapping of QTF drug with its three related compounds; namely lactam (LAC), N-oxide (OXD) and des-ethanol (DES) without prior separation or extraction step.

Methods:

So far there is no spectrophotometric method reported in the literature for the analysis of QTF drug with its three related compounds without interference. The First derivative zero crossing (1D-ZC), Spectrum subtraction (SS), and Simultaneous derivative ratio (S1DD) are well-developed methods used for determination and resolution of multicomponent mixtures. While Ratio difference isosbestic point method is a new method that needs two isoabsorptive points for its application and was successfully adopted for simultaneous estimation of ternary mixtures.

Results:

The linearity range was found in the range of (6-50 μg/mL) for Quetiapine fumarate, (6-110 μg/mL) for lactam, (4-28 μg/mL) for N-oxide and (6-32 μg/mL) for Des-ethanol. The method validation was performed according to ICH guidelines. The results were statistically compared with a reported HPLC method and no significant difference was obtained.

Conclusion:

The presented spectrophotometric technique highlighted the significance of different tools such as normalized spectra and isoabsorptive points, especially when combined together for the determination and resolution of complex quaternary mixtures as that of QTF and its three major impurities. The proposed methods were smart, accurate and sensitive and were able to determine the four components showing sever overlap without prior separation. The proposed methods are rapid, cheap ecofriendly (green method) and didn’t require any sophisticated programs and could be easily adopted for the routine determination of complex multicomponent mixtures with minimum sample preparation.

Degradation studies of quetiapine fumarate by liquid chromatography-diode array detection and tandem mass spectrometry methods

Quetiapine fumarate (QUE) is an antipsychotic agent with a chemical structure that is susceptible to degradation; therefore, it is important to study its stability using appropriate analytical tools. Knowledge of the stability profile of a drug is important because chemical degradation of its active component often results in a loss of potency, affecting its efficacy and safety. This current work reports degradation studies of QUE as drug substance, under different stress conditions such as oxidation, hydrolysis, heat, humidity and photolysis, by a stability-indicating LC method. The chemical stability was evaluated using a simple HPLC/diode array detection method, with a core-shell C₁₈ column under isocratic conditions, which allows the separation of all primary degradation products (DPs) in a short run time. QUE was mainly degraded under oxidative and hydrolytic conditions, with the formation of three and two DPs, respectively, which were identified by electrospray ionization-tandem mass spectrometry. The method was properly validated in terms of linearity, accuracy, precision, selectivity, robustness and quantitation limit. Commercial tablets containing 25 mg of QUE were quantified, with results obtained within the United States Pharmacopeia limits. The proposed method is suitable to assess the stability and perform routine analysis of QUE in pharmaceutical samples.

Analysis of quetiapine in human plasma using fluorescence spectroscopy

A simple and sensitive spectrofluorimetric method has been development for the assurance of quetiapine fumarate (QTF). The proposed method was utilized for measuring the fluorescence intensity of the yellow fluorescent product at 510nm (λ_ex 470nm). The fluorescent product has resulted from the nucleophilic substitution reaction of QTF with 4-chloro-7-nitrobenzofurazane (NBD-Cl) in Mcllvaine buffer (pH7.0). The diverse variables influencing the development of the reaction product were deliberately changed and optimized. The linear concentration range of the proposed method was of 0.2-2.0μgml^-1.The limits of detection and quantitation were 0.05 and 0.17μgml^-1, respectively. The proposed method was applied for the assurance of QTF in its tablets without interference from basic excipients. In addition, the proposed method was used for in vitro analysis of the QTF in spiked human plasma, the percent mean recovery was (n=3) 98.82±1.484%.

Freeze Dried Quetiapine-Nicotinamide Binary Solid Dispersions: A New Strategy for Improving Physicochemical Properties and Ex Vivo Diffusion

Improving the physicochemical properties and oral bioavailability of quetiapine fumarate (QF) enabling enhanced antipsychotic attributes are the main aims of this research. The freeze dried solid dispersion strategy was adopted using nicotinamide (NIC) as highly soluble coformer. The prepared dispersions were characterized using scanning electron microscopy (SEM) differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Static disc intrinsic dissolution rate and ex vivo diffusion through intestinal tissues were conducted and compared to pure quetiapine fumarate. The results demonstrated a highly soluble coamorphous system formed between quetiapine fumarate and nicotinamide at 1 : 3 molar ratio through H-bonding interactions. The results showed >14-fold increase in solubility of QF from the prepared dispersions. Increased intrinsic dissolution rate (from 0.28 to 0.603 mg cm⁻² min⁻¹) and faster flux rate through duodenum (from 0.027 to 0.041 mg cm⁻² h⁻¹) and jejunum (0.027 to 0.036 mg cm⁻² h⁻¹) were obtained. The prepared coamorphous dispersion proved to be effective in improving the drug solubility and dissolution rate and ex vivo diffusion. Therefore, binary coamorphous dispersions could be a promising solution to modify the physicochemical properties, raise oral bioavailability, and change the biopharmaceutics classification (BCS) of some active pharmaceutical ingredients.

Preparation, Characterization and Evaluation of Quetiapine Fumarate Solid Lipid Nanoparticles to Improve the Oral Bioavailability

Quetiapine fumarate is an antipsychotic drug with poor oral bioavailability (9%) due to first-pass metabolism. Present work is an attempt to improve oral bioavailability of quetiapine fumarate by incorporating in solid lipid nanoparticles (SLN). Six quetiapine fumarate SLN formulations were developed using three different lipids by hot homogenisation followed by ultrasonication. The drug excipient compatibility was studied by differential scanning calorimetry (DSC). Stable quetiapine fumarate SLNs having a mean particle size of 200–250 nm with entrapment efficiency varying in between 80% and 92% were developed. The physical stability of optimized formulation F3 was checked at room temperature for 2 months. Comparative bioavailability studies were conducted in male Wistar rats after oral administration of quetiapine fumarate suspension and SLN formulation. The relative bioavailability of quetiapine fumarate from optimized SLN preparation was increased by 3.71 times when compared with the reference quetiapine fumarate suspension. The obtained results are indicative of SLNs as potential lipid carriers for improving the bioavailability of quetiapine fumarate by minimizing first-pass metabolism.

A study of photodegradation of quetiapine by the use of LC-MS/MS method

Photodegradation of quetiapine under UVC irradiation in methanol solution was investigated and structural elucidation of its photodegradation products was performed with the use of the reversed phase UHPLC system coupled with accurate mass hybrid ESI-Q-TOF mass spectrometer. During one run all essential data for the determination of photodegradation kinetics and for the structural elucidation of the products was collected with the use of auto MS/MS mode. Five degradation products were found and their masses and formulas were obtained with high accuracy (0.26–5.02 ppm). For all the analyzed compounds, MS/MS fragmentation spectra were also obtained allowing structural elucidation of the unknown degradation products and indicating photodegradation pathways of quetiapine. The main photodegradation product was identified as 2-[2-[4-(5-oxidodibenzo[b,f][1,4]thiazepin-11-yl)-1-piperazinyl]ethoxy]-ethanol and the photodegradation reaction yields the first-order kinetics with the rate constant k = 0.1094 h−1.

A novel electrochemical sensor for assaying of antipsychotic drug quetiapine

A novel electrochemical sensor based on poly(2-hydroxy-5-[(4-sulfophenyl)azo]benzoic acid) film modified glassy carbon electrode for fast and simple quantification of trace amount of quetiapine fumarate (QF) was developed. It exhibits excellent enhancement effects on the electrooxidation of QF facilitating preconcentration of drug molecules on the electrode surface. Based on its strong adsorptive activity, the concentration of QF in pharmaceutical formulations and biological fluids was determined directly by voltammetry with excellent sensitivity and high selectivity. The introduction of carboxylated and sulfonated functionalities in polymer film improves the uniform selectivity for positively charged target QF molecules. The calibration curve is linear in QF concentration range of 8.0 × 10(-8) to 7.5 × 10(-6)M with detection limit 1.9 × 10(-8) and sensitivity 8.96 × 10(5) μA M(-1). The presented sensor has long term stability and good reproducibility with benefits of fast response time, ease of preparation and regeneration of the surface that makes the proposed method useful in the determination of QF in real samples.