Simultaneous determination of the brand new two-drug combination for the treatment of hepatitis C: Sofosbuvir/ledipasvir using smart spectrophotometric methods manipulating ratio spectra

Trio-Colored Appraisal of Microwave-Assisted Synthesis of Carbon Quantum Dots as a Fluorescence Turn Off Nanoprobe for Analyzing Ledipasvir in Tablets and Rat Feces: Study of Silymarin Impact on Excretion Recovery

The current work offers a rigorous way for the microwave-assisted synthesis of N and S doped carbon quantum dots (QDs). The latter are deemed highly sensitive and selective fluorescence sensors that were widely investigated in pharmaceutical analysis. Quenching of luminescence of the prepared QDs in lab fabricated sensor at λ emission = 418 nm after excitation at 370 nm was implemented to quantify the anti-HCV drug Ledipasvir (LDP). LDP showed a linear response within the dynamic range of 1-40 μM. The calculated LDP detection and quantification limits were 313.06 and 948.67 nM, respectively. Besides the analysis of LDP in bulk and commercial dosage form, the scope of application extended to evaluate the effect of the nutraceutical silymarin (liver support) on the excretion of LDP in rat feces. The compliance with the green and white analytical chemistry fundamentals is comprehensively investigated and compared with selected versatile reported procedures. Numerous prevalent metrics, namely, analytical eco-scale, AGREE, RGB12, RGB fast, BAGI, and complex GAPI, were employed. Our developed fluorometric procedure demonstrated great sensitivity, selectivity, and functionality that outperformed other sophisticated platforms. Thus, the utility of the depicted procedure in pharmaceutical analysis and studying pharmacokinetics aspects is profoundly proven.

Sofosbuvir: A comprehensive profile

Sofosbuvir, a nucleotide analogue, is an antiviral medication that belongs to the class of direct-acting antivirals (DAAs). It is primarily used in the treatment of chronic hepatitis C virus (HCV) infections. Sofosbuvir works by inhibiting the replication of HCV, disrupting its ability to produce RNA and effectively reducing the viral load in the body. This chapter offers a comprehensive examination of sofosbuvir, including its nomenclature, physiochemical attributes, synthesis, and thermal analysis. Furthermore, it presents various analytical methods employed for both spectrophotometric and chromatographic assessments of sofosbuvir in different matrices.

A new fluorescence probe for sofosbuvir analysis in dosage form and spiked human plasma

A simple, rapid, and low-cost technique was developed to allow reliable analysis of the anti-hepatitis C drug sofosbuvir in bulk, tablet form, and spiked human plasma. This method depends on the ability of sofosbuvir to quench the fluorescence of the newly synthesized 2-amino-3-cyano-4,6-dimethylpyridine (reagent 3). Elemental analysis and spectral data were used to validate the structure of the synthesized reagent. The newly synthesized reagent exhibited a satisfactory level of fluorescence emission at 365 nm after excitation at 247 nm. All experimental variables that might affect the quenching process were analyzed and optimized. Linearity, range, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ) were all validated in accordance with the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines. The concentration range was shown to be linear between 0.1 and 1.5 μg/mL. The technique was effectively utilized for sofosbuvir analysis in both its tablet dosage form and spiked human plasma, with mean percentage recoveries of 100.13 ± 0.35 and 94.26 ± 1.69, respectively.

Computational design for eco-friendly visible spectrophotometric platform used for the assay of the antiviral agent in pharmaceutical dosage form

Nowadays, the analytical community is focusing on developing new analytical methods that incorporate principles of green analytical chemistry to reduce adverse impacts on the environment and humans. In this study, we focused specifically on establishing a correlated connection between theoretical and experimental applications via developing green, and eco-friendly visible spectrophotometric methods. These methods were relied on charge-transfer complexation (CTC) between ledipasvir and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), or chloranilic acid (CA) for sensitive colorimetric analysis of ledipasvir in the presence of sofosbuvir (Sofolanork plus®). The results were evaluated as modern computational chemistry using molecular modeling technology. At ambient temperature, the reactions for DDQ and CA took 15 and 10 min, respectively, to produce a purple red-colored solution with DDQ absorbing maximally at 588 nm and a purple-colored solution with CA absorbing maximally at 522 nm. Linearity was achieved for ledipasvir utilizing DDQ and CA in the concentration ranges of 8-80 µg.mL^-1 and 40-400 µg.mL^-1, respectively. The precision and accuracy of the methods mentioned were determined. Finally, the results were statistically compared to a previously published spectrophotometric technique, and no significant differences were found.

Innovative derivative/zero ratio spectrophotometric method for simultaneous determination of sofosbuvir and ledipasvir: Application to average content and uniformity of dosage units

An innovative simple, rapid and sensitive spectrophotometric method was developed for the simultaneous analysis of sofosbuvir (SOF) and ledipasvir (LED) in their combined dosage forms. Sofosbuvir with ledipasvir (SOF/LED) as a combined dosage form was tried at the pandemic COVID 19 crisis. This technique has the advantages of both zero order and first order spectrophotometry. The zero and first derivative amplitudes were measured at 274.2 nm for SOF (zero crossing point of LED in first derivative spectrum) and 314 nm for LED (zero crossing point of SOF in first derivative spectrum) over the concentration range of 2.0-50.0 μg mL^-1 with coefficients of determination (R²) > 0.9999 for both drugs and mean percentage recoveries of 100.25 ± 1.61 and 99.85 ± 0.99 for SOF and LED; respectively. This original method was validated according to ICH requirements and statistically compared to published comparison methods. This method was applied to estimate the average content and the uniformity of dosage units of SOF/LED combined dosage form according to British Pharmacopeia requirements.

Spectral analysis of severely overlapping spectra based on newly developed mathematical filtration techniques and ratio spectra manipulations: An application to the concurrent determination of dapoxetine and sildenafil in combined dosage form

BACKGROUND

Dapoxetine hydrochloride (DAP) and sildenafil citrate (SIL) have proven clinically effective in the treatment of comorbid conditions like erectile dysfunction and premature ejaculation. The analysis of DAP and SIL combinations represents a challenge because of the severe overlap of these compounds' spectra. Six newly developed methods were proven effective for resolving such a challenging overlap. They also exhibited the advantage of simplicity as they depend on the zero-order spectrum and only require simple mathematical handling.

OBJECTIVE

We suggested six simple, precise, and sensitive spectrophotometric methods based on mathematical filtration techniques and ratio spectra manipulations to resolve the spectra of DAP and SIL in their bulk and combined pharmaceutical dosage form and estimate the relevant individual concentrations.

METHODS

The first three methods were based on the zero-order range and involved modest mathematical manipulations. They are the induced dual-wavelength, Fourier self-deconvolution, and absorptivity factor spectrophotometric methods. Three other methods that are based on ratio spectra manipulation were developed: ratio difference, mean centering of the ratio spectra, and derivative ratio spectrum.

RESULTS

We determined the performance of the suggested methods for estimating DAP and SIL in their laboratory mixtures and their combined pharmaceutical dosage form. The linear ranges for DAP and SIL were 1-40 µg/ml and 2-60 µg/ml, respectively. The detection limits were in the 0.18-1.10 µg/ml range for DAP and in the 0.68-1.11 µg/ml range for SIL. The developed methods were validated as per the ICH guidelines for linearity, detection limit, quantitation limit, selectivity, precision, and accuracy. Normal probability, interval, and Tukey's simultaneous significant difference plots were utilized to confirm and better visualize the analysis of variance test results. Statistically, no significant difference was observed to exist between results obtained from the hereby developed and the previously reported methods.

A Review on Analytical Strategies for the Assessment of Recently Approved Direct Acting Antiviral Drugs

Human beings are in dire need of developing an efficient treatment against fierce viruses like hepatitis C virus (HCV) and Coronavirus (COVID-19). These viruses have already caused the death of over two million people all over the world. Therefore, over the last years, many direct-acting antiviral drugs (DAADs) were developed targeting nonstructural proteins of these two viruses. Among these DAADs, several drugs were found more effective and safer than the others as sofosbuvir, ledipasvir, grazoprevir, glecaprevir, voxilaprevir, velpatasvir, elbasvir, pibrentasvir and remdesivir. The last one is indicated for COVID-19, while the rest are indicated for HCV treatment. Due to the valuable impact of these DAADs, larger number of analytical methods were required to meet the needs of the clinical studies. Therefore, this review will highlight the current approaches, published in the period between 2017 to present, dealing with the determination of these drugs in two different matrices: pharmaceuticals and biological fluids with the challenges of analyzing these drugs either alone, with other drugs, in presence of interferences (pharmaceutical excipients or endogenous plasma components) or in presence of matrix impurities, degradation products and metabolites. These approaches include spectroscopic, chromatographic, capillary electrophoretic, voltametric and nuclear magnetic resonance methods that have been reported during this period. Moreover, the analytical instrumentation and methods used in determination of these DAADs will be illustrated in tabulated forms.

Rapid and sensitive UHPLC-DAD method for simultaneous determination of sofosbuvir and ledipasvir in human serum

Today, the direct-acting antiviral agents (DAAs) such as sofosbuvir (SOF) and ledipasvir (LED) are widely used to treat the hepatitis virus infection. The aim of this study was to develop a rapid, simple and valid method for simultaneous determination of SOF and LED in human plasma for bioavailability and pharmacokinetic studies. Chromatographic analysis was performed on the C₁₈ column (Blue Orchid, 1.8 μm, 50 × 2 mm) using 0.1 % formic acid in water (pH 2.6) and acetonitrile (60:40; v/v) as mobile phase at a flow rate of 0.5 mL/min. The UV detector was set at 328 nm and 260 nm for analysis of SOF and LED, respectively. To 400 μL of plasma, 100 μL of clonazepam as the internal standard (I.S, 7 μg/mL) was added and the mixture subjected to liquid-liquid extraction using 1000 μL diethyl ether. The calibration curves were linear with coefficients of variation less than 8% for all analyses. The limit of quantification (LOQ) was 20 and 5 ng/mL for SOF and LED, respectively. The results of inter-day and intra-day precision showed good reproducibility and the total analysis time was 1.2 min. This method successfully applied for determination SOF and LED in four healthy volunteers.

Micelle sensitized synchronous spectrofluorimetric approaches for the simultaneous determination of simeprevir and ledipasvir: Application to pharmaceutical formulations and human plasma

Simeprevir (SMV) is commonly co-administered with ledipasvir (LDS) and sofosbuvir (SOF) as an effective combination regimen for treatment naive hepatitis C virus infected patients. In the present study, two spectrofluorimetric approaches were combined together for the development of highly sensitive, rapid, simple and accurate method for simultaneous quantification of SMV and LDS. The native fluorescence intensity values of SMV and LDS were enhanced by the addition of Tween-80 micellar system, while second derivative of the synchronous fluorescence intensity of the drugs at Δλ = 120 nm enabled the determination of both drug concomitantly. Different experimental parameters affecting the synchronous fluorescence of the cited drugs were carefully evaluated for their optimization. The peak amplitudes of the second derivative synchronous fluorimetry were measured at 429 nm for SMV and at 417 nm for LDS. The fluorescence-concentration plots were rectilinear over the range of 60-1500 and 36-540 ng mL^-1 with lower detection limits of 9.0 and 6.0 ng mL^-1 and quantification limits of 27.0 and 17.0 ng mL^-1 for SMV and LDS respectively. The method was successfully applied for the determination of both drugs in their pure forms as well as their pharmaceutical products and human plasma without any significant interference. Statistical comparison with the reported method revealed excellent accuracy and precision of the proposed method.

Development and validation of a versatile HPLC-DAD method for simultaneous determination of the antiviral drugs daclatasvir, ledipasvir, sofosbuvir and ribavirin in presence of seven potential impurities. Application to assay of dosage forms and dissolution studies

This study describes a simple, sensitive, specific and generic HPLC-DAD method for simultaneous determination of four drugs prescribed for treatment of Hepatitis C Virus (HCV) infection. Investigated drugs include daclatasvir (DAC), ledipasvir (LED), sofosbuvir (SOF) and ribavirin (RIB). Successful separation was accomplished using Thermohypersil BDS-C8 column (4.6 × 250 mm, 5 µm) with gradient elution of the mobile phase consisted of mixed phosphate buffer pH 7.5 and methanol. Gradient elution started with 25% methanol, ramped up linearly to 80% in 15 min then kept constant till the end of the run. Flow rate was 1.5 mL/min. Peak areas were measured at 235, 260, 315, and 332 nm for RIB, SOF, DAC, and LED, respectively. Peaks of the analytes were perfectly resolved with retention times 2.0, 12.1, 14.7, and 17.2 min for RIB, SOF, DAC, and LED, respectively. The developed method was validated according to ICH guidelines with respect to system suitability, linearity, ranges, accuracy, precision, specificity, robustness, and limits of detection and quantification. The proposed method showed good linearity in the ranges 5-500, 2-300, 0.5-75, and 0.5-75 µg/mL for RIB, SOF, DAC, and LED respectively. Limits of detection were 0.10-0.66 μg/mL for the analyzed drugs. Specificity was established by separation of target drugs from 7 process-related impurities for SOF including its major metabolite (GS-331007). Applicability of the proposed method to real life situations was assessed through the analysis of four different pharmaceutical formulations and satisfactory results were obtained. Additionally, dissolution profiles of the 4 drugs were studied using the developed method.

Earth-friendly spectrophotometric methods for simultaneous determination of ledipasvir and sofosbuvir: Application to average content and uniformity of dosage unit testing

Simple, rapid, sensitive, accurate, precise and earth-friendly spectrophotometric methods were developed for the simultaneous analysis of ledipasvir (LED) and sofosbuvir (SOF) without interference of both sunset yellow dye and copovidone excipients (the most probable interferents) in their combined dosage form. These proposed methods were based on measurement of LED in synthetic mixtures and combined dosage form by first derivative (¹D) spectrophotometry at 314 nm over the concentration range of 2-50 μg mL^-1 with coefficient of determination (R²) > 0.9999, mean percentage recovery of 99.98 ± 0.62. On the other hand, SOF in synthetic mixtures and combined dosage form was determined by five methods. Method I is based on the use of ¹D spectrophotometry at 274.2 nm (zero crossing point of LED). Method II involves the application of conventional dual wavelength method (DW) at the absolute difference between SOF zero order amplitudes at 261 nm (λ_max of SOF) and 364.7 nm. At these wavelengths, the absolute difference between LED zero order amplitudes was observed to equal zero. Method III depends on isosbestic point method (ISP) in which the total concentration of both drugs was measured at isosbestic point at 262.7 nm. Concentration of SOF could be obtained by subtraction of LED concentration. While, method IV depends on absorbance correction method (absorption factor method), which is based on determination of SOF concentration at 262.7 nm (λ_ISP) and LED at 333 nm (λ_max of LED). Finally, method V depends on absorbance ratio method (Q-analysis) in which 262.7 nm (λ_ISP) and 261 nm (λ_max of SOF) were selected to determine SOF concentration. The linearity range for all methods for SOF determination was 2-50 μg mL^-1 with coefficient of determination (R²) > 0.9999. Methods I, II & III were also applied for determination of SOF concentration in single dosage form. Their mean percentage recoveries were 100.35 ± 1.85, 99.97 ± 0.54 and 100.03 ± 0.49, for the three methods respectively. The proposed methods were validated according to international conference of harmonization (ICH) requirements and statistically compared to published reference methods. The ANOVA test confirmed that there is no significant differences between the proposed methods, and can be used for routine analysis of LED and SOF in commercial tablets. These developed methods were applied to estimate the average content and uniformity of dosage unit for LED/SOF combined dosage form and SOF single dosage form according to British pharmacopeia (BP) requirements.

Specific stability indicating spectrofluorimetric method for determination of ledipasvir in the presence of its confirmed degradation products; application in human plasma

A rapid and specific spectrofluorimetric method with higher sensitivity was developed for determination of ledipasvir (LDS) in tablets and human plasma. The proposed method relies on hydrogen bonding formations between the hydroxyl groups of polyoxyethylene 50 stearate and LDS, causing significant enhancement of its native fluorescence. The fluorescence intensity was measured at 430 nm after excitation at 340 nm. The fluorescence-concentration plot was rectilinear over the range 1-400 ng mL^-1 with detection and quantification limits of 0.25 and 1.10 ng mL^-1, respectively. The high sensitivity of the proposed method permits its application for ledipasvir determinations in real human plasma even in the presence of co-administered drugs sofosbuvir and ribavirin. Moreover, the proposed method was further extended to stability studies of ledipasvir after exposure to different forced degradation conditions according to ICH guidelines, along with the structural elucidation of its degradation products utilizing IR and Mass spectra. A proposal for the degradation pathways was presented.

New, simple and sensitive HPTLC method for simultaneous determination of anti-hepatitis C sofosbuvir and ledipasvir in rabbit plasma

Sofosbuvir (SOF) and ledipasvir (LDS) represent anti-hepatitis C binary mixture. Herein, a fast high-performance thin-layer chromatography (HPTLC) method was developed, validated and applied for simultaneous determination of SOF and LDS in biological matrix. An innovative strategy was designed which based on coupling dual wavelength detection with HPTLC. This strategy enabled sensitive, specific, high sample throughput and cost-effective determination of the SOF-LDS binary mixture. The developed HPTLC procedure is based on a simple liquid-liquid extraction, enrichment of the analytes and subsequent separation with UV detection. Separations were performed on HPTLC silica gel 60 F₂₅₄ aluminum plates with a mobile phase consisting of ethyl acetate-glacial acetic acid (100:5, v/v). The R_f values for SOF and LDS were 0.62 and 0.30, respectively. Dual wavelength scanning was carried out in the absorbance mode at 265 and 327 nm for SOF and LDS, respectively. The linear ranges were 40-640 and 9-144 ng/band for SOF and LDS, respectively with correlation coefficients of 0.9998. The detection limits were 10.61 and 2.54 ng/band and the quantitation limits were 32.14 and 7.70 ng/band for SOF and LDS, respectively indicating high sensitivity of the proposed method. Consequently, this permits in vitro and in vivo application of the proposed method in rabbit plasma with good percentage recovery (95.68-103.26%). Validation parameters were assessed according to ICH guidelines. The proposed method represents a simple, high sample throughput and economic alternative to the already existing more complicated reported LC-MS/MS techniques. The method would afford an efficient tool for therapeutic drug monitoring and bioavailability studies of SOF and LDS.

A facile synthesis of 3D NiFe2O4 nanospheres anchored on a novel ionic liquid modified reduced graphene oxide for electrochemical sensing of ledipasvir: Application to human pharmacokinetic study

Novel and sensitive electrochemical sensor was fabricated for the assay of anti-HCV ledipasvir (LEDV) in different matrices. The designed sensor was based on 3D spinel ferromagnetic NiFe₂O₄ nanospheres and reduced graphene oxide (RGO) supported by morpholinium acid sulphate (MHS), as an ionic liquid (RGO/NSNiFe₂O₄/MHS). This sensor design was assigned to synergistically tailor the unique properties of nanostructured ferrites, RGO, and ionic liquid to maximize the sensor response. Electrode modification prevented aggregation of NiFe₂O_4, increasing electroactive surface area and allowed remarkable electro-catalytic oxidation of LEDV with an enhanced oxidation response. Differential pulse voltammetry was used for detection LEDV in complex matrices whereas; cyclic voltammetry and other techniques were employed to characterize the developed sensor properties. All experimental factors regarding sensor fabrication and chemical sensing properties were carefully studied and optimized. Under the optimum conditions, the designated sensor displayed a wide linear range (0.4-350 ng mL^-1) with LOD of 0.133 ng mL^-1. Additionally, the proposed sensor demonstrated good selectivity, stability and reproducibility, enabling the quantitative detection of LEDV in Harvoni^® tablets, human plasma and in a pharmacokinetic study. Our findings suggest that the developed sensor is a potential prototype material for fabrication of high-performance electrochemical sensors.