An ultra-high-performance chromatography method to study the long term stability of gemcitabine in dose banding conditions

Gemcitabine is an analogue of cytidine arabinoside, used alone or in combination chemotherapy to treat various type of cancer. The dose-banding of gemcitabine provides the opportunity to anticipate the preparation of this anticancer drug on condition of carrying out stability studies. The aim of this study is to develop and validate a stability-indicating ultra-high-performance Liquid Chromatography (UHPLC) method for measuring the concentration of gemcitabine and to evaluate its stability at standardised rounded doses in polyolefin bags. The UHPLC with photodiode array (PDA) detector method was developed and validated (linearity, precision, accuracy, limits of detection and quantification, robustness and degradation test). Thirty polyolefin bags of gemcitabine (1600 mg/292 ml (n = 10), 1800 mg/297 ml (n = 10) and 2000 mg/303 ml (n = 10)) were prepared under aseptic conditions and stored at 5 ± 3 °C and 23 ± 2 °C for 49 days. Physical stability tests were periodically performed: visual and microscopic inspection and optical densities. The chemical stability was evaluated through pH monitoring and chromatographic assays. The results confirm the stability of Gemcitabine at selected standardised rounded doses of 1600 mg, 1800 mg and 2000 mg in NaCl 0.9% polyolefin bags for at least 49 days at 5 ± 3 °C and 23 ± 2 °C, allowing in-advance preparation.

Regulatory Perspective Development and Validation of Novel RP-HPLC Method of Midostaurin Drug Substance using Analytical Quality by Design approach; Identified Major Degradation Compounds Mass by Using LC-MS technique

Midostaurin (MTN) was designated as an orphan medicinal product, and it is an emerging drug for treating acute myeloid leukemia and advanced systematic mastocytosis, respectively. The proposed method was developed and validated to evaluate related impurities of MTN. Those impurities were separated by using YMC Trait C18 ExRS, (150 mm × 4.6 mm), 3 μm column. The mobile phase A consists of a 10 mM concentration of phosphate buffer adjusted to pH 3.0 with diluted orthophosphoric acid and mobile phase B contains 90 % acetonitrile with 10 % water. The optimized chromatographic conditions such as flow rate 0.5 mL min^-1 , injection volume 10 μL, UV detection at 290 nm, and a linear gradient program set upto 65 minutes. It was developed through an analytical QbD approach. A systematic flow chart explained the evaluation, control, and life cycle management method. As part of the method evaluation, a risk assessment was conducted. It has been validated as per current ICH guidelines. The recovery study and linearity ranges were established from LOQ to 150 % optimal concentrations. The validation results were found between 95.5 to 102.5 % for recovery and r² 0.9998 to 0.9999 for linearity of all identified impurities. The method precision results were achieved below 10% of RSD. Performed forced degradation studies in chemical and physical stress conditions. The compound was sensitive to chemical stress conditions. During the study, the analyte was degraded, converted into identified degradation impurities, and found its molecular mass by the LC-MS technique.

Stability-indicating method development for quantification of bromopride, its impurities, and degradation products by ultra-high performance liquid chromatography applying Analytical Quality by Design principles

A comprehensive forced degradation study for bromopride was carried out in accordance with International Conference on Harmonization (ICH) recommendations followed by the identification and prospecting of the major degradation products. The analytical quality by design (AQbD) concepts were used to develop a stability-indicating method for bromopride and five organic impurities quantitation by ultra-high performance liquid chromatography with UV detection (UHPLC-UV). Two screenings and one optimization design were performed, including a Monte Carlo simulation to assess the Method Operable Design Region (MODR). The AQbD approach provided a high degree of method understanding in a very short period of time, less than two weeks, and the validated MODR provided information on robust analytical conditions contributing to the assignment of suitable control strategies.

A stability-indicating UPLC method for the determination of curcumin diethyl disuccinate, an ester prodrug of curcumin, in raw materials

A stability-indicating reversed-phase ultra-performance liquid chromatographic (UPLC) method for quantitative analysis of curcumin diethyl disuccinate (CDD) in raw materials was developed for applications in product development and quality control. Chromatographic separation was performed using the Waters ACQUITY UPLC® H-Class system consisting of an ACQUITY UPLC® BEH C18 (1.7 μm, 2.1 × 50 mm) column and a photodiode array detector set at a wavelength of 400 nm. The mobile phase consisting of 2%v/v acetic acid in water and acetonitrile was delivered at a flow rate of 0.3 mL/min under gradient elution program. The method was validated according to the ICH Q2(R1) guideline for the validation of analytical procedures. The method was found to be linear over the concentration range of 8-12 μg/mL with the coefficient of determination >0.995. The accuracy of the method established as %recovery ranged from 98.3 - 100.8%. The precision of the method expressed as %CV was found to be <1%. The coelution of degradation products from six stress test conditions was not observed. The method was robust under the variation of chromatographic parameters. The method was successfully applied in the determination of CDD content in raw materials.

Acyclovir chemical kinetics with the discovery and identification of newly reported degradants and degradation pathways involving formaldehyde as a degradant and reactant intermediate

The purpose of this research was to determine acyclovir (ACV) acidic degradation kinetics which is relevant to gastric retentive device product design. A stability-indicating method revealed two unknown degradation products which have been identified by mass spectrometry as ACV and guanine formaldehyde adducts. In addition to the formation of these adducts, a proposed degradation scheme identifies the formation of methyl acetal ethylene glycol, formaldehyde, ethylene glycol, and guanine as additional ACV degradation products. pH-rate profiles were explained by using a rate law which assumed acid-catalyzed hydrolysis of protonated and unprotonated ACV. The predicted and observed rate constants were in good agreement. Data-driven excipient selection recommendations were based on the chemical kinetic study results, degradation scheme, and pH-rate profiles. The average activation energy for the degradation reaction was determined to be 31.3±1.6kcal/mol. The predicted ACV t_90% at 37°C and pH 1.2 was calculated to be 7.2days. As a first approximation, this suggests that ACV gastric retentive devices designed to deliver drug for 7days should have acceptable drug product stability in the stomach.

Formulation, stability testing, and analytical characterization of melatonin-based preparation for clinical trial

A new institutional clinical trial assessed the improvement of sleep disorders in 40 children with autism treated by immediate-release melatonin formulation in different regimens (0.5 mg, 2 mg, and 6 mg daily) for one month. The objectives of present study were to (i) prepare low-dose melatonin hard capsules for pediatric use controlled by two complementary methods and (ii) carry out a stability study in order to determine a use-by-date. Validation of preparation process was claimed as ascertained by mass uniformity of hard capsules. Multicomponent analysis by attenuated total reflectance Fourier transformed infrared (ATR-FTIR) of melatonin/microcrystalline cellulose mixture allowed to identify and quantify relative content of active pharmaceutical ingredients and excipients. Absolute melatonin content analysis by high performance liquid chromatography in 0.5 mg and 6 mg melatonin capsules was 93.6%±4.1% and 98.7%±6.9% of theoretical value, respectively. Forced degradation study showed a good separation of melatonin and its degradation products. The capability of the method was 15, confirming a risk of false negative <0.01%. Stability test and dissolution test were compliant over 18 months of storage with European Pharmacopoeia. Preparation of melatonin hard capsules was completed manually and melatonin in hard capsules was stable for 18 months, in spite of low doses of active ingredient. ATR-FTIR offers a real alternative to HPLC for quality control of high-dose melatonin hard capsules before the release of clinical batches.

Development of a Stability-Indicating Stereoselective Method for Quantification of the Enantiomer in the Drug Substance and Pharmaceutical Dosage Form of Rosuvastatin Calcium by an Enhanced Approach

A novel, simple, precise, and stability-indicating stereoselective method was developed and validated for the accurate quantification of the enantiomer in the drug substance and pharmaceutical dosage forms of Rosuvastatin Calcium. The method is capable of quantifying the enantiomer in the presence of other related substances. The chromatographic separation was achieved with an immobilized cellulose stationary phase (Chiralpak IB) 250 mm x 4.6 mm x 5.0 μm particle size column with a mobile phase containing a mixture of n-hexane, dichloromethane, 2-propanol, and trifluoroacetic acid in the ratio 82:10:8:0.2 (v/v/v/v). The eluted compounds were monitored at 243 nm and the run time was 18 min. Multivariate analysis and statistical tools were used to develop this highly robust method in a short span of time. The stability-indicating power of the method was established by subjecting Rosuvastatin Calcium to the stress conditions (forced degradation) of acid, base, oxidative, thermal, humidity, and photolytic degradation. Major degradation products were identified and found to be well-resolved from the enantiomer peak, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection and limit of quantification, precision, linearity, accuracy, and robustness. The method exhibited consistent, high-quality recoveries (100 ± 10%) with a high precision for the enantiomer. Linear regression analysis revealed an excellent correlation between the peak responses and concentrations (r(2) value of 0.9977) for the enantiomer. The method is sensitive enough to quantify the enantiomer above 0.04% and detect the enantiomer above 0.015% in Rosuvastatin Calcium. The stability tests were also performed on the drug substances as per ICH norms.

An Approach to Transfer Methods from HPLC to UHPLC Techniques in Some Carbapenems

Stability-indicating LC methods were developed and validated for the quantitative determination of doripenem, meropenem and tebipenem in the presence of their degradation products formed during forced degradation studies. Isocratic HPLC and UHPLC separations were performed with a core–shell Kinetex 1.7, 2.6 and 5 µm, all C18, 100A, 100 × 2.1 mm columns and the mobile phase composed of acetonitrile and 12 mmol L⁻¹ ammonium acetate in different ratios. The flow rates of the mobile phase were: 0.5 mL min⁻¹ for 1.7 µm column, and 1.0 mL min⁻¹ for 2.6 and 5 µm ones. Detection wavelength was 298 nm and temperature was set at 30 °C. All analysed drugs were exposed to stress conditions which caused their hydrolysis and thermal degradation. The methods were validated by evaluation of linearity, accuracy, precision, selectivity and robustness. Proposed methods were successfully applied for the determination of investigated antibiotics during kinetic studies in aqueous solutions and in the solid state. The advantages of chromatographic procedures which are based on the use of C18 stationary phases with different particle sizes in the analysis of selected carbapenems were discussed.

Two and three way spectrophotometric-assisted multivariate determination of linezolid in the presence of its alkaline and oxidative degradation products and application to pharmaceutical formulation

Linezolid (LIN) is determined in the presence of its alkaline (ALK) and oxidative (OXD) degradation products without preliminary separation based on ultraviolet spectrophotometry using two-way chemometric methods; principal component regression (PCR) and partial least-squares (PLS), and three-way chemometric methods; parallel factor analysis (PARAFAC) and multi-way partial least squares (N-PLS). A training set of mixtures containing LIN, ALK and OXD; was prepared in the concentration ranges of 12-18, 2.4-3.6 and 1.2-1.8 μg mL(-1), respectively according to a multilevel multifactor experimental design. The multivariate calibrations were obtained by measuring the zero-order absorbance from 220 to 320 nm using the training set. The validation of the multivariate methods was realized by analyzing their synthetic mixtures. The capabilities of the chemometric analysis methods for the analysis of real samples were evaluated by determination of LIN in its pharmaceutical preparation with satisfactory results. The accuracy of the methods, evaluated through the root mean square error of prediction (RMSEP), was 0.058, 0.026, 0.101 and 0.026 for LIN using PCR, PLS, PARAFAC and N-PLS, respectively. Protolytic equilibria of LIN and its degradation products were evaluated using the corresponding absorption spectra-pH data obtained with PARAFAC. The obtained pKa values of LIN, ALK and OXD are 5.70, 8.90 and 6.15, respectively. The results obtained were statistically compared to that of a reported HPLC method, and there was no significant difference between the proposed methods and the reported method regarding both accuracy and precision.

A Stability-Indicating HPLC Method for the Determination of Nitrosylcobalamin (NO-Cbl), a Novel Vitamin B12 Analog

Nitrosylcobalamin (NO-Cbl), a novel vitamin B12 analog and anti-tumor agent, functions as a biologic 'Trojan horse', utilizing the vitamin B12 transcobalamin II transport protein and cell surface receptor to specifically target cancer cells. a stability-indicating HPLC method was developed for the detection of NO-Cbl during forced degradation studies. This method utilized an ascentis® RP-amide (150 mm × 4.6 mm, 5 μm) column at 35 °C with a mobile phase (1.0 mL min-1) combining a gradient of methanol and an acetate buffer at pH 6.0. Detection wavelengths of 450 and 254 nm were used to detect corrin and non-corrin-based products, respectively. NO-Cbl, synthesized from hydroxocobalamin and pure nitric oxide gas, was subjected to degradative stress conditions including oxidation, hydrolysis and thermal and radiant energy challenge. The method was validated by assessing linearity, accuracy, precision, detection and quantitation limits and robustness. The method was applied successfully for purity assessment of synthesized NO-Cbl and for the determination of NO-Cbl during kinetic studies in aqueous solution and in solid-state degradation assessments. This HPLC method is suitable for the separation of cobalamins in aqueous and methanolic solutions, for routine detection of NO-Cbl and for purity assessment of synthesized NO-Cbl. additionally, this method has potential application in identification and monitoring of diseases involving altered nitric oxide homeostasis where vitamin B12 therapy is utilized to scavenge excess nitric oxide, subsequently resulting in the in vivo production of NO-Cbl.

Implementation of design of experiments for optimization of forced degradation conditions and development of a stability-indicating method for furosemide

The study involved optimization of forced degradation conditions and development of a stability-indicating method (SIM) for furosemide employing the design of experiment (DoE) concept. The optimization of forced degradation conditions, especially hydrolytic and oxidative, was done by application of 2(n) full factorial designs, which helped to obtain the targeted 20-30% drug degradation and also enriched levels of degradation products (DPs). For the selective separation of the drug and its DPs for the development of SIM, DoE was applied in three different stages, i.e., primary parameter selection, secondary parameter screening and method optimization. For these three, IV-optimal, Taguchi orthogonal array and face-centred central composite designs were employed, respectively. The organic modifier, buffer pH, gradient time and initial hold time were selected as primary parameters. Initial and final organic modifier percentage, and flow rate came out as critical parameters during secondary parameter screening, which were further evaluated during method optimization. Based on DoE results, an optimized method was obtained wherein a total of twelve DPs were separated successfully. The study also exposed the degradation behaviour of the drug in different forced degradation conditions.

Validated liquid chromatographic determination of a novel ACE inhibitor in the presence of its hydrolytic and oxidative degradation products as per ICH guidelines

Imidapril hydrochloride (IMD) is a recently developed prodrug-type angiotensin-converting enzyme (ACE) inhibitor. Due to its instability under both hydrolytic and oxidative conditions, development of rapid, simple and sensitive methods for its determination in the presence of its possible degradation products is essential. We proposed two simple liquid chromatographic methods associated with ultraviolet detection. The first method is an HPTLC-densitometric one in which separation of IMD from its degradation products was achieved followed by densitometric scanning at 220 nm using silica gel F254 plates and chloroform:ethanol:acetic acid (3:0.5:0.1, v/v/v) as the developing system. The second method was based on RP-HPLC in which the separation was performed using C18 analytical column and isocratic elution system with acetonitrile: 0.15% triethylamine (pH=2.2) (40:60, v/v). The optimum flow rate was 1.5 mL min(-1) and the detection was at 220 nm. Validation was conducted in compliance with the ICH guidelines and the methods were successfully applied for IMD determination in its commercial tablets. The obtained results were statistically compared to those obtained by applying reported HPLC method where no significant difference was found in accordance with accuracy and precision.

Improvement of a stability-indicating method by Quality-by-Design versus Quality-by-Testing: a case of a learning process

The understanding of the method is a major concern when developing a stability-indicating method and even more so when dealing with impurity assays from complex matrices. In the presented case study, a Quality-by-Design approach was applied in order to optimize a routinely used method. An analytical issue occurring at the last stage of a long-term stability study involving unexpected impurities perturbing the monitoring of characterized impurities needed to be resolved. A compliant Quality-by-Design (QbD) methodology based on a Design of Experiments (DoE) approach was evaluated within the framework of a Liquid Chromatography (LC) method. This approach allows the investigation of Critical Process Parameters (CPPs), which have an impact on Critical Quality Attributes (CQAs) and, consequently, on LC selectivity. Using polynomial regression response modeling as well as Monte Carlo simulations for error propagation, Design Space (DS) was computed in order to determine robust working conditions for the developed stability-indicating method. This QbD compliant development was conducted in two phases allowing the use of the Design Space knowledge acquired during the first phase to define the experimental domain of the second phase, which constitutes a learning process. The selected working condition was then fully validated using accuracy profiles based on statistical tolerance intervals in order to evaluate the reliability of the results generated by this LC/ESI-MS stability-indicating method. A comparison was made between the traditional Quality-by-Testing (QbT) approach and the QbD strategy, highlighting the benefit of this QbD strategy in the case of an unexpected impurities issue. On this basis, the advantages of a systematic use of the QbD methodology were discussed.

Stability-Indicating HPLC Method for the Determination of Cefcapene Pivoxil

The stability-indicating LC assay method was developed and validated for quantitative determination of cefcapene pivoxil in the presence of degradation products formed during forced degradation studies. An isocratic RP-HPLC method was developed with a Lichrospher RP-18 (250 mm × 4.6 mm, 5 μm) column and the mobile phase composed of 45 volumes of acetonitrile and 55 volumes of mixture composed of citric acid 10 mmol L⁻¹ and potassium chloride 18 mmol L⁻¹. The flow rate of the mobile phase was 1 mL min⁻¹. Detection wavelength was 270 nm and temperature was 30 °C. Cefcapene pivoxil, similar to other cephalosporins, was subjected to stress conditions of degradation in aqueous solutions including hydrolysis, oxidation, and thermal degradation. The method was validated with regard to linearity, accuracy, precision, selectivity, and robustness. The method was applied successfully for the determination of cefcapene pivoxil during kinetic studies in aqueous solutions (pH and thermal degradation) and in solid state (oxidative, thermal, and radiolytic degradation).

Stress Degradation Behavior of Atorvastatin Calcium and Development of a Suitable Stability-Indicating LC Method for the Determination of Atorvastatin, its Related Impurities, and its Degradation Products

A rapid, reversed-phase liquid chromatographic method was developed for the quantitative determination of Atorvastatin calcium, its related substances (12 impurities), and degradation impurities in bulk drugs. The chromatographic separation was achieved on a Zorbax Bonus-RP column by employing a gradient elution with water–acetonitrile–trifluoroacetic acid as the mobile phase in a shorter run time of 25 min. The flow rate was 1.0 mL/min and the detection wavelength was 245 nm. The drug substance was subjected to stress studies such as hydrolysis, oxidation, photolysis, and thermal degradation, and considerable degradation was observed in acidic hydrolysis, oxidative, thermal, and photolytic stress conditions. The formed degradation products were reported and were well-resolved from the Atorvastatin and its related substances. The stressed samples were quantified against a qualified reference standard and the mass balance was found to be close to 99.5% (w/w) when the response of the degradant was considered to be equal to the analyte (i.e. Atorvastatin), which demonstrates the stability-indicating capability of the method. The method was validated in agreement with ICH requirements. The method developed here was single and shorter (25 min method for the determination of all 12 related impurities of Atorvastatin and its degradation products), with clearly better resolution and higher sensitivity than the European (85 min method for the determination of six impurities) and United States pharmacopeia (115 min and 55 min, two different methods for the determination of six related substances).

Simultaneous Determination of Sitagliptin Phosphate Monohydrate and Metformin Hydrochloride in Tablets by a Validated UPLC Method

A novel approach was used to develop and validate a rapid, specific, accurate and precise reverse phase ultra performance liquid chromatographic (UPLC) method for the simultaneous determination of Sitagliptin phosphate monohydrate and Metformin hydrochloride in pharmaceutical dosage forms. The chromatographic separation was achieved on Aquity UPLC BEH C8 100 × 2.1 mm, 1.7 μm, column using a buffer consisting of 10 mM potassium dihydrogen phosphate and 2 mM hexane-1-sulfonic acid sodium salt (pH adjusted to 5.50 with diluted phosphoric acid) and acetonitrile as organic solvent in a gradient program. The flow rate was 0.2 mL min⁻¹ and the detection wavelength was 210 nm. The limit of detection (LOD) for Sitagliptin phosphate monohydrate and Metformin hydrochloride was 0.2 and 0.06 μg mL⁻¹, respectively. The limit of quantification (LOQ) for Sitagliptin phosphate monohydrate and Metformin hydrochloride was 0.7 and 0.2 μg mL⁻¹, respectively. This method was validated with respect to linearity, accuracy, precision, specificity and robustness. The method was also found to be stability-indicating.

Stability-indicating HPTLC method for simultaneous determination of nateglinide and metformin hydrochloride in pharmaceutical dosage form

A stability indicating high performance thin layer chromatography (HPTLC) method was developed and validated for determination of two anti-diabetic drugs, nateglinide and metformin hydrochloride in co-formulations. Study was performed on pre-coated silica gel HPTLC plates using chloroform:ethyl acetate:acetic acid (4:6:0.1 v/v/v) as the mobile phase. A TLC scanner set at 216 nm was used for direct evaluation of the chromatograms in the reflectance/absorbance mode. Method was validated according to ICH guidelines. The correlation coefficients of calibration curves were found to be 0.996 and 0.995 in the concentration range of 200-2400 and 500-3000 ng band(-1) for nateglinide and metformin, respectively. The method had an accuracy of 99.72% for nateglinide and 100.08% for metformin hydrochloride. The method had the potential to determine these drugs simultaneously from dosage forms without any interference of the tablets excipients. Nateglinide and metformin hydrochloride were also subjected to acid, base, oxidation, wet, heat and photo-degradation studies. The degradation products obtained were well resolved from the pure drugs with significantly different Rf values. As the method could effectively separate the drugs from its degradation products, it can be used for stability-indicating analysis.

Determination of lumiracoxib by a validated stability-indicating MEKC method and identification of its degradation products by LC-ESI-MS studies

A stability-indicating MEKC method was developed and validated for the analysis of lumiracoxib (LMC) in pharmaceutical formulations using nimesulide as the internal standard (IS). Optimal conditions for the separation of LMC and degradation products were investigated. The method employed 50 mM borate buffer and 50 mM anionic detergent SDS solution at pH 9.0. MEKC method was performed on a fused-silica capillary (50 μm id; effective length, 40 cm) maintained at 30°C. The applied voltage was 20 kV and photodiode array (PDA) detector was set at 208 nm. The method was validated in accordance with the International Conference on Harmonisation requirements. The stability-indicating capability of the method was established by enforced degradation studies combined with peak purity assessment using PDA detection. The degradation products formed under stressed conditions were investigated by LC-ESI-MS and the two degraded products were identified. MEKC method was linear over the concentration range of 5-150 μg/mL (r(2) =0.9999) of LMC. The method was precise, accurate, with LOD and LOQ of 1.34 and 4.48 μg/mL, respectively. The robustness was proved by a fractional factorial design evaluation. The proposed MEKC method was successfully applied for the quantitative analysis of LMC in tablets to support the quality control.