Development and optimization of SPE-HPLC-UV/ELSD for simultaneous determination of nine bioactive components in Shenqi Fuzheng Injection based on Quality by Design principles

Application of QbD based approach in development and validation of RP-HPLC method for simultaneous estimation of methotrexate and baicalin in dual-drug-loaded liposomes

The present study delineates the development of a novel, rugged and sensitive stability-indicating risk-based HPLC method for the concurrent estimation of methotrexate (MTX) and baicalin (BCL) in dual-drug-loaded-nanopharmaceuticals based on an analytical quality-by-design approach. Preliminary screening trials along with systemic risk analysis were performed, endeavouring to explicate the critical method attributes, namely pH, percentage of orthophosphoric acid and percentage of acetonitrile, that influence the critical quality attributes. Box-Behnken design was utilized for the optimization of the tailing factor as the response for MTX and BCL in a short run time. The chromatographic conditions were optimized by performing 17 experimental runs using design expert software. The chromatographic conditions were selected after the analysis of the optimized zone within the confines of the design space: water:acetonitrile adjusted to a pH of 3.0 with 0.05% orthophosphoric acid (60:40, %v/v) was the mobile phase, the flow rate was 1.0 ml/min and an analytical C₁₈ column was used at an isobestic wavelength of 282 nm. Furthermore, the optimized method was validated in accordance with the International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines and was found to be within the prescribed limits. Therefore, the developed reversed-phase-high-performance liquid chromatography method has a high degree of practical utility for synchronous detection of MTX and BCL in pharmaceutical nano-dosage forms such as protein-based nanoparticles, nanocrystals, polymeric nanoparticles and metallic nanoparticles in in vivo and in vitro studies.

Determination of the intermediates in glycolysis and tricarboxylic acid cycle with an improved derivatization strategy using gas chromatography-mass spectrometry in complex samples

Traditional Chinese medicine (TCM) is recognized as a complex matrix, and improved analytical methods are crucial to extract the key indicators and depict the interaction and alteration of the complex matrix. Shenqi Fuzheng Injection (SQ), a water extract of Radix Codonopsis and Radix Astragali, has demonstrated preventative effects on myotube atrophy induced by chemotherapeutic agents. To achieve the improved analytical capability of complex biological samples, we established a highly reproducible, sensitive, specific, and robust gas chromatography-tandem mass spectrometry (GC-MS) method to detect glycolysis and tricarboxylic acid (TCA) cycle intermediates with optimized factors in the extraction and derivatization process. Our method detected fifteen metabolites and covered most intermediate metabolites in glycolysis and TCA cycles, including glucose, glucose-6-phosphate, fructose-6-phosphate, dihydroxyacetone phosphate, 3-diphosphoglycerate, phosphoenolpyruvate, pyruvate, lactate, citrate, cis-aconitate, isocitrate, α-ketoglutarate, succinate, fumarate, and malate. Through methodological verification of the method, it was found that the linear correlation coefficients of each compound in the method were greater than 0.98, all of which had lower limits of quantification, the recovery rate was 84.94-104.45%, and the accuracy was 77.72-104.92%. The intraday precision was 3.72-15.37%, the interday precision was 5.00-18.02%, and the stability was 7.85-15.51%. Therefore, the method has good linearity, accuracy, precision, and stability. The method was further applied to study the attenuating effects of the SQ in a chemotherapeutic agents-induced C2C12 myotube atrophy model to evaluate the changes in the tricarboxylic acid cycle and glycolytic products under the action by the complex systems of TCM and disease model. Our study provided an improved method to explore TCM's pharmacodynamic constituents and action mechanisms.

Quality by design-based development and validation of an HPLC method for simultaneous estimation of pregabalin and piperine in dual drug-loaded liposomes

The current research work describes the development of a rapid HPLC method for the concurrent detection of pregabalin and piperine in dual drug-loaded nanoformulations. The primary goal was to recognize the chromatographic conditions wherein propitious segregation of the integrants with quality peaks can be attained. An attempt to expound the target analytical profile was made to accomplish this goal, and critical method attributes (CMAs), viz. percentage acetonitrile content, injection volume and pH, which affect critical quality attributes (CQAs), were identified using systemic risk analysis. Box-Behnken design was employed to develop a relationship between CMAs and CQAs, which engenders an analytical design space. Efficient chromatographic separation for pregabalin and piperine was attained using an analytical C₁₈ column and mobile phase comprising acetonitrile-water (pH 6.9; 70:30%, v/v) in an isocratic elution mode with a 1 ml/min flow rate. The elution was descried at an isosbestic wavelength of 221 nm using a photodiode array detector. The International Conference on Harmonization guidelines were adopted for the developed HPLC method. The validated HPLC method can be further utilized for the simultaneous quantification and detection of pregabalin and piperine in other lipid-based nanopharmaceuticals such as polymeric nanoparticles, nanocrystals, solid-lipid nanoparticles, metallic nanoparticles, etc., in in vitro and in vivo studies.

Analytical Quality by Design (AQbD) Approach to the Development of Analytical Procedures for Medicinal Plants

Scientific regulatory systems with suitable analytical methods for monitoring quality, safety, and efficacy are essential in medicinal plant drug discovery. There have been only few attempts to adopt the analytical quality by design (AQbD) strategy in medicinal plants analysis over the last few years. AQbD is a holistic method and development approach that understands analytical procedure, from risk assessment to lifecycle management. The enhanced AQbD approach reduces the time and effort necessary to develop reliable analytical methods, leads to flexible change control through the method operable design region (MODR), and lowers the out-of-specification (OOS) results. However, it is difficult to follow all the AQbD workflow steps in the field of medicinal plants analysis, such as defining the analytical target profiles (ATPs), identifying critical analytical procedure parameters (CAPPs), among others, because the complexity of chemical and biological properties in medicinal plants acts as a barrier. In this review, various applications of AQbD to medicinal plant analytical procedures are discussed. Unlike the analysis of a single compound, medicinal plant analysis is characterized by analyzing multiple components contained in biological materials, so it will be summarized by focusing on the following points: Analytical methods showing correlations within analysis parameters for the specific medicinal plant analysis, plant raw material diversity, one or more analysis targets defined for multiple phytochemicals, key analysis attributes, and analysis control strategies. In addition, the opportunities available through the use of design-based quality management techniques and the challenges that coexist are also discussed.

Simultaneous Extraction and Determination of Characteristic Steroidal Saponins and Homoisoflavonoids in Zhejiang Ophiopogon japonicus

Zhejiang Ophiopogonjaponicus (ZOJ) is a specific variety of Ophiopogon japonicus with characteristic steroidal saponins and homoisoflavonoids, which are also main pharmacodynamic constituents with clinical effects, including curing inflammation and cardiovascular diseases. However, few analysis methods were applied to simultaneously and quantitatively determine two kinds of its constituents, and hazardous organic solvents are mostly used for extraction. In this study, a new validated simultaneous extraction and determination method for four characteristic steroidal saponins and homoisoflavonoids in ZOJ was established by ionic liquid–ultrasonic extraction (IL-UAE) combined with HPLC-DAD-ELSD analysis, which can be used for the quality control of ZOJ. Chromatographic separation was performed with a DAD wavelength at 296 nm, and the ELSD parameters of the drift tube temperature (DTT), atomizer temperature (AT), and nitrogen gas pressure (NGP) were set at 20% heating power, 70 °C, and 25 psi, respectively. The optimal IL-UAE conditions were 1 mol/L [Bmim]CF₃SO₃ aqueous solution, a liquid–material ratio of 40 mL/g, and an ultrasonic time of 60 min. The proposed method is reliable, reproducible, and accurate, which were verified with real sample assays. Consequently, this work will be helpful for the quality control of ZOJ. It can also present a promising reference for the simultaneous extraction and determination of different kinds of constituents in other medicinal plants.

Authentication of Shenqi Fuzheng Injection via UPLC-Coupled Ion Mobility—Mass Spectrometry and Chemometrics with Kendrick Mass Defect Filter Data Mining

Nearly 5% of the Shenqi Fuzheng Injection’s dry weight comes from the secondary metabolites of Radix codonopsis and Radix astragali. However, the chemical composition of these metabolites is still vague, which hinders the authentication of Shenqi Fuzheng Injection (SFI). Ultra-high performance liquid chromatography with a charged aerosol detector was used to achieve the profiling of these secondary metabolites in SFI in a single chromatogram. The chemical information in the chromatographic profile was characterized by ion mobility and high-resolution mass spectrometry. Polygonal mass defect filtering (PMDF) combined with Kendrick mass defect filtering (KMDF) was performed to screen potential secondary metabolites. A total of 223 secondary metabolites were characterized from the SFI fingerprints, including 58 flavonoids, 71 saponins, 50 alkaloids, 30 polyene and polycynes, and 14 other compounds. Among them, 106 components, mainly flavonoids and saponins, are contributed by Radix astragali, while 54 components, mainly alkaloids and polyene and polycynes, are contributed by Radix codonopsis, with 33 components coming from both herbs. There were 64 components characterized using the KMDF method, which increased the number of characterized components in SFI by 28.70%. This study provides a solid foundation for the authentification of SFIs and the analysis of its chemical composition.

A Single-Arm Phase II Study to Evaluate Efficacy and Safety of First-Line Treatment With DCVAC/LuCa, Standard of Care Chemotherapy and Shenqi Fuzheng Injection in Advanced (Stage IIIB/IV) Non-Small Cell Lung Cancer Patients

OBJECTIVES

To evaluate the efficacy and safety of first-line treatment with a dendritic cell vaccination for lung cancer (DCVAC/LuCa), standard of care chemotherapy and Shenqi Fuzheng injection in patients with advanced (stage IIIB/IV) non-small cell lung cancer.

PATIENTS AND METHODS

Patients with histologically or cytologically confirmed recurrent metastatic or advanced NSCLC (stage IIIB/IV) with wild-type epidermal growth factor receptor (EGFR) or EGFR mutation which does not confer increased tumor susceptibility to EGFR-interacting drugs were recruited. For the treatment period, the first cycle of standard of care therapy (SoC) started 2 to 14 days after the leukapheresis procedure. SoC continued 4 to 6 cycles. DCVAC/LuCa was administered from the second cycle of SoC. DCVAC/LuCa was administered in a 3-week cycle schedule (5 doses) and then in a 6-week cycle schedule. Shenqi Fuzheng injection was administered 3 days before each DCVAC/LuCa administration for a total of 14 daily doses. Patients would undergo disease evaluation by computed tomography (CT) scan every 3 months. The primary and secondary endpoint was efficacy with regard to objective response rate (ORR) and progression free survival (PFS). The safety profile was measured by: incidence, type, and severity of all adverse events (AEs), laboratory abnormalities (blood routine test, urine test, and chemical test), physical status, and vital signs. Qi insufficiency was evaluated by tongue diagnosis and questionnaire survey with "Classification and Determination of constitution in TCM."

RESULTS

Twenty-three patients from 3 hospitals who received combination therapy were included. ORR was 34.8% (95% CI:16.4%-57.3%). Median duration of response was 5.51 m (95% CI:2.70-8.32). Median PFS was 10.72 m (95% CI:4.52-16.93), 1-year survival was 77.8%. mOS was 21.97 m (95% CI:13.68-30.25). There was 1 severe AE related to a history of heart disease and there were no adverse events related to DCVAC/LuCa treatment. Qi insufficiency was improved significantly (P < .0001) from 41.19 ± 14.58 before treatment to 10.52 ± 16.58 after treatment.

CONCLUSION

DCVAC/LuCa, combined with standard of care chemotherapy and Shenqi Fuzheng injection exhibited good benefit in Chinese patients with recurrent metastatic or advanced (stage IIIB/IV) NSCLC, and also significantly improved Qi insufficiency constitution. There were no related adverse events with DCVAC/LuCa treatment.

Establishment of Deep-Eutectic-Solvent-Assisted Matrix Solid-Phase Dispersion Extraction for the Determination of Four Flavonoids in Scutellariae Radix Based on the Concept of Quality by Design

BACKGROUND

Sample preparation is the most crucial step in analytical schemes. Micro-matrix solid-phase dispersion, as a method for microextraction of analytes, has prevailed recently for its low sample and extraction solvent consumption. However, small amounts of adsorbent or sample, or a short extraction time, always bring uncertainty to the result when using this method.

OBJECTIVE

The aim was to develop a simple and reliable method of deep-eutectic-solvent-assisted ultrasonic-synchronized matrix solid-phase dispersion microextraction for the analysis of four flavonoids in Scutellariae Radix based on the concept of quality by design.

METHOD

The ZSM-5 molecular sieve was used as a new adsorbent in the micro-matrix solid-phase dispersion process. Single-factor and Box-Behnken designs were used to construct the design space.

RESULTS

Verification of the experiment demonstrated that the design space is robust. Under optimal conditions, all analytes showed good linearity (R2 > 0.999), high reproducibility (RSD < 2.24%) and stability (RSD < 2.87%), and satisfactory recoveries (95.90-102.31%), which indicated that the established method is reliable and reproducible. Moreover, it has been successfully applied to determine the flavonoids in nine batches of Scutellariae Radix.

CONCLUSIONS

The results indicate a great potential for analyzing complicated samples especially with small amount and helping to promote the quality control of the sample preparation process for traditional Chinese medicines.

HIGHLIGHTS

A systematic approach using a facile deep-eutectic-solvent-assisted ultrasonic-synchronized matrix solid-phase dispersion extraction coupled with HPLC for the analysis of flavonoids in Scutellariae Radix has been developed based on the concept of quality by design.

Development of an HPLC-MS method for the determination of four terpene trilactones in Ginkgo biloba leaf extract via quality by design

Previously reported HPLC-evaporative light scattering detection methods for terpene trilactone determination in Ginkgo biloba leaf extract (EGBL) have complicated sample preparation steps and are time-consuming. Thus, in this work, an HPLC-MS method for the determination of terpene trilactones in EGBL was developed with a novel analytical quality by design approach to provide robust and simple measurements. For this purpose, analytical target profiles and systematic risk analyses were performed to identify potential critical method attributes and critical method parameters. After screening experiments, a Box-Behnken design approach was utilized to investigate the relationships between critical method attributes and critical method parameters. A hypercube design space obtained by a Monte Carlo method was used for choosing the analytical control strategy. Then, verification experiments were performed within the design space, and the models were found to be accurate. After that, the optimized method was verified and successfully used for quality control analysis of EGBL from different manufacturers, and the results were almost the same as those determined by HPLC-evaporative light scattering detection. To our knowledge, this is the first study to establish a robust HPLC-MS method for determination of terpene trilactones in EGBL based on a novel analytical quality by design concept, which can improve the quality control of commercial EGBL.

Establishment of extraction design space for ursolic acid from Paulowniae Flos based on the concept of quality by design

INTRODUCTION

The application of quality by design (QbD) concept needs to be strengthened in the field of traditional Chinese medicine research. The extraction process has an important influence on the effectiveness of the drug, and the combination of QbD and the extraction process of the active ingredient helps to improve the effectiveness of the drug.

OBJECTIVE

To establish the extraction design space for ursolic acid (UA) from Paulowniae Flos based on the concept of QbD.

METHODS

The extraction yield of the target component UA was taken as critical quality attributes (CQAs), extraction time, extraction temperature, ethanol concentration and liquid-solid ratio, as critical process parameters (CPPs). Box-Behnken design (BBD) was applied to optimise the design space and the chromatographic conditions were performed on a Shimadzu C18 reversed-phase column with 0.1% (v/v) acetic acid aqueous water-acetonitrile (7:13, v/v) as the mobile phase at a 1 mL/min flow rate, using UA standard as a control and detection at 210 nm.

RESULTS

The single factor investigation and BBD experiment were used to construct the design space, while verification experiments and methodological validation were used to demonstrate that the space was robust and analytical methods were appropriate. The operating space of ethanol concentration 93-98%, liquid-solid ratio 28-37 mL/g and extraction temperature 70-78.3°C was recommended.

CONCLUSION

The proposed methodology can help to promote the quality control of the Chinese medicine extraction process and facilitate the production operation of the enterprise easier.

Clinical efficacy and safety of Shenqi Fuzheng injection for the treatment of chronic heart failure: Protocol for a meta-analysis and systematic review

BACKGROUND

Chronic heart failure (CHF) is one of the most serious cardiovascular diseases. Shenqi Fuzheng injection (SQFZI), as a Chinese herbal injection, is usually used for the treatment of CHF. However, the clinical evidence of SQFZI for the treatment of CHF is unclear.

METHODS

Two researchers will dependently search literatures of SQFZI for CHF from Chinese National Knowledge Infrastructure database, VIP database, Chinese Biological and Medicine database, Wangfang database, MEDLINE, EMBASE, Cochrane Library and Web of Science. These inclusive data of included studies will be conducted by RevMan 5.3 software.

RESULTS

This meta-analysis and systematic review will provide a series of outcome measures to verify clinical efficacy and safety of SQFZI for treating CHF, including New York Heart Association (NYHA) function classification, left ventricular ejection fraction, left ventricular end-diastolic dimension, cardiac output, stroke volume, brain natriuretic peptide, N-terminal pro-brain natriuretic peptide, and adverse events.

CONCLUSIONS

This meta-analysis and systematic review will provide up-to-date clinical evidence to assess SQFZI treatment efficacy for CHF patients.

Efficacy and safety of Shenqi Fuzheng injection combined with platinum-based chemotherapy for stage III/IV non-small cell lung cancer: A protocol for systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Shenqi Fuzheng injection (SFI) is a commonly used anti-cancer Chinese patent medicine and has long been prescribed as adjunctive treatment to platinum-based chemotherapy (PBC) in patients with stage III/IV non-small cell lung cancer (NSCLC). However, the efficacy and safety of this combination therapy remain unclear.

METHODS

A systematic review and meta-analysis will be conducted following the Preferred Reported Items for Systematic Review and Meta-analysis (PRISMA) guidelines. Seven databases will be searched for relevant studies from their inception to the present date: PubMed, Web of Science, Cochrane Library, EMBASE, ClinicalTrials.gov, China National Knowledge Infrastructure (CNKI), and Wanfang Databases. All randomized clinical trials comparing SFI in combination with PBC versus PBC alone will be retrieved and assessed for inclusion. Two researchers will independently perform the selection of the studies, data extraction, and synthesis. The Cochrane Risk of Bias Tool will be used to evaluate the risk of bias of the RCTs. The primary endpoint is the disease control rate (DCR), the secondary outcomes are the objective response rate (ORR), survival rate, quality of life (QOL), cellular immune function, and toxicities. Review Manager 5.3 (Nordic Cochrane Centre, Cochrane Collaboration, 2014 Copenhagen, Denmark) will be used to analyze the outcomes.

RESULTS

This study will systematically evaluate the efficacy and safety of SFI combined with platinum-based chemotherapy in the treatment of stage III/IV NSCLC. The results will be published in a peer-reviewed journal.

CONCLUSION

This systematic review will evaluate the effects of SFI as adjunctive treatment to platinum-based chemotherapy in the patients with stage III/IV non-small cell lung cancer, thus providing evidence to the clinical application of this combination therapy.

PROSPERO REGISTRATION NUMBER

CRD42019137196.

A novel quality by design approach for developing an HPLC method to analyze herbal extracts: A case study of sugar content analysis

The aim of this study was to present a novel analytical quality by design (AQbD) approach for developing an HPLC method to analyze herbal extracts. In this approach, critical method attributes (CMAs) and critical method parameters (CMPs) of the analytical method were determined using the same data collected from screening experiments. The HPLC-ELSD method for separation and quantification of sugars in Codonopsis Radix extract (CRE) samples and Astragali Radix extract (ARE) samples was developed as an example method with a novel AQbD approach. Potential CMAs and potential CMPs were found with Analytical Target Profile. After the screening experiments, the retention time of the D-glucose peak of CRE samples, the signal-to-noise ratio of the D-glucose peak of CRE samples, and retention time of the sucrose peak in ARE samples were considered CMAs. The initial and final composition of the mobile phase, flow rate, and column temperature were found to be CMPs using a standard partial regression coefficient method. The probability-based design space was calculated using a Monte-Carlo simulation method and verified by experiments. The optimized method was validated to be accurate and precise, and then it was applied in the analysis of CRE and ARE samples. The present AQbD approach is efficient and suitable for analysis objects with complex compositions.

Rapid HPLC Analytical Method Development for Herbal Medicine Formulae Based on Retention Rules Acquired from the Constituting Herbs

Herbal medicine (HM) formulae are the combinations of two or more types of constituting herbs. This study has proposed a novel approach to efficiently develop HPLC methods for HM formulae, which take advantage of the mutual retention rules between HM formulae and their constituting herbs. An HM formula composed of two herbs, Radix Salviae Miltiorrhizae and Rhizoma Chuanxiong, was taken as a case study. Based on design of experiments and stepwise multiple linear regression, models relating the analytical parameters to the chromatographic parameters were built (correlation coefficients >0.9870) for chemical compounds in the two herbs. These models representing the retention rules were utilized to predict the elution profile of the formula. The analytical parameters were numerically optimized to ensure adequate separation of the analytes. In validation experiments, satisfactory separations were achieved without any pre-experiments on the formula. The approach can significantly increase the HPLC method development efficiency for HM formulae.

Statistical Model Based HPLC Analytical Method Adjustment Strategy to Adapt to Different Sets of Analytes in Complicated Samples

INTRODUCTION

On account of the complicated compositions of the products like traditional Chinese medicines (TCMs) and functional foods, it is a common practice to determine different sets of analytes in the same product for different purposes.

OBJECTIVE

To efficiently develop the corresponding HPLC methods, a statistical model based analytical method adjustment (SMB-AMA) strategy was proposed.

METHODS

In this strategy, the HPLC data acquired with design of experiments methodology were efficiently utilised to build the retention models for all the analytes and interferences shown in the chromatograms with multivariate statistical modelling methods. According to the set of analytes under research, Monte-Carlo simulations were conducted based on these retention models to estimate the probability of achieving adequate separations between all the analytes and their interferences. Then the analytical parameters were mathematically optimised to the point giving a high value of this probability to compose a robust HPLC method. Radix Angelica Sinensis (RAS) and its TCM formula with Folium Epimedii (FE) were taken as the complicated samples for case studies.

RESULTS

The retention models for the compounds in RAS and FE were built independently with correlation coefficients all above 0.9799. The analytical parameters were tactfully adjusted to adapt to six cases of different sets of analytes and different sample matrices. In the validation experiments using the adjusted analytical parameters, satisfactory separations were acquired.

CONCLUSION

The results demonstrated that the SMB-AMA strategy was able to develop HPLC methods rationally and rapidly in the adaption of different sets of analytes. Copyright © 2017 John Wiley & Sons, Ltd.

An overview of experimental designs in HPLC method development and validation

Chemometric approaches have been increasingly viewed as precious complements to high performance liquid chromatographic practices, since a large number of variables can be simultaneously controlled to achieve the desired separations. Moreover, their applications may efficiently identify and optimize the significant factors to accomplish competent results through limited experimental trials. The present manuscript discusses usefulness of various chemometric approaches in high and ultra performance liquid chromatography for (i) methods development from dissolution studies and sample preparation to detection, considering the progressive substitution of traditional detectors with tandem mass spectrometry instruments and the importance of stability indicating assays (ii) method validation through screening and optimization designs. Choice of appropriate types of experimental designs so as to either screen the most influential factors or optimize the selected factors' combination and the mathematical models in chemometry have been briefly recalled and the advantages of chemometric approaches have been emphasized. The evolution of the design of experiments to the Quality by Design paradigm for method development has been reviewed and the Six Sigma practice as a quality indicator in chromatography has been explained. Chemometric applications and various strategies in chromatographic separations have been described.

Review: DNA Barcoding and Chromatography Fingerprints for the Authentication of Botanicals in Herbal Medicinal Products

In the last two decades, there has been a tremendous increase in the global use of herbal medicinal products (HMPs) due to their claimed health benefits. This has led to increase in their demand and consequently, also, resulted in massive adulteration. This is due to the fact that most of the traditional methods cannot identify closely related species in a process product form. Therefore the urgent need for simple and rapid identification methods resulted in the discovery of a novel technique. DNA barcoding is a process that uses short DNA sequence from the standard genome for species identification. This technique is reliable and is not affected by external factors such as climates, age, or plant part. The difficulties in isolation of DNA of high quality in addition to other factors are among the challenges encountered using the DNA barcoding in the authentication of HMP. These limitations indicated that using DNA barcoding alone may ineffectively authenticate the HMP. Therefore, the combination of DNA barcoding with chromatographic fingerprint, a popular and generally accepted technique for the assessment and quality control of HMP, will offer an efficient solution to effectively evaluate the authenticity and quality consistency of HMP. Detailed and quality information about the main composition of the HMPs will help to ascertain their efficacy and safety as these are very important for quality control.

Rapid Method Development in Hydrophilic Interaction Liquid Chromatography for Pharmaceutical Analysis Using a Combination of Quantitative Structure-Retention Relationships and Design of Experiments

A design-of-experiment (DoE) model was developed, able to describe the retention times of a mixture of pharmaceutical compounds in hydrophilic interaction liquid chromatography (HILIC) under all possible combinations of acetonitrile content, salt concentration, and mobile-phase pH with R² > 0.95. Further, a quantitative structure-retention relationship (QSRR) model was developed to predict retention times for new analytes, based only on their chemical structures, with a root-mean-square error of prediction (RMSEP) as low as 0.81%. A compound classification based on the concept of similarity was applied prior to QSRR modeling. Finally, we utilized a combined QSRR-DoE approach to propose an optimal design space in a quality-by-design (QbD) workflow to facilitate the HILIC method development. The mathematical QSRR-DoE model was shown to be highly predictive when applied to an independent test set of unseen compounds in unseen conditions with a RMSEP value of 5.83%. The QSRR-DoE computed retention time of pharmaceutical test analytes and subsequently calculated separation selectivity was used to optimize the chromatographic conditions for efficient separation of targets. A Monte Carlo simulation was performed to evaluate the risk of uncertainty in the model's prediction, and to define the design space where the desired quality criterion was met. Experimental realization of peak selectivity between targets under the selected optimal working conditions confirmed the theoretical predictions. These results demonstrate how discovery of optimal conditions for the separation of new analytes can be accelerated by the use of appropriate theoretical tools.