Validated reverse phase HPLC diode array method for the quantification of intact bevacizumab, infliximab and trastuzumab for long-term stability study

Hydrogel formats to model potential drug interactions occurring at the subcutaneous injection site

We have previously developed an in vitro instrument, termed subcutaneous injection site simulator (SCISSOR), that can be used to monitor release properties of an active pharmaceutical ingredient (API) and formulation components of a medicine designed for SC injection. Initial studies to validate the SCISSOR instrument applications used a simple hyaluronic acid (HA) hydrogel to monitor early release events. We now report a type of cross-linked HA that can, when combined with HA, provide a hydrogel (HA-XR) with optical clarity and rheological properties that remain stable for at least 6 days. Incorporation of 0.05-0.1 mg/mL of collagens isolated from human fibroblasts (Col F), bovine type I collagen (Col I), chicken collagen type II (Col II), or chondroitin sulphate (CS) produced HA or HA-XR hydrogel formats with optical clarity and rheological properties comparable to HA or HA-XR alone. HA + Col F hydrogel had a much greater effect on release rates of 70 kDa compared to 4 kDa dextran, while Col F incorporated into the HA-XR hydrogel accentuated differences in release rates of prandial and basal forms of insulin as well as decreased the release rate of denosumab. A hydrogel format of HA + Col I was used to examine the complex events for bevacizumab release under conditions where a target ligand (vascular endothelial growth factor) can interact with extracellular matrix (ECM). Together, these data have demonstrated the feasibility of using a cross-linked HA format to examine API release over multiple days and incorporation of specific ECM elements to prepare more biomimetic hydrogels that allow for tractable examination of their potential impact of API release.

Voltammetric studies and spectroscopic investigations of the interaction of an anticancer drug bevacizumab-DNA and analytical applications of disposable pencil graphite sensor

A sensitive, simple, fast electrochemical biosensor for the DNA interaction of bevacizumab (BEVA), which is used as a targeted drug in cancer treatment, was developed using the differential pulse voltammetry (DPV) technique with pencil graphite electrode (PGE). In the work, PGE was electrochemically activated in a supporting electrolyte medium of +1.4 V/60 s (PBS pH 3.0). Surface characterization of PGE was carried out by SEM, EDX, EIS, and CV techniques. Determination and electrochemical properties of BEVA were examined with CV and DPV techniques. BEVA gave a distinct analytical signal on the PGE surface at a potential of +0.90 V (vs. Ag/AgCl). In the procedure proposed in this study, BEVA gave a linear response on PGE in PBS (pH 3.0 containing 0.02 M NaCl) (0.1 mg mL-1 - 0.7 mg mL-1) with LOD and LOQ values of 0.026 mg mL-1 and 0.086 μg mL-1, respectively. BEVA was reacted with 20 μg mL-1 DNA in PBS for 150 s and analytical peak signals for adenine and guanine bases were evaluated. The interaction between BEVA-DNA was supported by UV-Vis. Absorption spectrometry and the binding constant was determined as 7.3 × 104.

Comparative stability study and aggregate analysis of Bevacizumab marketed formulations using advanced analytical techniques

Bevacizumab (Bvz) is the most preferred recombinant humanized monoclonal antibody in biosimilar development due to its prominence as a standard treatment in the oncology space. Therapeutic monoclonal antibodies are typically more complex and unlikely to produce a replica. As a result, regulatory agencies allow approval of biosimilars that differ structurally and functionally from their reference product, but these differences should not have any clinical significance. To identify these significant discrepancies, it is essential to perform a thorough characterization of critical product attributes both in real-time and after storage until the product's expiration. In the present study, two Bvz biosimilar brands (Bio-1 and Bio-2) marketed in India were evaluated and compared with the reference product Avastin® to assess their degree of similarity. A comprehensive physicochemical characterization of biosimilars and reference product was performed using orthogonal techniques including LC-ESI-QTOF, MALDI-TOF, FTIR-ATR, iCIEF, rCE, nrCE, UV280, and RP-HPLC. Furthermore, Bvz formulations under study were subjected to various stress conditions of thermal (elevated temperature 50 ± 2 °C), chemical (acidic pH 3.0 ± 0.2, neutral pH 7.0 ± 0.2, and basic pH 10.0 ± 0.2), and mechanical (agitation 200 rpm) for comparative stability evaluation. Any alteration in the secondary structure of the native protein was detected and quantified using far-UV circular dichroism (CD), indicating an average of 15% and 11% loss in native antiparallel β-sheet conformation respectively in Bio-1 and Bio-2 upon exposure to elevated temperature and high pH. Additionally, covalent or non-covalent aggregates formed as a function of elevated temperature and agitation were quantified using SEC-MALS.

Analysis of Denosumab by a Validated CZE Method and Determination of Sialic Acids by the RP-HPLC Method

A capillary zone electrophoresis (CZE) method was developed and validated to quantitate the monoclonal antibody denosumab (DmAb) and its charge variants in pharmaceutical products, demonstrating excellent precision, linearity and accuracy. Separations were obtained with migration times of 11.3 min for DmAb and the calibration curve was linear in the range of 0.95-20 mg/mL. The analytical comparability of seven batches of Prolia® showed mean differences of the estimated content/potencies of 1.87% lower, and 0.84 and 1.21% higher compared with the size-exclusion and reversed-phase liquid chromatography (SE-HPLC and RP-HPLC) methods and the osteoclast antiproliferative bioassay, respectively, with non-significant differences (P > 0.05). An RP-HPLC method with fluorescence detection (RP-HPLC-F), performed on a Kinetex® EVO C18 column (5 μm, 100 Å, 250 mm × 4.6 mm), was optimized to determine the levels of sialic acids of DmAb biomolecules, giving mean concentrations of 0.16 and 0.17 μg N-acetylneuraminic acid/mg DmAb for Prolia® and Xgeva® pharmaceutical products, respectively. The results demonstrated the capability of each one of the methods, and their use in combination constitutes a strategy to monitor instability, thereby assuring the quality and the batch-to-batch consistency of the biotechnology-derived medicine.

Method for identification and quantification of intact teduglutide peptide using (RP)UHPLC-UV-(HESI/ORBITRAP)MS

Teduglutide (Revestive®, 10 mg mL^-1) is a recombinant human glucagon-like peptide 2 analogue, used in the treatment of short bowel syndrome, a serious and highly disabling condition which results from either too small a length of intestine or loss of critical intestinal function. The determination of therapeutic compounds of protein-nature is always challenging due to their complex structure. In this work, we present a fast, straightforward reversed phase (RP)UHPLC-UV-(HESI/ORBITRAP)MS method for the identification and quantification of the intact teduglutide peptide. The method has been developed and validated in accordance with the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines; therefore, linearity, limits of detection and quantification, accuracy (precision and trueness), robustness, system suitability and specificity using the signal from the UV and MS, have been evaluated. The validation performance parameters obtained from the UV and MS signals were compared throughout the work, to select the most suitable. To study the specificity of the method and the impact of medicine mishandling under hospital conditions, force degradation studies were performed, i.e. thermal (40 °C and 60 °C), shaking (mechanical) and light (accelerated exposition) effects. Identification by the exact mass of teduglutide was achieved and it was confirmed that the peptide does not undergo any post-translational modifications (PTMs). To the best of our knowledge, the present work reports the first method developed for the simultaneous identification, structural characterization, and quantification of the therapeutic teduglutide peptide. Finally, the proposed method is able to indicate stability when quantifying the intact teduglutide since detects and characterises the exact mass of the degradation/modification products.

Anticancer Drugs: Recent Strategies to Improve Stability Profile, Pharmacokinetic and Pharmacodynamic Properties

In past decades, anticancer research has led to remarkable results despite many of the approved drugs still being characterized by high systemic toxicity mainly due to the lack of tumor selectivity and present pharmacokinetic drawbacks, including low water solubility, that negatively affect the drug circulation time and bioavailability. The stability studies, performed in mild conditions during their development or under stressing exposure to high temperature, hydrolytic medium or light source, have demonstrated the sensitivity of anticancer drugs to many parameters. For this reason, the formation of degradation products is assessed both in pharmaceutical formulations and in the environment as hospital waste. To date, numerous formulations have been developed for achieving tissue-specific drug targeting and reducing toxic side effects, as well as for improving drug stability. The development of prodrugs represents a promising strategy in targeted cancer therapy for improving the selectivity, efficacy and stability of active compounds. Recent studies show that the incorporation of anticancer drugs into vesicular systems, such as polymeric micelles or cyclodextrins, or the use of nanocarriers containing chemotherapeutics that conjugate to monoclonal antibodies can improve solubility, pharmacokinetics, cellular absorption and stability. In this study, we summarize the latest advances in knowledge regarding the development of effective highly stable anticancer drugs formulated as stable prodrugs or entrapped in nanosystems.

Coupling of Trastuzumab chromatographic profiling with machine learning tools: A complementary approach for biosimilarity and stability assessment

Biosimilar products present a growing opportunity to improve the global healthcare systems. The amount of accepted variability during the comparative assessments of biosimilar products introduces a significant challenge for both the biosimilar developers and the regulatory authorities. The aim of this study was to explore unsupervised machine learning tools as a mathematical aid for the interpretation and visualization of such comparability under control and stress conditions using data extracted from high throughput analytical techniques. For this purpose, a head-to-head analysis of the physicochemical characteristics of three Trastuzumab (TTZ) approved biosimilars and the originator product (Herceptin®) was performed. The studied quality attributes included the primary structure and identity by peptide mapping (PM) with reversed-phase chromatography-UV detection, size and charge profiles by stability-indicating size exclusion and cation exchange chromatography. Stress conditions involved pH and thermal stress. Principal component analysis (PCA) and two of the widely used cluster analysis tools, namely, K-means and Density-based Spatial Clustering of Applications with Noise (DBSCAN), were explored for clustering and feature representation of varied analytical datasets. It has been shown that the clustering patterns delineated by the used algorithms changed based on the included chromatographic profiles. The applied data analysis tools were found effective in revealing patterns of similarity and variability between i) intact and stressed as well as ii) originator and biosimilar samples.

Development and validation of a rapid RP-HPLC method for simultaneous quantification of paclitaxel and cetuximab in immunoliposomes

The development of rational therapies against complex diseases, such as cancer, has increased in the past few years due to the advances of 'omics' technologies. Concomitantly, several efforts have been made to design sophisticated drug delivery systems in order to increase specificity and drug accumulation in tumor sites. The complexity of these drug delivery systems highlights the need for suitable analytical methods to determine encapsulation/conjugation efficiency of drugs and molecules responsible for the targeted delivery. Therefore, this study focuses on the development and validation of a RP-HPLC-DAD methodology for concurrent quantification of paclitaxel (PTX) and cetuximab (CTX) in immunoliposomes. Chromatographic separation was achieved using a wide pore C₈ column, and a gradient mobile phase consisting of 0.1% trifluoroacetic acid (TFA) in Milli-Q water/acetonitrile/isopropanol with a flow rate of 1 mL min^-1. Drug peaks were fully separated and detected at 280 nm using UV detector. The method was validated according to ICH and FDA guidelines in terms of specificity and forced degradation studies, system suitability, linearity, limit of detection, limit of quantification, repeatability, intermediate precision, accuracy, robustness, and short-term stability. The developed method was linear over the concentration range of 37.5-150 μg mL^-1 of PTX and 75-300 μg mL^-1 of CTX. All parameters evaluated satisfied the acceptance criteria, according to both FDA and ICH guidelines. The applicability of the analytical method was assessed following the development of PTX-loaded immunoliposomes conjugated with CTX. Thus, the present study shows a novel, simple, stability-indicating and suitable method to quantify simultaneously PTX and CTX in immunoliposomes.

A Critical Review of Biological Properties, Delivery Systems and Analytical/Bioanalytical Methods for Determination of Bevacizumab

Bevacizumab is a chimeric monoclonal human-murine antibody originated from murine monoclonal antibody (muMAb A4.6.1) with the human immunoglobulin IgG1. BVZ binds the extracellular portion of vascular endothelial growth factor receptors (VEGFR), which have tyrosine kinase activity. The mechanism of action of BVZ involves binding to VEGFR, Flt-1 (VEGFR-1) and KDR/Flk-1 (VEGFR-2), inducing homodimerization of two receptor subunits, and, consequently, autophosphorylation of their tyrosine kinase domains located inside the cytoplasm. With the advent of nanostructured systems it is increasingly necessary to look for safe analytical methods, ensuring the reliability of the results obtained by them, becoming essential to ensure the quality of medicines. In this work, the incorporation of bevacizumab in to different drug delivery systems was presented. Moreover, detailed investigation was performed about methods for qualitative and quantitative analyses of bevacizumab, including, biological fluids, and drug delivery systems, were investigated. Most recently high performance liquid chromatography coupled with various detectors, liquid chromatography, mass spectrometry and ELISA were used for this purpose. Thus, this review was performed to evaluate the benefits of bevacizumab carried by nanostructured systems and the analytical methods available for detection and quantification of these drugs.

A validated size exclusion chromatography method coupled with fluorescence detection for rapid quantification of bevacizumab in ophthalmic formulations

Bevacizumab is a full-length human monoclonal antibody used to treat various neovascular diseases such as wet age-related macular degeneration (AMD), diabetic eye disease and other problems of the retina. Monthly intravitreal injections of bevacizumab (Avastin^®) are effective in the treatment of wet AMD. However, there is a growing demand in the development of sustained release ophthalmic formulations. Therefore, this study aims, for the first time, to develop a rapid, simple, and sensitive method using size exclusion chromatography coupled with fluorescence detection for routine quantification of bevacizumab in ophthalmic formulations and during in vitro release studies. The selected chromatographic conditions included an aqueous mobile phase composed of 35 mM sodium phosphate buffer and 300 mM sodium chloride (pH 6.8), a flow rate of 0.5 mL/min, and the fluorescence detector was operated at excitation and emission wavelengths of 280 and 340 nm, respectively. The peak area-concentration relationship maintained its linearity over concentration range of 0.1-20 μg/mL (R² = 0.9993), and the quantitation limit was 100 ng/mL. The method was validated for specificity, accuracy, precision, and robustness. The developed method had a run time of 6 min at temperature 25 °C, making it a unique validated method for rapid and cost-effective quantification of bevacizumab.

Forced Degradation Testing as Complementary Tool for Biosimilarity Assessment

Oxidation of monoclonal antibodies (mAbs) can impact their efficacy and may therefore represent critical quality attributes (CQA) that require evaluation. To complement classical CQA, bevacizumab and infliximab were subjected to oxidative stress by H₂O₂ for 24, 48, or 72 h to probe their oxidation susceptibility. For investigation, a middle-up approach was used utilizing liquid chromatography hyphenated with mass spectrometry (LC-QTOF-MS). In both mAbs, the Fc/2 subunit was completely oxidized. Additional oxidations were found in the light chain (LC) and in the Fd’ subunit of infliximab, but not in bevacizumab. By direct comparison of methionine positions, the oxidized residues in infliximab were assigned to M55 in LC and M18 in Fd’. The forced oxidation approach was further exploited for comparison of respective biosimilar products. Both for bevacizumab and infliximab, comparison of posttranslational modification profiles demonstrated high similarity of the unstressed reference product (RP) and the biosimilar (BS). However, for bevacizumab, comparison after forced oxidation revealed a higher susceptibility of the BS compared to the RP. It may thus be considered a useful tool for biopharmaceutical engineering, biosimilarity assessment, as well as for quality control of protein drugs.