Estudo da permeabilidade de fármacos por meio do modelo de saco intestinal de ratos / Study of drug permeability through the rat gut sac model

Os parâmetros de permeabilidade e solubilidade são fundamentais à absorção oral de fármacos e a partir dessas características, foi criado o Sistema de Classificação Biofarmacêutica, através do qual os fármacos são divididos em quatro classes. Atualmente, para a determinação da solubilidade de um fármaco, existem diversos métodos padronizados por agências regulatórias, no entanto, para a determinação da permeabilidade, os ensaios são passíveis de diversas variações em sua execução, diminuindo a confiabilidade dos resultados obtidos e impossibilitando a comparação dos mesmos quando realizados com técnicas diferentes umas das outras. O objetivo do presente trabalho é avaliar as variáveis experimentais do modelo do saco intestinal que podem influenciar nos resultados de permeabilidade aparente de fármacos e na viabilidade do tecido. O presente estudo foi aprovado pelo Comitê de Ética no Uso de Animais da FCF-USP (109.2018-P574). Foram utilizados 33 Rattus norvegicus da linhagem Wistar, machos, jovens adultos, com peso entre 200 g e 300 g. Para realização do procedimento, cada animal permaneceu em jejum por cerca de quatro horas e após adequada anestesia a porção do jejuno do intestino delgado foi retirada e dividida em seis segmentos de aproximadamente 8,5cm cada. Foram realizados experimentos com e sem inversão do saco intestinal, submetidos a diferentes tempos de banho de gelo após sua ressecção, na presença ou ausência de inibidor da glicoproteína-P (verapamil). Os fármacos naproxeno e famotidina foram empregados como marcadores de alta e baixa permeabilidade, respectivamente. A losartana foi utilizada como substrato da glicoproteína P. Cada um dos sacos intestinais foi colocado em um tubo de ensaio contendo tampão Krebs, a 37°C, saturado com gás carbogênio. Para avaliação da integridade e viabilidade dos segmentos intestinais, observou-se a presença de movimentos peristálticos e coletaram-se amostras do meio de incubação nos tempos 0, 30, 45, 60, 90 e 120 minutos para quantificação dos fármacos e de glicose, uma vez que esta é ativamente transportada para a serosa do intestino delgado. Determinou-se a permeabilidade aparente de cada fármaco e as concentrações de glicose nas diferentes condições experimentais, realizou-se planejamento fatorial multinível e os resultados foram analisados por análise variância (ANOVA), seguida de pós-teste de Tukey. Observou-se que as variáveis experimentais interferiram de forma significativa na viabilidade tecidual e na permeabilidade aparente dos fármacos. Não foram observadas diferenças significativas da permeabilidade de fármacos nos diferentes segmentos do jejuno. A glicose mostrou-se um bom marcador de viabilidade tecidual e foi constatado que a presença ou ausência de movimentos peristálticos não está relacionada diretamente com a viabilidade do tecido. Uma vez que foram constatadas tantas interferências nos resultados, é imprescindível que os procedimentos experimentais sejam padronizados, para que os resultados apresentem menor variabilidade e possam ser comparados entre si

The permeability and solubility parameters are fundamental to the oral absorption of drugs and from these characteristics, the Biopharmaceutical Classification System was created, through which drugs are divided into four classes. Currently, for the determination of the solubility of a drug, there are several methods standardized by regulatory agencies, however, for the determination of permeability, the tests are subject to several variations in their execution, reducing the reliability of the results obtained and making it impossible to compare the results obtained. same when performed with different techniques. The aim of this study is to evaluate if different experimental conditions can influence the results of apparent drug permeability and tissue viability on gut sac model. The present study was approved by the Ethics Committee for the Use of Animals of FCF-USP (109.2018-P574). Thirty-three male, young adult Rattus norvegicus were used, weighing between 200 g and 300 g. To perform the procedure, each animal fasted for about four hours and after adequate anesthesia, the portion of the jejunum of the small intestine was removed and divided into six segments of approximately 8.5 cm each. Experiments were performed with and without inversion of the gut sac, submitted to different times of ice bath after its resection, in the presence or absence of a P-glycoprotein inhibitor (verapamil). The drugs naproxen and famotidine were used as markers of high and low permeability, respectively. Losartan was used as a substrate for P-glycoprotein. Each of the gut sacs was placed in a test tube containing Krebs buffer, at 37°C, saturated with carbogen gas. To evaluate the integrity and viability of the intestinal segments, the presence of peristaltic movements was observed and samples of the incubation medium were collected at 0, 30, 45, 60, 90 and 120 minutes for quantification of drugs and glucose, as it is actively transported to the serosa of the small intestine. The apparent permeability of each drug and the glucose concentrations were determined under different experimental conditions, multilevel factorial design was performed and the results were analyzed by analysis of variance (ANOVA), followed by Tukey's post-test. It was observed that the experimental variables significantly interfered in the tissue viability and in the apparent permeability of the drugs. No significant differences in drug permeability were observed in the different segments of the jejunum. Glucose proved to be a good marker of tissue viability and it was found that the presence or absence of peristaltic movements is not directly related to tissue viability. Since so many interferences were found in the results, it is essential that the experimental procedures be standardized, so that the results show less variability and can be compared between different authors

A Comparison Between Emerging and Current Biophysical Methods for the Assessment of Higher-Order Structure of Biopharmaceuticals.

The higher-order structure (HOS) of protein therapeutics is a critical quality attribute directly related to their function. Traditionally, the HOS of protein therapeutics has been characterized by methods with low to medium structural resolution such as Fourier-transform infrared (FTIR), circular dichroism (CD), and intrinsic fluorescence spectroscopy, and differential scanning calorimetry (DSC). Recently, high-resolution nuclear magnetic resonance (NMR) methods have emerged as powerful tools for HOS characterization. NMR is a multi-attribute method with unique capabilities to provide information about all the structural levels of proteins in solution. We have in this study compared 1 D 1H Profile NMR with the established biophysical methods for HOS assessments using a set of blended samples of the monoclonal antibodies belonging to the subclasses IgG1 and IgG2. The study shows that Profile NMR can distinguish between most sample combinations (93%), DSC can differentiate 61% of the sample combinations, and near-ultraviolet CD spectroscopy can differentiate 52% of the sample combinations, whereas no significant distinction could be made between any samples using FTIR or intrinsic fluorescence. Our data therefore show that NMR has superior ability to address differences in HOS, a feature that could be directly applicable in comparability and similarity assessments.

Enabling Robust and Rapid Raw Material Identification and Release by Handheld Raman Spectroscopy.

A fast, reproducible, non-destructive method to confirm raw material identification in real-time upon material receipt within a warehouse environment is desired. Current practices in pharmaceutical manufacturing often employ compendia methods for raw material identification tests, which require sample preparation prior to time-consuming chemical analysis and often employ subjective spectral comparisons. We have developed, qualified, and validated a rapid objective identity method ("Rapid ID") by Raman spectroscopy using the Bruker BRAVO handheld Raman spectrometer for 46 common raw materials used in upstream and downstream biopharmaceutical cell culture-based processes. Materials in the Raman identification library include amino acids and other solid neat organic chemicals, liquid organics, polyatomic salts, polymers, emulsifiers, peptides, aqueous solutions, and buffers. Selection of reference spectra and hit quality index limit(s) was based upon a comprehensive spectral survey across multiple suppliers and lots to account for normal cause spectral variation. Method repeatability and reproducibility, selectivity, and robustness against various operational and environmental factors (e.g., instrumental variance, material packaging, and thermal effects) were evaluated. Benefits of a handheld Raman Rapid ID approach include significant reduction of the time for raw material quality release from weeks to minutes, enhanced objectivity, and robust data integrity via autonomous electronic reporting. In addition, routine collection of rich spectroscopic data on raw materials can be leveraged to support further continuous improvement initiatives, including routine monitoring of method performance, continuous improvement of the library, proactive detection of shifts in raw material properties, and provision of data for investigations focused on raw materials. Rapid ID methods are consistent with the move toward the principles of Pharma 4.0-high automated processes with continuous process verification and a holistic control strategy.LAY ABSTRACT: A fast, reproducible, non-destructive method is desired to confirm raw material identification in real time upon receipt within a warehouse environment. We have developed, qualified and validated a rapid objective identity method ("Rapid ID") by Raman spectroscopy using the Bruker BRAVO handheld Raman spectrometer for 46 common raw materials used in upstream and downstream biopharmaceutical cell culture-based processes. Benefits of a handheld Raman Rapid ID approach include significant time reduction of raw material quality release from weeks to minutes, enhanced objectivity, and robust data integrity via autonomous electronic reporting. Rapid ID methods are consistent with the move toward the principles of Pharma 4.0: high automated processes with continuous process verification and a holistic control strategy.

Larger Pore Size Hollow Fiber Membranes as a Solution to the Product Retention Issue in Filtration-Based Perfusion Bioreactors.

Tangential flow filtration (TFF) and alternating tangential flow (ATF) filtration technologies using hollow fiber membranes are commonly utilized in perfusion cell culture for the production of monoclonal antibodies; however, product retention remains a known and common problem with these systems. To address this issue, commercially available hollow fibers ranging from several hundred kilo-Daltons (kDa) to 0.65 µm in nominal pore size are tested and are all demonstrated to undergo moderate to severe product retention. Further investigation revealed accumulation of particles in the same size range (≈20-200 nm) as the pores. Based on the assumption that these particles contribute to product retention and membrane plugging, a hollow fiber with an unconventionally larger pore size is subsequently identified and demonstrated to drastically reduce product retention with no impact to cell clarification. Furthermore, these hollow fibers demonstrate surprisingly high membrane capacities, making them an attractive solution to the problem of product retention in perfusion reactors.

Delivery Considerations of Highly Viscous Polymeric Fluids Mimicking Concentrated Biopharmaceuticals: Assessment of Injectability via Measurement of Total Work Done "WT".

An account is given of the recent development of the highly viscous complex biopharmaceuticals in relation to syringeability and injectability. The specific objective of this study is to establish a convenient method to examine problem of the injectability for the needle-syringe-formulation system when complex formulations with diverse viscosities are used. This work presents the inter-relationship between needle size, syringe volume, viscosity, and injectability of polymeric solutions having typical viscosities encountered in concentrated biologics, by applying a constant probe crosshead speed on the plunger-syringe needle assembly and continuously recording the force-distance profiles. A computerized texture analyzer was used to accurately capture, display, and store force, displacement, and time data. The force-distance curve and area under the curve are determined, and total work done for complete extrusion of the syringe content was calculated automatically by applying an established Matlab program. Various concentrations (i.e., 0.5-4% w/v of polymeric fluids/dispersions) of polyethylene oxide (PEO) and hydroxypropyl methylcellulose (HPMC) with viscosity ranges of 5-100 cP mimicking concentrated monoclonal antibody solutions and complex biopharmaceutical formulations are investigated. Results indicate that calculated values of total work done to completely extrude the syringe content are the most appropriate parameter that describes viscosity-injection force of dispersed formulations. Additionally, the rheological properties of HPMC and PEO fluids in the context of syringeability and injectability are discussed.

Effect of Coadministered Water on the In Vivo Performance of Oral Formulations Containing N-Acetylcysteine: An In Vitro Approach Using the Dynamic Open Flow-Through Test Apparatus.

The drug plasma profile after oral administration of immediate release dosage forms can be affected by the human gastrointestinal physiology, the formulation, and the drug itself. In this work, we investigated the in vivo and in vitro performance of two formulations (granules vs. tablet) containing the highly soluble drug N-Acetylcysteine (BCS class I). Thereby, special attention was paid to the effect of the dosage form and the coadministration of water on drug release. Interestingly, the in vivo results from a pharmacokinetic study with 11 healthy volunteers indicated that the drug plasma concentrations were comparable for the tablet given with water as well as for the granules given with and without water. In order to mechanistically understand this outcome, we used a biorelevant dissolution test device, the dynamic open flow-through test apparatus. With the aid of this test apparatus, we were able to simulate biorelevant parameters, such as gastric emptying, hydrodynamic flow as well as physical stress. By this, it was possible to mimic the intake conditions of the clinical trial (i.e., drug intake with and without water). Whereas the experiments in the USP paddle apparatus revealed differences between the two formulations, we could not observe significant differences in the release profiles of the two formulations by using the dynamic open flow-through test apparatus. Even by considering the different intake conditions, drug release was slow and amounted to around 30% until simulated gastric emptying. These results suggest that dissolution was irrespective of coadministered water and the formulation. Despite the high aqueous solubility of N-Acetylcysteine, the limiting factor for drug release was the slow dissolution rate in relation to the gastric emptying rate under simulated gastric conditions. Thus, in case of administration together with water, large amounts of the drug are still present in the stomach even after complete gastric emptying of the water. Consequently, the absorption of the drug is largely controlled by the nature of gastric emptying of the remaining drug. The data of this study indicated that the water emptying kinetics are only determining drug absorption if drug release is rapid enough. If this is not the case, physiological mechanisms, such as the migrating motor complex, play an important role for oral drug delivery.

Validation of Dissolution Testing with Biorelevant Media: An OrBiTo Study.

Dissolution testing with biorelevant media has become widespread in the pharmaceutical industry as a means of better understanding how drugs and formulations behave in the gastrointestinal tract. Until now, however, there have been few attempts to gauge the reproducibility of results obtained with these methods. The aim of this study was to determine the interlaboratory reproducibility of biorelevant dissolution testing, using the paddle apparatus (USP 2). Thirteen industrial and three academic laboratories participated in this study. All laboratories were provided with standard protocols for running the tests: dissolution in FaSSGF to simulate release in the stomach, dissolution in a single intestinal medium, FaSSIF, to simulate release in the small intestine, and a "transfer" (two-stage) protocol to simulate the concentration profile when conditions are changed from the gastric to the intestinal environment. The test products chosen were commercially available ibuprofen tablets and zafirlukast tablets. The biorelevant dissolution tests showed a high degree of reproducibility among the participating laboratories, even though several different batches of the commercially available medium preparation powder were used. Likewise, results were almost identicalbetween the commercial biorelevant media and those produced in-house. Comparing results to previous ring studies, including those performed with USP calibrator tablets or commercially available pharmaceutical products in a single medium, the results for the biorelevant studies were highly reproducible on an interlaboratory basis. Interlaboratory reproducibility with the two-stage test was also acceptable, although the variability was somewhat greater than with the single medium tests. Biorelevant dissolution testing is highly reproducible among laboratories and can be relied upon for cross-laboratory comparisons.

Gastrointestinal and Systemic Disposition of Diclofenac under Fasted and Fed State Conditions Supporting the Evaluation of in Vitro Predictive Tools.

This study aimed to gain further insight into the gastrointestinal disposition of the weakly acidic BCS class II drug diclofenac and the implications for systemic drug exposure in humans under fasted and fed state conditions. For this purpose, gastrointestinal and blood samples were collected from healthy volunteers after oral intake of a commercially available tablet of the potassium salt of diclofenac (i.e., Cataflam) in different prandial states. Subsequently, these in vivo data served as a reference for the evaluation of in vitro tools with different levels of complexity, i.e., a conventional USP II dissolution apparatus, a modified version of the dynamic open flow through test apparatus, and the TNO gastrointestinal model equipped with the recently developed advanced gastric compartment (TIMagc). In vivo data suggested impaired drug dissolution and/or immediate precipitation in the fasted stomach, linked to the acidity of the gastric environment. Similarly, a vast presence of solid drug material in the stomach was observed under fed state conditions, which could be attributed to a marked delay in intragastric tablet disintegration after drug intake with a meal. Emptying of solid drug from the stomach into the duodenum generally resulted in rapid intestinal drug (re)dissolution in both test conditions, explaining the absence of a food effect on the extent of overall systemic exposure for diclofenac. In vitro tools were found to be capable of predicting in vivo intraluminal (and systemic) disposition of this compound, the extent of which depended on the degree to which the dynamic nature of the gastrointestinal process(es) to be investigated was simulated.

Throughput Optimization of Continuous Biopharmaceutical Manufacturing Facilities.

In order to operate profitably under different product demand scenarios, biopharmaceutical companies must design their facilities with mass output flexibility in mind. Traditional biologics manufacturing technologies pose operational challenges in this regard due to their high costs and slow equipment turnaround times, restricting the types of products and mass quantities that can be processed. Modern plant design, however, has facilitated the development of lean and efficient bioprocessing facilities through footprint reduction and adoption of disposable and continuous manufacturing technologies. These development efforts have proven to be crucial in seeking to drastically reduce the high costs typically associated with the manufacturing of recombinant proteins. In this work, mathematical modeling is used to optimize annual production schedules for a single-product commercial facility operating with a continuous upstream and discrete batch downstream platform. Utilizing cell culture duration and volumetric productivity as process variables in the model, and annual plant throughput as the optimization objective, 3-D surface plots are created to understand the effect of process and facility design on expected mass output. The model shows that once a plant has been fully debottlenecked it is capable of processing well over a metric ton of product per year. Moreover, the analysis helped to uncover a major limiting constraint on plant performance, the stability of the neutralized viral inactivated pool, which may indicate that this should be a focus of attention during future process development efforts.LAY ABSTRACT: Biopharmaceutical process modeling can be used to design and optimize manufacturing facilities and help companies achieve a predetermined set of goals. One way to perform optimization is by making the most efficient use of process equipment in order to minimize the expenditure of capital, labor and plant resources. To that end, this paper introduces a novel mathematical algorithm used to determine the most optimal equipment scheduling configuration that maximizes the mass output for a facility producing a single product. The paper also illustrates how different scheduling arrangements can have a profound impact on the availability of plant resources, and identifies limiting constraints on the plant design. In addition, simulation data is presented using visualization techniques that aid in the interpretation of the scientific concepts discussed.

Trend analysis of performance parameters of pre-packed columns for protein chromatography over a time span of ten years.

Pre-packed small scale chromatography columns are increasingly used for process development, for determination of design space in bioprocess development, and for post-licence process verifications. The packing quality of 30,000 pre-packed columns delivered to customers over a period 10 years has been analyzed by advanced statistical tools. First, the data were extracted and checked for inconsistencies, and then were tabulated and made ready for statistical processing using the programming language Perl (https://www.perl.org/) and the statistical computing environment R (https://www.r-project.org/). Reduced HETP and asymmetry were plotted over time to obtain a trend of packing quality over 10 years. The obtained data were used as a visualized coefficient of variation analysis (VCVA), a process that has often been applied in other industries such as semiconductor manufacturing. A typical fluctuation of reduced HETP was seen. A Tsunami effect in manufacturing, the effect of propagation of manufacturing deviations leading to out-of-specification products, was not observed with these pre-packed columns. Principal component analysis (PCA) showed that all packing materials cluster. Our data analysis showed that the current commercially available chromatography media used for biopharmaceutical manufacturing can be reproducibly and uniformly packed in polymer-based chromatography columns, which are designed for ready-to-use purposes. Although the number of packed columns has quadrupled over one decade the packing quality has remained stable.

A scale-down cross-flow filtration technology for biopharmaceuticals and the associated theory.

Use of microfiltration (MF) and ultrafiltration (UF) in cross-flow mode has been intensifying in downstream processing for expensive biopharmaceuticals. A scale-down cross-flow module with ring channel was constructed for reducing costs and increasing throughput. Commensurate with its validation, a new scale down (or scale up) theoretical framework has been further developed to 3 operational parities: (1) ratio of initial sample volume to membrane area, (2) shear force adjacent to membrane surface, and (3) initial permeate flux. By keeping identical initial physicochemical properties, we show that these 3 operational parities are equivalent to 2 further time-dependent theoretical parities for flux and transmission respectively. Importantly, transmission sensitively reflects membrane conditions for partially transmissible molecules or particles. Computational fluid dynamics simulation was conducted to confirm nearly identical shear forces for the mini and its reference filters. Permeate fluxes in suspension containing Escherichia coli phage T7, a monoclonal antibody (MAb) or other proteins, and transmission (with phage T7) were measured. For application demonstration, diafiltration and concentration modes were applied to the MAb, and separation mode to a mixture of bovine serum albumin and lysozyme. In conclusion, the developed scale-down filter has been shown to behave identically or similarly to its reference filter.

Factors to Govern Soluble and Insoluble Aggregate-formation in Monoclonal Antibodies.

The aggregation formation of monoclonal antibodies as biopharmaceuticals induced by heat stress was evaluated by size-exclusion chromatography, and the formation rate was correlated with several physicochemical parameters of the antibodies to clarify the factors to govern the aggregate formation. The parameters we studied were: the melting temperature (Tm) and the standard enthalpy of the melting point (ΔmH°) evaluated by differential scanning calorimetry under given and common conditions; the wavelength (λmax) and the intensity (Fint) of the maximum fluorescence peak of 1-anilinonaphthalene-8-sulfonate as a probe dye; the z-average diameter (D) evaluated by dynamic light scattering; and the isoelectric point (pI) and the hydrophobic index (Hpho) of the complementarity determining region calculated from the amino acid sequence. Multivariate statistical analysis with these explanatory variables based on Akaike's information criterion indicates that the soluble aggregate formation is negatively correlated with Tm and pI, while the insoluble aggregate formation is positively correlated with Fint and pI. Based on these results, the mechanisms of the aggregate formation and methods to prevent the formation are discussed.

A Review of the Aging Process and Facilities Topic.

Aging facilities have become a concern in the pharmaceutical and biopharmaceutical manufacturing industry, so much that task forces are formed by trade organizations to address the topic. Too often, examples of aging or obsolete equipment, unit operations, processes, or entire facilities have been encountered. Major contributors to this outcome are the failure to invest in new equipment, disregarding appropriate maintenance activities, and neglecting the implementation of modern technologies. In some cases, a production process is insufficiently modified to manufacture a new product in an existing process that was used to produce a phased-out product. In other instances, manufacturers expanded the facility or processes to fulfill increasing demand and the scaling occurred in a non-uniform manner, which led to non-optimal results. Regulatory hurdles of post-approval changes in the process may thwart companies' efforts to implement new technologies. As an example, some changes have required 4 years to gain global approval. This paper will address cases of aging processes and facilities aside from modernizing options.

Particle shedding from peristaltic pump tubing in biopharmaceutical drug product manufacturing.

In a typical manufacturing setup for biopharmaceutical drug products, the fill and dosing pump is placed after the final sterile filtration unit in order to ensure adequate dispensing accuracy and avoid backpressure peaks. Given the sensitivity of protein molecules, peristaltic pumps are often preferred over piston pumps. However, particles may be shed from the silicone tubing employed. In this study, particle shedding and a potential turbidity increase during peristaltic pumping of water and buffer were investigated using three types of commercially available silicone tubing. In the recirculates, mainly particles of around 200 nm next to a very small fraction of particles in the lower micrometer range were found. Using 3D laser scanning microscopy, surface roughness of the inner tubing surface was found to be a determining factor for particle shedding from silicone tubing. As the propensity toward particle shedding varied between tubing types and also cannot be concluded from manufacturer's specifications, individual testing with the presented methods is recommended during tubing qualification. Choosing low abrasive tubing can help to further minimize the very low particle counts to be expected in pharmaceutical drug products.

Metabolomics as a tool for drug discovery and personalised medicine. A review.

Studying the effects of drugs on the metabolome constitutes a huge part of the metabolomics discipline. Whether the approach is associated with drug discovery (altered pathways due to the disease that provide future targets and information into the mechanism of action or resistance, etc.) or pharmacometabolomics (studying the outcome of treatment), there have been many aspiring published articles in this area. With specific experimental design, including fingerprinting analysis with different analytical platforms in a non-targeted way, the approach is advancing towards the discovery of markers for the implication of personalised medicine, while also providing information that could help to improve the efficacy and reduce the side effects associated with a treatment. In this review, the evolution of pharmacometabolomics from other areas of drug efficacy metabolomics studies is explored.

Use of MMV as a Single Worst-Case Model Virus in Viral Filter Validation Studies.

Typical platform processes for biopharmaceutical products derived from animal cell lines include a parvovirus filtration unit operation to provide viral safety assurance of the drug product. The industry has adopted this platform unit operation and gained a wider understanding of its performance attributes, leading to the possibility of streamlined approaches to virus clearance validation. Here, the concept of virus validation on a parvovirus-grade filter with a single worst-case model virus is presented. Several lines of evidence, including published literature and Amgen's own data, support the use of a parvovirus, such as mouse minute virus (MMV), as a worst-case model virus to assess virus removal by parvovirus filters. The evidence presented includes a discussion of the design and manufacture of virus filters with a size exclusion mechanism for removal. Next, the characteristics of different model viruses are compared and a risk assessment on the selection of the relevant model viruses for clearance studies is presented. Finally, a comprehensive summary of literature and Amgen data is provided, comparing the clearance of larger viruses against MMV. Together, this analysis provides a strong scientific rationale for the use of a single, worst-case model virus for assessing virus removal by parvovirus filters, which will ultimately allow for more efficient and streamlined viral clearance study designs. LAY ABSTRACT: Demonstrating the virus clearance capability of a purification process is an important aspect of biopharmaceutical process development. A key component of the viral safety of the process is the inclusion of a parvovirus-grade filter as an effective and robust virus removal step. Traditional methodologies for viral clearance studies have been based on a conservative, data-intensive approach, but recent trends in the field of virus clearance and process development show evolution towards streamlined and more efficient study designs that are based on understanding the mechanism of viral clearance by downstream unit operations. The publication of scientific datasets and awareness of the underlying mechanisms involved with these unit operations have fueled this trend. Here, the concept of virus validation on a parvovirus-grade filter using a parvovirus as single, worst-case model virus is presented. Multiple lines of evidence are provided to support this proposal, including a review of published literature and Amgen historical data. The adoption of this approach provides benefits in terms of cost savings for executing viral clearance studies, but it also simplifies the necessary dataset and focuses on only supplying value-added information to demonstrate the viral safety of the process.

Development and application of a robust N-glycan profiling method for heightened characterization of monoclonal antibodies and related glycoproteins.

A highly robust hydrophilic interaction liquid chromatography (HILIC) method that involves both fluorescence and mass spectrometric detection was developed for profiling and characterizing enzymatically released and 2-aminobenzamide (2-AB)-derivatized mAb N-glycans. Online HILIC/mass spectrometry (MS) with a quadrupole time-of-flight mass spectrometer provides accurate mass identifications of the separated, 2-AB-labeled N-glycans. The method features a high-resolution, low-shedding HILIC column with acetonitrile and water-based mobile phases containing trifluoroacetic acid (TFA) as a modifier. This column and solvent system ensures the combination of robust chromatographic performance and full compatibility and sensitivity with online MS in addition to the baseline separation of all typical mAb N-glycans. The use of TFA provided distinct advantages over conventional ammonium formate as a mobile phase additive, such as, optimal elution order for sialylated N-glycans, reproducible chromatographic profiles, and matching total ion current chromatograms, as well as minimal signal splitting, analyte adduction, and fragmentation during HILIC/MS, maximizing sensitivity for trace-level species. The robustness and selectivity of HILIC for N-glycan analyses allowed for method qualification. The method is suitable for bioprocess development activities, heightened characterization, and clinical drug substance release. Application of this HILIC/MS method to the detailed characterization of a marketed therapeutic mAb, Rituxan(®), is described.

Bio-relevant dissolution testing of hard capsules prepared from different shell materials using the dynamic open flow through test apparatus.

Current compendial dissolution and disintegrating testing is unable to mimic physiological conditions affecting gastric drug release from immediate release dosage forms. In order to obtain more realistic data, a novel test setup was developed that we term a 'dynamic open flow through test apparatus'. It is based on the previously described dissolution stress test device and attempts to simulate the intra-gastric dissolution conditions pertinent to immediate release dosage forms administered under fasting conditions with respect to flow rates, intra-gastric temperature profiles and gastric motility. The concept of the dynamic open flow through test apparatus has been tested using five different types of hard capsules: conventional hard gelatin capsules (HGC), three hypromellose based capsules (Vcaps, Vcaps Plus and DRcaps) and pullulan based capsules (Plantcaps). These were of different sizes but all contained 100mg caffeine in each formulation, adjusted to avoid buoyancy by addition of excipient. When the capsules were stressed in the apparatus under the dynamic flow conditions applying mild pressure simulating gastric motility, release from release from Vcaps Plus, Vcaps and Plantcaps capsules was very well comparable to HGC. Capsules are usually swallowed with cold water and the temperature dependency of release from gelatin was noted as a significant factor, since heat exchange in the stomach is slow.

Development of a bio-relevant dissolution test device simulating mechanical aspects present in the fed stomach.

A novel bio-relevant in vitro dissolution device was designed to mimic intragastric conditions after food intake paying particular consideration to mechanical aspects: the Fed Stomach Model (FSM). The FSM represents a fully computer-controlled dynamic flow-through system, in which dosage forms are hosted in so-called gastric vessels. Dosage form movement profiles as well as pressures can be simulated in a physiologically relevant manner. This proof-of-concept study aimed at the investigation of the effects of individual parameters and complex test programs on the drug delivery behavior of diclofenac sodium bilayer extended release tablets. Magnetic marker monitoring experiments demonstrated the applicability of the FSM to simulate intragastric movement velocities of solid oral dosage forms equivalent to in vivo data. Dissolution experiments revealed the relevance of all simulated parameters (i.e. pressure, dosage form movement and pump rate). Moreover, three different test scenarios with test programs specific for fundus, antrum and gastric emptying considered the variability of intragastric transit of solid oral dosage forms after food intake and were confirmed to be reasonable. Dissolution rates were low under conditions specific for fundus owing to low shear stresses. In contrast, higher amounts of the drug were released under high stress conditions simulating antral transit and gastric emptying. Concluding, the FSM can be a valuable tool for bio-relevant dissolution testing due to its potential of precise and reproducible simulation of mechanical parameters characteristic for the fed stomach.

Risk-based scientific approach for determination of extractables/leachables from biomanufacturing of antibody-drug conjugates (ADCs).

Recent developments in biopharmaceutical processes twined with a desire to remove cleaning and cross-contamination issues from drug production have led to the widespread introduction of single-use technologies and systems within operations. One key area that end users need to address with the advent of these single-use solutions is the potential for increased levels of extractables and leachables within a process, which need to be evaluated and understood as part of any regulatory submission. A science-based and practical method for characterization of extractables and leachables from single-use systems used in manufacturing antibody-drug conjugates has been developed and described in detail. This risk-based approach minimizes the amount of test work while meeting the regulatory requirements to ensure the drug safety and quality. The test design is optimized and the analytical methods (gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry, and inductively coupled plasma/mass spectrometry) are shown to be suitable for quantifying and identifying the extracted chemical compounds. Application of this characterization method speeds up the filing process for qualification and validation of single-use systems used in bioprocesses.