Applying quality by design (QbD) concept for fabrication of chitosan coated nanoliposomes

In the present investigation, a quality by design (QbD) strategy was successfully applied to the fabrication of chitosan-coated nanoliposomes (CH-NLPs) encapsulating a hydrophilic drug. The effects of the processing variables on the particle size, encapsulation efficiency (%EE) and coating efficiency (%CE) of CH-NLPs (prepared using a modified ethanol injection method) were investigated. The concentrations of lipid, cholesterol, drug and chitosan; stirring speed, sonication time; organic:aqueous phase ratio; and temperature were identified as the key factors after risk analysis for conducting a screening design study. A separate study was designed to investigate the robustness of the predicted design space. The particle size, %EE and %CE of the optimized CH-NLPs were 111.3?nm, 33.4% and 35.2%, respectively. The observed responses were in accordance with the predicted response, which confirms the suitability and robustness of the design space for CH-NLP formulation. In conclusion, optimization of the selected key variables will help minimize the problems related to size, %EE and %CE that are generally encountered when scaling up processes for NLP formulations. The robustness of the design space will help minimize both intra-batch and inter-batch variations, which are quite common in the pharmaceutical industry.     

Real‐time product attribute control to manufacture antibodies with defined N‐linked glycan levels

Pressures for cost‐effective new therapies and an increased emphasis on emerging markets require technological advancements and a flexible future manufacturing network for the production of biologic medicines. The safety and efficacy of a product is crucial, and consistent product quality is an essential feature of any therapeutic manufacturing process. The active control of product quality in a typical biologic process is challenging because of measurement lags and nonlinearities present in the system. The current study uses nonlinear model predictive control to maintain a critical product quality attribute at a predetermined value during pilot scale manufacturing operations. This approach to product quality control ensures a more consistent product for patients, enables greater manufacturing efficiency, and eliminates the need for extensive process characterization by providing direct measures of critical product quality attributes for real time release of drug product. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1433–1441, 2015     

一种高效快速浓缩腺相关病毒载体的方法

腺相关病毒载体(adeno associatedviralvector,AAVvector)是一种具有良好应用前景的基因治疗载体。研究中往往需要高滴度的重组AAV病毒(>105v g /细胞),为此利用完整的腺相关病毒颗粒具有耐受有机溶剂的特点,创造性地采用了一种用乙醇沉淀重组AAV病毒的方法,达到了高效、快速浓缩AAV载体的目的。结果表明,乙醇沉淀法可以高效浓缩AAV载体,并且对病毒的结构和活性没有明显影响。用这种方法可以方便地将低滴度的AAV病毒变成高滴度,解决动物体内实验中每点注射体积受到限制的问题。     

Summary of the National Institute of Standards and Technology and US Food And Drug Administration cell counting workshop: Sharing practices in cell counting measurements

The emergence of cell-based therapeutics has increased the need for high-quality, robust and validated measurements for cell characterization. Cell count, being one of the most fundamental measures for cell-based therapeutics, now requires increased levels of measurement confidence. The National Institute of Standards and Technology (NIST) and the US Food and Drug Administration (FDA) jointly hosted a workshop focused on cell counting in April 2017 entitled “NIST-FDA Cell Counting Workshop: Sharing Practices in Cell Counting Measurements.” The focus of the workshop was on approaches for selecting, designing and validating cell counting methods and overcoming gaps in obtaining sufficient measurement assurance for cell counting. Key workshop discussion points, representing approximately 50 subject matter experts from industry, academia and government agencies, are summarized here. A key conclusion is the need to design the most appropriate cell counting method, including control/measurement assurance strategies, for a specific counting purposes. There remains a need for documentary standards for streamlining the process to develop, qualify and validate cell counting measurements as well as community-driven efforts to develop new or improved biological and non-biological reference materials.     

Assessment of structural and functional similarity of biosimilar products: Rituximab as a case study

Biosimilars are products that are similar in terms of quality, safety, and efficacy to an already licensed reference/ innovator product and are expected to offer improved affordability. The most significant source of reduction in the cost of development of a biosimilar is the reduced clinical examination that it is expected to undergo as compared to the innovator product. However, this clinical relief is predicated on the assumption that there is analytical similarity between the biosimilar and the innovator product. As a result, establishing analytical similarity is arguably the most important step towards successful development of a biosimilar. Here, we present results from an analytical similarity exercise that was performed with five biosimilars of rituximab (Ristova®, Roche), a chimeric mouse/ human monoclonal antibody biotherapeutic, that are available on the Indian market. The results show that, while the biosimilars exhibited similarity with respect to protein structure and function, there were significant differences with respect to size heterogeneity, charge heterogeneity and glycosylation pattern.     

Assessment of chemical modifications of sites in the CDRs of recombinant antibodies: Susceptibility vs. functionality of critical quality attributes

Modifications like asparagine deamidation, aspartate isomerization, methionine oxidation, and lysine glycation are typical degradations for recombinant antibodies. For the identification and functional evaluation of antibody critical quality attributes (CQAs) derived from chemical modifications in the complementary-determining regions (CDRs) and the conserved regions, an approach employing specific stress conditions, elevated temperatures, pH, oxidizing agents, and forced glycation with glucose incubation, was applied. The application of the specific stress conditions combined with ion exchange chromatography, proteolytic peptide mapping, quantitative liquid chromatography mass spectrometry, and functional evaluation by surface plasmon resonance analysis was adequate to identify and functionally assess chemical modification sites in the CDRs of a recombinant IgG1. LC-Met-4, LC-Asn-30/31, LC-Asn-92, HC-Met-100c, and HC Lys-33 were identified as potential CQAs. However, none of the assessed degradation products led to a complete loss of functionality if only one light or heavy chain of the native antibody was affected.     

Assessment of chemical modifications of sites in the CDRs of recombinant antibodies

Modifications like asparagine deamidation, aspartate isomerization, methionine oxidation, and lysine glycation are typical degradations for recombinant antibodies. For the identification and functional evaluation of antibody critical quality attributes (CQAs) derived from chemical modifications in the complementary-determining regions (CDRs) and the conserved regions, an approach employing specific stress conditions, elevated temperatures, pH, oxidizing agents, and forced glycation with glucose incubation, was applied. The application of the specific stress conditions combined with ion exchange chromatography, proteolytic peptide mapping, quantitative liquid chromatography mass spectrometry, and functional evaluation by surface plasmon resonance analysis was adequate to identify and functionally assess chemical modification sites in the CDRs of a recombinant IgG1. LC-Met-4, LC-Asn-30/31, LC-Asn-92, HC-Met-100c, and HC Lys-33 were identified as potential CQAs. However, none of the assessed degradation products led to a complete loss of functionality if only one light or heavy chain of the native antibody was affected.     

Impact of IgG Fc‐Oligosaccharides on Recombinant Monoclonal Antibody Structure,Stability, Safety,and Efficacy

Glycosylation of the conserved asparagine residue in the CH2 domain is the most common posttranslational modification of recombinant monoclonal antibodies. Ideally, a consistent oligosaccharide profile should be maintained from early clinical material to commercial material for the development of recombinant monoclonal therapeutics, though variation in the profile is a typical result of process changes. The risk of oligosaccharide variation posed to further development is required to be thoroughly evaluated based on its impact on antibody structure, stability, efficacy and safety. The variation should be controlled within a range so that there is no detrimental impact on safety and efficacy and thus allowing the use of early phase safety and efficacy data to support project advancement to later phase. This review article focuses on the current scientific understanding of the commonly observed oligosaccharides found in recombinant monoclonal antibodies and their impact on structure, stability and biological functions, which are the basis to evaluate safety and efficacy. It also provides a brief discussion on critical quality attribute (CQA) assessment with regard to oligosaccharides based on the mechanism of action (MOA). © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1173–1181, 2017     

Rates of growth and increase ofMyzus persicae on virus-infected potatoes according to type of virus-vector relationship

Growth, reproduction and survival (=performance) of the aphidMyzus persicae Sulzer was measured on virus-free and virus-infected potato plants The principle objective was to evaluate if various viral infections affected aphid performance differently, and if so, whether any order in the performance response of the aphid was discernible according to the type of virus-vector relationship. Three viruses varying in their dependency onM. persicae as a vector were used. Plants infected with potato leafroll virus (PLRV), a circulative virus highly dependent uponM. persicae for dispersal and transmission, were superior hosts as determined by the significantly greater mean relative growth rate (MRGR) and intrinsic rate of increase (r_m) ofM. persicae compared with those of aphids reared on other plants. Plants infected with potato virus Y, a noncirculative virus less dependent uponM. persicae for dispersal than PLRV, were intermediate in their quality based upon intermediate MRGR and r_m values. Plants infected with potato virus X, a nonvectored virus independent ofM. persicae, were least suitable hosts along with the group of virus-free plants according to the lower MRGR and r_m values.     

腺相关病毒载体介导的人内皮抑素的体外表达及对内皮细胞抑制作用的研究

抗血管生成基因治疗是一有希望的抑制肿瘤生长及转移的方法.在实验中构建了含有人内皮抑素(endostatin)基因的重组腺相关病毒载体rAAV-hE.所包装纯化的重组病毒滴度达0.5×1012v.g./ml.rAAV-hE能有效感染培养细胞,EIA法检测培养液上清中内皮抑素浓度达36.42ng/ml.rAAV介导所表达的内皮抑素对人脐静脉内皮细胞(ECV-304)和牛毛细血管内皮细胞(BCE)具有抗增殖抑制作用,抑制率分别为68.1%和41.6%.此结果为进一步的动物实验奠定了基础,表明重组腺相关病毒载体介导的抗血管生成有望应用于肿瘤基因治疗.     

Development of a quantitative mass spectrometry multi-attribute method for characterization,quality control testing and disposition of biologics

Regulatory agencies have recently recommended a Quality by Design (QbD) approach for the manufacturing of therapeutic molecules. A QbD strategy requires deep understanding at the molecular level of the attributes that are crucial for safety and efficacy and for insuring that the desired quality of the purified protein drug product is met at the end of the manufacturing process. A mass spectrometry (MS)-based approach to simultaneously monitor the extensive array of product quality attributes (PQAs) present on therapeutic molecules has been developed. This multi-attribute method (MAM) uses a combination of high mass accuracy / high resolution MS data generated by Orbitrap technology and automated identification and relative quantification of PQAs with dedicated software (Pinpoint). The MAM has the potential to replace several conventional electrophoretic and chromatographic methods currently used in Quality Control to release therapeutic molecules. The MAM represents an optimized analytical solution to focus on the attributes of the therapeutic molecule essential for function and implement QbD principles across process development, manufacturing and drug disposition.     

腺伴随病毒载体介导HPV16 E6E7基因转化人胎食管上皮细胞

为了证实人乳头瘤病毒16型（HPV16）感染与食管鳞状细胞癌发生的关系,构建了包含HPV16E6E7基因的重组腺伴随病毒载体并包装重组病毒,重组病毒感染人胎食管粘膜组织,注射SCID小鼠皮下,在TPA协同下12周左右诱发肿瘤。PCR及打点杂交检测到瘤组织中HPV16E6E7基因的存在,HE染色表明为恶性鳞状上皮癌,培养形态及透射电镜观察证实了瘤组织的上皮来源。以上结果对于阐明食管癌发生的病毒病因、食管癌发生的分子机制以及为食管癌防治提供了理论和实践依据。     

Functional assessment of antibody oxidation by native mass spectrometry

Oxidation of methionine (Met) residues is one of several chemical degradation pathways for recombinant IgG1 antibodies. Studies using several methodologies have indicated that Met oxidation in the constant IgG1 domains affects in vitro interaction with human neonatal Fc (huFcRn) receptor, which is important for antibody half-life. Here, a completely new approach to investigating the effect of oxidative stress conditions has been applied. Quantitative ultra-performance liquid chromatography mass spectrometry (MS) peptide mapping, classical surface plasmon resonance and the recently developed FcRn column chromatography were combined with the new fast-growing approach of native MS as a near native state protein complex analysis in solution. Optimized mass spectrometric voltage and pressure conditions were applied to stabilize antibody/huFcRn receptor complexes in the gas phase for subsequent native MS experiments with oxidized IgG1 material. This approach demonstrated a linear correlation between quantitative native MS and IgG-FcRn functional analysis.

In our study, oxidation of the heavy chain Met-265 resulted in a stepwise reduction of mAb3/huFcRn receptor complex formation. Remarkably, a quantitative effect of the heavy chain Met-265 oxidation on relative binding capacity was only detected for doubly oxidized IgG1, whereas IgG1 with only one oxidized heavy chain Met-265 was not found to significantly affect IgG1 binding to huFcRn. Thus, mono-oxidized IgG1 heavy chain Met-265 most likely does not represent a critical quality attribute for pharmacokinetics.