Process analytical technology in the pharmaceutical industry: a toolkit for continuous improvement

Process analytical technology (PAT) refers to a series of tools used to ensure that quality is built into products while at the same time improving the understanding of processes, increasing efficiency, and decreasing costs. It has not been widely adopted by the pharmaceutical industry. As the setting for this paper, the current pharmaceutical manufacturing paradigm and PAT guidance to date are discussed prior to the review of PAT principles and tools, benefits, and challenges. The PAT toolkit contains process analyzers, multivariate analysis tools, process control tools, and continuous improvement/knowledge management/information technology systems. The integration and implementation of these tools is complex, and has resulted in uncertainty with respect to both regulation and validation. The paucity of staff knowledgeable in this area may complicate adoption. Studies to quantitate the benefits resulting from the adoption of PAT within the pharmaceutical industry would be a valuable addition to the qualitative studies that are currently available.     

The Financial Returns on Investments in Process Analytical Technology and Lean Manufacturing: Benchmarks and Case Study

The combined deployment of process analytical technology (PAT) and Lean manufacturing offers extraordinary financial opportunities for pharmaceutical manufacturers at every scale. While many articles have been published describing the economic and quality opportunities presented by improved pharmaceutical manufacturing performance, greater understanding of the financial benefits of PAT and Lean at the individual company level is needed to support accurate valuation of corporate investments in manufacturing performance upgrades. This paper describes research using industrial benchmarks and published data for publicly-traded companies to demonstrate the value potential posed by combined deployment of PAT and Lean in pharmaceutical manufacturing operations. A method of estimating the financial return on investments in PAT and Lean is described by considering their impact on the profitability of a hypothetical mid-sized generic pharmaceutical manufacturer. The results of the case study show that based on benchmark data for the generic drug manufacturers, it is possible to return savings of up to 6% of revenues by improving process capability and supply chain management through strategic deployment of PAT and Lean manufacturing.     

A Systematic Framework for Process Control Design and Risk Analysis in Continuous Pharmaceutical Solid-Dosage Manufacturing

The paradigm shift in the pharmaceutical industry to continuous manufacturing, which has recently progressed from conceptual demonstration to pilot production, has stimulated the development and application of process systems engineering (PSE) tools for implementing efficient and robust control strategies. In this study, a systematic framework for process control design and risk analysis for continuous pharmaceutical solid-dosage manufacturing is proposed, consisting of system identification with state-space models; control design and analysis metrics; hierarchical three-layer control structures; risk mapping, assessment and planning (Risk MAP) strategies; and control performance indicators. The framework is applied to a feeding-blending system, wherein the major source of variance in the product quality arises. It can be demonstrated that the variance in the feeding-blending system can be mitigated and managed through the proposed systematic framework for control design and risk analysis. The process analytical technology (PAT) tool for mass fraction measurement of active pharmaceutical ingredient (API) and its relative standard deviation (RSD) were indispensable to achieve an efficient control design at the advanced layers. Specifically, the improvements in control performance by implementing advanced model-based control strategy are found to be limited by model-plant mismatch and the sampling time of the PAT tools.     

Melt extrusion with poorly soluble drugs – An integrated review

Over the last few decades, hot melt extrusion (HME) has emerged as a successful technology for a broad spectrum of applications in the pharmaceutical industry. As indicated by multiple publications and patents, HME is mainly used for the enhancement of solubility and bioavailability of poorly soluble drugs. This review is focused on the recent reports on the solubility enhancement via HME and provides an update for the manufacturing/scaling up aspects of melt extrusion. In addition, drug characterization methods and dissolution studies are discussed. The application of process analytical technology (PAT) tools and use of HME as a continuous manufacturing process may shorten the drug development process; as a result, the latter is becoming the most widely utilized technique in the pharmaceutical industry. The advantages, disadvantages, and practical applications of various PAT tools such as near and mid-infrared, ultraviolet/visible, fluorescence, and Raman spectroscopies are summarized, and the characteristics of other techniques are briefly discussed. Overall, this review also provides an outline for the currently marketed products and analyzes the strengths, weaknesses, opportunities and threats of HME application in the pharmaceutical industry.     

Applications of process analytical technology to crystallization processes

Crystallizations of pharmaceutical active ingredients, particularly those that posses multiple polymorphic forms, are among the most critical and least understood pharmaceutical manufacturing processes. Many process and product failures can be traced to a poor understanding and control of crystallization processes. The Food and Drug Administration's process analytical technology (PAT) initiative is a collaborative effort with industry to introduce new and efficient manufacturing technologies into the pharmaceutical industry. PAT's are systems for design, analysis, and control of manufacturing processes. They aim to assure high quality through timely measurements of critical quality and performance attributes of raw materials, in-process materials, and final products. Implementation of PAT involves scientifically based process design and optimization, appropriate sensor technologies, statistical and information tools (chemometrics), and feedback process control strategies working together to produce quality products. This review introduces the concept of PAT and discusses its application to crystallization processes through review of several case studies. A variety of in situ analytical methods combined with chemometric tools for analysis of multivariate process information provide a basis for future improvements in modeling, simulation, and control of crystallization processes.     

Advancing non-destructive analysis of 3D printed medicines

Pharmaceutical 3D printing (3DP) has attracted significant interest over the past decade for its ability to produce personalised medicines on demand. However, current quality control (QC) requirements for traditional large-scale pharmaceutical manufacturing are irreconcilable with the production offered by 3DP. The US Food and Drug Administration (FDA) and the UK Medicines and Healthcare Products Regulatory Agency (MHRA) have recently published documents supporting the implementation of 3DP for point-of-care (PoC) manufacturing along with regulatory hurdles. The importance of process analytical technology (PAT) and non-destructive analytical tools in translating pharmaceutical 3DP has experienced a surge in recognition. This review seeks to highlight the most recent research on non-destructive pharmaceutical 3DP analysis, while also proposing plausible QC systems that complement the pharmaceutical 3DP workflow. In closing, outstanding challenges in integrating these analytical tools into pharmaceutical 3DP workflows are discussed.     

Three ‘D’s: Design approach,dimensional printing,and drug delivery systems as promising tools in healthcare applications

The development of pharmaceutical drug products is required for the treatment of disease, which has resulted in an increasing number of approvals by regulatory agencies across the globe. To establish a hassle-free manufacturing process, the systematic use of a quality-by-design (QbD) approach combined with process analytical technology (PAT) and printing techniques can revolutionize healthcare applications. Printing technology has been emerged in various dimensions, such as 3D, 4D, and 5D printing, with respect to their production capabilities, durability, and accuracy of pharmaceutical manufacturing, which can efficiently deliver novel patient-centric healthcare products with holistic characteristics. In this review, we provide current trends in pharmaceutical product development using a design approach and high-quality printing techniques.     

PAT: From Western solid dosage forms to Chinese materia medica preparations using NIR‐CI

Near‐infrared chemical imaging (NIR‐CI) is an emerging technology that combines traditional near‐infrared spectroscopy with chemical imaging. Therefore, NIR‐CI can extract spectral information from pharmaceutical products and simultaneously visualize the spatial distribution of chemical components. The rapid and non‐destructive features of NIR‐CI make it an attractive process analytical technology (PAT) for identifying and monitoring critical control parameters during the pharmaceutical manufacturing process. This review mainly focuses on the pharmaceutical applications of NIR‐CI in each unit operation during the manufacturing processes, from the Western solid dosage forms to the Chinese materia medica preparations. Finally, future applications of chemical imaging in the pharmaceutical industry are discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Improving drug manufacturing with process analytical technology

Within the process analytical technology (PAT) framework, as presented in the US Food and Drug Administration guidelines, the aim is to design, develop and operate processes consistently to ensure a pre-defined level of quality at the end of the manufacturing process. Three PAT implementation scenarios can be envisaged. Firstly, PAT could be used in its most modest version (in an almost non-PAT manner) to simply replace an existing quality control protocol (eg, using near-infrared spectroscopy for an in-process quality control, such as moisture content). Secondly, the use of in-process monitoring and process analysis could be integrated to enhance process understanding and operation for an existing industrial process. Thirdly, PAT could be used extensively and exclusively throughout development, scale-up and full-scale production of a new product and process. Although the first type of implementations are well known, reports of the second and third types remain scarce. Herein, results obtained from PAT implementations of the second and third types are described for two industrial processes for preparing bulk active pharmaceutical ingredients, demonstrating the benefits in terms of increased process understanding and process control.     

Near infrared and Raman spectroscopy for the in-process monitoring of pharmaceutical production processes

Within the Process Analytical Technology (PAT) framework, it is of utmost importance to obtain critical process and formulation information during pharmaceutical processing. Process analyzers are the essential PAT tools for real-time process monitoring and control as they supply the data from which relevant process and product information and conclusions are to be extracted. Since the last decade, near infrared (NIR) and Raman spectroscopy have been increasingly used for real-time measurements of critical process and product attributes, as these techniques allow rapid and nondestructive measurements without sample preparations. Furthermore, both techniques provide chemical and physical information leading to increased process understanding. Probes coupled to the spectrometers by fiber optic cables can be implemented directly into the process streams allowing continuous in-process measurements. This paper aims at reviewing the use of Raman and NIR spectroscopy in the PAT setting, i.e., during processing, with special emphasis in pharmaceutics and dosage forms.     

In-line monitoring of granule moisture in fluidized-bed dryers using microwave resonance technology

This is the first report on in-line moisture measurement of pharmaceutical products by microwave resonance technology. In order to meet the FDA’s PAT approach, a microwave resonance sensor appropriate for pharmaceutical use was developed and implemented into two different fluidized-bed dryers. The novel sensor enables a continuous moisture measurement independent from the product density. Hence, for the first time precise real time determination of the moisture in pharmaceutical granules becomes possible. The qualification of the newly developed sensor was performed by drying placebo granules under experimental conditions and the validation using drug loaded granules under real process conditions. The results of the investigations show good correlations between water content of the granules determined by the microwave resonance sensor and both reference methods, loss on drying by infrared light exposure and Karl Fischer titration. Furthermore, a considerable time saving in the drying process was achieved through monitoring the residual water content continuously by microwave resonance technology instead of the formerly used discontinuous methods.     

Drug product characterization by macropixel analysis of chemical images

Traditional monitoring of pharmaceutical manufacturing combines physical sampling and analytical methodologies (e.g. HPLC). Process analytical technology (PAT) can be implemented to collect real-time measurements, although successful monitoring requires that sampling be representative. The maximum spot size for a spectroscopic tool (e.g. near-infrared; Raman) should be equivalent to a single dosage size. A smaller spot size may provide a PAT tool that is sensitive to monitoring process changes, but if too small, produces non-reproducible data. The current study uses chemical imaging to determine appropriate spot size. A chemical image is an array of pixels which maps the chemical composition of the sample. "Macropixel Analysis" is introduced as a measure of image heterogeneity based on clusters of pixels (macropixels) within near-infrared chemical images. Analyses were conducted using non-overlapping tiles of macropixels (Discrete-Level Tiling) and all possible macropixels of the image (Continuous-Level Moving Block). Both methods minimize the variance between macropixel intensities by varying the size of the macropixels. Spot size is then chosen as the minimum macropixel size for which the range of macropixel intensities falls within an acceptable criterion. Both imaging-based algorithms provide useful quantitative information about the heterogeneity of pharmaceutical products.     

药品连续制造全球监管发展现状与思考

目的：在连续制造技术越来越多地应用在药品领域这一背景下,综述相关法规指南从概念探索、 正式发起至发布的发展历程,介绍全球多个采用连续制造技术生产药品获批上市的概况,探讨促进我国业界和监管机构借鉴全球药品连续制造发展经验。方法：通过对比传统的批量制造技术以分析连续制造具有的优势和面临的挑战,结合对全球监管指南制定过程中各监管机构对策的梳理,研究相关共识的发展考量和意义。结果：药品连续制造监管发展已经进入了新的时代,我国相关法规指南的制定和产业技术水平提升需要借鉴全球发展的经验,特别是国际人用药品注册技术协调会及美、欧、日等国家药品监督管理机构或国际组织的现有指南在批定义、工艺验证、稳定性等方面的监管对策,为该新兴技术的监管科学研究提供理论基础。结论：通过对药品连续制造全球监管发展现状的综述和思考,为我国相关法规、技术指南和标准的制定提供参考,并希望为产业发展发挥促进作用。     

双螺杆制粒技术及其在药物制剂领域中的应用

双螺杆制粒(twin screw granulation,TSG)是制药行业新兴的一种连续湿法制粒技术,目前在国内制药行业报道较少。本文系统介绍了双螺杆挤出制粒机的结构及工作原理,制剂的处方特点及工艺参数对所得颗粒的形状、粒径、孔隙率等性质的影响,并综述了目前国内外TSG的发展现状以及面临的机遇和挑战。虽然TSG技术仍存在一些问题,但是其独特的工艺过程在连续制造生产模式中显示出巨大的优势和潜力。TSG技术的这些优势将会吸引更多研究者的关注,伴随着过程分析技术的发展,将来可能成为制药行业的一个研究热点。     

An update on the contribution of hot-melt extrusion technology to novel drug delivery in the twenty-first century: part I

Introduction: Currently, hot melt extrusion (HME) is a promising technology in the pharmaceutical industry, as evidenced by its application to manufacture various FDA-approved commercial products in the market. HME is extensively researched for enhancing the solubility and bioavailability of poor water-soluble drugs, taste masking, and modifying release in drug delivery systems. Additionally, its other novel opportunities or pharmaceutical applications, and capability for continuous manufacturing are being investigated. This efficient, industrially scalable, solvent-free, continuous process can be easily automated and coupled with other novel platforms for continuous manufacturing of pharmaceutical products.

Areas covered: This review focuses on updates on solubility enhancement of poorly water-soluble drugs and process analytical tools such as UV/visible spectrophotometry; near-infrared spectroscopy; Raman spectroscopy; and rheometry for continuous manufacturing, with a special emphasis on fused deposition modeling 3D printing.

Expert opinion: The strengths, weakness, opportunities, threats (SWOT) and availability of commercial products confirmed wide HME applicability in pharmaceutical research. Increased interest in continuous manufacturing processes makes HME a promising strategy for this application. However, there is a need for extensive research using process analytical tools to establish HME as a dependable continuous manufacturing process.     

在线过程分析技术在抗生素等药物结晶中的应用

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Real-Time Monitoring of Powder Mass Flowrates for Plant-Wide Control of a Continuous Direct Compaction Tablet Manufacturing Process

While measurement and monitoring of powder/particulate mass flow rate are not essential to the execution of traditional batch pharmaceutical tablet manufacturing, in continuous operation, it is an important additional critical process parameter. It has a key role both in establishing that the process is in a state of control, and as a controlled variable in process control system design. In current continuous tableting line operations, the pharmaceutical community relies on loss-in-weight feeders to monitor and understand upstream powder flow dynamics. However, due to the absence of established sensing technologies for measuring particulate flow rates, the downstream flow of the feeders is monitored and controlled using various indirect strategies. For example, the hopper level of the tablet press is maintained as a controlled process output by adjusting the turret speed of the tablet press, which indirectly controlling the flow rate. This gap in monitoring and control of the critical process flow motivates our investigation of a novel PAT tool, a capacitance-based sensor (ECVT), and its effective integration into the plant-wide control of a direct compaction process. First, the results of stand-alone experimental studies are reported, which confirm that the ECVT sensor can provide real-time measurements of mass flow rate with measurement error within -1.8 ~ 3.3% and with RMSE of 0.1 kg/h over the range of flow rates from 2 to 10 kg/h. The key caveat is that the powder flowability has to be good enough to avoid powder fouling on the transfer line walls. Next, simulation case studies are carried out using a dynamic flowsheet model of a continuous direct compression line implemented in Matlab/Simulink to demonstrate the potential structural and performance advantages in plant-wide process control enabled by mass flow sensing. Finally, experimental studies are performed on a direct compaction pilot plant in which the ECVT sensor is located at the exit of the blender, to confirm that the powder flow can be monitored instantaneously and controlled effectively at the specified setpoint within a plant-wide feedback controller system.     

智能制造理念在血液制品产业的应用研究

目的：通过分析智能制造理念下,质量源于设计（quality by design,QbD）与血液制品生产的相关性、过程分析技术（process analytical technology,PAT）在血液制品QbD中的应用以及关键质量环节的QbD实施,以期推动我国血液制品行业升级,实现血液制品的智能生产。方法：采取前瞻性研究方法,查阅、检索以"智能制造" "血液制品" "质量源于设计"过程分析技术"为关键词的文献,对智能制造理念在血液制品的应用研究进行论述。结果与结论：基于我国制药工业的自动化与信息化的水平与现状,制药工业的"智能制造"已逐步发展起来,QbD已被引入我国新版药品GMP,强调了与药品注册、上市制度的有效衔接。在科学监管的要求下,QbD理念已成为血液制品行业界的共识,实施QbD,通过基于问题的审核（question-based review,QbR）,将有助于全面提高我国血液制品的质量,提升产品的竞争力。     

Near-infrared reflectance spectroscopy as a process analytical technology tool in Ginkgo biloba extract qualification

Here, we describe the use of near-infrared diffuse reflectance spectroscopy for qualification of Ginkgo biloba extract as raw material for use in pharmaceutical products. G. biloba extract shows unpredicted and uncontrolled variability in some of its quality specifications, intrinsic to its natural origin, which have influence on the manufacturing process of solid dosage forms (viz. granulation and compression). Some of these properties could not be determined by conventional quality control tests, so we investigated the use of NIR to qualify the batches of Ginkgo extract accordingly to its different features and establish a relationship with some of the manufacturing steps behaviour based on their qualification. Several approaches were evaluated, and the NIR method developed demonstrated to be sensitive to changes in important quality specifications and therefore adequate to qualify incoming batches of G. biloba extract. This could be considered a process analytical technology (PAT) application since it: (1) establishes the source of variability in a qualitative way, (2) explains its propagation to the final product quality attributes and (3) lays the basis for a control strategy to be applied in the manufacturing process.     

Assessment of Diffuse Transmission Mode in Near-Infrared Quantification—Part I: The Press Effect on Low-Dose Pharmaceutical Tablets

Quantitative applications for pharmaceutical solid dosage forms using near-infrared (NIR) spectroscopy are central to process analytical technology (PAT) manufacturing designs. A series of studies were conducted to evaluate the use of NIR transmission mode under various pharmaceutical settings. The spectral variability in relation to tablet physical parameters were investigated using placebo tablets with different thickness and porosity steps and both variables showed an exponential relationship with the detected transmittance signal drop. The drug content of 2.5% m/m folic acid tablets produced under extremely different compaction conditions was predicted and found to agree with UV assay results after inclusion of extreme physical outliers to the training sets. NIR transmission was also shown to traverse a wide section of the tablet by comparing relative blocking intensities from different regions of the tablet surface and >90% of the signal was detected through a central area of 7 mm diameters of the tablet surface. NIR Quantification of both film thickness and active ingredient for film-coated tablets are examined in part II of this study. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:4877–4886, 2009