A case study on decentralized manufacturing of 3D printed medicines

Pharmaceutical 3D printing (3DP) is one of the emerging enabling technologies of personalised medicines as it affords the ability to fabricate highly versatile dosage forms. In the past 2 years, national medicines regulatory authorities have held consultations with external stakeholders to adapt regulatory frameworks to embrace point-of-care manufacturing. The proposed concept of decentralized manufacturing (DM) involves the provision of feedstock intermediates (pharma-inks) prepared by pharmaceutical companies to DM sites for manufacturing into the final medicine. In this study, we examine the feasibility of this model, with respect to both manufacturing and quality control. Efavirenz-loaded granulates (0-35%w/w) were produced by a manufacturing partner and shipped to a 3DP site in a different country. Direct powder extrusion (DPE) 3DP was subsequently used to prepare printlets (3D printed tablets), with mass ranging 266-371 mg. All printlets released more than 80% drug load within the first 60 min of the in vitro drug release test. An in-line near-infrared spectroscopy system was used as a process analytical technology (PAT) to quantify the printlets' drug load. Calibration models were developed using partial least squares regression, which showed excellent linearity (R² = 0.9833) and accuracy (RMSE = 1.0662). Overall, this work is the first to report the use of an in-line NIR system to perform real-time analysis of printlets prepared using pharma-inks produced by a pharmaceutical company. By demonstrating the feasibility of the proposed distribution model through this proof-of-concept study, this work paves the way for investigation of further PAT tools for quality control in 3DP point-of-care manufacturing.

Dual-spectrum online monitoring of puerarin and total flavonoids contents during the extraction process of Pueraria lobata

In the extraction process of traditional Chinese medicine (TCM), the rapid detection of the active components of TCM plays a vital role. We pioneered the choice of dual-spectrum technology based on near-infrared (NIR) and ultraviolet-visible (UV-Vis) spectra and applied it to the quantitative monitoring of online extraction of puerarin and total flavonoids from Pueraria lobata. An online monitoring system was constructed to fulfill the dual-spectrum online monitoring. The extraction solution flows from a flask into a pipeline under the control of a peristaltic pump, removing the solid residues contained in the solution with filters. When the extraction solution flows into the cuvette, it will be measured with NIR and UV-Vis portable spectrometers. After finishing the spectra collection, the peristaltic pump will reverse to push the extraction solution back to the flask. The partial least squares (PLS) models were established to quantitatively analyze puerarin and total flavonoids by NIR, UV-Vis, and dual-spectrum data. As for NIR, UV-Vis and dual-spectrum, the RMSEP (mg/mL) of the puerarin models were 0.0803, 0.0500, and 0.0351, and those of the total flavonoids models were 0.4373, 0.2402, and 0.1795, respectively. The results show that the dual-spectrum online monitoring system is simple, stable and fast (a few seconds) in operation, and accurate in prediction. Compared with individual NIR or UV-Vis spectra, the dual-spectra contains more comprehensive information, and the prediction ability is stronger. This method is expected to become a promising tool for the quantitative analysis of other traditional Chinese medicines.

Small footprint liquid chromatography-mass spectrometry for pharmaceutical reaction monitoring and automated process analysis

Liquid chromatography (LC) has broad applicability in the pharmaceutical industry, from the early stages of drug discovery to reaction monitoring and process control. However, small footprint, truly portable LC systems have not yet been demonstrated and fully evaluated practically for on-line, in-line or at-line pharmaceutical analysis. Herein, a portable, briefcase-sized capillary LC fitted with a miniature multi-deep UV-LED detector has been developed and interfaced with a portable mass spectrometer for on-site pharmaceutical analysis. With this configuration, the combined small footprint portable LC-UV/MS system was utilized for the determination of small molecule pharmaceuticals and reaction monitoring. The LC-UV/MS system was interfaced directly with a process sample cart and applied to automated pharmaceutical analysis, as well as also being benchmarked against a commercial process UPLC system (Waters PATROL system). The portable system gave low detection limits (∼3 ppb), a wide dynamic range (up to 200 ppm) and was used to confirm the identity of reaction impurities and for studying the kinetics of synthesis. The developed platform showed robust performance for automated process analysis, with less than 5.0% relative standard deviation (RSD) on sample-to-sample reproducibility, and less than 2% carryover between samples. The system has been shown to significantly increase throughput by providing near real-time analysis and to improve understanding of synthetic processes.

Continuous downstream processing of milled electrospun fibers to tablets monitored by near-infrared and Raman spectroscopy

Electrospinning is a technology for manufacture of nano- and micro-sized fibers, which can enhance the dissolution properties of poorly water-soluble drugs. Tableting of electrospun fibers have been demonstrated in several studies, however, continuous manufacturing of tablets have not been realized yet. This research presents the first integrated continuous processing of milled drug-loaded electrospun materials to tablet form supplemented by process analytical tools for monitoring the active pharmaceutical ingredient (API) content. Electrospun fibers of an amorphous solid dispersion (ASD) of itraconazole and poly(vinylpyrrolidone-co-vinyl acetate) were produced using high speed electrospinning and afterwards milled. The milled fibers with an average fiber diameter of 1.6 ± 0.9 µm were continuously fed with a vibratory feeder into a twin-screw blender, which was integrated with a tableting machine to prepare tablets with ~ 10 kN compression force. The blend of fibers and excipients leaving the continuous blender was characterized with a bulk density of 0.43 g/cm³ and proved to be suitable for direct tablet compression. The ASD content, and thus the API content was determined in-line before tableting and at-line after tableting using near-infrared and Raman spectroscopy. The prepared tablets fulfilled the USP <905> content uniformity requirement based on the API content of ten randomly selected tablets. This work highlights that combining the advantages of electrospinning (e.g. less solvent, fast and gentle drying, low energy consumption, and amorphous products with high specific surface area) and the continuous technologies opens a new and effective way in the field of manufacturing of the poorly water-soluble APIs.

Towards better understanding of the influence of process parameters in roll compaction/dry granulation on throughput, ribbon microhardness and granule failure load

A key quality attribute for solid oral dosage forms is their hardness and ability to withstand breaking or grinding. If the product is to be manufactured continuously, it can be of interest to monitor the hardness of the material at different stages of manufacturing. Using the controlled process parameters of roll compaction/dry granulation specific compaction force, roll speed and gap width, hardness of the resulting ribbons and granules can be predicted. For the first time, in this study two yield variables (corrected torque of the granulation unit and throughput of material) are used to predict the granules failure load. The increase in granule hardness was monitored in-line when the specific compaction force was increased during the compaction process. This opens the way for in-line control of material hardness, and its use for feedback and feedforward control loops for future continuous manufacturing processes.

Combination of a rotating tube sample divider and dynamic image analysis for continuous on-line determination of granule size distribution

The granule size distribution is a critical quality attribute of granules. It has a great impact on further packaging or processing. Due to increasing interest in continuous manufacturing techniques, it is of high interest to develop an in-line or on-line tool to monitor the granule size distribution. However, development of an in-line measurement tool for granule size distribution was challenging since large throughput and inhomogeneous product stream are limiting factors for current particle size analyzers. In this study, continuous sampling was tested in conjunction to a continuous on-line method of size determination using dynamic image analysis. A rotating tube sample divider was used to split previously compacted material in representative samples at different ratios and the sample was directly conveyed to the particle size analyzer where the granule size distribution was determined. The method was tested for different granule sizes to determine limits of detection and its ability to detect these changes immediately, as this enables real-time monitoring of the process. This research is the base for development of control tools concerning the granule size distributions for continuous granulation processes.

Implementation of real-time and in-line feedback control for a fluid bed granulation process

The application of process analytical technologies (PAT) to monitor critical quality attributes (CQAs) provides an important approach to enhance process understanding and improve the reliability of pharmaceutical production processes. The present study focuses on the first PAT based feedback control system for a fluid bed granulation batch process. Real-time particle size measurement by in-line spatial filtering technique (SFT) using a modified time-based buffer system was applied to define a target particle size after spraying a specific amount of binder solution. After identifying an appropriate control variable, a suitable strategy for feedback control was established, followed by tuning of the control loop to obtain best performance of the integrated system. By adapting the final target particle size within a specified range good functionality of the system could be demonstrated. Investigations of the robustness further showed that the implemented system enables the production of a predefined target particle size also by varying process and formulation parameters. The effect of increasing spray rates and binder concentrations on the particle size could be compensated in a given range by feedback control ensuring a predefined product quality. The study provides an advanced approach for quality assurance of fluid bed granulation.

Raman spectroscopy in pharmaceutical product design

Almost 100 years after the discovery of the Raman scattering phenomenon, related analytical techniques have emerged as important tools in biomedical sciences. Raman spectroscopy and microscopy are frontier, non-invasive analytical techniques amenable for diverse biomedical areas, ranging from molecular-based drug discovery, design of innovative drug delivery systems and quality control of finished products. This review presents concise accounts of various conventional and emerging Raman instrumentations including associated hyphenated tools of pharmaceutical interest. Moreover, relevant application cases of Raman spectroscopy in early and late phase pharmaceutical development, process analysis and micro-structural analysis of drug delivery systems are introduced. Finally, potential areas of future advancement and application of Raman spectroscopic techniques are discussed.

In-line monitoring of particle size in a fluid bed granulator: investigations concerning positioning and configuration of the sensor

According to the ICH Q8 guideline, analytic technologies (PAT) are important tools for characterization and optimization of pharmaceutical manufacturing processes. Particle size as a critical quality attribute for granules is therefore an important parameter that should be monitored during the fluid bed granulation process. This work focusses on optimizing position and configuration of an SFT-sensor for the in-line measurement of particle size distribution in a Glatt GPCG 3 fluid bed granulator. As model-substances, different grades of microcrystalline cellulose were used. The in-line measured particle size and particle rate in the sensor were evaluated. A sensor position in the deceleration zone of the granulator was found to be promising for in-line particle size measurement. Most reliable data were generated in this position when the probe was placed in a distance of 11cm from the chamber wall to avoid bias by the inlet air stream. No major influence of rotation angle of the probe was found in this position. Furthermore, an entire fluid bed granulation process was successfully monitored with the sensor installed in the optimized setting.