Abstract Freeze-drying is the preferred method for stabilizing live, attenuated virus vaccines. After decades of research on several aspects of the process like the stabilization and destabilization ...mechanisms of the live, attenuated viruses during freeze-drying, the optimal formulation components and process settings are still matter of research. The molecular complexity of live, attenuated viruses, the multiple destabilization pathways and the lack of analytical techniques allowing the measurement of physicochemical changes in the antigen's structure during and after freeze-drying mean that they form a particular lyophilization challenge. The purpose of this review is to overview the available information on the development of the freeze-drying process of live, attenuated virus vaccines, herewith focusing on the freezing and drying stresses the viruses can undergo during processing as well as on the mechanisms and strategies (formulation and process) that are used to stabilize them during freeze-drying.
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.
Picture of wet granulation module of ConsiGma™-25system. Effect plots showing the influence of process variables (number of kneading elements, barrel temperature, binder addition method, screw speed, ...angle of kneading elements and throughput) on granule (PSD, amount of fines) and tablet (dissolution, percentage drug released after 45min) properties.
The aim of the current study was to screen theophylline (125mg) tablets manufactured via twin screw granulation in order to improve process understanding and knowledge of process variables that determine granule and tablet quality. A premix of theophylline anhydrate, α-lactose monohydrate and PVP (ratio: 30/67.5/2.5,w/w) was granulated with demineralized water. Experiments were done using the high-shear wet granulation module (based on twin screw granulation) of the ConsiGma™-25unit (a continuous tablet manufacturing system) for particle size enlargement. After drying, granules were compressed using a MODUL™ P tablet press (compression force: 10kN, tablet diameter: 12mm). Using a D-optimal experimental design, the effect of several process variables (throughput (10–25kg/h), screw speed (600–950rpm), screw configuration (number (2, 4, 6 and 12) and angle (30°, 60° and 90°) of kneading elements), barrel temperature (25–40°C) and method of binder addition (dry versus wet)) on the granulation process (torque and temperature increase in barrel wall), granule (particle size distribution, friability and flowability) and tablet (tensile strength, porosity, friability, disintegration time and dissolution) quality was evaluated. The results showed that the quality of granules and tablets can be optimized by adjusting specific process variables (number of kneading elements, barrel temperature and binder addition method) during a granulation process using a continuous twin screw granulator.
Summary
What is known and Objective: There is little evidence from well‐designed randomized controlled trials of the impact of community pharmacist intervention on the clinical management of ...patients with type 2 diabetes. It is also not known how sustainable any observed effects on glycaemic control are, over time. This study was initiated to address both these issues.
Methods: A 6‐month, randomized, controlled parallel‐group trial in 66 community pharmacies was conducted in Belgium. Patients were randomly assigned to receive usual pharmacist care (n = 135) or a predefined pharmacist intervention (n = 153). The intervention mainly focused on correct medication use, medication adherence and healthy lifestyle promotion. Primary outcome was glycaemic control, as measured by fasting plasma glucose and HbA1c. Sustainability of changes in glycaemic control was assessed by additional glucose measurements 18 months after the end of the study.
Results and Discussion: The intervention significantly reduced HbA1c (between‐group difference: 0·5%, P = 0.009). The largest impact on HbA1c was observed when pharmacotherapy changes (i.e., type and/or dose of hypoglycaemic agents) initiated by the physician were sustained with pharmaceutical care: HbA1c was reduced by 1·05% in the intervention group, whose medication was changed, compared with a reduction of 0·02% in the therapy‐modification only, group. It was also found that the diabetes education program resulted in improved self‐management and better knowledge of diabetes. Eighteen months after the end of the formal study period, the mean HbA1c of the intervention group did not differ significantly from the control group (7·4% vs. 7·2%).
What is new and Conclusion: This study provides new evidence, from a randomized controlled trial, of the beneficial effect of community pharmacist intervention in the clinical management of type 2 diabetic patients. However, questions remain about the sustainability of the observed improvements.
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This study presents a framework for process and product development on a continuous direct compression manufacturing platform. A challenging sustained release formulation with high ...content of a poorly flowing low density drug was selected. Two HPMC grades were evaluated as matrix former: standard Methocel CR and directly compressible Methocel DC2. The feeding behavior of each formulation component was investigated by deriving feed factor profiles. The maximum feed factor was used to estimate the drive command and depended strongly upon the density of the material. Furthermore, the shape of the feed factor profile allowed definition of a customized refill regime for each material. Inline NIRs was used to estimate the residence time distribution (RTD) in the mixer and monitor blend uniformity. Tablet content and weight variability were determined as additional measures of mixing performance. For Methocel CR, the best axial mixing (i.e. feeder fluctuation dampening) was achieved when an impeller with high number of radial mixing blades operated at low speed. However, the variability in tablet weight and content uniformity deteriorated under this condition. One can therefore conclude that balancing axial mixing with tablet quality is critical for Methocel CR. However, reformulating with the direct compressible Methocel DC2 as matrix former improved tablet quality vastly. Furthermore, both process and product were significantly more robust to changes in process and design variables. This observation underpins the importance of flowability during continuous blending and die-filling. At the compaction stage, blends with Methocel CR showed better tabletability driven by a higher compressibility as the smaller CR particles have a higher bonding area. However, tablets of similar strength were achieved using Methocel DC2 by targeting equal porosity. Compaction pressure impacted tablet properties and dissolution. Hence controlling thickness during continuous manufacturing of sustained release tablets was crucial to ensure reproducible dissolution.
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It was the aim of this study to develop high drug loaded (>30%, w/w), thermoplastic polyurethane (TPU)-based dosage forms via fused deposition modelling (FDM). Model drugs with ...different particle size and aqueous solubility were pre-processed in combination with diverse TPU grades via hot melt extrusion (HME) into filaments with a diameter of 1.75 ± 0.05 mm. Subsequently, TPU-based filaments which featured acceptable quality attributes (i.e. consistent filament diameter, smooth surface morphology and good mechanical properties) were printed into tablets. The sustained release potential of the 3D printed dosage forms was tested in vitro. Moreover, the impact of printing parameters on the in vitro drug release was investigated. TPU-based filaments could be loaded with 60% (w/w) fine drug powder without observing severe shark skinning or inconsistent filament diameter. During 3D printing experiments, HME filaments based on hard TPU grades were successfully converted into personalized dosage forms containing a high concentration of crystalline drug (up to 60%, w/w). In vitro release kinetics were mainly affected by the matrix composition and tablet infill degree. Therefore, this study clearly demonstrated that TPU-based FDM feedstock material offers a lot of formulation freedom for the development of personalized dosage forms.
Characterisation and drug release from ethylene-vinyl acetate matrices.
Different ethylene vinyl acetate grades (EVA9, EVA15, EVA28 and EVA40 having a VA content of 9%, 15%, 28% and 40%, ...respectively) were characterized via differential scanning calorimetry. Glass transition temperature (Tg), polymer crystallinity, melting point and polymer flexibility were positively influenced by the vinyl acetate content. The processability of EVA-based formulations produced by means of hot-melt extrusion (2mm die) was evaluated in function of VA content, extrusion temperature (60–140°C) and metoprolol tartrate (MPT, used as model drug) concentration (10–60%). Matrices containing 50% MPT resulted in smooth-surfaced extrudates, whereas at 60% drug content severe surface defects (shark skinning) were observed. Drug release from EVA/MPT matrices (50/50, w/w) was affected by the EVA grades: 90% after 24h for EVA15 and 28, while EVA9 and EVA40 formulations released 80% and 60%, respectively. Drug release also depended on drug loading and extrusion temperature. For all systems, the total matrix porosity (measured by X-ray tomography) was decreased after dissolution due to elastic rearrangement of the polymer. However, the largest porosity reduction was observed for EVA40 matrices as partial melting of the structure (melt onset temperature: 34.7°C) also contributed (thereby reducing the drug release pathway and yielding the lowest release rate from EVA40 formulations).
The Simulator of the Human Intestinal Microbial Ecosystem (SHIME) used to evaluate the stability of EVA during gastrointestinal transit showed that EVA was not modified during GI transit, nor did it affect the GI ecosystem following oral administration.
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In this work a continuous direct compression process was developed for a low-dosed drug product. Each unit operation of the GEA CDC-50 system was thoroughly investigated. This paper ...aimed to tackle the macroscopic and microscopic blend uniformity challenges inherently associated with continuous direct compression of cohesive and agglomerated APIs formulated at low dose. Density, compressibility and flow were identified as key material properties at the feeding stage. The screw speed coupled with powder flow regulated the gravimetric feeding performance. The impact of process and design variables was elucidated at the blending stage. The impeller configuration (number and pattern of radial mixing blades) and speed were key variables to steer the residence time distribution at the blending stage. An impeller configuration with distributed radial mixing blades could sufficiently filter the steady state feeding variability at low mixer speed, but exerted limited strain and shear on the blend. Hence micro-agglomerates persisted through the blending process and occasionally resulted in super potent tablets. Therefore, a new configuration was evaluated with more radial mixing blades centered on the impeller. This configuration resulted in a long mixing time at high tip speed which induced a maximized strain and shear. Consequently, excellent uniformity of the blend and tablets at macroscopic and microscopic level was achieved. Besides, this impeller improved robustness towards feeding disturbances, changes in process settings and variable blend properties. Next, it was demonstrated that the lubrication step requires critical attention during the design of the equipment, formulation and process. This study provided abundant evidence that an optimized continuous direct compression process allows direct compression of challenging low-dose drug products.
Experimental setup.
The aim of this study was to evaluate the suitability of Raman spectroscopy as a Process Analytical Technology (PAT) tool for the in-line determination of the active ...pharmaceutical ingredient (API) concentration and the polymer–drug solid state during a pharmaceutical hot-melt extrusion process.
For in-line API quantification, different metoprolol tartrate (MPT) – Eudragit® RL PO mixtures, containing 10%, 20%, 30% and 40% MPT, respectively, were extruded and monitored in-line in the die using Raman spectroscopy. A PLS model, regressing the MPT concentrations versus the in-line collected Raman spectra, was developed and validated, allowing real-time API concentration determination. The correlation between the predicted and real MPT concentrations of the validation samples is acceptable (
R
2
=
0.997). The predictive performance of the calibration model is rated by the root mean square error of prediction (RMSEP), which is 0.59%.
Two different polymer–drug mixtures were prepared to evaluate the suitability of Raman spectroscopy for in-line polymer–drug solid state characterization. Mixture 1 contained 90% Eudragit® RS PO and 10% MPT and was extruded at 140
°C, hence producing a solid solution. Mixture 2 contained 60% Eudragit® RS PO and 40% MPT and was extruded at 105
°C, producing a solid dispersion. The Raman spectra collected during these extrusion processes provided two main observations. First, the MPT Raman peaks in the solid solution broadened compared to the corresponding solid dispersion peaks, indicating the presence of amorphous MPT. Second, peak shifts appeared in the spectra of the solid dispersion and solid solution compared to the physical mixtures, suggesting interactions between Eudragit® RS PO and MPT, most likely hydrogen bonds. These shifts were larger in the spectra of the solid solution. DSC analysis confirmed these Raman solid state observations and the interactions seen in the spectra. Raman spectroscopy is a potential PAT-tool for in-line determination of the API concentration and the polymer–drug solid state during pharmaceutical hot-melt extrusion.
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