Film Impact Transitions Crack Mac 364 [REPACK]
Conventional solvent-based film coating involves deposition of a thin polymer film on the surface of the tablet core, typically using a spray method. The coating solution or suspension contains polymers and other ingredients such as pigments and plasticizers, which is sprayed onto a rotating tablet bed inside a pan . The drying process is accomplished by passing hot air through the tablet bed and permits removal of the solvent to leave a thin film on the surface of each tablet core . Film formation depends on the physicochemical properties of polymers . Plasticizers are also used to reduce the glass transition temperature (Tg) and increase flexibility to avoid cracking and subsequent peel-off of polymer films . Many coating techniques have been developed for solvent-based or solvent free processes to improve the efficiency of the coating process. However, each method has its own advantages and disadvantages and may require continuous technical refinement. Tablet film coating is a technology-driven process, and the evolution of coated dosage forms depends on advancements in coating technology, equipment, analytical techniques, and coating materials.
film impact transitions crack mac 364
Major challenges in active coating include (1) determining the coating end point to achieve target potency, (2) ensuring tablet-to-tablet API content uniformity, and (3) maximizing coating efficiency (ratio of amount of APIs deposited on core tablets to amount of APIs sprayed) [13,32,87]. During active film coating, tablets are periodically sampled and analyzed for weight gain as well as the amount of API deposited on core tablets using an in-process assay . Based on this in-process assay, additional amounts of coating suspension are further sprayed until the coating end-point is reached to obtain the target potency. When coating conditions, especially spray rate, remain constant during the entire coating process, a linear relationship was observed between the actual API amount deposited on core tablets and coating time [13,32,87]. Control on the spraying operation is also important to ensure the content uniformity in active film coating. Content uniformity is affected by various process variables in the operation including spraying rate, inlet air temperature, residual moisture, pan speed, atomization pressure, and drug properties . Therefore, it is important to understand the factors and coating mechanisms that impact content uniformity .
Various PAT tools have been used to monitor the coating process of solid dosage forms and maintain the high quality of final products. These tools include spectroscopic techniques, imaging techniques, and microscopic techniques: (i) spectroscopic techniques include near-infrared spectrum (NIRS), Raman spectroscopy, and laser-induced breakdown spectroscopy (LIBS); (ii) imaging techniques include terahertz pulse imaging (TPI), near-infrared imaging, and magnetic resonance imaging (MRI); and (iii) microscopic techniques include confocal laser scanning microscope (CLSM), atomic force microscope (AFM), and scanning electron microscope (SEM) . Among spectroscopic techniques, NIRS is one of the most widely used process analysis technologies; it is rapid, non-destructive, and cost-effective. NIRS can be used to analyze the coating thickness, coating end point, and coating uniformity. In addition, it can be used to predict drug release rate in combination with multivariate analysis . NIRS has a disadvantage that the assignment of bands for more complex organic materials is complicated due to the absorption overlap of overtones and combination tones . Raman spectroscopy examining the vibrational transitions in molecules is also applicable for quantitative analysis of the coating process. It can be used for real-time monitoring of drug polymorphic transformation and also determining drug contents, coating thickness, and coating uniformity . Raman spectroscopy is a non-destructive method and requires little or no sample preparation. However, one major disadvantage of Raman spectroscopy is the inherently weak signal intensity, resulting in low sensitivity [110,111]. Furthermore, its application can be limited, particularly in the case of colored samples since interfering luminescence produced in many systems can mask the Raman spectrum . Among imaging techniques, terahertz pulsed imaging (TPI) can be used to investigate the effect of coating equipment on the structure of applied film coatings and subsequent drug release performance . This method allows for rapid image acquisition of samples of different shapes and sizes. It is a powerful tool for assessing pharmaceutical tablet coating quality and process control due to its high measurement precision [113,114]. In addition, it is a noninvasive analytical tool and does not cause thermal damage to the samples. However, it has disadvantages of high cost and low capacity [113,115]. Optical Coherence Tomography (OCT) is also increasingly applied to pharmaceutical film coatings, allowing fast and non-destructive analysis of coating thickness and quality via high-resolution cross-sectional images . Sacher et al.  demonstrated the applicability of OCT in an industrial-scale pan coating process for real time monitoring of tablet coating quality (thickness, homogeneity, and roughness). OCT yields high-resolution images to assess both inter- and intra- tablet coating homogeneity and support active process control .