Browsing by Subject "tabletability"
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(2023)Microcrystalline cellulose (MCC) is a purified, partially depolymerized cellulose, which is obtained by treating α-cellulose with mineral acids. Ever since the first microcrystalline cellulose was commercialized, different grades of microcrystalline cellulose have widely been used in the manufacture of solid dosage forms, such as tablets. MCC obtained from different sources will exhibit different physico-chemical properties, including moisture content, degree of polymerization, crystallinity, and particle morphology. In wet granulation, microcrystalline cellulose can be used as a filler, binder, and disintegrant. Recently, Aalto University has introduced a novel microcrystalline cellulose obtained from renewable raw materials by an integrated process, which has a short retention time, low energy and chemical consumption. However, very few studies have evaluated the use of AaltoCellTM as an excipient in solid dosage forms. The objective of this study was to evaluate the filler properties of three grades of AaltoCellTM to prepare paracetamol tablets with 50% (w/w) drug load and compare AaltoCellTM with a commercial microcrystalline cellulose, Vivapur 101. Due to the poor flowability of paracetamol and the experimental microcrystalline celluloses, it is challenging to direct compress tablets from paracetamol and microcrystalline mixtures. Thus, the powder mixtures were granulated by high-shear wet granulation method to improve the flowability. After the granulation, the formulations were characterized for particle size distribution, morphology and powder flow. Carr’s index Hausner ratio and angle of repose were calculated to evaluate the flowability of the formulations. In addition, an image-based analysis of powder flow was performed. A rotary tablet press equipped with single punches of 9 mm diameter was used to compress tablets. To evaluate the quality of tablets, European Pharmacopoeia tests of friability, disintegration, uniformity of mass, uniformity of content and dissolution were conducted. The AaltoCellTM A and Vivapur 101 formulations had the smallest particle size, whereas the AaltoCellTM B had the largest particle size. According to Carr’s index and Hausner ratio, the flowability of AaltoCellTM powders and Vivapur 101 varied from poor to very, very poor. After the granulation, the flowability of AaltoCellTM B and AaltoCellTM C were classified as good, while AaltoCellTM A and Vivapur 101 formulations had fair flowability. However, the results were conflicting with the flowability index values obtained in the image-based analysis. According to the results, the AaltoCellTM tablets complied with all criteria of European Pharmacopoeia and were comparable with Vivapur 101 tablets. The average tablet weight deviated ± 3.2% from the target weight. The variations in weight and drug content were small, as indicated by low RSD values. The disintegration time of the AaltoCellTM tablets was between 1-8.5 minutes. In addition, the AaltoCellTM tablets had fast dissolution with 78-84% of paracetamol released within 1 minute. Overall, AaltoCellTM is a promising excipient for use as a filler in tablets. In further studies, characterizing the powder properties, such as morphology, surface properties and hygroscopicity, would provide a better understanding of the properties of AaltoCellTM.
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(2017)Twin screw granulation (TSG) has gained considerable interest as a continuous wet granulation method in the pharmaceutical industry and has been studied the most. However, there is still lack of understanding how continuous granulation affects the material compaction behavior even though it has been noticed in several dry and batch wet granulation studies that the granulation process has an influence on the final tablet strength. Thus, studies on the material compactability and tabletability after continuous wet granulation are relevant for the overall understanding of twin screw granulation process and its effect on material behavior in tableting. Hence, the main objective of this study was to investigate the influence of continuous twin screw granulation on the compactability and tabletability of commonly used excipients. Additionally, the impact of binder on the compaction behavior of materials was examined. Furthermore, the suitability of two "loss in compressibility" models i.e. the Unified Compaction Curve (UCC) model and a porosity model to predict the loss in tablet strength after twin screw granulation and for the materials used was assessed. Earlier, the models have been applied to dry and batch wet granulations only. Full factorial design of three variables (binder type, binder addition method and the number of kneading elements) with two levels was conducted for the ConsiGma1 twin screw granulation of formulations containing microcrystalline cellulose (MCC), mannitol or anhydrous dicalcium phosphate (DCPA) as the main excipient and polyvinylpyrrolidone (PVP) or hydroxypropyl cellulose (HPC) as binder. Magnesium stearate was added as lubricant after granulation prior to tableting. In addition to the full factorial design, granulation with PVP, dry binder addition and four kneading elements was repeated for each main excipient. In total this made 27 experiments. The granules were dried and milled after granulation and all the batches were tableted. Additionally, all the formulations were direct compressed in order to be able to detect the change in compactability and tabletability after granulation. Torque of the granulation was determined as well as bulk density and particle size distribution of the granules. Additionally, the tensile strength and porosity of the tablets were analysed. Tabletability and compactability were determined based on the compaction pressure and the obtained tensile strength and porosity values of the tablets. Furthermore, parameters (PWG, TWG and εWG) describing the loss in compressibility models were calculated. MCC experienced loss in compactability and tabletability after twin screw granulation due to hornification effect. On the other hand, the compaction behavior of mannitol improved due to the formation of porous granules. The compactability of DCPA decreased and the tabletability increased. However, the change was only moderate presumably due to brittle nature of DCPA. Additionally, the binder type had an effect of the compaction behavior of the materials, PVP producing stronger tablets compared with the less hydrophilic HPC. However, the binder addition method played only a small role in modifying the compaction behavior. The UCC model was applicable to MCC as loss in tabletability was detected. Thus, the model can be used to predict tablet tensile strength when MCC is granulated with twin screw granulator. Additionally, the UCC model can be used to design the granulation process to achieve a target tensile strength based on small scale preliminary studies thus reducing the resources needed for case-studies. However, the UCC model was not feasible to mannitol and DCPA because they experienced improvement in tabletability after twin screw granulation. The porosity model was applicable to MCC and DCPA but not to mannitol as it showed improvement in compactability. The porosity model described the loss in compactability of MCC only moderately due to lack of tensile strength data points and the linearity of the tensile strength-porosity relationship. However, the model described well the loss in compactability of DCPA at tablet porosities achieved with compaction pressures used in industry. As a conclusion, the results demonstrate that twin screw granulation can have a significant impact on the final tablet strength and that the compaction behavior of the formulation can change either way depending on the used materials. Furthermore, the small influence of the binder addition method on the tablet strength indicates that the time consuming binder dissolving process step can be excluded from the tablet production chain enabling continuous manufacturing with twin screw granulation.
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(2021)Tablet is the most common pharmaceutical dosage form due to ease of administration, chemical and physical stability, and relatively low manufacturing cost. Direct compression is the preferred method for tablet production. Direct compression formulations typically contain a considerable amount of excipients. Therefore, excipients can have a significant effect on the tableting properties of formulations. More research is needed for better comprehension of the compression behaviour of different materials. The objective of this work was to investigate tableting properties of different excipients and their binary mixtures with two different laboratory scale tableting devices; the Gamlen® D1000 Powder Compaction Analyzer and the FlexiTab®. The excipients used were microcrystalline cellulose (MCC), lactose, mannitol, starch, and dicalcium phosphate (DCP). Different compression pressures were used to survey the compression behaviour of the excipients at a wide pressure range. In addition, potential effects of compression speed, dwell time, and lubrication method were considered. The excipients and their binary mixtures were characterised based on compressibility (solid fraction vs. compression pressure) and tabletability (tensile strength vs. compression pressure). The results obtained with the devices were compared to enhance process understanding. Based on the compressibility curves, it appeared that plastic deformation was the main compression mechanism of MCC and starch and fragmentation the main compression mechanism of lactose, mannitol, and DCP. The tabletability of MCC was excellent, and also the tabletability of mannitol was good. The tabletability of DCP was intermediate, whereas lactose and starch had inferior tabletabilities. In general, the tabletabilities and compressibilities of the binary mixtures were more or less what was expected based on the results of the individual materials. The results obtained with the different speed parameters and lubrication methods were mainly in line with the perceptions of the compression mechanisms of different materials. In overall, the results obtained in the Gamlen and FlexiTab experiments were quite similar. However, tensile strengths appeared generally slightly lower in the FlexiTab experiments. Probable explanations are the higher compression speed of the FlexiTab and differences in hardness measurements. This study indicated that the FlexiTab and Gamlen devices have different benefits. The Gamlen device is clearly very suitable for investigating tableting properties during formulation development, but the FlexiTab device has the advantages of higher compression speed and automatic powder feeding mechanism. Tabletability results were slightly better with the Gamlen, but more experiments are needed for solving the reasons (e.g. compression speed and hardness measurements). More information of the compression behaviour of different materials could be obtained by analyzing punch displacement data and by using different compression equations.
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