A compressibility and compactibility study of real tableting mixtures: The impact of wet and dry granulation versus a direct tableting mixture

Sample Size Requirements of a Pharmaceutical Material Library: A Case in Predicting Direct Compression Tablet Tensile Strength by Latent Variable Modeling

The material library is an emerging, new data-driven approach for developing pharmaceutical process models. How many materials or samples should be involved in a particular application scenario is unclear, and the impact of sample size on process modeling is worth discussing. In this work, the direct compression process was taken as the research object, and the effects of different sample sizes of material libraries on partial least squares (PLS) modeling in the prediction of tablet tensile strength were investigated. A primary material library comprising 45 materials was built. Then, material subsets containing 5 × i (i = 1, 2, 3, …, 8) materials were sampled from the primary material library. Each subset underwent sampling 1000 times to analyze variations in model fitting performance. Both hierarchical sampling and random sampling were employed and compared, with hierarchical sampling implemented with the help of the tabletability classification index d. For each subset, modeling data were organized, incorporating 18 physical properties and tableting pressure as the independent variables and tablet tensile strength as the dependent variable. A series of chemometric indicators was used to assess model performance and find important materials for model training. It was found that the minimum R2 and RMSE values reached their maximum, and the corresponding values were kept almost unchanged when the sample sizes varied from 20 to 45. When the sample size was smaller than 15, the hierarchical sampling method was more reliable in avoiding low-quality few-shot PLS models than the random sampling method. Two important materials were identified as useful for building an initial material library. Overall, this work demonstrated that as the number of materials increased, the model's reliability improved. It also highlighted the potential for effective few-shot modeling on a small material library by controlling its information richness.

Cylindrical granules in the development of mesalazine solid formulations (Ⅱ): The contribution of high aspect ratio to favorable tabletability

Recently, cylindrical granules have been applied in pharmaceutical fields and their aspect ratio (AR) is considered an important factor in the manufacturing process. However, the relationships between AR and the tableting process were seldom reported. This study aims to clarify the role of AR in the tableting process of cylindrical granules. First, mesalazine cylindrical granules with different AR were extruded, and their physical attributes were then comprehensively characterized. Subsequently, their compression behaviors and tableting performances were systematically assessed. Notably, it was found that the cylindrical granules with high AR possessed good anti-deformation capacity and favorable tabletability. Finally, the dissolution test suggested that tablets compressed from cylindrical granules with higher AR showed lower dissolution rates. Collectively, findings in this study identified that the AR of cylindrical granules was a critical factor in the tableting process and provided valuable guidance for the application of these granules in oral solid formulations.

Optimization of Pregelatinized Taro Boloso-I Starch as a Direct Compression Tablet Excipient

Background. Tablets are still the most preferred means of drug delivery. The search for new and improved direct compression tablet excipients is an area of research focus. This is because the direct compression method overcomes the drawbacks of granulation methods of tablet production. It exempts several treatment steps associated with the granulation methods. The requirements for the powders to be directly compressible include flowability, low friction tendency, compressibility, and fast disintegration capacity. Taro Boloso-I is a new variety of Colocasia esculenta (L. Schott) yielding 67% more than a previously reported variety (Godare) in Ethiopia. This study is aimed at enhancing the flowability while keeping the compressibility and compactibility of the pregelatinized Taro Boloso-I starch. Methods. Central composite design was used for the optimization of two factors which were the temperature and duration of pregelatinization against 4 responses. The responses were angle of repose, Hausner’s ratio, Heckel’s yield pressure, and tablet breaking force. Results and Discussions. An increase in the temperature resulted in decrease in both the angle of repose and the Hausner ratio and that of time decreased angle of repose as well. The Heckel yield pressure was observed to increase with increasing levels of both temperature and time. The pregelatinized starch prepared by heating 15% slurry of Taro Boloso-I starch at the pregelatinization temperature of 66.22°C for 20 min showed desired flow property and compressibility. Conclusions. Pregelatinized Taro Boloso-I starch could be regarded as a potential direct compression excipient in terms of flowability, compressibility, and compactibility. The PGTBIS could perform better as filler and binder in direct compression tablets than the Starch 1500® in terms of compactibility.

Surface Modifiers on Composite Particles for Direct Compaction

Direct compaction (DC) is considered to be the most effective method of tablet production. However, only a small number of the active pharmaceutical ingredients (APIs) can be successfully manufactured into tablets using DC since most APIs lack adequate functional properties to meet DC requirements. The use of suitable modifiers and appropriate co-processing technologies can provide a promising approach for the preparation of composite particles with high functional properties. The purpose of this review is to provide an overview and classification of different modifiers and their multiple combinations that may improve API tableting properties or prepare composite excipients with appropriate co-processed technology, as well as discuss the corresponding modification mechanism. Moreover, it provides solutions for selecting appropriate modifiers and co-processing technologies to prepare composite particles with improved properties.

Understanding the Multidimensional Effects of Polymorphism, Particle Size and Processing for D-Mannitol Powders

The relevance of the polymorphic form, particle size, and processing of mannitol for the mechanical properties of solid oral dosage forms was examined. Thus, particle and powder properties of spray granulated β D-mannitol, β D-mannitol, and δ D-mannitol were assessed in this study with regards to their manufacturability. D-mannitol is a commonly used excipient in pharmaceutical formulations, especially in oral solid dosage forms, and can be crystallized as three polymorphic forms, of which β is the thermodynamically most stable form and δ is a kinetically stabilized polymorph. A systematic analysis of the powders as starting materials and their respective roller compacted granules is presented to elucidate the multidimensional effects of powder and granules characteristics such as polymorphic form, particle size, and preprocessing on the resulting tablets’ mechanical properties. In direct compression and after roller compaction, δ polymorph displayed superior tableting properties over β mannitol, but was outperformed by spray granulated β mannitol. This could be primarily correlated to the higher specific surface area, leading to higher bonding area and more interparticle bonds within the tablet. Hence, it was shown that surface characteristics and preprocessing can prevail over the impact of polymorphism on manufacturability for oral solid dosage forms.

Evaluation of the Formulation Parameter-Dependent Redispersibility of API Nanoparticles from Fluid Bed Granules

The production of nanosuspensions of poorly soluble active pharmaceutical ingredients (API) is a popular technique to counteract challenges regarding bioavailability of such active substances. A subsequent drying of the nanosuspensions is advantageous to improve the long-term stability and the further processing into solid oral dosage forms. However, associated drying operations are critical, especially with regard to nanoparticle growth, loss in redispersibility and associated compromised bioavailability. This work extends a previous study regarding the applicability of an API (itraconazole) nanosuspension as a granulation liquid in a fluidized bed process with focus on the influence of applied formulation parameters on the structure of obtained nanoparticle-loaded granules and their nanoparticle redispersibility. Generally, a higher dissolution rate of the carrier material (glass beads, lactose, mannitol or sucrose) and a higher content of a matrix former/hydrophilic polymer (PVP/VA or HPMC) in the granulation liquid resulted in the formation of coarser and more porous granules with improved nanoparticle redispersibility. HPMC was found to have advantages as a polymer compared with PVP/VA. In general, a better redispersibility of the nanoparticles from the granules could be associated with better dispersion of the API nanoparticles at the surface of the granules as deduced from the thickness of nanoparticle-loaded layers around the granules. The layer thickness on granules was assessed by means of confocal Raman microscopy. Finally, the dispersion of the nanoparticles in the granule layers was exemplarily described by calculation of theoretical mean nanoparticle distances in the granule layers and was correlated with data obtained from redispersibility studies.

The effect of granules characters on mechanical properties of press-coated tablets: A comparative study

The aim of this study was to investigate the correlation between critical granules characters (including particle size, surface roughness, and apparent porosity) and mechanical properties of press-coated tablets. Granules of a model formulation were prepared through Roll Compaction Granulation (RCG), High Shear Granulation (HSG), and Fluidized Bed Granulation (FBG) to prepare granules with different surface roughness and apparent porosity. The surface roughness and porosity of granules had a significantly greater effect on mechanical properties than the particle size of granules. Whether for brittle or plastic materials, FBG granules with the roughest surface and the greatest apparent porosity exhibited the best compression properties. The elastic recovery test, the interlayer adhesion forces study, the break pattern test, and the X-ray microcomputed tomography investigation suggested that granules with great apparent porosity and rough surfaces could contribute to the production of stable press-coated structures. Moreover, for press-coated tablets prepared using granules, the proper granules in the coat layer could eliminate the side effect of the rigid core on the mechanical strength. The above understandings will be conducive to the selection of compatible and appropriate granules characters, which can enhance mechanical properties and extend the application of press-coated tablets.

Streamlining tablet lubrication design via model-based design of experiments

In oral solid dosage production through direct compression powder lubrication must be carefully selected to facilitate the manufacturing of tablets without degrading product manufacturability and quality (e.g. dissolution). To do so, several semi-empirical models relating compression performance to process operating conditions have been developed. Among them, we consider an extension of the Kushner and Moore model (Kushner and Moore, 2010, International Journal Pharmaceutics, 399:19) that is useful for the purpose, but requires an extensive experimental campaign for parameters identification. This implies the preparation and compression of multiple powder blends, each one with a different lubrication extent. In turn, this translates into a considerable consumption of Active Pharmaceutical Ingredient (API), and into time-consuming experiments. We tackled this issue by proposing a novel model-based design of experiments (MBDoE) approach, which minimizes the number of optimal blends for model calibration, while obtaining statistically sound parameters estimates and model predictions. Both sequential and parallel MBDoE configurations were compared. Experimental results involving two placebo blends with different lubrication sensitivity showed that this methodology is able to reduce the experimental effort by 60-70% with respect to the standard industrial practice independently of the formulation considered and configuration (i.e. parallel vs. sequential) adopted.

Improving Tableting Performance of Lactose Monohydrate by Fluid-Bed Melt Granulation Co-Processing

Co-processing is commonly used approach to improve functional characteristics of pharmaceutical excipients to become suitable for tablet production by direct compression. This study aimed to improve tableting characteristics of lactose monohydrate (LMH) by co-processing by fluid-bed melt granulation with addition of hydrophilic (PEG 4000 and poloxamer 188) and lipophilic (glyceryl palmitostearate) meltable binders. In addition to binding purpose, hydrophilic and lipophilic excipients were added to achieve self-lubricating properties of mixture. Co-processed mixtures exhibit superior flow properties compared to pure LMH and comparable or better flowability relative to commercial excipient Ludipress^®. Compaction of mixtures co-processed with 20% PEG 4000 and 20% poloxamer 188 resulted in tablets with acceptable tensile strength (>2 MPa) and good lubricating properties (ejection and detachment stress values below 5 MPa) in a wide range of compression pressures. While the best lubricating properties were observed when glyceryl palmitostearate was used as meltable binder, obtained tablets failed to fulfil required mechanical characteristics. Although addition of meltable binder improves interparticle bonding, disintegration time was not prolonged compared to commercial excipient Ludipress^®. Co-processed mixtures containing 20% of either PEG 4000 or poloxamer 188 showed superior tabletability and lubricant properties relative to LMH and Ludipress^® and can be good candidates for tablet production by direct compression.

Manufacturability and Properties of Granules and Tablets Using the Eco-Friendly Granulation Method Green Fluidized Bed Granulation Compared to Direct Compression

This study aimed to compare the manufacturability and granule and tablet properties of green fluidized bed granulation (GFBG) and of direct compression (DC). Acetaminophen was used as a low compactability model drug. The process time of GFBG to produce final mixtures was comparable to that of DC, and thus GFBG could be considered a simple process. DC could not produce 30% drug load tablets owing to poor granule flowability, whereas no problems were observed in the GFBG tableting process up to 80% of drug load. Tablets prepared with GFBG showed higher tensile strength than those prepared using DC. Compactability evaluation results show that the yield pressure of the granules prepared with GFBG was significantly lower than that of DC, suggesting that the granules prepared with GFBG were easily plastically deformed. Moreover, tablets prepared with GFBG showed fast disintegration, which was faster than that of DC. We conclude that GFBG produces granules with higher drug content and desired physicochemical properties at low cost.

Enhancing the Poor Flow and Tableting Problems of High Drug-Loading Formulation of Canagliflozin Using Continuous Green Granulation Process and Design-of-Experiment Approach

Maximization of drug-loading can significantly reduce the size of dosage form and consequently decrease the cost of manufacture. In this research, two challenges were addressed: poor flow and tableting problems of high-drug loading (>70%) formulation of canagliflozin (CNG), by adopting the moisture-activated dry granulation (MADG) process. In this method, heating and drying steps were omitted so, called green granulation process. A 3² full-factorial design was performed for optimization of key process variables, namely the granulation fluid level (X₁) and the wet massing time (X₂). Granulation of CNG was carried out in the presence of polyvinylpyrrolidone, and the prepared granules were compressed into tablets. Regression analysis demonstrated the significant (p ≤ 0.05) effect of X₁ and X₂ on properties of granules and corresponding tablets, with pronounced impact of X₁. Additionally, marked improvement of granules’ properties and tableting of CNG were observed. Furthermore, the optimized process conditions that produced good flow properties of granules and acceptable tablets were high level of granulation fluid (3.41% w/w) and short wet massing time (1.0 min). Finally, the MADG process gives the opportunity to ameliorate the poor flow and tableting problems of CNG with lower amounts of excipients, which are important for successful development of uniform dosage unit.

An Investigation into the Influence of Process Parameters and Formulation Variables on Compaction Properties of Liquisolid Systems

Liquisolid technology, as a promising approach for bioavailability enhancement, has received increasing attention in recent years. However, literature reports addressing the challenges for its industrial application, particularly those related to compaction behavior of liquisolid systems, are scarce. The aim of this study was to investigate the influence of process parameters and formulation variables on the flowability, wetting, and compaction properties of the liquisolid systems prepared in a fluid bed processor. The experiments with microcrystalline cellulose, as a carrier, were performed according to 2³ full factorial design. The effects of liquid content, spray air pressure, and liquid feed rate on the properties of liquisolid systems were investigated. Liquisolid admixtures with microcrystalline cellulose were compared with those prepared with novel carriers, Fujicalin^® and Neusilin^® US2. "Out-die" Heckel, modified Walker, and Kuentz-Leuenberger models were used to analyze the compressibility of liquisolid admixtures. The results obtained showed that an increase in liquid content (in the range of 10 to 15%) led to a decrease in flowability of liquisolid admixtures with microcrystalline cellulose, as well as more pronounced influence of spraying conditions. On the other hand, higher liquid content led to higher compressibility. Fujicalin^® and Neusilin^® US2 liquisolid admixtures were found to have superior flowability and compressibility in comparison with those with microcrystalline cellulose, despite the considerably higher liquid load (50-55% liquid content in Neusilin^® US2 compacts). Acceptable compactibility of the investigated liquisolid systems was observed. The fluid bed processor was shown to be suitable equipment for production of liquisolid systems, but with careful adjustment of process parameters.

High-Molecular-Weight Hypromellose from Three Different Suppliers: Effects of Compression Speed, Tableting Equipment, and Moisture on the Compaction

Use of higher tableting speeds is gaining increasing importance for pharmaceutical industry. There is a profound lack of new studies of mechanical properties of hypromellose, and none of them evaluate different suppliers. Thus, the objective of this study was to investigate flow and compaction properties of different grades of hypromellose (type 2208) from three different suppliers, with particular focus on the effect of the compression speed. The flow properties were determined using flow time, shear cell, Carr index, and constant B from initial part of Heckel profile. Compaction properties were quantified using "out-of-die" Heckel, Walker, and Kuentz-Leuenberger models; two tensile strength profiles (tabletability and compactibility); and elastic recovery. Compaction was performed by both an instrumented single-punch press and a high-speed rotary press simulator. Due to larger, rounder, and smoother particles, both Methocel™ DC grades together with Benecel™ K4M showed better flow properties compared with other materials, with Metolose® K100M having the worst flow. Overall, Benecel™ K100M and Metolose® K100M showed the best compaction properties, closely followed by Metolose® K4M. Heckel analysis showed the highest compressibility of Benecel™ K100M, followed by both Methocel™ DC grades. Kuentz-Leuenberger model showed to have no practical superiority in comparison with Heckel model in the compression pressure range used. Results of strain rate sensitivity showed that Methocel™ K4M DC was the least susceptible to change of tableting speed, followed by Methocel™ K100M DC and both grades of Benecel™, and in contrast, both grades of Metolose® were the most sensitive. Effect of moisture on compaction was also studied.

The Fundamental and Functional Property Differences Between HPMC and PVP Co-Processed Herbal Particles Prepared by Fluid Bed Coating

Core-shell composite particles (CPs) are the most preferred choice for direct compaction (DC), but their application in herbal tablets is limited. Hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) are usually employed as the shell materials, but there are few, if any, researches exploring the different effects of HPMC and PVP on the properties of herbal CPs. In this study, the CPs containing HPMC (CP X-H) and CPs containing PVP (CP X-P) were prepared based on herbal powders (X). Their physical properties were characterized comprehensively. The differences in properties between CP X-H and CP X-P were explored, and their mechanism analysis was also performed profoundly. The results demonstrated that (i) CP X-H and CP X-P exhibited similar flowability; (ii) CP X-H generally exhibited better compactibility, larger particle size, and more uniform particle size distribution, and lower bulk density, tap density, and hygroscopicity than CP X-P; (iii) compared with the tablets produced with CP X-P, ones with CP X-H exhibited similar weight variation (%), lower friability, and longer disintegration time. The mechanism analysis manifested that the differences in physical properties between HPMC and PVP were the important and fundamental factors, which led to the differences in structure and surface morphology of particles, and in fundamental properties of CPs. These findings are beneficial to the development of herbal core-shell CPs for DC.

Influence of Formulation Parameters on Redispersibility of Naproxen Nanoparticles from Granules Produced in a Fluidized Bed Process

The particle size reduction of active pharmaceutical ingredients is an efficient method to overcome challenges associated with a poor aqueous solubility. With respect to stability and patient's convenience, the corresponding nanosuspensions are often further processed to solid dosage forms. In this regard, the influence of several formulation parameters (i.e., type of carrier material, type and amount of additional polymeric drying excipient in the nanosuspension) on the redispersibility of naproxen nanoparticle-loaded granules produced in a fluidized bed process was investigated. The dissolution rate of the carrier material (i.e., sucrose, mannitol, or lactose) was identified as a relevant material property, with higher dissolution rates (sucrose > mannitol > lactose) resulting in better redispersibility of the products. Additionally, the redispersibility of the product granules was observed to improve with increasing amounts of polymeric drying excipient in the nanosuspension. The redispersibility was observed to qualitatively correlate with the degree of nanoparticle embedding on the surface of the corresponding granules. This embedding was assumed to be either caused by a partial dissolution and subsequent resolidification of the carrier surface dependent on the dissolution rate of the carrier material or by resolidification of the dissolved polymeric drying excipient upon drying. As the correlation between the redispersibility and the morphology of the corresponding granules was observed for all investigated formulation parameters, it may be assumed that the redispersibility of the nanoparticles is determined by their distance in the dried state.

Formulation, Development and Scale-Up of Fixed-Dose Combination Tablets Containing Zidovudine, Lamivudine and Nevirapine

Background:

The development of antiretroviral associations in a single dosage form aims to ensure improved efficacy, low costs and better adherence to treatment.

Objective:

This work performed the pharmacotechnical development, coating, and stability studies of fixed-dose combination tablets of zidovudine, lamivudine and nevirapine (300 + 200 + 150 mg, respectively).

Methods:

Qualitative and quantitative planning of diluents (101 and 250 microcrystalline cellulose, spray-dried monohydrate lactose and corn starch) and coating polymers (Opadry white II HP® and Instacoat Aqua Moistshield II®) were analyzed, and direct compression (DC) and wet granulation (WG) methods were tested aiming the development of the pharmaceutical form. Quality control was carried out according to the specifications set by official compendia. The chosen formulation was scaled-up and the industrial batches were submitted to accelerated and long-term stability studies.

Results:

The batches obtained by WG met the requirements, using 101 microcrystalline cellulose, corn starch and Opadry white II HP® as excipients. The DC trial was not possible due to the need of a greater ratio of excipients to improve formulation properties.

Conclusion:

Thus, this study brings a new therapeutic alternative for HIV treatment, contributing to the development of another possibility to simplify drug administration.

A compression behavior classification system of pharmaceutical powders for accelerating direct compression tablet formulation design

In this paper, a compression behavior classification system (CBCS) for direct compression (DC) pharmaceutical powders is presented. Seven descriptors from a series of compression models for powder compressibility, compactibility and tabletability analysis were included in the CBCS. A new tabletability index d was proposed to differentiate three categories of tensile strength (TS) vs. pressure relationships, and its physical meaning was explained thoroughly. 130 materials containing diverse pharmaceutical excipients and natural product powders (NPPs) were fully characterized and were compiled into an in-house developed material library, in which 70 materials with potential DC applications were used to justify the effectiveness of the CBCS. Principle component analysis (PCA) was used to uncover the latent structure of compression variables. Moreover, partial least squares (PLS) regression models are established in prediction of both tablet TS and solid fraction (SF) based on the raw materials' physical characteristics, the compression behavior indices and the compression force. The obtained scores and loadings are used to group the materials and the compression variables, respectively. Different categories of tabletability for DC powders were clearly clustered along two orthogonal directions pointing to the index d and the compression force. Finally, a multi-objective design space was identified under the latent variable space, summarizing the operationally possible region for both material properties and compression pressure required in DC tablet formulation design.

Use of roller compaction and fines recycling process in the preparation of erlotinib hydrochloride tablets

This study focuses on improving the manufacturing process for a generic immediate-release tablet containing erlotinib hydrochloride by adding a fines recycling process during roller compaction. Due to the large fraction of small-sized API particles, the starting powder mixture was inconsistently fed into the roller compactor. Consequently, poorly flowing granules with a high ratio of fines were produced. A fines recycling step was, therefore, added to the existing roller compaction process to minimize the risks caused by the poor granule flow. A laboratory scale roller compactor and a tablet simulator were used to prepare granules at various process conditions. The effect of dry granulation parameters on size distribution, API distribution, powder flow, compaction properties, and dissolution profile was evaluated. The granule batch after fines recycling had markedly improved size distribution and flowability while maintaining acceptable tablet tensile strength and rapid dissolution profile. The application of the fines recycling process at commercial scale resulted in reliable dissolution performance and batch-to-batch consistency, which were further confirmed by bioequivalence to the reference product. Understanding how granule properties are impacted by the fines recycling process may enable fine-tuning of the dry granulation process for optimal product quality.

Performance Characteristics of a Novel Vibration Technique for the Densification of a Powder Bed within a Die of a Rotary Tablet Press - a Proof of Concept

The aim of this study was to investigate the concept of lower punch vibration as a possible approach to densify the powder bed within the die of a rotary tablet press. Therefore, a laboratory vibration equipment was developed to obtain a better understanding of the performance characteristics and effects of a pneumatically generated vibration system on pharmaceutical powders. For this purpose, two widely used pharmaceutical powders, basic magnesium carbonate (Pharmagnesia MC Type F) and microcrystalline cellulose (Ceolus® KG1000), both with different physical properties, were investigated. The powders were characterized by laser diffraction, scanning electron microscopy, helium pycnometry, ring shear testing, gas adsorption, and by determination of the powder flowability. Furthermore, the extent of densification within the die during vibration was visualized by a high-speed camera system and analyzed by an image-analyzing software. It was observed that lower punch vibration was able to densify the powder bed to a sufficient extent and within an adequate time period. Consequently, the presented results revealed that lower punch vibration may be a promising technique to remove entrapped air from powder beds, thus obtaining a denser powder bed within the die, which might potentially improve the tableting process and prevent complications during tablet manufacture.

Influence of spray nozzle aperture during high shear wet granulation on granule properties and its compression attributes

The distribution of granulating liquid is known to affect the high shear wet granulation process but the impact of the spray nozzle attributes is still unclear. While homogenous liquid distribution can be achieved by using a spray nozzle, the effect of different nozzle aperture sizes on granule properties is not well understood. In this study, nozzles of different aperture sizes were used to introduce the granulating liquid in high shear wet granulation using different process parameters. Design of experiment approach was utilised to assess effect of process parameters on granule properties. Granules produced with different spray nozzles were evaluated for binder distribution inhomogeneity, size, shape, flowability and compression attributes such as tabletability and yield pressure. Coarser granules with better flow properties were produced using the smaller aperture size nozzle. On the other hand, granules had better tabletability and lower yield pressure when larger aperture size nozzle was used. Furthermore, size of granules produced by using larger aperture size nozzle was more affected by changes in the process variables which could be influenced by the differences in granulating liquid feed rate and spray droplet size. Although the granules aspect ratios were comparable across the nozzle aperture sizes, granules produced from smaller aperture size nozzle appeared to be rounder. Regardless of the nozzle aperture sizes, homogenous binder distribution was achieved. The findings from this study could be a useful guide to the selection of the appropriate nozzle aperture size in wet granulation.

Oral Modified Release Multiple-Unit Particulate Systems: Compressed Pellets, Microparticles and Nanoparticles

Oral modified-release multiparticulate dosage forms, which are also referred to as oral multiple-unit particulate systems, are becoming increasingly popular for oral drug delivery applications. The compaction of polymer-coated multiparticulates into tablets to produce a sustained-release dosage form is preferred over hard gelatin capsules. Moreover, multiparticulate tablets are a promising solution to chronic conditions, patients’ adherence, and swallowing difficulties if incorporated into orodispersible matrices. Nonetheless, the compaction of multiparticulates often damages the functional polymer coat, which results in a rapid release of the drug substance and the subsequent loss of sustained-release properties. This review brings to the forefront key formulation variables that are likely to influence the compaction of coated multiparticulates into sustained-release tablets. It focusses on the tabletting of coated drug-loaded pellets, microparticles, and nanoparticles with a designated section on each. Furthermore, it explores the various approaches that are used to evaluate the compaction behaviour of particulate systems.

High-shear granulation of high-molecular weight hypromellose: effects of scale-up and process parameters on flow and compaction properties

CONTEXT

Knowledge of the effects of high-shear granulation process parameters and scale-up on the properties of the produced granules is essential for formulators who face challenges regarding poor flow and compaction during development of modified release tablets based on high-molecular weight hypromellose (hydroxypropylmethylcellulose (HPMC)) polymers. Almost none of the existing studies deal with realistic industrial formulation.

OBJECTIVE

The aim was to investigate the effects of scale-up and critical process parameters (CPPs) of high-shear granulation on the quality attributes of the granules, particularly in terms of the flow and compaction, using a realistic industrial formulation based on HPMC K100M polymer.

METHODS

The flow properties were determined using flow time, Carr index, tablet mass, and crushing strength variations. The compaction properties were quantified using the 'out-of-die' Heckel and modified Walker models, as well as the tensile strength profile and elastic recovery. High-shear granulation was performed at different scales: 4 L, 300 L, and 600 L.

RESULTS AND CONCLUSION

The scale itself had larger effects on the granule properties than the CPPs, which demonstrated high robustness of formulation on the individual scale level. Nevertheless, to achieve the desired flow and compaction, the values of the CPPs need to be precisely selected to fine-tune the process conditions. The best flow was achieved at high volumes of water addition, where larger and more spherical granules were obtained. The CPPs showed negligible influence on the compaction with no practical implications, however, the volume of water addition volume was identified as having the largest effects on compaction.

Use of Mixer Torque Rheometer to Clarify the Relationship between the Kneading States of Wet Mass and the Dissolution of Final Product in High Shear Granulation

The properties of wet mass, which indicate the progress of high shear granulation processes, usually have an effect on final product properties, such as tablet dissolution. The mixer torque rheometer (MTR) is a useful tool for quantitatively measuring the 'kneading state' of wet mass and detecting differences in granules. However, there have been no studies of the relationship between the MTR torque and the final product properties to date. In this study, we measured the MTR torque of wet granules at different kneading states, which were prepared by changing the granulation conditions. We then evaluated the relationship between the MTR torque and the dissolution rate of the final product properties. The amperage of the high shear granulator is usually monitored during granulation, but we could not detect a difference in the kneading state through the amperage. However, using MTR torque we were able to quantify the difference of the wet mass. Moreover, MTR torque showed a high correlation with dissolution, compared with the correlations with other intermediate properties, such as granules particle size and tablet hardness. These other properties are affected by following processes and are not properties that directly relate to the kneading state. Thus, MTR torque is a property of wet mass after granulation, and it can be used to directly evaluate differences of the kneading state, and as a result, dissolution. These results indicate the importance of controlling the kneading state, i.e., the progress of granulation, and the utility of MTR for detecting differences in wet mass.

Development and Optimization of a Starch-Based Co-processed Excipient for Direct Compression Using Mixture Design

The development of novel excipients with enhanced functionality has been explored using particle engineering by co-processing. The aim of this study was to improve the functionality of tapioca starch (TS) for direct compression by co-processing with gelatin (GEL) and colloidal silicon dioxide (CSD) in optimized proportions. Design of Experiment (DoE) was employed to optimize the composition of the co-processed excipient using the desirability function and other supporting studies as a basis for selecting the optimized formulation. The co-processed excipient (SGS) was thereafter developed by the method of co-fusion. Flow and compaction studies of SGS were carried out in comparison to its parent component (TS) and physical mixture (SGS-PM). Tablets were prepared by direct compression (DC) containing ibuprofen (200 mg) as a model for poor compressibility using SGS, Prosolv®, and StarLac® as multifunctional excipients. The optimized composition of SGS corresponded to TS (90%), GEL (7.5%), and CSD (2.5%). The functionality of SGS was improved relative to SGS-PM in terms of flow and compression. Tablets produced with SGS were satisfactory and conformed to USP specifications for acceptable tablets. SGS performed better than Prosolv® in terms of disintegration and was superior to StarLac with respect to tensile strength and disintegration time. The application of DoE was successful in optimizing and developing a starch-based co-processed excipient that can be considered for direct compression tableting.

On the die compaction of powders used in pharmaceutics

Die compaction is widely used in the compaction of pharmaceutical powders (tableting). It is well known that the powder densification is a result of particle rearrangement and particle deformation. The former is considered to be the governing mechanism of densification in an initial stage of compaction and the latter is regarded as the governing mechanism in the compaction at the higher pressure range. As a more realistic assumption, one can consider that a simultaneous performance of both the rearrangement and deformation mechanisms takes place from the beginning of compaction. To mathematically formulate this assumption, a piston equation is presented where the material relative density is given as a function of the applied pressure on the powder. From the equation, it is possible to obtain the contribution of each mechanism to the material densification at each value of the applied pressure. In the continuation, the piston equation is applied to the tabletting of some pharmaceutical powders. These are the powders of Ascorbic Acid, Avicel^® PH 101, Avicel^® PH 301, Emcompress^®, Sodium Chloride, and Tablettose^® whose tableting results have been previously published in the literature. The results show the piston equation as a suitable approach to describe the tabletting of pharmaceutical powders.

New gentle-wing high-shear granulator: impact of processing variables on granules and tablets characteristics of high-drug loading formulation using design of experiment approach

The aim of this work was to study the application of design of experiment (DoE) approach in defining design space for granulation and tableting processes using a novel gentle-wing high-shear granulator. According to quality-by-design (QbD) prospective, critical attributes of granules, and tablets should be ensured by manufacturing process design. A face-centered central composite design has been employed in order to investigate the effect of water amount (X₁), impeller speed (X₂), wet massing time (X₃), and water addition rate (X₄) as independent process variables on granules and tablets characteristics. Acetaminophen was used as a model drug and granulation experiments were carried out using dry addition of povidone k30. The dried granules have been analyzed for their size distribution, density, and flow pattern. Additionally, the produced tablets have been investigated for; weight uniformity, breaking force, friability and percent capping, disintegration time, and drug dissolution. Results of regression analysis showed that water amount, impeller speed and wet massing time have significant (p < .05) effect on granules and tablets characteristics. However, the water amount had the most pronounced effect as indicated by its higher parameter estimate. On the other hand, water addition rate showed a minimal impact on granules and tablets properties. In conclusion, water amount, impeller speed, and wet massing time could be considered as critical process variables. Thus, understanding the relationship between these variables and quality attributes of granules and corresponding tablets provides the basis for adjusting granulation variables in order to optimize product performance.

Implementation of quality by design approach in manufacturing process optimization of dry granulated, immediate release, coated tablets - a case study

The aim of this study was to optimize the process of tablets compression and identification of film-coating critical process parameters (CPPs) affecting critical quality attributes (CQAs) using quality by design (QbD) approach. Design of experiment (DOE) and regression methods were employed to investigate hardness, disintegration time, and thickness of uncoated tablets depending on slugging and tableting compression force (CPPs). Plackett-Burman experimental design was applied to identify critical coating process parameters among selected ones that is: drying and preheating time, atomization air pressure, spray rate, air volume, inlet air temperature, and drum pressure that may influence the hardness and disintegration time of coated tablets. As a result of the research, design space was established to facilitate an in-depth understanding of existing relationship between CPPs and CQAs of intermediate product (uncoated tablets). Screening revealed that spray rate and inlet air temperature are two most important factors that affect the hardness of coated tablets. Simultaneously, none of the tested coating factors have influence on disintegration time. The observation was confirmed by conducting film coating of pilot size batches.

Effects of Manufacturing Methods on Dissolution and Absorption of Ketoconazole in the Presence of Organic Acid as a pH Modifier

Poorly water-soluble compounds have a potential risk of low and variable bioavailability caused by incomplete dissolution. Incorporation of organic acids as pH modifiers is effective method for solubility enhancement of basic compounds and requires no special technique and equipment. The purpose of this study was to evaluate the effect of manufacturing method on the extent of drug solubility enhancement. We successfully prepared the granules and tablets containing ketoconazole (KZ), which is weakly basic, as a model compound and citric acid as a pH modifier using conventional wet and dry granulations. KZ solubility under non-sink condition was enhanced with supersaturation using both wet and dry granulations. High-shear granulation was the most effective method in terms of KZ dissolution enhancement, because both an intimate contact and strong bonding between KZ and incorporated acid were achieved. KZ dissolved amount from the granules prepared by high-shear granulation was about eight times higher than that from the granules without the acid. The granulation involved to suppress a diffusion of acid dissolved, leading to the effectively maintained supersaturation state. The bioavailability of KZ after oral administration to rats was improved by applying high-shear granulation with citric acid independent of gastrointestinal pH. The granules prepared by high-shear granulation showed the bioavailability about 1.7-fold higher than that of the physical mixture in rats with and without neutralization of stomach. As a result, both the dissolution and absorption rates of KZ after oral administration were enhanced using conventional manufacturing technology.

The performance of HPMC matrix tablets using various agglomeration manufacturing processes

CONTEXT

The flow and compaction properties of a compaction mixture or powder and the drug-release profile of final tablets are important critical quality attributes (CQAs) that have an impact on the overall performance of hydrophilic matrix tablets. The selection of granulation method can importantly affect these CQAs.

OBJECTIVE

This study investigates various agglomeration methods of sustained-release formulation using HPMC K4M as a release polymer with various wet- and dry-granulation techniques.

MATERIALS AND METHODS

Flow properties were determined using flow time, angle of response, and the Carr index. Compaction properties were evaluated using "out of die" Heckel model. Release of carvedilol was tested as 12-h drug-dissolution profile.

RESULTS AND CONCLUSION

Compression mixtures made using the wet-granulation method exhibit better flow and compression properties than compression mixtures made using the dry-granulation method. The direct compression method proved to be the least appropriate manufacturing method because the compression mixture has very poor flow and the lowest compressibility/compactibility index. The choice of granulation technique significantly influences the swelling behavior and drug-dissolution profile of the final matrix tablets, also resulting in dissimilar release profiles. The choice of granulation method has the greatest influence on the drug-release profile. The direct compression method provides tablets with the fastest drug-release profile, followed by the dry-granulation and wet-granulation methods. The particle size of granules and porosity of tablets play an important role, contributing to differences in drug-release profiles.