Sticking and Picking in Pharmaceutical Tablet Compression: An IQ Consortium Review

Past, current, and future: Application of image analysis in small molecule pharmaceutical development

The often-perceived limitations of image analysis have for many years impeded the widespread application of such systems as first line characterisation tools. Image analysis has, however, undergone a notable resurgence in the pharmaceutical industry fuelled by developments system capabilities and the desire of scientists to characterize the morphological nature of their particles more adequately. The importance of particle shape as well as size is now widely acknowledged. With the increasing use of modelling and simulations, and ongoing developments though the integration of machine learning and artificial intelligence, the utility of image analysis is increasing significantly driven by the richness of the data obtained. Such datasets provide means to circumvent the requirement to rely on less informative descriptors and enable the move towards the use of whole distributions. Combining the improved particle size and shape measurement and description with advances in modelling and simulations is enabling improved means to elucidate the link between particle and bulk powder properties. In addition to improved capabilities to describe input materials, approaches to characterize single components within multicomponent systems are providing scientists means to understand how their material may change during manufacture thus providing a means to link the behaviour of final dosage forms with the particle properties at the point of action. The aim is to provide an overview of image analysis and update readers with innovations and capabilities to other methods in the small molecule arena. We will also describe the use of AI for the improved analysis using image analysis.

The development of an innovative method to improve the dissolution performance of rivaroxaban

Recent advancements in the formulation of solid dosage forms involving active ingredient-cyclodextrin complexes have garnered considerable attention in pharmaceutical research. While previous studies predominantly focused on incorporating these complexes into solid states, issues regarding incomplete inclusion prompted the exploration of novel methods. In this study, we aimed to develop an innovative approach to integrate liquid-state drug-cyclodextrin inclusion complexes into solid dosage forms. Our investigation centered on rivaroxaban, a hydrophobic compound practically insoluble in water, included in hydroxypropyl-β-cyclodextrin at a 1:1 M ratio, and maintained in a liquid state. To enhance viscosity, hydroxypropyl-cellulose (2 % w/w) was introduced, and the resulting dispersion was sprayed onto the surface of cellulose pellets (CELLETS®780) using a Caleva Mini Coater. The process parameters were meticulously controlled, with atomization air pressure set at 1.1 atm and a fluidizing airflow maintained at 35-45 m3/h. Characterization of the coated cellets, alongside raw materials, was conducted using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) analyses. Physicochemical evaluations affirmed the successful incorporation of rivaroxaban into hydroxypropyl-β-cyclodextrin, with the final cellets demonstrating excellent flowability, compressibility, and adequate hardness. Quantitative analysis via the HPLC-DAD method confirmed a drug loading of 10 mg rivaroxaban/750 mg coated cellets. In vitro dissolution studies were performed in two distinct media: 0.022 M sodium acetate buffer pH 4.5 with 0.2 % sodium dodecyl sulfate (mirroring compendial conditions for 10 mg rivaroxaban tablets), and 0.05 M phosphate buffer pH 6.8 without surfactants, compared to reference capsules and conventional tablet formulations. The experimental capsules exhibited similar release profiles to the commercial product, Xarelto® 10 mg, with enhanced dissolution rates observed within the initial 10 min. This research presents a significant advancement in the development of solid dosage forms incorporating liquid-state drug-cyclodextrin inclusion complexes, offering a promising avenue for improving drug delivery and bioavailability.

UV-VIS imaging-based investigation of API concentration fluctuation caused by the sticking behaviour of pharmaceutical powder blends

Surface powder sticking in pharmaceutical mixing vessels poses a risk to the uniformity and quality of drug formulations. This study explores methods for evaluating the amount of pharmaceutical powder mixtures adhering to the metallic surfaces. Binary powder blends consisting of amlodipine and microcrystalline cellulose (MCC) were used to investigate the effect of the mixing order on the adherence to the vessel wall. Elevated API concentrations were measured on the wall and within the dislodged material from the surface, regardless of the mixing order of the components. UV imaging was used to determine the particle size and the distribution of the API on the metallic surface. The results were compared to chemical maps obtained by Raman chemical imaging. The combination of UV and VIS imaging enabled the rapid acquisition of chemical maps, covering a substantially large area representative of the analysed sample. UV imaging was also applied in tablet inspection to detect tablets that fail to meet the content uniformity criteria. The results present powder adherence as a possible source of poor content uniformity, highlighting the need for 100% inspection of pharmaceutical products to ensure product quality and safety.

Uncovering the mechanism of Tenofovir amibufenamide fumarate punch sticking by combining direct compression experiment and computational simulation

Punch sticking during tablet manufacturing is a prevalent issue for many active pharmaceutical ingredients (APIs) encountered by the pharmaceutical industry. Tenofovir amibufenamide fumarate (TMF), a heavyweight drug for the treatment of hepatitis B, was selected as a model drug due to its tendency to punch sticking during tablet compression. In this study, the cause of sticking was explored by investigating crystal habits, excipients and structure characteristics. The difference in sticking of three crystal habits can be visually represented through direct compression experiments on powdered samples and analysis of crystal surfaces. The excipients play a direct role in decreasing the probability of sticking, and the extent of sticking can be assessed by measuring the tensile strength of the tablet. Additionally, the plasticity index was utilized to theoretically analyze the potential enhancements of four excipients. These experimental results indicate that the block-shaped crystals have superior ability of anti-sticking and that suitable excipients can significantly improve the sticking situation of TMF. Ultimately, the phenomenon of punch sticking was additionally examined through computational calculations, focusing on the mechanical characteristics of TMF molecules and intermolecular interactions. The strategy of combining experiments and simulation calculations has broader significance for the study of drug production.

Determining the Impact of Roller Compaction Processing Conditions on Granulate and API Properties: Impact of Formulation API Load

Previous work demonstrated that roller compaction of a 40%w/w theophylline-loaded formulation resulted in granulate consisting of un-compacted fractions which were shown to constitute between 34 and 48%v/v of the granulate dependent on processing conditions. The active pharmaceutical ingredient (API) primary particle size within the un-compacted fraction was also shown to have undergone notable size reduction. The aim of the current work was to test the hypothesis that the observations may be more indicative of the relative compactability of the API due to the formulation being above the percolation threshold. This was done by assessing the impact of varied API loads in the formulation on the non-granulated fraction of the final granulate and the extent of attrition of API particles within the non-granulated fraction. The influence of processing conditions for all formulations was also investigated. The results verify that the observations, both of this study and the previous work, are not a consequence of exceeding the percolation threshold. The volume of un-compacted material within the granulate samples was observed to range between 34.7 and 65.5% depending on the API load and roll pressure, whilst the API attrition was equivalent across all conditions.

One Factor at a Time and factorial experimental design for formulation of l-carnitine microcapsules to improve its manufacturability

l-carnitine is an essential dietary supplement of physiological importance. Handling and manufacture of l-carnitine is difficult due to its hygroscopic nature, resulting in impairing its flow properties, as well as solid dosage form stability. The study aimed at reducing l-carnitine hygroscopicity through its encapsulation within a hydrophobic, pH-insensitive polymer. A solid in oil in oil (s/o/o) emulsion solvent evaporation technique for microencapsulation was adopted to exclude the possibility of water uptake. The polymers used were two ethyl cellulose (EC) grades with different viscosities. The chosen solvent for the polymer was acetone, and liquid paraffin was the dispersion medium in which both the drug and polymer were insoluble. Sixteen formulations were developed, and evaluated to study the formulation parameters as anti-coalescent type, mixing speed, surfactant type and polymer ratio, and viscosity grade. A "One Factor at A Time" (OFAT) design of experiment, and a factorial design were utilized. Study results revealed that successful microencapsulation occurred by using Aerosil 200 (0.1 %) as anti-coalescent, a mixing speed of 1000 rpm, and Ethocel Std 20 at a 3:1 drug-to-polymer ratio. Microcapsule formulation containing l-carnitine base, successfully compressed into tablets, showed acceptable water content, disintegration time, hardness, and dissolution. Moreover, it showed acceptable stability upon storage at 40 °C at 75 % RH for six months compared to l-carnitine tablets prepared by wet granulation.

Worsened punch sticking by external lubrication with magnesium stearate

External lubrication of tooling with magnesium stearate (MgSt) is a common strategy to eliminate punch sticking when compressing powders with a high sticking propensity, such as many pure active pharmaceutical ingredients (APIs). We found that it actually led to aggravated punch sticking at low compaction pressures. This counterintuitive phenomenon was explained based on interplay of forces among the punch tip, MgSt, and API. The explanation is supported by the observed effects of pressure and mechanical properties of APIs on this phenomenon.

Novel bioequivalent oral disintegrating tablet of aripiprazole prepared by direct compression technique with shortened disintegration time

Herein, we aimed to formulate a novel oral disintegrating tablet (ODT) of aripiprazole (ARP) capable of rapid disintegration using a direct compression technique. Different ODTs were fabricated with directly compressible excipients, and their disintegration time, wettability (water absorption ratio and wetting time), and mechanical properties (hardness and friability) were evaluated. The optimized ODT comprised F-Melt® type C, Prosolv® SMCC HD90, and Na croscarmellose (10 mg of ARP in a 130 mg tablet). The ODT with 3.1-5.2 kp hardness exhibited rapid disintegration (14.1-17.2 sec), along with appropriate mechanical strength (friability < 0.24%). In a bioequivalent study in Korean healthy subjects (randomized, single-dose, two-period crossover design, n = 37), the novel ODT offered the equivalent pharmacokinetic profile to that of a conventional immediate release tablet (Otsuka, Abilify®, Japan), despite different disintegration and dissolution profiles. The 90% confidence intervals of the geometric mean test to reference ratios considering the area-under-the-curve and maximum plasma drug concentrations were 1.0306-11051 and 0.9448-1.1063, respectively, satisfying FDA regulatory criteria for bioequivalence. The novel ART ODT was physicochemically stable under the accelerated storage condition (40 °C, RH75%) for 24 weeks. Therefore, the novel ARP-loaded ODT is expected to be an alternative to oral ARP therapy, providing improved patient adherence.

Effects of tableting process parameters and powder lubrication levels on tablet surface temperature and moisture content

Punch sticking is a recurrent problem during the pharmaceutical tableting process. Powder moisture content plays a key role in the buildup of sticking; it evaporates due to increased tablet temperature, accumulates at the punch-tablet interface, and causes sticking through capillary force. This study investigated the effects of compaction pressure (CP), compaction speed (CS), and lubrication level (magnesium stearate (MgSt) ratio) on tablet surface temperature (TST) and tablet surface moisture content (TSMC). TST and TSMC were measured with an infrared thermal camera and near-infrared sensor, respectively. Microcrystalline cellulose was used as the tableting powder and MgSt as the lubricant. The low range of CS values (16-32 mm/s) considered in this study did not have significant effects on TST and TSMC. MgSt ratio had a significant positive effect on TST; this may be explained by the increase in powder blend effusivity with the addition of MgSt. However, MgSt ratio did not have a significant effect on TSMC. CP had a significant positive effect on both TST and TSMC. Increased CP induced higher heat generation through particle deformation and friction during the compaction phase, leading to increased TST. Furthermore, the water vapor diffusion rate through the powder bed might have increased due to the rise in thermal energy and led to further moisture accumulation at the tablet-punch interface, causing the significant positive effect of CP on TSMC. This result may explain the occurrence of sticking regardless of the CP applied during the tableting process.

Moisture Behavior of Pharmaceutical Powder during the Tableting Process

The moisture content of pharmaceutical powder is a key parameter contributing to tablet sticking during the tableting process. This study investigates powder moisture behavior during the compaction phase of the tableting process. Finite element analysis software COMSOL Multiphysics^® 5.6 was used to simulate the compaction microcrystalline cellulose (VIVAPUR PH101) powder and predict temperature and moisture content distributions, as well as their evolution over time, during a single compaction. To validate the simulation, a near-infrared sensor and a thermal infrared camera were used to measure tablet surface temperature and surface moisture, respectively, just after ejection. The partial least squares regression (PLS) method was used to predict the surface moisture content of the ejected tablet. Thermal infrared camera images of the ejected tablet showed powder bed temperature increasing during compaction and a gradual rise in tablet temperature along with tableting runs. Simulation results showed that moisture evaporate from the compacted powder bed to the surrounding environment. The predicted surface moisture content of ejected tablets after compaction was higher compared to that of loose powder and decreased gradually as tableting runs increased. These observations suggest that the moisture evaporating from the powder bed accumulates at the interface between the punch and tablet surface. Evaporated water molecules can be physiosorbed on the punch surface and cause a capillary condensation locally at the punch and tablet interface during dwell time. Locally formed capillary bridge may induce a capillary force between tablet surface particles and the punch surface and cause the sticking.

Enabling direct compression tablet formulation of celecoxib by simultaneously eliminating punch sticking, improving manufacturability, and enhancing dissolution through co-processing with a mesoporous carrier

The development of a high quality tablet of Celecoxib (CEL) is challenged by poor dissolution, poor flowability, and high punch sticking propensity of CEL. In this work, we demonstrate a particle engineering approach, by loading a solution of CEL in an organic solvent into a mesoporous carrier to form a coprocessed composite, to enable the development of tablet formulations up to 40% (w/w) of CEL loading with excellent flowability and tabletability, negligible punch sticking propensity, and a 3-fold increase in in vitro dissolution compared to a standard formulation of crystalline CEL. CEL is amorphous in the drug-carrier composite and remained physically stable after 6 months under accelerated stability conditions when the CEL loading in the composite was ≤ 20% (w/w). However, crystallization of CEL to different extents from the composites was observed under the same stability condition when CEL loading was 30-50% (w/w). The success with CEL encourages broader exploration of this particle engineering approach in enabling direct compression tablet formulations for other challenging active pharmaceutical ingredients.

Understanding the role of magnesium stearate in lowering punch sticking propensity of drugs during compression

The sticking of active pharmaceutical ingredient (API) to the surfaces of compaction tooling, frequently referred to as punch sticking, causes costly downtime or product failures in commercial tablet manufacturing. Magnesium stearate (MgSt) is a common tablet lubricant known to ameliorate the sticking problem, even though there exist exceptions. The mechanism by which MgSt lowers punch sticking propensity (PSP) by covering API surface is sensible but not yet experimentally proven. This work was aimed at elucidating the link between PSP and surface area coverage (SAC) of tablets by MgSt, in relation to some key formulation properties and process parameters, namely MgSt concentration, API loading, API particle size, and mixing conditions. The study was conducted using two model APIs with known high PSPs, tafamidis (TAF) and ertugliflozin-pyroglutamic acid (ERT). Results showed that PSP decreases exponentially with increasing SAC by MgSt. The composition of material stuck to punch face was also explored to better understand the onset of punch sticking and the impact of possible MgSt-effected punch conditioning event.

Evaluating the effect of glidants on tablet sticking propensity of ketoprofen using powder rheology

Punch sticking has been a leading drawback that has challenged successful tablet manufacturing since its initial conception. Due to the capricious nature of the complication, this can arise during any phase of the development process. Even now, identifying such a problem is a prerequisite during the initial stage of development. The present study evaluated the role of Aerosil®200, talc, and Syloid®244 as glidants in varying amounts ranging from 0.0 percent to 2.0 percent w/w on tablets sticking relatively to five different metal surfaces, with ketoprofen as the model drug. Powder rheology is a predictable technique used to calculate the sticking index. The sticking index of each formulation in comparison to each metal coupon was identified by calculating the kinematic angle of internal friction and the angle of wall friction using the shear cell test and wall friction test, respectively. Interestingly, glidants were found to reduce the sticking propensity of the powder blend in a concentration-dependent manner. In addition, the compression study validated the expected sticking tendency ranking order. According to the research data, the sticking index could effectively be utilized to envisage the possibility of tablet sticking, i.e., by selecting the formulation's excipient and their percentages or selecting appropriate punched metal surfaces in the tableting process.

Upscaling of external lubrication from a compaction simulator to a rotary tablet press

External lubrication is a highly valuable alternative lubrication method as it minimizes the negative impact on tablet properties encountered when using internal lubrication. In current study, experiments were performed with automated external lubrication systems implemented in a compaction simulator and rotary tablet press using three lubricants (magnesium stearate (MgSt), sodium stearyl fumarate (SSF) and glyceryl dibehenate (DBHG)). The effect of process parameters related to the tableting process (main compaction pressure and tableting speed) and external lubrication systems (spraying time, atomizing pressure, dust extraction system and lubricant feed rate) on the responses was studied for a placebo formulation which is non-processable without lubrication. Low and comparable ejection forces were recorded for all lubricants on both tablet presses. No negative effect on tensile strength was observed for process parameters of both external lubrication systems, irrespective of lubricant type. Disintegration times were slightly higher for SSF compared to MgSt and DBHG for the tablets produced on the rotary tablet press, linked to higher lubricant concentrations on the tablets for SSF, while disintegration times were similar for all lubricant types on the compaction simulator. The potential of external lubrication for implementation on production scale tableting equipment and during scale-up was demonstrated for multiple lubricants.

Evaluating Spray Drying and Co-Precipitation as Manufacturing Processes for Amorphous Solid Dispersions of a Low Tg API

Amorphous solid dispersions feature prominently in the approach to mitigate low bioavailability of poorly water-soluble small molecules, particularly in the early development space focusing on toxicity evaluations and clinical studies in normal healthy volunteers, where high exposures are needed to establish safety margins. Spray drying has been the go-to processing route for a number of reasons, including ubiquitous availability of equipment, the ability to accommodate small scale deliveries, and established processes for delivering single phase amorphous material. Active pharmaceutical ingredients (APIs) with low glass transition temperatures (T_g) can pose challenges to this approach. This study addresses multiple routes towards overcoming issues encountered with a low T_g (∼ 12 °C) API during manufacture of a spray dry intermediate (SDI). Even once formulated as an amorphous solid dispersion (ASD) with HPMCAS-LG, the T_g of the ASD was sufficiently low to require the use of non-ideal solvents, posing safety concerns and ultimately resulting in low yields with frequent process interruptions to resolve product build-up. To resolve challenges with spray drying the HPMCAS-L SDI, higher T_g polymers were assessed during spray drying, and an alternative antisolvent precipitation-based process was evaluated to generate co-precipitated amorphous dispersions (cPAD) with either HPMCAS-L or the additional higher T_g polymers. Both approaches were found to be viable alternatives to achieve single phase ASDs while demonstrating comparable in vitro and in vivo bioperformance compared to the SDI. The results of this effort offer valuable considerations for future early-stage activities for ASDs with low T_g APIs.

An Insight into the Degradation Processes of the Anti-Hypertensive Drug Furosemide

Furosemide (FUR), an active pharmaceutical ingredient (API) belonging to a group of drugs known as loop diuretics, has widespread use, but, is characterized by a strong instability to light, which causes chemical transformations that could give a yellowing phenomenon and have a significant impact from a health and marketing point of view. Many studies have tried to explain this phenomenon under different experimental conditions, but no detailed explanation of the yellowing phenomenon has been provided. This work, unlike the others, provides an overall view and explanation of the behavior of FUR in relation to the yellowing phenomenon, both in the solution and in solid state, considering several aspects, such as light exposure, presence of oxygen, and moisture effects.

Insights into tablet sticking: a quantitative case study with an ibuprofen and methocarbamol-based formulation

OBJECTIVES AND METHODS

Tablet sticking is a continuous accumulation of pharmaceutical powder onto tooling surfaces during compression. Its occurrence greatly impacts tablet productivity, quality attributes, and tooling age. In a previous study, the authors proposed a multivariate data analysis approach to gain insights into tablet sticking directly on the industrial stage. The objective was to determine the combination of factors that could help distinguish between batches affected and unaffected by sticking. The present study aims to generalize this approach by extending it to quantitative predictions of punch sticking intensity. A total of 345 variables was gathered on 28 industrial batches of an ibuprofen and methocarbamol-based formulation.

RESULT AND CONCLUSION

Using PLS regression models, it was shown that the association of granulation duration and compression force allows to significantly explain ∼60% of sticking variations of studied formulation. In addition, unlike the classification models developed in the earlier work, the validation residues in the present study were found to be normally distributed (Shapiro-Wilks p value = 0.96) and independent from the target variable (R² = 9.5%).

A multivariate data analysis approach to tablet sticking on an industrial scale: a qualitative case study of an ibuprofen-based formulation

OBJECTIVES

Sticking is one of the most common and damaging issues that occur during tablet manufacturing. Sticking is the adhesion of powder onto tooling surfaces during compression. Because of the numerous factors involved in its occurrence, understanding tablet sticking requires the simultaneous investigation of these factors to clarify their possible interactions. However, conducting such a study experimentally can present a significant financial and technical burden. In this study, we aimed to leverage the large amount of data that is usually generated during industrial manufacturing to gain insights into sticking.

METHODS

This was achieved by collecting and analyzing a total of 71 historical batches that used an ibuprofen-based formulation. We associate each batch with a hundred parameters, including a qualitative descriptor of sticking, and employ a predefined methodology based primarily on multivariate data analysis.

RESULTS AND CONCLUSIONS

Our results highlight the role of lubrication, water content, and the low melting point of ibuprofen in its sticking tendency. Based on these findings, we propose and discuss an industrial manufacturing data analysis approach to sticking and its associated systematic methodology, consisting of collection, exploration, and data modeling.

The Role of Titanium Dioxide (E171) and the Requirements for Replacement Materials in Oral Solid Dosage Forms: An IQ Consortium Working Group Review

Titanium dioxide (in the form of E171) is a ubiquitous excipient in tablets and capsules for oral use. In the coating of a tablet or in the shell of a capsule the material disperses visible and UV light so that the contents are protected from the effects of light, and the patient or caregiver cannot see the contents within. It facilitates elegant methods of identification for oral solid dosage forms, thus aiding in the battle against counterfeit products. Titanium dioxide ensures homogeneity of appearance from batch to batch fostering patient confidence. The ability of commercial titanium dioxide to disperse light is a function of the natural properties of the anatase polymorph of titanium dioxide, and the manufacturing processes used to produce the material utilized in pharmaceuticals. In some jurisdictions E171 is being considered for removal from pharmaceutical products, as a consequence of it being delisted as an approved colorant for foods. At the time of writing, in the view of the authors, no system or material which could address both current and future toxicological concerns of Regulators and the functional needs of the pharmaceutical industry and patients has been identified. This takes into account the assessment of materials such as calcium carbonate, talc, isomalt, starch and calcium phosphates. In this paper an IQ Consortium team outlines the properties of titanium dioxide and criteria to which new replacement materials should be held.

A novel soluble lornoxicam-sodium chelate monohydrate with improved plasticity and tabletability

Lornoxicam (LOR), a BCS Ⅱ nonsteroidal anti-inflammatory drug, has been clinically utilized for moderate to severe acute pain management. However, it has poor water solubility and insufficient tabletability, leading to erratic absorption and challenge in tablet processability. This study reported a novel solid state of LOR (i.e., LOR sodium chelate monohydrate, LOR-Na·H₂O) with significantly improved solubility, dissolution rate and tabletability. The prepared chelate (CCDC No.: 2125157) contains LOR^-, Na⁺, and H₂O in a molar ratio of 1:1:1, where Na⁺ ions bridged with O(5) of amide group, and N(2) of pyridine group on LOR^-, as well as O(4) on H₂O through coordination bonds. LOR-Na·H₂O displayed a superior dissolution rate (5∼465 folds) than commercial LOR due to its increased wettability (contact angle: 74.5° vs 85.6°) and lower solvation free energy (∼2-fold). In addition, the significant improvement in tabletability was caused by high plasticity and deformability, which was attributed to its special interlayer gliding with weak bonding interactions across layers but strong coordination bonding interactions within layers. The novel LOR-Na·H₂O with significantly enhanced pharmaceutical performance offers a promising strategy for further product development.

Pharmaceutical Development of Film-Coated Mini-Tablets with Losartan Potassium for Epidermolysis Bullosa

Epidermolysis bullosa is a genetically heterogenous skin fragility disorder with multiorgan involvement appearing already in newborn children. Severe progressive fibrosis follows skin blistering, mucosa lesions, and wound healing, favouring development of highly aggressive squamous cell carcinomas. Losartan potassium (LP) has been described to show positive effects; therefore, it was of clinical interest to develop 2 mm mini-tablets with LP for treatment of the affected children. Several challenges emerged during development: limited flowability and sticking to punches were observed in the first tableting experiments due to a high drug load, and a bitter taste of the LP was reported. Sticking to punches was reduced by using SMCC 50 and a combination of different lubricants; however, direct compression trials on a Korsch XM 12 rotary press were not successful due to compaction phenomena in the hopper. Thus, an intermediate dry granulation was successfully introduced. Two final formulations of the mini-tablets complied with the requirements of the European Pharmacopoeia regarding disintegration times (<15 min) and friability (<1.0%); mean tensile strengths amounted to about 1 MPa as a compromise between manufacturability and sufficient mechanical strength for further coating studies. The subsequent coating step succeeded delaying the initial drug release for more than 2 min. An acceptance value ≤15 was matched for the coated mini-tablets, and stability studies showed a promising shelf life.

100% visual inspection of tablets produced with continuous direct compression and coating

Visual appearance of tablets is an important property for patients. Since the visual appearance is most strongly influenced by the applied coating, this necessitates a high level of process control and homogeneity in the coating process. In recent years, a number of tablet coaters have been developed that can be used in combination with continuous tablet production lines. In this study, 180 kg of tablets were produced using a continuous direct compaction line with a throughput of 25 kg/h. Tablets were consequently subdivided into 12 lots and coated in a semi-batch drum coater directly after compression. For a detailed understanding of intra-lot and lot-to-lot variability, a 100% visual inspection of the tablets was performed using an automatic tablet inspection and sorting machine. All tablets were analyzed from all 6 sides and the unsuitable tablets were sorted out. In the worst lot, only 1 out of around 300 tablets was sorted out due to color mismatch. For some tablets, edge chipping was also observed, which would presumably not be detected during routine sampling. Root causes for the defects could be found in the intentionally chosen set of old punches and in the operation parameters of the coater. Nonetheless, the lot-to-lot variability according to all criteria was very low.

A review of emerging technologies enabling improved solid oral dosage form manufacturing and processing

Tablets are the most widely utilized solid oral dosage forms because of the advantages of self-administration, stability, ease of handling, transportation, and good patient compliance. Over time, extensive advances have been made in tableting technology. This review aims to provide an insight about the advances in tablet excipients, manufacturing, analytical techniques and deployment of Quality by Design (QbD). Various excipients offering novel functionalities such as solubility enhancement, super-disintegration, taste masking and drug release modifications have been developed. Furthermore, co-processed multifunctional ready-to-use excipients, particularly for tablet dosage forms, have benefitted manufacturing with shorter processing times. Advances in granulation methods, including moist, thermal adhesion, steam, melt, freeze, foam, reverse wet and pneumatic dry granulation, have been proposed to improve product and process performance. Furthermore, methods for particle engineering including hot melt extrusion, extrusion-spheronization, injection molding, spray drying / congealing, co-precipitation and nanotechnology-based approaches have been employed to produce robust tablet formulations. A wide range of tableting technologies including rapidly disintegrating, matrix, tablet-in-tablet, tablet-in-capsule, multilayer tablets and multiparticulate systems have been developed to achieve customized formulation performance. In addition to conventional invasive characterization methods, novel techniques based on laser, tomography, fluorescence, spectroscopy and acoustic approaches have been developed to assess the physical-mechanical attributes of tablet formulations in a non- or minimally invasive manner. Conventional UV-Visible spectroscopy method has been improved (e.g. fiber-optic probes and UV imaging-based approaches) to efficiently record the dissolution profile of tablet formulations. Numerous modifications in tableting presses have also been made to aid machine product changeover, cleaning, and enhance efficiency and productivity. Various process analytical technologies have been employed to track the formulation properties and critical process parameters. These advances will contribute to a strategy for robust tablet dosage forms with excellent performance attributes.

Mean yield pressure from the in-die Heckel analysis is a reliable plasticity parameter

Despite the ability to characterize the plasticity of powders in a material-sparing and expedited manner, the in-die Heckel analysis has been widely criticized for its sensitivity to several factors, such as particle elastic deformation, tooling size, lubrication, and speed. Using materials exhibiting a wide range of mechanical properties, we show that the in-die P_y correlates strongly with three established plasticity parameters obtained from the out-of-die Heckel analysis, Kuentz-Leuenberger analysis, and macroindentation. Thus, the in-die P_y is a reliable parameter for quantifying powder plasticity in a material-sparing and expedited manner.

Application of Machine-Learning Algorithms for Better Understanding of Tableting Properties of Lactose Co-Processed with Lipid Excipients

Co-processing (CP) provides superior properties to excipients and has become a reliable option to facilitated formulation and manufacturing of variety of solid dosage forms. Development of directly compressible formulations with high doses of poorly flowing/compressible active pharmaceutical ingredients, such as paracetamol, remains a great challenge for the pharmaceutical industry due to the lack of understanding of the interplay between the formulation properties, process of compaction, and stages of tablets’ detachment and ejection. The aim of this study was to analyze the influence of the compression load, excipients’ co-processing and the addition of paracetamol on the obtained tablets’ tensile strength and the specific parameters of the tableting process, such as (net) compression work, elastic recovery, detachment, and ejection work, as well as the ejection force. Two types of neural networks were used to analyze the data: classification (Kohonen network) and regression networks (multilayer perceptron and radial basis function), to build prediction models and identify the variables that are predominantly affecting the tableting process and the obtained tablets’ tensile strength. It has been demonstrated that sophisticated data-mining methods are necessary to interpret complex phenomena regarding the effect of co-processing on tableting properties of directly compressible excipients.

Cocrystal engineering of pharmaceutical solids: therapeutic potential and challenges

This highlight presents an overview of pharmaceutical cocrystal production and its potential in reviving problematic properties of drugs in different dosage forms. The challenges and future outlook of its translational development are discussed.

Determining the Impact of Roller Compaction Processing Conditions on Granule and API Properties

The attrition of drug particles during the process of dry granulation, which may (or may not) be incorporated into granules, could be an important factor in determining the subsequent performance of that granulation, including key factors such as sticking to punches and bio-performance of the dosage form. It has previously been demonstrated that such attrition occurs in one common dry granulation process train; however, the fate of these comminuted particles in granules was not determined. An understanding of the phenomena of attrition and incorporation into granule will improve our ability to understand the performance of granulated systems, ultimately leading to an improvement in our ability to optimize and model the process. Unique feeding mechanisms, geometry, and milling systems of roller compaction equipment mean that attrition could be more or less substantial for any given equipment train. In this work, we examined attrition of API particles and their incorporation into granule in an equipment train from Gerteis, a commonly used equipment train for dry granulation. The results demonstrate that comminuted drug particles can exist free in post-milling blends of roller compaction equipment trains. This information can help better understand the performance of the granulations, and be incorporated into mechanistic models to optimize such processes.

In Vitro Evaluation of Enteric-Coated HPMC Capsules-Effect of Formulation Factors on Product Performance

A comparative study on different enteric-coated hard capsules was performed. The influence of different formulation factors like choice of enteric polymer, triethyl citrate (TEC) concentration (plasticizer), talc concentrations (anti-tacking agent), and different coating process parameters on the sealing performance of the capsule and the disintegration time were investigated. Furthermore, the influence of different disintegration test methods (with disc vs. without disc and 50 mM U.S. Pharmacopoeia (USP) buffer pH 6.8 vs. biopredictive 15 mM phosphate buffer pH 6.5) was evaluated. All formulations showed sufficient but not equivalent acid resistance when tested. Polymer type was the main factor influencing the capsule sealing and disintegration time. In addition, TEC and talc could affect the performance of the formulation. Regarding the choice of the disintegration test method, the presence of a disc had for the most part only limited influence on the results. The choice of disintegration buffer was found to be important in identifying differences between the formulations.

New approach to optimizing risk management of the sticking problem using scale-independent critical material attributes and the quantitative process parameter

In pharmaceutical manufacturing of solid formulations, blending with a lubricant is a key process in preventing sticking during compression. Sticking not only results in tablets with a disfigured appearance but also brings about the interruption of continuous operations. The aim of our study was to identify blending scale-independent critical material attributes (CMAs) in relation to the sticking problem to appropriately define the end-point of the blending process with magnesium stearate as lubricant. Results showed that the dispersive surface free energy (SFE) and the specific free energy absorptions (ΔGsp) of ethanol decreased during blending with magnesium stearate. As the two parameters decreased, the sticking problem was improved. In conclusion, we propose that the dispersive SFE and ΔGsp of ethanol are scale-independent CMAs, and that the minimum blending time (BT_min), which can be calculated from the two CMAs, of the quantitative process parameter show the minimum blending time required to achieve higher risk assessment of the sticking problem.

Improvements in sticking, hygroscopicity, and compactibility of effervescent systems by fluid-bed coating

Recently, effervescent tablets (ETs) have become increasingly popular with patients in clinics due to their fast disintegration by acid–alkali reactions in water. However, certain undesirable properties of ETs (e.g., sticking and high hygroscopicity) can limit their production and application. In particular, frequent sticking always severely decreases the tablet quality and productivity. Therefore, in this study, polyvinylpyrrolidone (PVP) at different usage levels, grades, or spray solution concentrations was coated onto the surfaces of both acidic and alkaline granules of ETs by means of the fluid-bed coating technique. In terms of fully characterized powder, tableting, and tablet properties, the following points were concluded: (i) a uniform coating of PVP onto the surfaces of these two granules not only resolved the sticking problem, but also effectively decreased the hygroscopicity and enhanced the compactibility; (ii) the improvements increased with an increase in the PVP content or PVP molecular weight and a decrease in the PVP spray solution concentration owing to the formation of an increasingly even and cohesive coating layer; (iii) the process of fluid-bed coating was not the simple superposition or simple mixing of two different materials' properties; (iv) the coating process did not cause significant influences on the disintegration time of ETs. Overall, it is fairly meaningful to further promote the development of ETs in practice since these problems have been overcome.

Recently, effervescent tablets (ETs) have become increasingly popular with patients in clinics due to their fast disintegration by acid–alkali reactions in water.

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.

Manufacturing classification system in the real world: factors influencing manufacturing process choices for filed commercial oral solid dosage formulations, case studies from industry and considerations for continuous processing

Following the first Manufacturing Classification System (MCS) paper, the team conducted surveys to establish which active pharmaceutical ingredient (API) properties were important when selecting or modifying materials to enable an efficient and robust pharmaceutical manufacturing process. The most commonly identified factors were (1) API particle size: small particle sizes are known to increase risk of processing issues; (2) Drug loading in the formulation: high drug loadings allow less opportunity to mitigate poor API properties through the use of excipients. The next step was to establish linkages with process decisions by identifying publicly-available proxies for these important parameters: dose (in place of drug loading) and BCS class (in place of particle size). Poorly-soluble API were seen as more likely to have controlled (smaller) particle size than more highly soluble API. Analysis of 435 regulatory filings revealed that higher doses and more poorly-soluble API was associated with more complex processing routes. Replacing the proxy factors with the original parameters should give the opportunity to demonstrate stronger trends. This assumption was tested by accessing a dataset relating to commercial tablet products. This showed that, for dry processes, a larger particle size was associated with higher achievable drug loading as determined by percolation threshold.