A Simple and Inexpensive Image Analysis Technique to Study the Effect of Disintegrants Concentration and Diluents Type on Disintegration

Investigation into the swelling and dissolution behaviour of Polymer-Excipient blends of PEO Utilising dissolution imaging

The use of dissolution imaging in analysing the behaviourof hydrophilic matrices and various types of excipients is examined in this study.The main aim was to investigate how different ratios of excipients with different solubility properties, such as lactose, microcrystalline cellulose, and dicalcium phosphate impact on the swelling properties and propranolol hydrochloride (PPN) release characteristics of polyethylene oxide matrix compacts. The surface properties of the compacts were investigated using a focus variation microscope after which dissolution studies were conducted to determine compact swelling and drug release properties. Smr2, a surface parameter representing the percentage of deeper valley structures on the surface, was used to calculate the proportion of the compact surface available for retaining lubrication (dissolution media in this case). Smr2 values of 83 and 84 were measured for the 1:1 and 1:3 PEO lactose compacts, respectively. This parameter utilised in this experiment gives an indication of the compact surface available for the initial hydration process and suggests a higher rate of hydration for the 1:1 and 1:3 PEO lactose compacts. The swelling studies revealed that a higher PEO ratio (3:1) resulted in more extensive gel layer formation as compared to the 1:3 compacts. All PEO:excipient compacts exhibited faster drug release than the compacts comprising PEO as the sole excipient. The quantity of PEO present was thus crucial in influencing the capacity of the matrix to control the release of PPN. This study underscores the potential for modifying drug release by altering the quantity of the matrix gel-former (PEO in this case) as well as the type or ratio of excipient used. The study also highlights the novelty of using UV dissolution imaging to image and quantify swelling and drug dissolution processes as well as providing qualitative observations such as channel formation which can support formulation optimisation and mechanistic understanding.

Dissolution of copovidone-based amorphous solid dispersions: Influence of atomic layer coating, hydration kinetics, and formulation

Atomic layer coating (ALC) is an emerging, solvent-free technique to coat amorphous solid dispersion (ASD) particles with a nanolayer ceramic coating that has been shown to improve powder characteristics and limit drug crystallization. Herein, we evaluate the impact of aluminum oxide coatings with varying thickness and conformality on the release behavior of ritonavir/copovidone ASDs. Release performance of powders, neat tablets, and formulated tablets was studied. Confocal fluorescence microscopy (CFM) was used to visualize particle hydration and phase separation during immersion of the ASD in aqueous media. CFM revealed particle hydration requires defects for solvent penetration, but coatings, regardless of thickness, had minor impacts on powder dissolution provided defects were present. In tablets where less surface area is exposed to the dissolution media due to gel formation, slowed hydration kinetics resulted in phase separation of the drug from the polymer in coated samples, limiting release. Formulation with two superdisintegrants, crospovidone and croscarmellose sodium, as well as lactose achieved ∼90% release in less than 10 minutes, matching the uncoated ASD particles of the same formulation. This study highlights the importance of hydration rate, as well as the utility of confocal fluorescence microscopy to provide insight into release and phase behavior of ASDs.

Functionality of wet-granulated disintegrant in comparison to directly incorporated disintegrant in a poorly water-soluble tablet matrix

Tablet disintegration is crucial for drug release and subsequent systemic absorption. Although factors affecting the disintegrant's functionality have been extensively studied, the impact of wet granulation on the performance of disintegrants in a poorly water-soluble matrix has received much less attention. In this study, the disintegrants, crospovidone (XPVP), croscarmellose sodium (CCS) and sodium starch glycolate (SSG), were wet-granulated with dibasic calcium phosphate dihydrate as the poorly water-soluble matrix and polyvinylpyrrolidone as the binder. The effect of wet granulation was studied by evaluating tablet tensile strength and disintegratability. Comparison between tablets with granulated or ungranulated disintegrants as well those without disintegrants were also made. Different formulations showed different degrees of sensitivity to changes in tablet tensile strength and disintegratability post-wet granulation. Tablet tensile strength decreased for tablets with granulated disintegrant XPVP or CCS, but to a smaller extent for SSG. While tablets with granulated XPVP or CCS had increased disintegration time, the increment was lesser than for SSG, suggesting that wet granulation impacted a swelling disintegrant more. The findings showed that tablets with wet-granulated disintegrant had altered the disintegrant's functionality. These findings could provide better insights into changes in the disintegrant's functionality after wet granulation.

In-situ particle analysis with heterogeneous background: a machine learning approach

We propose a novel framework that combines state-of-the-art deep learning approaches with pre- and post-processing algorithms for particle detection in complex/heterogeneous backgrounds common in the manufacturing domain. Traditional methods, like size analyzers and those based on dilution, image processing, or deep learning, typically excel with homogeneous backgrounds. Yet, they often fall short in accurately detecting particles against the intricate and varied backgrounds characteristic of heterogeneous particle-substrate (HPS) interfaces in manufacturing. To address this, we've developed a flexible framework designed to detect particles in diverse environments and input types. Our modular framework hinges on model selection and AI-guided particle detection as its core, with preprocessing and postprocessing as integral components, creating a four-step process. This system is versatile, allowing for various preprocessing, AI model selections, and post-processing strategies. We demonstrate this with an entrainment-based particle delivery method, transferring various particles onto substrates that mimic the HPS interface. By altering particle and substrate properties (e.g., material type, size, roughness, shape) and process parameters (e.g., capillary number) during particle entrainment, we capture images under different ambient lighting conditions, introducing a range of HPS background complexities. In the preprocessing phase, we apply image enhancement and sharpening techniques to improve detection accuracy. Specifically, image enhancement adjusts the dynamic range and histogram, while sharpening increases contrast by combining the high pass filter output with the base image. We introduce an image classifier model (based on the type of heterogeneity), employing Transfer Learning with MobileNet as a Model Selector, to identify the most appropriate AI model (i.e., YOLO model) for analyzing each specific image, thereby enhancing detection accuracy across particle-substrate variations. Following image classification based on heterogeneity, the relevant YOLO model is employed for particle identification, with a distinct YOLO model generated for each heterogeneity type, improving overall classification performance. In the post-processing phase, domain knowledge is used to minimize false positives. Our analysis indicates that the AI-guided framework maintains consistent precision and recall across various HPS conditions, with the harmonic mean of these metrics comparable to those of individual AI model outcomes. This tool shows potential for advancing in-situ process monitoring across multiple manufacturing operations, including high-density powder-based 3D printing, powder metallurgy, extreme environment coatings, particle categorization, and semiconductor manufacturing.

Imaging techniques for studying solid dosage formulation: Principles and applications

Classic methods for evaluating the disintegration and dissolution kinetics of solid dosage forms are no longer sufficient to meet the growing demands in the pharmaceutical field. Hence, scientists have turned to imaging techniques and computer technology to develop innovative visualization methods. These methods allow for a visual understanding of the disintegration or dissolution process and offer valuable insights into the drug release kinetics. This article aims to provide an overview of the commonly used imaging techniques and their applications in studying the disintegration or dissolution of solid dosage forms. Therefore, imaging presents a novel and alternative approach to understanding the mechanisms of disintegration and dissolution in the formulation study of solid dosages.

Development of Child-Friendly Lisdexamfetamine Chewable Tablets Using Ion Exchange Resin as a Taste-Masking Carrier Based on the Concept of Quality by Design (QbD)

Taste masking is critical to improving the compliance of pediatric oral dosage forms. However, it is challenging for extremely bitter lisdexamfetamine dimesylate (LDX) with a long half-life and given in large dose. The present study aims to develop an immediate-release, taste-masked lisdexamfetamine chewable tablet. Lisdexamfetamine-resin complexes (LRCs) were prepared using the batch method. The molecular mechanism of taste masking was explored by PXRD, PLM, STA, and FT-IR. The results showed that taste masking was attributed to the ionic interaction between drug and the resin. The ion exchange process conformed to first-order kinetics. The rate-limiting step of drug release was the diffusion of ions inside the particles, and the concentration of H⁺ was the key factor for immediate release. The masking efficiency of the prepared LRCs in saliva exceeded 96%, and the drug could be completely released within 15 min in aqueous HCl (pH 1.2). Furthermore, the SeDeM expert system was used for the first time to comprehensively study the powder properties of LRCs and to quickly visualize their defects (compressibility, lubricity/stability, and lubricity/dosage). The selection of excipients was targeted rather than traditional screening, thus obtaining a robust chewable tablet formulation suitable for direct compression. Finally, the difference between chewable tablets containing LRCs and chewable tablets containing lisdexamfetamine dimesylate was compared by in vitro dissolution test, electronic tongue, and disintegration test. In conclusion, an immediate-released, child-friendly lisdexamfetamine chewable tablets without bitterness was successfully developed by the QbD approach, using the SeDeM system, which may help in further development of chewable tablets.

Evaluation of binders in twin-screw wet granulation - Optimal combination of binder and disintegrant

The influence of localization (intragranular, split or extragranular) of three superdisintegrants (croscarmellose sodium, crospovidone, sodium starch glycolate) on granules and tablets after twin-screw granulation was studied. The aim was to find a suitable disintegrant type and disintegrant localization for lactose tablets manufactured with different hydroxypropyl cellulose (HPC) types. The disintegrants were found to decrease the particle size in granulation, where sodium starch glycolate had the lowest influence. The tablet tensile strength was not influenced strongly by the disintegrant type or localization. By contrast, the disintegration was dependent on the disintegrant type as well as the localization, where sodium starch glycolate performed worst. Intragranular croscarmellose sodium and extragranular crospovidone were identified as beneficial for chosen conditions because a satisfying tensile strength in combination with the fastest disintegration was found. These findings were achieved for one HPC type and the suitability of the best disintegrant-localization-combinations were confirmed for another two HPC types.

Modelling the Evolution of Pore Structure during the Disintegration of Pharmaceutical Tablets

Pharmaceutical tablet disintegration is a critical process for dissolving and enabling the absorption of the drug substance into the blood stream. The tablet disintegration process consists of multiple connected and interdependent mechanisms: liquid penetration, swelling, dissolution, and break-up. One key dependence is the dynamic change of the pore space in a tablet caused by the swelling of particles while the tablet takes up liquid. This study analysed the changes in the pore structure during disintegration by coupling the discrete element method (DEM) with a single-particle swelling model and experimental liquid penetration data from terahertz-pulsed imaging (TPI). The coupled model is demonstrated and validated for pure microcrystalline cellulose (MCC) tablets across three porosities (10, 15, and 22%) and MCC with three different concentrations of croscarmellose sodium (CCS) (2, 5, and 8% w/w). The model was validated using experimental tablet swelling from TPI. The model captured the difference in the swelling behaviour of tablets with different porosities and formulations well. Both the experimental and modelling results showed that the swelling was lowest (i.e., time to reach the maximum normalised swelling capacity) for tablets with the highest CCS concentration, cCCS = 8%. The simulations revealed that this was caused by the closure of the pores in both the wetted volume and dry volume of the tablet. The closure of the pores hinders the liquid from accessing other particles and slows down the overall swelling process. This study provides new insights into the changes in the pore space during disintegration, which is crucial to better understand the impact of porosity and formulations on the performance of tablets.

Stereomicroscope with Imaging Analysis: A Versatile Tool for Wetting, Gel Formation and Erosion Rate Determinations of Eutectic Effervescent Tablet

Wettability, gel formation and erosion behaviors could influence the drug release pattern of solid dosage forms. Typically, these parameters are evaluated using a variety of techniques. Nonetheless, there has been no previous research on versatile tool development for evaluating several tablet characteristics with a single tool. The aim of this study was to develop the versatile tool for measuring various physical properties of eutectic effervescent tablets and also investigate the relationship between these parameters with parameters from drug dissolution. Ibuprofen (IBU)-poloxamer 407 (P407) eutectic effervescent tablets were fabricated with a direct compression method. Their wetting properties, gel formation and erosion behaviors were investigated using a stereomicroscope with imaging analysis in terms of the liquid penetration distance, gel thickness and erosion boundary diameter, respectively. In addition, the dissolution rate (k) and disintegration time of eutectic effervescent tablets in 0.1 N HCl buffer pH 1.2 were also determined. Incorporation of P407 into the IBU tablet improved the tablet wetting properties with increasing liquid penetration distance under stereoscope. CO2 liberation from effervescent agents promoted tablet surface roughness from matrix erosion. The relationship between observed physical properties and disintegration and dissolution parameters suggested that the combination of erosion by effervescent agents and gel formation by P407 had a potential influence on dissolution enhancement of the formulation. Therefore, a developed stereomicroscope with an imaging analysis technique was exhibited as an alternative versatile tool for determining the wetting properties, gel formation and erosion behaviors of pharmaceutical solid dosage forms.

A generalized image analytical algorithm for investigating tablet disintegration

Commonly used methods for analyzing tablet disintegration are based on visual observations and can thus be user-dependent. To address this, a generally applicable image analytical algorithm has been developed for machine vision-based quantification of tablet disintegration. The algorithm has been tested with a conventional immediate release tablet, as well as model compacts disintegrating mainly through erosion, and finally, with a polymeric slow-release system. Despite differences in disintegration mechanisms between these compacts, the developed image analytical algorithm demonstrated its general applicability through quantifying the extent of disintegration without adaptation of image analytical parameters. The reproducibility of the approach was estimated with commercial tablets, and further, it could differentiate a range of different model compacts. The developed image analytical algorithm mimics the human decision-making processes and the current experience-based visual evaluation of disintegration time. In doing so the algorithmic method allows a user-independent approach for development of the optimal tablet formulation as well as gaining an understanding on how the selection of excipients and manufacturing processes ultimately influences tablet disintegration.

Seeing Is Believing: Time-Lapse Macro-Imaging of Morphological Changes of Solid Dosages as a Teaching and Research Tool

PURPOSE

Disintegration kinetics and behaviors are critical for the quality and performance of oral solid dosages. Instead of performing standard disintegration tests, herein, we aim to visualize these kinetic processes in real time.

METHOD

A visual acquisition system is developed to capture the morphological changes of tablets under static conditions via time-lapse macro-imaging. The system consists of: i) a customized quartz chamber, ii) a metal sieve with pore sizes ranging from 1 to 2 mm in diameter to allow rapid settling of the disintegrated particles, and iii) a temperature-controlled water bath. A typical workflow consists of the following steps: i) planning of the experiment to consider the type of the active pharmaceutical ingredient and drug release mechanism; ii) acquisition of photo-imaging data from at least two cameras arranged at different angles over a predetermined time period; iii) post-processing of the image data; iv) production of video clips and image analysis.

RESULTS

Representative works are shown to demonstrate the disintegration phenomenon or the morphological changes of solid drug products of various controlled- and extended-release mechanisms.

CONCLUSION

These video clips are used as teaching materials for students majoring in pharmacy or pharmaceutical chemistry, which also provide an insightful unique perspective of the microprocess during tablet fragmentation, disintegration or drug release.

Disintegration Testing Augmented by Computer Vision Technology

Oral solid dosage forms, specifically immediate release tablets, are prevalent in the pharmaceutical industry. Disintegration testing is often the first step of commercialization and large-scale production of these dosage forms. Current disintegration testing in the pharmaceutical industry, according to United States Pharmacopeia (USP) chapter <701>, only gives information about the duration of the tablet disintegration process. This information is subjective, variable, and prone to human error due to manual or physical data collection methods via the human eye or contact disks. To lessen the data integrity risk associated with this process, efforts have been made to automate the analysis of the disintegration process using digital lens and other imaging technologies. This would provide a non-invasive method to quantitatively determine disintegration time through computer algorithms. The main challenges associated with developing such a system involve visualization of tablet pieces through cloudy and turbid liquid. The Computer Vision for Disintegration (CVD) system has been developed to be used along with traditional pharmaceutical disintegration testing devices to monitor tablet pieces and distinguish them from the surrounding liquid. The software written for CVD utilizes data captured by cameras or other lenses then uses mobile SSD and CNN, with an OpenCV and FRCNN machine learning model, to analyze and interpreted the data. This technology is capable of consistently identifying tablets with ≥ 99.6% accuracy. Not only is the data produced by CVD more reliable, but it opens the possibility of a deeper understanding of disintegration rates and mechanisms in addition to duration.

Tablet Disintegration and Dispersion under In Vivo-like Hydrodynamic Conditions

Disintegration and dispersion are functional properties of tablets relevant for the desired API release. The standard disintegration test (SDT) described in different pharmacopoeias provides only limited information on these complex processes. It is considered not to be comparable to the biorelevant conditions due to the frequent occurrence of high hydrodynamic forces, among other reasons. In this study, 3D tomographic laser-induced fluorescence imaging (3D Tomo-LIF) is applied to analyse tablet disintegration and dispersion. Disintegration time (DT) and time-resolved particle size distribution in close proximity to the tablet are determined in a continuously operated flow channel, adjustable to very low fluid velocities. A case study on tablets of different porosity, which are composed of pharmaceutical polymers labelled with a fluorescent dye, a filler, and disintegrants, is presented to demonstrate the functionality and precision of the novel method. DT results from 3D Tomo-LIF are compared with results from the SDT, confirming the analytical limitations of the pharmacopoeial disintegration test. Results from the 3D Tomo-LIF method proved a strong impact of fluid velocity on disintegration and dispersion. Generally, shorter DTs were determined when cross-linked sodium carboxymethly cellulose (NaCMCXL) was used as disintegrant compared to polyvinyl polypyrrolidone (PVPP). Tablets containing Kollidon VA64 were found to disintegrate by surface erosion. The novel method provides an in-depth understanding of the functional behaviour of the tablet material, composition and structural properties under in vivo-like hydrodynamic forces regarding disintegration and the temporal progress of dispersion. We consider the 3D Tomo-LIF in vitro method to be of improved biorelevance in terms of hydrodynamic conditions in the human stomach.

Modeling the Tablet Disintegration Process Using the Finite Difference Method

The purpose of the study is to present the finite difference method (FDM) and demonstrate its utility in modeling mass transport processes that are pharmaceutically relevant. In particular, diffusion processes are ideally suited for FDM because the governing equation, Fick's second law of diffusion, can be readily solved using FDM over a finite space and time. The method entails the mesh creation, space and time discretization, and solving Fick's second law at each node using finite difference-based numerical schemes. We applied FDM to study tablet disintegration, in which the tablet water uptake was simulated with an effective water diffusion coefficient; the tablet disintegration was controlled by a designated critical water content parameter, beyond which the node is treated as being disintegrated from the tablet. The resulting simulation agreed with the experimental tablet disintegration behaviors, under both disintegration-controlled and water uptake-controlled conditions. This study highlighted the unique advantage of FDM, capable of providing spatial-temporal information on water uptake and evolution of tablet size and shape during tablet disintegration, which was otherwise not available using other methods. The FDM method enabled more in-depth tablet disintegration studies. The model also has the potential to be calibrated and incorporated in tablet formulation DoE studies.

Immediate-Release Formulations Produced via Twin-Screw Melt Granulation: Systematic Evaluation of the Addition of Disintegrants

The current study evaluated the effect of location and amount of various superdisintegrants on the properties of tablets made by twin-screw melt granulation (TSMG). Sodium-croscarmellose (CCS), crospovidone (CPV), and sodium starch glycolate (SSG) were used in various proportions intra- and extra-granular. Tabletability, compactibility, compressibility as well as friability, disintegration, and dissolution performance were assessed. The extra-granular addition resulted in the fasted disintegration and dissolution. CPV performed superior to CCS and SSG. Even if the solid fraction (SF) of the granules was lower for CPV, only a minor decrease in tabletability was observed, due to the high plastic deformation of the melt granules. The intra-granular addition of CPV resulted in a more prolonged dissolution profile, which could be correlated to a loss in porosity during tableting. The 100% intra-granular addition of the CPV resulted in a distinct decrease of the disintegration efficiency, whereas the performance of SSG was unaffected by the granulation process. CCS was not suitable to be used for the production of an immediate-release formulation, when added in total proportion into the granulation phase, but its efficiency was less impaired compared to CPV. Shortest disintegration (78 s) and dissolution (Q₈₀: 4.2 min) was achieved with CPV extra-granular. Using CPV and CCS intra-granular resulted in increased disintegration time and Q₈₀. However, at a higher level of appx. 500 s and appx. 15 min, only SSG showed a process and location independent disintegration and dissolution performance.

Tablet disintegration performance: Effect of compression pressure and storage conditions on surface liquid absorption and swelling kinetics

The disintegration process of pharmaceutical tablets is a crucial step in the oral delivery of a drug. Tablet disintegration does not only refer to the break up of the interparticle bonds, but also relates to the liquid absorption and swelling behaviour of the tablet. This study demonstrates the use of the sessile drop method coupled with image processing and models to analyse the surface liquid absorption and swelling kinetics of four filler combinations (microcrystalline cellulose (MCC)/mannitol, MCC/lactose, MCC/dibasic calcium phosphate anhydrous (DCPA) and DCPA/lactose) with croscarmellose sodium as a disintegrant. Changes in the disintegration performance of these formulations were analysed by quantifying the effect of compression pressure and storage condition on characteristic liquid absorption and swelling parameters. The results indicate that the disintegration performance of the MCC/mannitol and MCC/lactose formulations are driven by the liquid absorption behaviour. For the MCC/DCPA formulation, both liquid absorption and swelling characteristics affect the disintegration time, whereas DCPA/lactose tablets is primarily controlled by swelling characteristics of the various excipients. The approach discussed in this study enables a rapid (<1 min) assessment of characteristic properties that are related to tablet disintegration to inform the design of the formulation, process settings and storage conditions.

Image Analysis: A Versatile Tool in the Manufacturing and Quality Control of Pharmaceutical Dosage Forms

In pharmaceutical sciences, visual inspection is one of the oldest methods used for description in pharmacopeias and is still an important part of the characterization and qualification of active ingredients, excipients, and dosage forms. With the development of technology, it is now also possible to take images of various pharmaceutical dosage forms with different imaging methods in a size range that is hardly visible or completely invisible to the human eye. By analyzing high-quality designs, physicochemical processes can be understood, and the results can be used even in the optimization of the composition of the dosage form and in the development of its production. The present study aims to show some of the countless ways image analysis can be used in the manufacturing and quality assessment of different dosage forms. This summary also includes measurements and an evaluation of, amongst others, a less studied dosage form, medicated foams.

Alginates as tablet disintegrants: Understanding disintegration mechanisms and defining ranges of applications

Alginates are biopolymers that have been investigated for their use in food and medical fields. Minimal information is available regarding their potential application as tablet superdisintegrants. Here we studied the disintegration action of sodium alginate (SA), calcium alginate (CA) and alginic acid (AA). Initially, we characterised the swelling and wicking abilities and the disintegration mechanism of pure disintegrants. We found that the liquid uptake of both CA and AA is more swelling-driven in phosphate buffer and more wicking-driven in hydrochloric acid and water. CA acts by shape-recovery, AA by a combination of swelling and shape-recovery mechanisms. SA cannot be used as disintegrant due to gelling. In the second part of the paper, the disintegration time of formulations with different physico-chemical properties and different alginate concentrations (i.e. 4% and 10%) was measured, thus delivering a direct readout for the ranges of application of alginates as tablets disintegrants. The main observations are: i) CA and AA often provide very rapid disintegration, similarly to the superdisintegrants used as controls; ii) the action of CA is more susceptible to the medium conditions than AA; iii) CA underperforms in hard tablets containing a binder; iv) both CA and AA have slightly slower disintegration than other superdisintegrants in tablets containing a hydrophobic component. While the suitability of CA as a disintegrant is formulation- and medium- dependent, AA appears as a promising tablet superdisintegrant, particularly for the development of uncomplicated hydrophilic formulations for the nutraceutical and supplement industry, where natural ingredients are favoured.

Advancing the understanding of the tablet disintegration phenomenon - An update on recent studies

Disintegration is the de-aggregation of particles within tablets upon exposure to aqueous fluids. Being an essential step in the bioavailability cascade, disintegration is a fundamental quality attribute of immediate release tablets. Although the disintegration phenomenon has been studied for over six decades, some gaps of knowledge and research questions still exist. Three reviews, published in 2015, 2016 and 2017, have discussed the literature relative to tablet disintegration and summarised the understanding of this topic. Yet, since then more studies have been published, adding to the established body of knowledge. This article guides a step forward towards the comprehension of disintegration by reviewing, concisely, the most recent scientific updates on this topic. Initially, we revisit the mechanisms of disintegration with relation to the three most used superdisintegrants, namely sodium starch glycolate, croscarmellose sodium and crospovidone. Then, the influence of formulation, storage, manufacturing and media conditions on disintegration is analysed. This is followed by an excursus on novel disintegrants. Finally, we highlight unanswered research questions and envision future research venues in the field.

An improved method for the simultaneous determination of water uptake and swelling of tablets

Water uptake and swelling of tablets are processes occurring during active pharmaceutical ingredient (API) release. Thereby, disintegration is promoted and the enhanced exposure of API surface area to the release medium facilitates API dissolution. An experimental set-up for the simultaneous and time-resolved determination of water uptake and swelling of tablets has been developed. Water uptake was determined with a balance and swelling was determined with a camera. To validate the gravimetrical analysis, real-time water uptake measurements with inert test specimens were performed. The standard deviation of these measurements was considered to depict precision. A complementary gravimetrical analysis was employed to determine accuracy. For both, precision and accuracy, a maximum deviation of 6% was found. An algorithm for the symmetry-based 3D volume reconstruction was applied to obtain volumes of the tablets from 2D images. X-ray micro computed tomography was used to validate the accuracy and the determined volumes were in good accordance within 6% deviation. A case study with binary formulations of a filler and disintegrants confirmed reproducibility and demonstrated the ability of the method to discriminate formulation characteristics, such as disintegrant type, composition and porosity for water uptake and swelling with the necessary temporal resolution.

Exploring the performance-controlling tablet disintegration mechanisms for direct compression formulations

The design and manufacture of tablets is a challenging process due to the complex interrelationships between raw material properties, the manufacturing settings and the tablet properties. An important factor in formulation and process design is the fact that raw material and tablet properties drive the disintegration and dissolution performance of the final drug product. This study aimed to identify the mechanisms which control tablet disintegration for 16 different immediate-release placebo formulations based on raw material and tablet properties. Each formulation consisted of two fillers (47% each), one disintegrant and a lubricant. Tablets were manufactured by direct compression using four different combinations of the fillers microcrystalline cellulose (MCC), mannitol, lactose and dibasic calcium phosphate anhydrous (DCPA). The disintegration mechanism was primarily driven by the filler combination, where MCC/lactose tablets were identified as wettability controlled, MCC/mannitol tablets as dissolution controlled and DCPA-based tablets (MCC/DCPA and lactose/DCPA) as swelling controlled. A change of 2% in porosity for the wettability controlled tablets (MCC/lactose) caused a significant acceleration of the disintegration process (77% reduction of disintegration time), whereas for swelling controlled tablets (MCC/DCPA) the same porosity change did not considerably impact the disintegration process (3% change in disintegration time). By classifying these formulations, critical formulation and manufacturing properties can be identified to allow tablet performance to be optimised.

Disintegrant Selection in Hydrophobic Tablet Formulations

The hydrophobicity of poorly soluble drugs can delay tablets disintegration. We probed here the influence of different disintegrants on the disintegration of challenging hydrophobic formulations. Tablets containing diluents, hydrogenated vegetable oil and either sodium starch glycolate (SSG), croscarmellose sodium (CCS) or crospovidone (XPVP) were prepared. The disintegration time of tablets was tested immediately and after storage at 40 °C and 75% RH in sealed bags. Results show that storage and compression force had a negative effect on disintegration, particularly with 1% disintegrant. The performance of the three disintegrants was in the following order: CCS (best) > SSG > XPVP. For example, tablets containing 1% CCS, SSG and XPVP, compressed at 20 kN, disintegrated in ≈3, ≈12 and ≈69 min, respectively, after two months storage. Settling volume, liquid uptake and effect of storage on physical properties of the pure disintegrants were also studied and revealed that the reduced performance of XPVP is related to: 1) its rapid, yet short-range expansion upon liquid exposure and 2) its change of behaviour on storage. In conclusion, CCS ensured rapid disintegration at low concentration across various compression forces and storage times. Thus, the use of CCS in hydrophobic tablet formulations is recommended.

Quantification of swelling characteristics of pharmaceutical particles

Particle swelling is a crucial component in the disintegration of a pharmaceutical tablet. The swelling of particles in a tablet creates stress inside the tablet and thereby pushes apart adjoining particles, eventually causing the tablet to break-up. This work focused on quantifying the swelling of single particles to identify the swelling-limited mechanisms in a particle, i.e. diffusion- or absorption capacity-limited. This was studied for three different disintegrants (sodium starch glycolate/SSG, croscarmellose sodium/CCS, and low-substituted hydroxypropyl cellulose/L-HPC) and five grades of microcrystalline cellulose (MCC) using an optical microscope coupled with a bespoke flow cell and utilising a single particle swelling model. Fundamental swelling characteristics, such as diffusion coefficient, maximum liquid absorption ratio and swelling capacity (maximum swelling of a particle) were determined for each material. The results clearly highlighted the different swelling behaviour for the various materials, where CCS has the highest diffusion coefficient with 739.70 μm²/s and SSG has the highest maximum absorption ratio of 10.04 g/g. For the disintegrants, the swelling performance of SSG is diffusion-limited, whereas it is absorption capacity-limited for CCS. L-HPC is both diffusion- and absorption capacity-limited. This work also reveals an anisotropic, particle facet dependant, swelling behaviour, which is particularly strong for the liquid uptake ability of two MCC grades (PH101 and PH102) and for the absorption capacity of CCS. Having a better understanding of swelling characteristics of single particles will contribute to improving the rational design of a formulation for oral solid dosage forms.

Recent Strategic Developments in the Use of Superdisintegrants for Drug Delivery

Improving drug bioavailability in the pharmaceutical field is a challenge that has attracted substantial interest worldwide. The controlled release of a drug can be achieved with a variety of strategies and novel materials in the field. In addition to the vast development of innovative materials for improving therapeutic effects and reducing side effects, the exploration of remarkable existing materials could encourage the discovery of diverse approaches for adapted drug delivery systems. Recently, superdisintegrants have been proposed for drug delivery systems as alternative approaches to maximize the efficiency of therapy. Although superdisintegrants are well known and used in solid dosage forms, studies on strategies for the development of drug delivery systems using superdisintegrants are lacking. Therefore, this study reviews the use of superdisintegrants in controlled drug release dosage formulations. This overview of superdisintegrants covers developed strategies, types (including synthetic and natural materials), dosage forms and techniques and will help to improve drug delivery systems.

Swelling of Zein Matrix Tablets Benchmarked against HPMC and Ethylcellulose: Challenging the Matrix Performance by the Addition of Co-Excipients

Zein is an insoluble, yet swellable, biopolymer that has been extensively studied for its applications in drug delivery. Here, we screened the effect of co-excipients on the swelling and drug release of zein tablets. All throughout the study the behavior of zein was benchmarked against that of hydroxypropyl methylcellulose (HPMC) and ethylcellulose (EC). Tablets containing either zein, HPMC, or EC alone or in combination with co-excipients, namely lactose, dicalcium phosphate (DCP), microcrystalline cellulose (MCC), polyvinylpyrrolidone (PVP), or sodium lauryl sulfate (SLS) were prepared by direct compression. Matrix swelling was studied by taking continuous pictures of the tablets over 20 h, using a USB microscope connected to a PC. The overall size change and the axial and radial expansion of the tablets were automatically extrapolated from the pictures by image analysis. Moreover, drug release from tablets containing ternary mixtures of zein, co-excipients and 10% propranolol HCl was also studied. Results showed that zein matrices swelled rapidly at first, but then a plateau was reached, resulting in an initial rapid drug burst followed by slow drug release. HPMC tablets swelled to a greater extent and more gradually, providing a more constant drug release rate. EC did not practically swell, giving a nearly constant drug release pattern. Among the additives studied, only MCC increased the swelling of zein up to nearly three-fold, and thus suppressed drug burst from zein matrices and provided a nearly constant drug release over the test duration. Overall, the incorporation of co-excipients influenced the swelling behavior of zein to a greater extent compared to that of HPMC and EC, indicating that the molecular interactions of zein and additives are clearly more complex and distinct.

Evaluation of the Disintegration Action of Soy Polysaccharide by Image Analysis

Here we investigated the disintegration action of the natural superdisintegrant soy polysaccharide (SP) and benchmarked it against sodium starch glycolate (SSG) and crospovidone (XPVP). Kinetics and mechanism of disintegration of various tablet formulations were monitored using a USB microscope connected to a computer, followed by image analysis. SP acts mainly by a swelling mechanism and it is most effective at concentrations of 4-8%. Its disintegration action is comparable with that of SSG and XPVP, in most cases. However, SP underperforms compared with these superdisintegrants, in extremely hard tablets containing a hydrophobic component. Moreover, it is more negatively affected by the concentration of magnesium stearate than SSG and XPVP. The disintegration action of SP is not affected by pH and ionic strength of the medium, but it is compromised by the presence of ethanol. This indicates that the concomitant administration of alcoholic beverages might hamper the disintegration of SP-containing tablets. Overall, SP is a promising tablet disintegrant for pharmaceutical and nutraceutical products.

The influence of ethanol on superdisintegrants and on tablets disintegration

Disintegration of immediate release tablets originates from the volume expansion of disintegrants within the formulation. Here, we study the impact of ethanol on the disintegrant expansion and on tablets disintegration. The three most commonly used superdisintegrants, namely sodium starch glycolate (SSG), crospovidone (PVPP) and croscarmellose sodium (CCS) were investigated alone and incorporated in dicalcium phosphate and in drug-containing tablets. High (i.e. 40%), but not moderate (i.e. 10%), aqueous ethanol concentrations reduce the size expansion of the three disintegrants compared to water. This "ethanol effect" is the greatest for SSG, followed by CCS and then PVPP. Moreover, the presence of ethanol in the media can significantly influence the disintegration time of drug-containing tablets via affecting both the disintegrant action itself and the drug solubility. For example, the disintegration time of theophylline tablets containing SSG is 8.1-fold greater in 40% aqueous ethanol compared to water. Overall, this study brought to light the existence of a potentially significant interference of alcohol with the disintegration phenomenon, suggesting that the concomitant administration of tablets and intake of alcoholic beverages may affect, in some cases, tablets disintegration. More studies are now needed to verify the importance of the "ethanol effect" on disintegration of commercial dosage forms. Our findings also suggest that PVPP is the disintegrant that is the least affected by alcohol.