A Review of Disintegration Mechanisms and Measurement Techniques

In-situ monitoring of in vitro drug release processes in tablets using optical coherence tomography

Film-coated modified-release tablets are an important dosage form amenable to targeted, controlled, or delayed drug release in the specific region of the gastrointestinal (GI) tract. Depending on the film composition and interaction with the GI fluid, such coated products can modulate the local bioavailability, systemic absorption, protection as an enteric barrier, etc. Although the interaction of a dosage form with the surrounding dissolution medium is vital for the resulting release behavior, the underlying physicochemical phenomena at the film and core levels occurring during the drug release process have not yet been well described. In this work, we attempted to tackle this limitation by introducing a novel in vitro test based on optical coherence tomography (OCT) that allows an in-situ investigation of the sub-surface processes occurring during the drug release. Using a commercially available tablet based on osmotic-controlled release oral delivery systems (OROS), we demonstrated the performance of the presented prototype in terms of monitoring the membrane thickness and thickness variability, the surface roughness, the core swelling behavior, and the porosity of the core matrix throughout the in vitro drug release process from OROS. The superior spatial (micron scale) and temporal (less than 10 ms between the subsequent tomograms) resolution achieved in the proposed setup provides an improved understanding of the dynamics inside the microstructure at any given time during the dissolution procedure with the previously unattainable resolution, offering new opportunities for the design and testing of patient-centric dosage forms.

Fabrication and characterization of cocoa butter-based caffeine fast-melting tablets

Aim: The objective of this study was to develop and characterize the physical properties of fast-melting tablets (FMTs) using cocoa butter as the base and caffeine as the model drug. Method: The simple refrigerator freezing method was employed to prepare caffeine-loaded, FMTs from cocoa butter bases. Results: The F3 chosen formulation achieved a disintegration time of 1.20 min ± 0.035, which falls within the specified limit set by the European Pharmacopoeia. The cumulative drug release data of F3, was 88.52 and 94.08% within 60 and 75 min, respectively (NLT 85% as per US FDA requirement). All the other physical test standards for FMTs met the pharmacopeial specifications. Conclusion: Based on the findings, the simple refrigerator freezing method could be used to formulate FMTs.

Exosomes isolated from citrus lemon: a promising candidate for the treatment of Alzheimer's disease

Aim: To investigate the efficacy of exosome-like nanovesicles from citrus lemon (EXO-CLs) in combating oxidative stress associated with Alzheimer's disease. Materials & methods: EXO-CLs were isolated through differential ultracentrifugation, characterized for particle size and evaluated for antioxidant activity. Results: EXO-CLs exhibited a mean size of 93.77 ± 12.31 nm, demonstrated permeability across the blood-brain barrier (BBB) and displayed antioxidant activity comparable to ascorbic acid. Additionally, they were found to be non-toxic, with over 80% cell viability observed in SH-SY5Y cells. Conclusion: The study proposes that EXO-CLs could serve as an effective treatment for neurodegenerative diseases. This suggests a promising approach for targeted interventions in brain-related disorders, owing to the antioxidant properties and BBB permeability exhibited by EXO-CLs.

Calorimetric investigation on heat release during the disintegration process of pharmaceutical tablets

The compendial USP〈701〉 disintegration test method offers a crucial pass/fail assessment for immediate release tablet disintegration. However, its single end-point approach provides limited insight into underlying mechanisms. This study introduces a novel calorimetric approach, aimed at providing comprehensive process profiles beyond binary outcomes. We developed a novel disintegration reaction calorimeter to monitor the heat release throughout the disintegration process and successfully obtained enthalpy change profiles of placebo tablets with various porosities. The formulation comprised microcrystalline cellulose (MCC), anhydrous lactose, croscarmellose sodium (CCS), and magnesium stearate (MgSt). An abrupt temperature rise was observed after introducing the disintegration medium to tablets, and the relationship between the heat rise time and the tablet's porosity was investigated. The calorimeter's sensitivity was sufficient to discern distinct heat changes among individual tablets, and the analysis revealed a direct correlation between the two. Higher porosity corresponded to shorter heat rise time, indicating faster disintegration rates. Additionally, the analysis identified a concurrent endothermic process alongside the anticipated exothermic phenomenon, potentially associated with the dissolution of anhydrous lactose. Since lactose is the only soluble excipient within the blend composition, the endothermic process can be attributed to the absorption of heat as lactose molecules dissolve in water. The findings from this study underscore the potential of utilising calorimetric methods to quantify the wettability of complex compounds and, ultimately, optimise tablet formulations.

Proton Pump Inhibitors Do Not Affect the Bioavailability of a Novel Liquid Formulation of Levothyroxine

OBJECTIVE

This study evaluates the impact of a representative proton pump inhibitor (PPI) (omeprazole), administered simultaneously or staggered, on the pharmacokinetics of levothyroxine (LT4) solution (Tirosint-SOL).

METHODS

This was a randomized, 3-way crossover, comparative bioavailability study in 36 healthy adults under fasting conditions. Omeprazole 40 mg delayed-release capsule was administered once daily from Day 1 to 6 (mornings, Treatment-A; evenings, Treatment-B; none, Treatment-C) to increase and stabilize gastric pH. In the morning of Day 5, a single dose of LT4 solution 600 mcg was administered. Blood samples were collected 0 to 48 hours post-LT4 administration. Noncompartmental pharmacokinetic parameters were calculated for total serum thyroxine using baseline-corrected data. Maximum concentration (Cmax) and area under the concentration-time curve (AUC0-48) were included in an analysis of variance to obtain geometric mean ratios and 90% confidence intervals.

RESULTS

For both comparisons (A/C and B/C), geometric mean ratios and 90% confidence intervals for all parameters were within the equivalence boundaries (80%-125%), indicating bioequivalence: for A/C, AUC0-48 98.98% [94%-104%], and Cmax 91.68% [87%-97%]; for B/C, AUC0-48 98.94% [95%-103%], and Cmax 94.90% [90%-100%]. Median Tmax (time associated with Cmax) was similar across treatments.

CONCLUSION

This study demonstrated that Tirosint-SOL bioavailability is unaffected by coadministration of a representative PPI, given simultaneously or staggered by about 12 hours, compared to administration of LT4 solution alone. For hypothyroid patients on PPI therapy, administration of LT4 solution may reduce variations in thyroid stimulating hormone levels related to intermittent use of acid-reducing drugs and consequently the need for dose adjustments.

Ten years of the manufacturing classification system: a review of literature applications and an extension of the framework to continuous manufacture

The MCS initiative was first introduced in 2013. Since then, two MCS papers have been published: the first proposing a structured approach to consider the impact of drug substance physical properties on manufacturability and the second outlining real world examples of MCS principles. By 2023, both publications had been extensively cited by over 240 publications. This article firstly reviews this citing work and considers how the MCS concepts have been received and are being applied. Secondly, we will extend the MCS framework to continuous manufacture. The review structure follows the flow of drug product development focussing first on optimisation of API properties. The exploitation of links between API particle properties and manufacturability using large datasets seems particularly promising. Subsequently, applications of the MCS for formulation design include a detailed look at the impact of percolation threshold, the role of excipients and how other classification systems can be of assistance. The final review section focusses on manufacturing process development, covering the impact of strain rate sensitivity and modelling applications. The second part of the paper focuses on continuous processing proposing a parallel MCS framework alongside the existing batch manufacturing guidance. Specifically, we propose that continuous direct compression can accommodate a wider range of API properties compared to its batch equivalent.

Amelioration of tableting properties and dissolution rate of naproxen co-grinded with nicotinamide: preparation and characterization of co-grinded mixture

OBJECTIVE AND SIGNIFICANCE

Reducing the dimensions, when other additives are present, shows potential as a method to improve the dissolution and solubility of biopharmaceutical classification system class II drugs that have poor solubility. In this investigation, the process involved grinding naproxen with nicotinamide with the aim of improving solubility and the rate of dissolution.

METHODS

Naproxen was subjected to co-milling with urea, dimethylurea, and nicotinamide using a planetary ball mill for a duration of 90 min, maintaining a 1:1 molar ratio for the excipients (screening studies). The co-milled combinations, naproxen in its pure milled form, and a physical mixture were subjected to analysis using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), and solubility assessment. The mixture displaying the highest solubility (naproxen-nicotinamide) was chosen for further investigation, involving testing for intrinsic dissolution rate (IDR) and Fourier-transform infrared spectroscopy (FTIR) after co-milling for both 90 and 480 min.

RESULTS AND CONCLUSION

The co-milled combination, denoted as S-3b and consisting of the most substantial ratio of nicotinamide to naproxen at 1:3, subjected to 480 min of milling, exhibited a remarkable 45-fold increase in solubility and a 9-fold increase in IDR. XRPD analysis of the co-milled samples demonstrated no amorphization, while SEM images portrayed the aggregates of naproxen with nicotinamide. FTIR outcomes negate the presence of any chemical interactions between the components. The co-milled sample exhibiting the highest solubility and IDR was used to create a tablet, which was then subjected to comprehensive evaluation for standard attributes. The results revealed improved compressibility and dissolution properties.

Flexible modelling of the dissolution performance of directly compressed tablets

In this study, a compartmental disintegration and dissolution model is proposed for the prediction and evaluation of the dissolution performance of directly compressed tablets. This dissolution model uses three compartments (Bound, Disintegrated, and Dissolved) to describe the state of each particle of active pharmaceutical ingredient. The disintegration of the tablet is captured by three fitting parameters. Two disintegration parameters, β0 and βt,0, describe the initial disintegration rate and the change in disintegration rate, respectively. A third parameter, α, describes the effect of the volume of dissolved drug on the disintegration process. As the tablet disintegrates, particles become available for dissolution. The dissolution rate is determined by the Nernst-Brunner equation, whilst taking into account the hydrodynamic effects within the vessel of a USP II (paddle) apparatus. This model uses the raw material properties of the active pharmaceutical ingredient (solubility, particle size distribution, true density), lending it towards early development activities during which time the amount of drug substance available may be limited. Additionally, the strong correlations between the fitting parameters and the tablet porosity indicate the potential to isolate the manufacturing effects and thus implement the model as part of a real-time release testing strategy for a continuous direct compression line.

Machine learning modeling for ultrasonic quality attribute assessment of pharmaceutical tablets for continuous manufacturing and real-time release testing

In in-process quality monitoring for Continuous Manufacturing (CM) and Critical Quality Attributes (CQA) assessment for Real-time Release (RTR) testing, ultrasonic characterization is a critical technology for its direct, non-invasive, rapid, and cost-effective nature. In quality evaluation with ultrasound, relating a pharmaceutical tablet's ultrasonic response to its defect state and quality parameters is essential. However, ultrasonic CQA characterization requires a robust mathematical model, which cannot be obtained with traditional first principles-based modeling approaches. Machine Learning (ML) using experimental data is emerging as a critical analytical tool for overcoming such modeling challenges. In this work, a novel Deep Neural Network-based ML-driven Non-Destructive Evaluation (ML-NDE) modeling framework is developed, and its effectiveness for extracting and predicting three CQAs, namely defect states, compression force levels, and amounts of disintegrant, is demonstrated. Using a robotic tablet handling experimental rig, each attribute's distinct waveform dataset was acquired and utilized for training, validating, and testing the respective ML models. This study details an advanced algorithmic quality assessment framework for pharmaceutical CM in which automated RTR testing is expected to be critical in developing cost-effective in-process real-time monitoring systems. The presented ML-NDE approach has demonstrated its effectiveness through evaluations with separate (unused) test datasets.

Characterization of microcrystalline cellulose prepared from long and short fibers and its application in ibuprofen tablets

As a bio-based material, microcrystalline cellulose (MCC) has been applied in many fields including pharmaceuticals, foods, and cosmetics in recent years. However, traditional preparation methods of MCC are facing many challenges due to economic and eco-environmental issues. In this study, softwood dissolved pulp was sieved to long fiber (LF) and short fiber (SF), and subsequently to prepare LF-MCC and SF-MCC by hydrochloric acid hydrolysis at different acid dosages (3-7 wt%), reaction times (30-90 min), and temperatures (75-95 °C). The as-obtained MCC products were compared in terms of morphology, size, crystallinity, and chemical structure. The results indicated that the crystallinity and yield of LF-MCC were high, with maximum values of 78.41 % and 98.68 %, respectively. The particle size distribution of SF-MCC was more uniform in the range of 20-80 μm, with a maximum of 59.44 % at 20-80 μm occupancy proportion. Moreover, SF-MCC had a typical rod-like shape and larger surface area as well as better thermal behavior than LF-MCC. When LF-MCC and SF-MCC were used as fillers in the production of ibuprofen tablets, the tablets added with LF-MCC exhibited higher hardness, friability, dissolution rate, and shorter disintegration time. Therefore, this work is very beneficial for the preparation and application of MCC.

Use of Magnetic Resonance Imaging for Visualization of Oral Dosage Forms in the Human Stomach: A Scoping Review

Oral dosage forms are the most widely and frequently used formulations to deliver active pharmaceutical ingredients (APIs), due to their ease of administration and noninvasiveness. Knowledge of intragastric release rates and gastric mixing is crucial for predicting the API release profile, especially for immediate release formulations. However, knowledge of the intragastric fate of oral dosage forms in vivo to date is limited, particularly for dosage forms administered when the stomach is in the fed state. An improved understanding of gastric food processing, dosage form location, disintegration times, and food effects is essential for greater understanding for effective API formulation design. In vitro standard and controlled modeling has played a significant role in predicting the behavior of dosage forms in vivo. However, discrepancies are reported between in vitro and in vivo disintegration times, with these discrepancies being greatest in the fed state. Studying the fate of a dosage form in vivo is a challenging process, usually requiring the use of invasive methods, such as intubation. Noninvasive, whole body imaging techniques can however provide unique insights into this process. A scoping review was performed systematically to identify and critically appraise published studies using MRI to visualize oral solid dosage forms in vivo in healthy human subjects. The review identifies that so far, an all-purpose robust contrast agent or dosage form type has not been established for dosage form visualization and disintegration studies in the gastrointestinal system. Opportunities have been identified for future studies, with particular focus on characterizing dosage form disintegration for development after the consumption food, as exemplified by the standard Food and Drug Administration (FDA) high fat meal.

Semi-crystalline materials for pharmaceutical fused filament fabrication: Dissolution and porosity

A better understanding of crystallization kinetics and the effect on drug product quality characteristics is needed to exploit the use of semi-crystalline polymers in pharmaceutical fused filament fabrication. Filaments were prepared from polycaprolactone or polyethylene oxide loaded with a crystallization inhibitor or inducer, which was either 10% (w/w) ibuprofen or theophylline. A design-of-experiments approach was conducted to investigate the effect of nozzle temperature, bed temperature and print speed on the printed tablets' microstructure and dissolution kinetics. Helium pycnometry derived porosity proved an ideal technique to capture significant distortions in the tablets' microstructure. On the other hand, terahertz time domain spectroscopy (THz-TDS) analysis proved valuable to investigate additional enclosed pores of the tablets' microstructure. The surface roughness was analyzed using optical coherence tomography, showing the importance of extensional viscosity for printed drug products. Drug release occurred via erosion for tablets consisting of polyethylene oxide, which partly reduced the effect of the inner microstructure on the drug release kinetics. An initial burst release effect was noted for polycaprolactone tablets, after which drug release continued via diffusion. Both the pore and crystalline microstructure were deemed essential to steer drug release. In conclusion, this research provided guidelines for material and process choice when a specific microstructure has to be constructed from semi-crystalline materials. In addition, non-destructive tests for the characterization of printed products were evaluated.

Advanced analysis of disintegrating pharmaceutical compacts using deep learning-based segmentation of time-resolved micro-tomography images

The mechanism governing pharmaceutical tablet disintegration is far from fully understood. Despite the importance of controlling a formulation's disintegration process to maximize the active pharmaceutical ingredient's bioavailability and ensure predictable and consistent release profiles, the current understanding of the process is based on indirect or superficial measurements. Formulation science could, therefore, additionally deepen the understanding of the fundamental physical principles governing disintegration based on direct observations of the process. We aim to help bridge the gap by generating a series of time-resolved X-ray micro-computed tomography (μCT) images capturing volumetric images of a broad range of mini-tablet formulations undergoing disintegration. Automated image segmentation was a prerequisite to overcoming the challenges of analyzing multiple time series of heterogeneous tomographic images at high magnification. We devised and trained a convolutional neural network (CNN) based on the U-Net architecture for autonomous, rapid, and consistent image segmentation. We created our own μCT data reconstruction pipeline and parameterized it to deliver image quality optimal for our CNN-based segmentation. Our approach enabled us to visualize the internal microstructures of the tablets during disintegration and to extract parameters of disintegration kinetics from the time-resolved data. We determine by factor analysis the influence of the different formulation components on the disintegration process in terms of both qualitative and quantitative experimental responses. We relate our findings to known formulation component properties and established experimental results. Our direct imaging approach, enabled by deep learning-based image processing, delivers new insights into the disintegration mechanism of pharmaceutical tablets.

Comparison of Properties of Acetaminophen Tablets Prepared by Wet Granulation Using Freeze-Dried Versus Phase-Inversion Bacterial Cellulose as Diluent

Bacterial cellulose (BC) is an interesting material for drug delivery applications due to its high purity. This study aimed to compare the properties of tablets prepared by the wet granulation method using bacterial cellulose prepared by different methods as a diluent, using acetaminophen as a model drug. BC used as diluents were prepared using two different methods: freeze-drying (BC-FD) and phase-inversion (BC-PI), and their characteristics were analyzed and compared with that of commercial microcrystalline cellulose PH 101 (Comprecel® M101). Acetaminophen tablets were prepared by wet granulation using BC-FD, BC-PI, or Comprecel® M101 as diluents, and their tablet properties were examined. The result showed that the morphology, polymorph, and crystallinity of BC-PI and Comprecel® M101 were similar but they were different compared with that of BC-FD. Tablets could be successfully formed using BC-PI and Comprecel® M101 as diluents without any physical defects but the tablet prepared using BC-FD as diluent appeared chipped edge. The characteristics (thickness, weight variation, hardness, friability, disintegration, drug content, and dissolution) of the tablets prepared using BC-PI diluent were also similar to those prepared using Comprecel® M101 diluent, but those of BC-FD diluent were inferior. This indicates that BC prepared in BC-PI can potentially be used as a diluent for tablets prepared by wet granulation.

Time-Lapse Macro Imaging with Dissolution Tests for Exploring the Interrelationship Between Disintegration and Dissolution Behaviors of Solid Dosages

OBJECTIVE

This study aims to establish a Flow-through Visualization Dissolution System (FVDS) that combines time-lapse macro-imaging and a flow-through cell to simultaneously elucidate dissolution and disintegration profiles.

METHODS

Three cefaclor extended-release tablets (CEC-1, CEC-2, CEC-3) from different manufacturers were subjected to dissolution tests using both the US Pharmacopeia basket method and the FVDS method. Two dissolution media plans were implemented in FVDS: i) Plan I involved dissolution in pH1.0 medium for 12 h; ii) Plan II initiated dissolution in pH1.0 medium for 1 h, followed by pH6.8 phosphate buffer for 11 h. The resulting dissolution data were fitted using classic mathematical models. Pixel information was further extracted from images obtained using FVDS and plotted over time.

RESULTS

The basket method showed the cumulative dissolution of all three tablets in pH1.0, pH4.0 and water reached 80% within 6 h, but remained below 60% in the pH6.8 medium. The f2 values indicated CEC-2 was similar to CEC-1 in the pH4.0 medium, pH6.8 medium and water. Using FVDS with medium plan II, the cumulative dissolution of CEC-1 and CEC-2 reached about 80% showing similarity, while no similarity was observed between CEC-3 and CEC-1. The f2 factor of the percentage area change profiles also showed consistent results in the dissolution profile of medium plan II. However, FVDS with medium plan I cannot distinguish between CEC-2 and CEC-3.

CONCLUSION

FVDS offers an alternative to traditional dissolution methods by integrating imaging analysis as a complementary tool to disintegration and dissolution testing methods.

Model-Informed Drug Development: In Silico Assessment of Drug Bioperformance following Oral and Percutaneous Administration

The pharmaceutical industry has faced significant changes in recent years, primarily influenced by regulatory standards, market competition, and the need to accelerate drug development. Model-informed drug development (MIDD) leverages quantitative computational models to facilitate decision-making processes. This approach sheds light on the complex interplay between the influence of a drug's performance and the resulting clinical outcomes. This comprehensive review aims to explain the mechanisms that control the dissolution and/or release of drugs and their subsequent permeation through biological membranes. Furthermore, the importance of simulating these processes through a variety of in silico models is emphasized. Advanced compartmental absorption models provide an analytical framework to understand the kinetics of transit, dissolution, and absorption associated with orally administered drugs. In contrast, for topical and transdermal drug delivery systems, the prediction of drug permeation is predominantly based on quantitative structure-permeation relationships and molecular dynamics simulations. This review describes a variety of modeling strategies, ranging from mechanistic to empirical equations, and highlights the growing importance of state-of-the-art tools such as artificial intelligence, as well as advanced imaging and spectroscopic techniques.

Development of α-Cyclodextrin-Based Orally Disintegrating Tablets for 4-Phenylbutyrate

Despite major improvements brought about by the introduction of taste-masked formulations of 4-phenylbutyrate (PB), poor compliance remains a significant drawback to treatment for some pediatric and dysphagic patients with urea cycle disorders (UCDs). This study reports on the development of a cyclodextrin (CD)-based orally disintegrating tablet (ODT) formulation for PB as an alternative to existing formulations. This is based on previous reports of the PB taste-masking potential of CDs and the suitability of ODTs for improving compliance in pediatric and dysphagic populations. In preliminary studies, the interactions of PB with α and βCD in the solid state were characterized using X-ray diffraction, scanning electron microscopy, dissolution, and accelerated stability studies. Based on these studies, lyophilized PB-CD solid systems were formulated into ODTs after wet granulation. Evaluation of the ODTs showed that they had adequate physical characteristics, including hardness and friability and good storage stability. Notably, the developed αCD-based ODT for PB had a disintegration time of 28 s and achieved a slightly acidic and agreeable pH (≈5.5) in solution, which is suitable for effective PB-CD complexation and taste masking. The developed formulation could be helpful as an alternative to existing PB formulations, especially for pediatric and dysphagic UCD patients.

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.

Unravelling the functionality of anionic and non-ionic plant seed gums on milk protein cryogels conveying Lacticaseibacillus rhamnosus GG

Cryogels offer a promising macroporous platform that can be employed as either a functional ingredient in food composites or a colloidal template for incorporating bioactives, including probiotic living cells. The aim of the present work is to explore the functionality of two plant seed polysaccharides, flaxseed gum (FG) and alfalfa galactomannan (AAG), in individual and combined (1:1 ratio) milk protein-based cryogels, namely sodium caseinate (NaCas) and whey protein isolate (WPI). These cryogels were created by freeze-drying hydrogels formed via L.rhamnosus GG - a human gut-relevant probiotic strain - fermentation. Our findings showed that including gum in the composition limited volume contraction during lyophilisation, reduced macropore size and thickened cryogel skeleton vessels. Furthermore, gum-containing cryogels displayed improved thermal stability and slower water disintegration rates. The AAG-stabilised cryogels specifically showed a notable reduction in monolayer water content compared to FG. From a mechanistic viewpoint, AAG influenced the physicochemical and microstructural properties of the cryogels, most probably via its self-association during cryogenic processing, promoting the development of intertwined protein-gum networks. FG, on the other hand, enhanced these properties through electrostatic complexation with proteins. Cryogels made from protein-polysaccharide blends exhibited promising techno-functional properties for enhancing and diversifying food product innovation.

Visualizing disintegration of 3D printed tablets in humans using MRI and comparison with in vitro data

Three-dimensional (3D) printing is revolutionising the way that medicines are manufactured today, paving the way towards more personalised medicine. However, there is limited in vivo data on 3D printed dosage forms, and no studies to date have been performed investigating the intestinal behaviour of these drug products in humans, hindering the complete translation of 3D printed medications into clinical practice. Furthermore, it is unknown whether conventional in vitro release tests can accurately predict the in vivo performance of 3D printed formulations in humans. In this study, selective laser sintering (SLS) 3D printing technology has been used to produce two placebo torus-shaped tablets (printlets) using different laser scanning speeds. The printlets were administered to 6 human volunteers, and in vivo disintegration times were assessed using magnetic resonance imaging (MRI). In vitro disintegration tests were performed using a standard USP disintegration apparatus, as well as an alternative method based on the use of reduced media volume and minimal agitation. Printlets fabricated at a laser scanning speed of 90 mm/s exhibited an average in vitro disintegration time of 7.2 ± 1 min (measured using the USP apparatus) and 25.5 ± 4.1 min (measured using the alternative method). In contrast, printlets manufactured at a higher laser scanning speed of 130 mm/s had an in vitro disintegration time of 2.8 ± 0.8 min (USP apparatus) and 18.8 ± 1.9 min (alternative method). When tested in humans, printlets fabricated at a laser scanning speed of 90 mm/s showed an average disintegration time of 17.3 ± 7.2 min, while those manufactured at a laser scanning speed of 130 mm/s exhibited a shorter disintegration time of 12.7 ± 6.8 min. Although the disintegration times obtained using the alternative method more closely resembled those obtained in vivo, no clear correlation was observed between the in vitro and in vivo disintegration times, highlighting the need to develop better in vitro methodology for 3D printed drug products.

Sodium Starch Glycolate (SSG) from Sago Starch (Metroxylon sago) as a Superdisintegrant: Synthesis and Characterization

The characteristics of sago starch exhibit remarkable resemblances to those of cassava, potato, and maize starches. This review intends to discuss and summarize the synthesis and characterization of sodium starch glycolate (SSG) from sago starch as a superdisintegrant from published journals using keywords in PubMed, Scopus, and ScienceDirect databases by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020). There are many methods for synthesizing sodium starch glycolate (SSG). Other methods may include the aqueous, extrusion, organic solvent slurry, and dry methods. Sago starch is a novel form of high-yield starch with significant development potential. After cross-linking, the phosphorus content of sago starch increases by approximately 0.3 mg/g, corresponding to approximately one phosphate ester group per 500 anhydroglucose units. The degree of substitution (DS) of sodium starch glycolate (SSG) from sago ranges from 0.25 to 0.30; in drug formulations, sodium starch glycolate (SSG) from sago ranges from 2% to 8% w/w. Higher levels of sodium starch glycolate (SSG) (2% and 4% w/w) resulted in shorter disintegration times (within 1 min). Sago starch is more swellable and less enzymatically digestible than pea and corn starch. These investigations demonstrate that sago starch is a novel form of high-yield starch with tremendous potential for novel development as superdisintegrant tablets and capsules.

Fast time-resolved micro-CT imaging of pharmaceutical tablets: Insights into water uptake and disintegration

We use dynamic micro-computed tomography (micro-CT) with a high temporal resolution to visualize water penetration through the porous network of immediate-release pharmaceutical solid tablets and characterize dynamic swelling and disintegration mechanisms. We process the micro-CT images using two theoretical scenarios that reflect different paths of pore structure evolution: a scenario where tablet porosity remains constant during the swelling process and a scenario where the tablet porosity progressively diminishes and eventually closes during the swelling process. We calculate the time evolution of the volume of water absorbed by the tablet and, specifically, absorbed by the excipients and the pore structure, as well as the formation and evolution of cracks. In turn, the three-dimensional disintegration pattern of the tablets is reconstructed. Restricting attention to the limiting scenario where tablet porosity is assumed fixed during the swelling process, we couple liquid penetration due to capillary pressure described by the Lucas-Washburn theory with the first-order swelling kinetics of the excipients to provide a physical interpretation of the experimental observations. We estimate model parameters that are in agreement with values reported in the literature, and we demonstrate that water penetration is dominated by intra-particle porosity rather than inter-particle porosity.

Effect of tableting temperature on tablet properties and dissolution behavior of heat sensitive formulations

The tableting process involves the conversion of mechanical to thermal energy. This study evaluated the influence of temperature on the tableting behavior of formulations with different compositions. The tableting machine was equipped with a thermally controlled die to mimic the heat evolution from tableting on an industrial scale. Six formulations containing binders with a comparably low glass transition temperature were examined. Besides the polymer type and concentration, the filler was varied. Paracetamol was chosen as the model active pharmaceutical ingredient. The investigation included alterations in tabletability, disintegration and dissolution. Elevated temperatures led to an enhanced tabletability. The polymer type and concentration were decisive for the extent of alterations. The variation of the filler composition played a minor role due to the high melting points of its components. The results were confirmed in disintegration and dissolution studies. A high binding capacity and a low glass transition temperature resulted in a stronger delay of disintegration. The dissolution was sustained. Increased concentrations of the binding polymer enhanced the effect. If the tableting behavior of a formulation is changed by elevated temperatures during formulation development and production, a change of the binder type or concentration should be considered to ensure a reproducible tablet quality.

At-line porosity sensing for non-destructive disintegration testing in immediate release tablets

Fully automated at-line terahertz time-domain spectroscopy in transmission mode is used to measure tablet porosity for thousands of immediate release tablets. The measurements are rapid and non-destructive. Both laboratory prepared tablets and commercial samples are studied. Multiple measurements on individual tablets quantify the random errors in the terahertz results. These show that the measurements of refractive index are precise, with the standard deviation on a single tablet being about 0.002, with variation between measurements being due to small errors in thickness measurement and from the resolution of the instrument. Six batches of 1000 tablets each were directly compressed using a rotary press. The tabletting turret speed (10 and 30 rpm) and compaction pressure (50, 100 and 200 MPa) were varied between the batches. As expected, the tablets compacted at the highest pressure have far lower porosity than those compacted at the lowest pressure. The turret rotation speed also has a significant effect on porosity. This variation in process parameters resulted in batches of tablets with an average porosity between 5.5 and 26.5%. Within each batch, there is a distribution of porosity values, the standard deviation of which is in the range 1.1 to 1.9%. Destructive measurements of disintegration time were performed in order to develop a predictive model correlating disintegration time and tablet porosity. Testing of the model suggested it was reasonable though there may be some small systematic errors in disintegration time measurement. The terahertz measurements further showed that there are changes in tablet properties after storage for nine months in ambient conditions.

Mucoadhesive Alginate/Pectin Films Crosslinked by Calcium Carbonate as Carriers of a Model Antifungal Drug-Posaconazole

The mucosal membrane of the oral cavity, due to its unique structure and availability, constitutes an appropriate site for the delivery of drugs, both with local and systemic effects. Mucoadhesive buccal films are drug dosage forms that due to their convenience of application, flexibility and size, are characterized by patients' compliance. Sodium alginate and pectin are natural polymers from the polysaccharides group, with mucoadhesive properties, that are widely applied to obtain buccal films. However, their hydrophilic nature and poor water resistance limit their application in sustained drug release formulations. Hence, the aim of this investigation was to design alginate/pectin buccal films by a one-step crosslinking technique-with the application of calcium carbonate. This technique was applied to prepare crosslinked alginate and alginate/pectin mucoadhesive films with a model antifungal drug-posaconazole. The obtained formulations were evaluated for the impact of crosslinking and pectin's presence on their pharmaceutical, mucoadhesive, mechanical and physicochemical properties. Additionally, the antifungal activity of the prepared films against Candida spp. was evaluated. It was shown that pectin's presence in the formulations improved flexibility, mucoadhesion and antifungal activity. The crosslinking process reduced mucoadhesiveness and antifungal activity but significantly enhanced the mechanical properties and stability and enabled prolonged drug release.

Advances in Structure Pharmaceutics from Discovery to Evaluation and Design

Drug delivery systems (DDSs) play an important role in delivering active pharmaceutical ingredients (APIs) to targeted sites with a predesigned release pattern. The chemical and biological properties of APIs and excipients have been extensively studied for their contribution to DDS quality and effectiveness; however, the structural characteristics of DDSs have not been adequately explored. Structure pharmaceutics involves the study of the structure of DDSs, especially the three-dimensional (3D) structures, and its interaction with the physiological and pathological structure of organisms, possibly influencing their release kinetics and targeting abilities. A systematic overview of the structures of a variety of dosage forms, such as tablets, granules, pellets, microspheres, powders, and nanoparticles, is presented. Moreover, the influence of structures on the release and targeting capability of DDSs has also been discussed, especially the in vitro and in vivo release correlation and the structure-based organ- and tumor-targeting capabilities of particles with different structures. Additionally, an in-depth discussion is provided regarding the application of structural strategies in the DDSs design and evaluation. Furthermore, some of the most frequently used characterization techniques in structure pharmaceutics are briefly described along with their potential future applications.

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.

An evaluation of microcrystalline cellulose attributes affecting compaction-induced pellet coat damage through a multi-faceted analysis

Pellet coat damage in multi-unit pellet system (MUPS) tablets has previously been studied and addressed with limited success. The effects of lactose filler material attributes on pellet coat damage have been relatively well-studied but a similar understanding of microcrystalline cellulose (MCC) is lacking notwithstanding its high cushioning potential. Hence, the relationships between MCC attributes and pellet coat damage were investigated. Single pellet in minitablets (SPIMs) were used to isolate pellet-filler effects and reveal the under-unexplored impact of risk factors found in MUPS tablets. MUPS tablets and SPIMs were prepared with various grades of MCC and pellets with an ethylcellulose or acrylic coat at various compaction pressures. Subsequently, the extent of pellet coat damage was determined by dissolution test and quantified using two indicators to differentiate the nature of the damage. A multi-faceted analytical approach incorporated linear regression, correlations and a classification and regression tree algorithm and evaluated how MCC attributes, such as flowability, particle size and plastic deformability, exert various influences on the extent of ethylcellulose and acrylic pellet coat damage. This analysis improved the understanding of the different mechanisms by which pellet coat damage to these two polymer types occurs which can help enhance future pellet coat damage mitigation strategies.

Exploiting common ion addition to accelerate zolpidem hemitartrate release from Eudragit EPO extrudates

The current study aimed at optimizing a previously developed non-clinical formulation for use in zolpidem deprescribing. The formulation under investigation consists of extruded zolpidem hemitartrate (30% w/w) and Eudragit EPO (70% w/w) mixtures which display unsatisfactory dissolution behavior. Both milled extrudates and physical mixtures were compressed to produce tablets with identical target weight and solid fraction. First, the susceptibility of zolpidem hemitartrate towards heat and shear degradation was identified utilizing thermal and HPLC-DAD analysis. The drug salt proved prone to thermally induced disproportionation. Moreover, the impurity content increased after applying hot melt extrusion although ICH guidelines were still attained. Secondly, extrudates and physical mixtures were subjected to FTIR analysis. As a result, interaction and protonation of the dimethyl aminoethyl group from Eudragit EPO resulting from zolpidem disproportionation was elucidated. As such, the formulations' slow dissolution kinetics in comparison to formulations containing non-ionizable polymers (e.g. Kollidon 12PF and Kollidon VA64) is explained. Finally, addition of tartaric acid, a microenvironmental pH modulator and common ion, proved a successful method to increase dissolution kinetics. The amount of drug released after 15 min increased drastically from 10 to 40% upon the addition of 5% tartaric acid. Immediate release behavior (80% within 15 min) was however not yet attained.

On the influence of raw material attributes on process behaviour and product quality in a continuous WET granulation tableting line

Continuous manufacturing of oral solids is a complex process in which critical material attributes (CMAs), formulation and critical process parameters (CPPs) play a fundamental role. However, assessing their effect on the intermediate and final product's critical quality attributes (CQAs) remains challenging. The aim of this study was to tackle this shortcoming by evaluating the influence of raw material properties and formulation composition on the processability and quality of granules and tablets on a continuous manufacturing line. Powder-to-tablet manufacturing was performed using four formulations in various process settings. Pre-blends of different drug loadings (2.5 % w/w and 25% w/w) and two BCS classes (Class I and II) were continuously processed on an integrated process line ConsiGmaTM 25, including twin screw wet granulation, fluid bed drying, milling, sieving, in-line lubrication and tableting. The liquid-to-solid ratio and the granule drying time were varied to process granules under nominal, dry and wet conditions. It was shown that the BCS class and the drug dosage influenced the processability. Intermediate quality attributes, such as the loss on drying and the particle size distribution, directly correlated with the raw material's properties and process parameters. Process settings had a profound impact on the tablet's hardness, disintegration time, wettability and porosity.

Pharmacotechnical, Physico-Chemical, and Antioxidant Evaluation of Newly Developed Capsule Formulations

The excess of free radicals causes numerous imbalances in the body that lead to premature aging, the degradation of internal structures, and the appearance of numerous pathologies responsible for the increased risk of premature death. The present work aims to evaluate the physical, chemical, pharmacotechnical, and antioxidant activity of newly achieved capsule formulations. These two formulations were F1_a.i., which contains melatonin:biotin:coenzyme Q10 (weight ratio of 1:2:60), and F2_a.i., which contains quercetin:resveratrol:biotin:coenzyme Q10 (weight ratio of 10:10:1:10). The adequate selection of the excipient types and amounts for final capsule formulations (F1_c.c., F2_c.c.) was based on preformulation studies performed on the powders containing active ingredients. The antioxidant activity assessed using three methods (ABTS, DPPH, and FRAP) compared with acid ascorbic as a positive control demonstrated that the F2_c.c. formulation possesses the strongest antioxidant capacity. The results confirmed the suitable formulation and the accurate selection of the types and amounts of active ingredients, as well as the auxiliary excipients used in newly developed capsule formulations as supplements with an excellent antioxidant effect on the human body.

Non-destructive Detection of Disintegrant Levels in Compressed Oral Solid Dosage Forms

Quality issues related to compressed oral solid dosage (OSD) forms, such as tablets, arise during the design, development, and production stages, despite established processes and robust production tools. One of the primary quality concerns is the disintegration properties and drug release profile of immediate-release OSD products, which depend on their micro-texture and micro-viscoelastic properties at the grain level. These properties are influenced by the composition of the formulation, particularly the disintegrant level in the tablet matrix and the porosity of the matrix. In this study, a novel, rapid, non-destructive ultrasonic characterization technique was proposed to correlate the sensitivity of propagating elastic wave speeds, physical/mechanical properties, and the dispersion profile of the OSD material with the disintegrant level (% w/w) in the formulation and the compression force applied during tableting. The proposed characterization framework involves transmitting pressure (longitudinal) and shear (transverse) waves through the OSDs to calculate the speed of sound, which in turn provides information on the apparent Young's and shear moduli. In addition, the attenuation profile of the propagating wave is obtained through dispersion analysis. To investigate the impact of disintegrants and compression force on ultrasonic wave propagation in OSDs, we incorporated seven levels of a frequently used disintegrant. In each formulation, OSDs are compacted in five compaction forces. The sensitivity of wave speeds, physical/mechanical properties, and attenuation profile was observed with each disintegrant and compression force level. The utilization of ultrasonic techniques may present a viable solution for rapid, non-destructive, non-invasive, and cost-effective testing methods required in continuous manufacturing (CM) and real-time release testing (RTRT), and its practical utility in pharmaceutical manufacturing is also discussed.

Application of biorelevant in vitro assays for the assessment and optimization of ASD-based formulations for pediatric patients

Amorphous solid dispersions (ASD) have been a successful formulation strategy to overcome the poor aqueous solubility of many novel drugs, but the development of pediatric formulations presents a special challenge due to variable gastrointestinal conditions in children. It was the aim of this work to design and apply a staged biopharmaceutical test protocol for the in vitro assessment of ASD-based pediatric formulations. Ritonavir was used as a model drug with poor aqueous solubility. Based on the commercial ASD powder formulation, a mini-tablet and a conventional tablet formulation were prepared. Drug release from the three formulations was studied in different biorelevant in vitro assays (i.e. MicroDiss, two-stage, transfer model, tiny-TIM) to consider different aspects of human GI physiology. Data from the two-stage and transfer model tests indicated that by controlled disintegration and dissolution excessive primary precipitation can be prevented. However, this advantage of the mini-tablet and tablet formulation did not translate into better performance in tiny-TIM. Here, the in vitro bioaccessibility was comparable for all three formulations. In the future, the staged biopharmaceutical action plan established herein will support the development of ASD-based pediatric formulations by improving the mechanistic understanding so that formulations are developed for which drug release is robust against variable physiological conditions.

Enhanced in-situ liquid transport investigation setup for pharmaceutical tablet disintegration analysis using terahertz radiation

The disintegration process of pharmaceutical solid dosage forms commences on contact with the dissolution medium and continues with subsequent spontaneous imbibition of the medium in the tablet matrix. Identifying the location of the liquid front in situ during imbibition, therefore, plays a significant role in understanding and modelling the disintegration process. Terahertz pulsed imaging (TPI) technology can be used to investigate this process by its ability to penetrate and identify the liquid front in pharmaceutical tablets. However, previous studies were limited to samples suitable for a flow cell environment, i.e. flat cylindrical disk shapes; thus, most commercial tablets could only be measured with prior destructive sample preparation. This study presents a new experimental setup named open immersion to measure a wide range of pharmaceutical tablets in their intact form. Besides, a series of data processing techniques to extract subtle features of the advancing liquid front are designed and utilised, effectively increasing the maximum thickness of tablets that can be analysed. We used the new method and successfully measured the liquid ingress profiles for a set of oval convex tablets prepared from a complex eroding immediate-release formulation.

Effect of co-processed excipient type on properties of orodispersible tablets containing captopril, tramadol, and domperidone

An important feature of orodispersible tablets (ODTs) is the convenient administration of the drugs, in some cases, faster onset of action, stability maintenance, and dose precision. This work focused on the preparation of ODTs containing mannitol-based co-processed excipients Prosolv® ODT G2, Ludiflash® and Parteck® ODT in combination with tramadol, captopril, and domperidone by direct compression. Prosolv® ODT G2 showed high energy of plastic deformation due to the content of microcrystalline cellulose. Parteck® ODT provided compact tablets due to the content of granulated mannitol. All drugs decreased tensile strength, increased friability, prolonged disintegration time, and decreased the porosity of tablets. Tablets containing Prosolv® ODT G2 with captopril, domperidone, and tramadol; and Parteck® ODT with domperidone met the requirements for ODTs production, i.e., friability ≤ 1% and disintegration time ≤ 180 s, fast wetting time, high water absorption ratio, and adequate tensile strength. The disintegration time was tested using both the pharmacopeial method and the BJKSN-13 apparatus. The results indicate the significant difference between these methods, with the disintegration time being longer when tested with the BJKSN-13 instrument.

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.

Design expert software assisted development and evaluation of empagliflozin and sitagliptin combination tablet with improved in-vivo anti-diabetic activities

Background

The combination of empagliflozin and sitagliptin to treat type-2 diabetes might be more economical and patient compliance with an additive improvement in glycemic control due to complementary modes of action.

Aim of the study

To design, formulate and optimize an immediate tablet dosage form containing empagliflozin and sitagliptin utilizing statistically reliable study design followed by in-vitro and in-vivo testing.

Method

ology: To determine the effects of copovidone (X1) and croscarmellose sodium (X2) amounts on the dependent variables of disintegration time and percent drug release, the formulation was developed using Design Expert Software v.13's direct compression method-based central composite design optimization study. The formulations' assay, dissolution, friability, hardness, weight variation, disintegration, and anti-diabetic effects were evaluated in comparison to the standard drug. The analysis included the use of high performance liquid chromatography (HPLC) assay methods. Mice were employed to investigate the efficacy of an anti-diabetic drug after they were administered a high-fat diet and two injections of streptozotocin at a dosage of 30 mg/kg BW each.

Results

Formulation of F3 out of nine had all in-vitro parameters at the most satisfactory condition. It was found that assay of the best formulation is 100.99% and 100.19% for empagliflozin and sitagliptin respectively. The disintegration time of F3 was found at 5.32 min. Percentage release of empagliflozin in 30 min was found 89.05% while sitagliptin was with 93.76%. The results showed that administration of F3 significantly reduced FBG (68.61%, p < 0.0001), total cholesterol levels (70.29 ± 0.48; p < 0.0001), triglycerides (70.20 ± 0.40, p < 0.0001); HDL levels (52.50 ± 0.31; p < 0.0001), LDL levels (33.34 ± 0.28; p < 0.0001), compared to diabetic control, this effect was comparable to metformin treatment.

Conclusion

The direct compression approach has been used to develop, and optimize a new combination tablet incorporating empagliflozin and sitagliptin with better dissolution rate and anti-diabetic action.

Citric acid esterified Glutinous Assam bora rice starch enhances disintegration and dissolution efficiency of model drug

The current work was designed to study the starch's physicochemical attributes, tablet disintegration and dissolution efficiency and its derivatives obtained from the glutinous Assam bora rice (G-ABR) variety of Assam, Northeast India. Starch was isolated by a simple protein denaturation method, and a starch derivative was prepared through citric acid modification. G-ABRS and citrated G-ABRS were characterized through FTIR, DSC, XRD and SEM. The rate of consolidation, consolidation index, angle of internal friction, packing rearrangement and cohesive properties were determined to investigate their applications as functional excipients in pharmaceutical industries. G-ABRS and citrated G-ABRS exhibited better packing rearrangement and cohesive properties than standard corn starch. Furthermore, immediate release of API from the tablet compact was observed when the starch concentration increased from 1 to 5 %, indicating facilitation of the tablet compact disintegration. Therefore, G-ABRS and citrated G-ABRS are potentially functional and sustainable materials for pharmaceutical industries.

Predicting mini-tablet dissolution performance utilizing X-ray computed tomography

Mini-tablets (MTs) have been utilized as an alternative to monolithic tablets due to their ease of use for pediatric populations, dose flexibility and tailoring of drug release profiles. Similar to monolithic tablets, MTs can develop film coat and internal core defects during manufacturing processes that may adversely affect their dissolution performance. The use of x-ray computed microtomography (XRCT) is well documented for monolithic tablets as a means of identifying internal defects, but applications to MTs have not been well studied. In this study, we have developed a workflow that analyzes reconstructed XRCT images of enteric-coated mini-tablets using deep learning convolutional neural networks. This algorithm was utilized to extract key physical features of individual MTs, such as micro-crack volume and enteric coat thickness. By performing dissolution studies on individual MTs, correlations were established based on the physical parameters obtained by XRCT and the dissolution performance, enabling prediction of dissolution performance utilizing non-destructive imaging data. This workflow provides insight into the physical variability of MT populations that are generated during manufacturing, enabling optimization of critical tableting and coating parameters to achieve the target dissolution criteria. Through this mechanistic understanding, quality is built into the final drug product through rational development of formulation and process parameters.

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.

Coating of Primary Powder Particles Improves the Quality of Binder Jetting 3D Printed Oral Solid Products

Binder jetting (BJ) 3D printing is especially suitable for the fabrication of an orodispersible solid dosage form, as it is an efficient way to avoid the use of mechanical forces typical for compaction-based processes. However, one of the existing challenges related to pharmaceutical applications of BJ is the relatively high amount of binder needed in the primary powder to ensure the sufficient mechanical strength of printed products. In this study, a strategy based on pre-processing with a thin layer coating was explored. With this strategy, the matrix particles (lactose monohydrate) of the primary powder for BJ 3D printing were coated with the binder (polyvinylpyrrolidone, PVP). The investigated compositions of the primary powder contained PVP at three levels, namely, 10 %, 15% and 20% (w/w). The primary powder compositions were prepared with or without the coated lactose powder, and they were subsequently 3D BJ printed into oral solid products with paracetamol as a model active drug substance. The presence of coated lactose in the primary powder increased the interparticulate interactions in the BJ 3D printed products. Especially for the composition with a relatively small amount of binder (i.e., 10% and 15% w/w PVP in the primary powder), the use of coated particles significantly improved the resistance to crushing and decreased the disintegration time of printed products. In conclusion, thin layer coating is an effective way to pre-process primary powder particles for BJ 3D printing of oral solid products.

Formulation-dependent stability mechanisms affecting dissolution performance of directly compressed griseofulvin tablets

During drug product development, stability studies are used to ensure that the safety and efficacy of a product are not affected during storage. Any change in the dissolution performance of a product must be investigated, as this may indicate a change in the bioavailability. In this study, three different griseofulvin formulations were prepared containing microcrystalline cellulose (MCC) with either mannitol, lactose monohydrate, or dibasic calcium phosphate anhydrous (DCPA). The tensile strength, porosity, contact angle, disintegration time, and dissolution rate were measured after storage under five different accelerated temperature and humidity conditions for 1, 2, and 4 weeks. The dissolution rate was found to decrease after storage for all three batches, with the change in dissolution rate strongly correlating with the storage humidity. The changes in physical properties of each formulation were found to relate to either the premature swelling (MCC/DCPA, MCC/lactose) or dissolution (MCC/mannitol) of particles during storage. These results are also discussed with consideration of the performance- and stability-controlling mechanisms of placebo tablets of the same formulations (Maclean et al., 2021; Maclean et al., 2022).

Semi-mechanistic reduced order model of pharmaceutical tablet dissolution for enabling Industry 4.0 manufacturing systems

We propose a generalization of the Weibull dissolution model, referred to as generalized Weibull dissolution model, that seamlessly captures all three fractional dissolution rates experimentally observed in pharmaceutical solid tablets, namely decreasing, increasing, and non-monotonic rates. This is in contrast to traditional reduced order models, which capture at most two fractional dissolution rates and, thus, are not suitable for a wide range of product formulations hindering, for example, the adoption of knowledge management in the context of Industry 4.0. We extend the generalized Weibull dissolution model further to capture the relationship between critical process parameters (CPPs), critical materials attributes (CMAs), and dissolution profile to, in turn, facilitate real-time release testing (RTRT) and quality-by-control (QbC) strategies. Specifically, we endow the model with multivariate rational polynomials that interpolate the mechanistic limiting behavior of tablet dissolution as CPPs and CMAs approach certain values of physical significance (such as the upper and lower bounds of tablet porosity or lubrication conditions), thus the semi-mechanistic nature of the reduced order model. Restricting attention to direct compaction and using various case studies from the literature, we demonstrate the versatility and the capability of the semi-mechanistic ROM to estimate changes in dissolution due to process disturbances in tablet weight, porosity, lubrication conditions (i.e., the total amount of shear strain imparted during blending), and moisture content in the powder blend. In all of the cases considered in this work, the estimations of the model are in remarkable agreement with experimental data.

Mechanistic study of the formation of arbutin polymorphs and solvates

Six solid forms of arbutin are successfully obtained and four single crystal structures are reported for the first time. Further, the formation mechanism of arbutin solvates is proposed and rationalized.

Studying the dissolution of immediate release film coating using terahertz pulsed imaging

Coated tablets introduce complexity to the dissolution process, even with readily soluble immediate release coating layers. Therefore, a more detailed understanding of the physical steps involved in the dissolution process can improve the efficiency of formulation and process design. The current study uses terahertz pulsed imaging to visualise the hydration process of microcrystalline cellulose (MCC) tablet cores that were film coated with an immediate release coating formulation upon exposure to the dissolution medium. Film coated tablets that were prepared from three levels of core porosity (10%, 20% and 30%) and with coating thickness in the range of 30μm to 250μm were investigated. It was possible to resolve and quantify the distinct stages of wetting of the coating layer, swelling of the MCC particles at the core surface, and dissolution of the coating layer followed by the ingress of dissolution media into the tablet core. The liquid transport process through the coating layer was highly consistent and scalable. The penetration rate through the coating layer and the tablet core both strongly depended on coating thickness and core porosity.

Enhancement of the Solubility and Dissolution Rate of Telmisartan by Surface Solid Dispersions Employing Superdisintegrants, Hydrophilic Polymers and Combined Carriers

Telmisartan (Tel) is a potent antihypertensive drug with a very poor aqueous solubility, especially in pH ranging from 3 to 9 (i.e., biological fluids) that results in poor bioavailability. Our aim was to improve Tel solubility and dissolution rates without the need for expensive multistep procedures, and without inclusion of alkalinizers. This study adopted the use of surface solid dispersions (SSDs) employing superdisintegrants, hydrophilic polymers and combined carriers including a superdisintegrant with a hydrophilic polymer. Tel-SSDs were formulated using thesolvent evaporation method. Compatibility between Tel and different carriers was examined via FT-IR. Tel-SSDs were evaluated optically and thermally to reveal a complete loss of the crystalline nature of the drug. Both drug content and percentage yield were calculated to judge the efficiency of the preparation technique used. Saturation, aqueous solubility, and dissolutions rates were determined. Dissolution profiles were studied using model dependent and independent approaches and were subjected to the pair-wise procedure using the DDsolver software program. Effect of aging was studied by comparing the drug content and dissolution profiles of freshly prepared SSDs with aged samples. All Tel-SSDs showed acceptable physical properties. Tel-SSDs showed pertinent enhancement related to the carrier used. Combined surface solid dispersions employing superdisintegrant croscarmellose sodium with either hydrophilic polymer PEG 4000 or Poloxamer 407 gave remarkable enhancement in solubility and dissolution rates of Tel where more than 90% of the drug was released within 20 min. The effect of aging results proved a non-significant difference in the drug content and dissolution profiles between fresh and aged samples. Formulation of Tel SSDs using combined carriers proved to be effective in enhancing the aqueous solubility and dissolution rates of Tel, as well as showing good stability upon aging.