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

Potential of Powder Rheology for Detecting Unforeseen Cross-Contamination of Foreign Active Pharmaceutical Ingredients

Unexpected cross-contamination by foreign components during the manufacturing and quality control of pharmaceutical products poses a serious threat to the stable supply of drugs and the safety of customers. In Japan, in 2020, a mix-up containing a sleeping drug went undetected by liquid chromatography during the final quality test because the test focused only on the main active pharmaceutical ingredient (API) and known impurities. In this study, we assessed the ability of a powder rheometer to analyze powder characteristics in detail to determine whether it can detect the influence of foreign APIs on powder flow. Aspirin, which was used as the host API, was combined with the guest APIs (acetaminophen from two manufacturers and albumin tannate) and subsequently subjected to shear and stability tests. The influence of known lubricants (magnesium stearate and leucine) on powder flow was also evaluated for standardized comparison. Using microscopic morphological analysis, the surface of the powder was observed to confirm physical interactions between the host and guest APIs. In most cases, the guest APIs were statistically detected due to characteristics such as their powder diameter, pre-milling, and cohesion properties. Furthermore, we evaluated the flowability of a formulation incorporating guest APIs for direct compression method along with additives such as microcrystalline cellulose, potato starch, and lactose. Even in the presence of several additives, the influence of the added guest APIs was successfully detected. In conclusion, powder rheometry is a promising method for ensuring stable product quality and reducing the risk of unforeseen cross-contamination by foreign APIs.

Implementation of mechanistic modeling and global sensitivity analysis (GSA) for design, optimization, and scale-up of a roller compaction process

The pharmaceutical industry has been shifting towards the application of mechanistic modeling to improve process robustness, enable scale-up, and reduce time to market. Modeling approaches have been well-developed for processes such as roller compaction, a continuous dry granulation process. Several mechanistic models/approaches have been documented with limited application to high drug-loaded formulations. In this study, the Johanson model was employed to optimize roller compaction processing and guide its scale-up for a high drug loaded formulation. The model was calibrated using a pilot-scale Minipactor and was validated for a commercial-scale Macropactor. Global sensitivity analysis (GSA) was implemented to determine the impact of process parameter variations (roll force, gap, speed) on a quality attribute [solid fraction (SF)]. The throughput method, which estimates SF values of ribbons using granule production rate, was also studied. The model predicted SF values for all 14 Macropactor batches within ± 0.04 SF. The throughput method estimated SF with ± 0.06 SF for 7 out of 11 batches. GSA confirmed that roll force had the largest impact on SF. This case study represents a process modeling approach to build quality into the products/processes and expands the use of mechanistic modeling during drug product development.

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.

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

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

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

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

Development of self-microemulsifying tablets containing dutasteride for enhanced dissolution and pharmacokinetic profile

This study aimed to develop self-microemulsifying tablets containing the hydrophobic drug dutasteride for easy administration and high in vivo absorption. The candidate lipids and surfactants were formulated into a self-microemulsifying drug delivery system (SMEDDS), and their mean droplet size upon dilution was evaluated. The SMEDDS containing Capmul® MCM, Captex® 355, and Cremophor® EL showed improved dissolution in the gastric medium when compared to the dissolution of the conventional product (Avodart®) and the raw drug. Among the various porous silicon microparticles for solidifying SMEDDS, Neusilin® US2 showed favorable properties in terms of maximum adsorption capacity, powder flow, and compaction. However, the amount of drug released from the solidified SMEDDS after the adsorption process was lower than that of liquid SMEDDS, indicating incomplete desorption. After observing the effect of the solid-to-liquid ratio and pre-filling the pores with blank SMEDDS, complete desorption was obtained when the pores were first adsorbed with polyvinylpyrrolidone. The self-microemulsifying tablets exhibited improved bioavailability (29.9% and 15.2%) compared to the conventional soft gelatin product. Therefore, the proposed system could successfully solubilize the hydrophobic drug while maintaining rapid and complete desorption from the solid carrier, resulting in enhanced in vivo performance.

Investigation of critical factors affecting mechanical characteristics of press-coated tablets using a compaction simulator

Press-coated tablets have become an indispensable dosage form in chronotherapeutic drug delivery. Drug release from press-coated tablets has been extensively studied, yet there is little knowledge about their mechanical characteristics. This study aimed to systematically investigate the effects of critical factors on the structure, layer adhesion, and delamination tendency of the tablets. Material elasticity was found to play an important role in determining tablet structure in that excessive elastic mismatch between core and shell materials caused tablet defects during decompression and ejection. Unlike bilayer tablets, the overall strength of press-coated tablets was more affected by binding capacity of coating materials than by the core properties. Shell/core ratio was another factor affecting tablet integrity against external stresses. To mitigate the risk of delamination, poor layer adhesion must be compensated by increasing the coating thickness or enhanced by optimizing the formulation and process (e.g., core plasticity/brittleness, initial core solid fraction, and compression speed). X-ray micro-computed tomography revealed the presence of a shell-core gap and inhomogeneous density distribution within the tablet where the side coat appeared as the least dense and weakest region. These findings will enable the improvement of tablet quality and widen the application of press coating in industrial manufacturing.

Systematic approach to elucidate compaction behavior of acyclovir using a compaction simulator

In this research, various approaches were attempted with a compaction simulator to investigate the unidentified compaction behavior of acyclovir, a model compound. Various indicators for the compaction behavior of acyclovir were obtained and compared with those of three commonly used excipients with relatively well-known compaction behavior. From two frequently used powder compaction models, the Heckel and Walker models, curvature of plot, yield stress, D₀, SRS value, and W value were acquired. In addition, compression and elastic energies were obtained during the loading and unloading phases, respectively. The ratio of the two energies was also utilized. To characterize the mechanical properties of materials during bond formation, the radial tensile strength of powder compacts was measured. For all evaluations, the effects of compaction rate and lubrication were studied simultaneously. We found that primary particles of acyclovir were compacted mainly by plastic flow, with high viscoelasticity and low particle interactions. Their bond formation was highly sensitive to strain rate and lubrication. This study showed the potential application of a compaction simulator to elucidate the compaction behavior of a material of interest.