Crystalline Active Pharmaceutical Ingredients Research Articles

Dry Amorphization of Itraconazole Using Mesoporous Silica and Twin-Screw Technology.

Background/Objectives: Amorphization of an active pharmaceutical ingredient (API) can improve its dissolution and enhance bioavailability. Avoiding solvents for drug amorphization is beneficial due to environmental issues and potential solvent residues in the final product. Methods: Dry amorphization using a twin-screw extruder is presented in this paper. A blend of mesoporous silica particles and crystalline itraconazole was processed using a pharma-grade laboratory scale twin-screw extruder. The influence of different screw configurations and process parameters was tested. Particle size and shape are compared in scanning electron microscopy (SEM) images. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) are used to determine the residual amount of crystalline itraconazole in the final product. Results: An optimized screw configuration for the process was found which leads to more than 90% amorphous API when processed at room temperature. Full amorphization was reached at 70 °C. The specific mechanic energy (SME) introduced into the material during twin-screw processing is crucial for the dry amorphization. The higher the SME, the lower the residual amount of crystalline API. Two months after processing, however, recrystallization was observed by XRD. Conclusions: Dry processing using a twin-screw extruder is continuous, free of solvents and can be performed at low temperatures. This study proves the concept of twin-screw processing with mesoporous silica for dry amorphization of itraconazole.

Process-Induced Crystal Surface Anisotropy and the Impact on the Powder Properties of Odanacatib.

Crystalline active pharmaceutical ingredients with comparable size and surface area can demonstrate surface anisotropy induced during crystallization or downstream unit operations such as milling. To the extent that varying surface properties impacts bulk powder properties, the final drug product performance such as stability, dissolution rates, flowability, and dispersibility can be predicted by understanding surface properties such as surface chemistry, energetics, and wettability. Here, we investigate the surface properties of different batches of Odanacatib prepared through either jet milling or fast precipitation from various solvent systems, all of which meet the particle size specification established to ensure equivalent biopharmaceutical performance. This work highlights the use of orthogonal surface techniques such as Inverse Gas Chromatography (IGC), Brunauer-Emmett-Teller (BET) surface area, contact angle, and X-ray Photoelectron Spectroscopy (XPS) to demonstrate the effect of processing history on particle surface properties to explain differences in bulk powder properties.

The Influence of PVP Polymer Topology on the Liquid Crystalline Order of Itraconazole in Binary Systems.

This study presents a novel approach by utilizing poly(vinylpyrrolidone)s (PVPs) with various topologies as potential matrices for the liquid crystalline (LC) active pharmaceutical ingredient itraconazole (ITZ). We examined amorphous solid dispersions (ASDs) composed of ITZ and (i) self-synthesized linear PVP, (ii) self-synthesized star-shaped PVP, and (iii) commercial linear PVP K30. Differential scanning calorimetry, X-ray diffraction, and broad-band dielectric spectroscopy were employed to get a comprehensive insight into the thermal and structural properties, as well as global and local molecular dynamics of ITZ-PVP systems. The primary objective was to assess the influence of PVPs' topology and the composition of ASD on the LC ordering, changes in the temperature of transitions between mesophases, the rate of their restoration, and finally the solubility of ITZ in the prepared ASDs. Our research clearly showed that regardless of the PVP type, both LC transitions, from smectic (Sm) to nematic (N) and from N to isotropic (I) phases, are effectively suppressed. Moreover, a significant difference in the miscibility of different PVPs with the investigated API was found. This phenomenon also affected the solubility of API, which was the greatest, up to 100 μg/mL in the case of starPVP 85:15 w/w mixture in comparison to neat crystalline API (5 μg/mL). Obtained data emphasize the crucial role of the polymer's topology in designing new pharmaceutical formulations.

Evaluation of Individual and Crystal Population Dissolution Rates by Time-Resolved X-ray Microtomography.

The intrinsic dissolution rate (IDR) is an important parameter in pharmaceutical science that measures the rate at which a pure crystalline active pharmaceutical ingredient dissolves in the absence of diffusion limitations. Traditional IDR measurement techniques do not capture the complex interplay between particle morphology, fluid flow, and dissolution dynamics. The dissolution rate of individual particles can differ from the population average because of factors such as particle size, surface roughness, or exposure of individual crystal facets to the dissolution medium. The aim of this work was to apply time-resolved X-ray microtomography imaging and simultaneously measure the individual dissolution characteristics of a large population of crystalline particles placed in a packed bed perfused by the dissolution medium. Using NaCl crystals in three different size fractions as a model, time-resolved microtomography made it possible to visualize the dissolution process in a custom-built flow cell. Subsequent 3D image analysis was used to evaluate changes in the shape, size, and surface area of individual particles by tracking them as they are dissolved. Information about the particle population statistics and intrabatch variability provided a deeper insight into the dissolution process that can complement established IDR measurements.

Modernizing non-classical protein crystallization through industry 4.0: Advanced monitoring and modelling utilizing process analytical technology

Modernizing manufacturing processes of pharmaceutical drug products with advanced monitoring and modelling can aid in the transition towards Industry 4.0 with the benefit of increased productivity. This study investigated the use of process analytical technology in combination with partial least squares (PLS) regressions to create two soft sensors to predict the mass fraction of crystallised active pharmaceutical ingredient (API) and mass fraction of dissolved API during a non-classical protein crystallization with amorphous precursors. The PLS model for predicting the amount of crystalline API was based on Raman spectra, chord length distributions and turbidity data using small-angle X-ray scattering as a reference method. The model had a root mean square error on cross-validation (RMSECV) of 5 %. The model predicting mass fraction of dissolved API was based only on the Raman spectra and used high performance liquid chromatography as reference method. This model had a RMSECV of 3 % A two-step nucleation model was fitted to the predictions from the sensors and showed good agreement between data and model with a root mean square error of 2 %.

Molecular insights into kinetic stabilization of amorphous solid dispersion of pharmaceuticals.

Poor aqueous solubility of crystalline active pharmaceutical ingredients (APIs) restricts their bioavailability. Amorphous solid dispersions with biocompatible polymer excipients offer a solution to overcome this problem, potentially enabling a broader use of many drug candidate molecules. This work addresses various aspects of the in silico design of a suitable combination of an API and a polymer to form such a binary solid dispersion. Molecular interactions in such bulk systems are tracked at full atomic resolution within molecular-dynamics (MD) simulations, enabling to identify API-polymer pairs that exhibit the most beneficial interactions. Importance of these interactions is manifold: increasing the mutual miscibility, kinetic stabilization of their amorphous dispersions and impedance of the spurious recrystallization of the API component. MD tools are used to investigate the structural and cohesive properties of pure compounds and mixtures, with a special emphasis on molecular interactions, microscopic structures and internal dynamics. This analysis is then accompanied by a macroscopic image of the energetic compatibility and vitrification tendency of the mixtures in terms of their excess enthalpies and glass transition temperatures. Density-functional theory (DFT) and non-covalent interaction (NCI) analysis fortify our computational conclusions and enable us to map the intensities of particular NCI among the individual target materials and relevant molecular sites therein. Three archetypal polymer excipients and four API molecules are included in this study. The results of our computational analysis of molecular interactions in bulk systems agree with the experimentally observed trends of solubility of the given API in polymers. Our calculations confirm PVP as the most potent acceptor of hydrogen bonding among the three considered polymer excipients, whereas ibuprofen molecules are predicted to be the most efficient hydrogen bond donors among our four target APIs. Our simulations also suggest that carbamazepine does not exhibit particularly strong interactions with the considered polymer excipients. Although current MD cannot offer quantitative accuracy of many of the discussed descriptors, current computational models focusing on NCI of APIs with polymer excipients contribute to understanding of the behavior of these materials at the molecular level, and thus also to the rational design of novel efficient drug formulations.

Impact of Solid-State Properties on the Aerosolization Performance of Spray-Dried Curcumin Powders

Amorphous and crystalline active pharmaceutical ingredients (APIs) are both widely studied for pulmonary delivery. The past research mainly studied the impact of solid-state properties on pharmacokinetic attributes; however, the influence of solid-state properties on aerosolization performance was much less studied. This study aimed to investigate the different aerosolization performances of amorphous and crystalline curcumin (Cur) stabilized with L-leucine. Cur was spray-dried with different concentrations of L-leucine (0, 5, 20, 35, and 50%, w/w) as both solution-based and suspension-based formulations to acquire amorphous and crystalline Cur powders. The physicochemical properties of the spray-dried powders, including particle size, morphology, and solid-state characteristics, were studied. The aerosolization performance as well as dissolution properties were evaluated. It was found that 35% (w/w) L-leucine or above led to the formation of amorphous Cur in the spray-dried powders, and the amorphous Cur powders exhibited higher FPF (70.8%, with 50% L-leucine, w/w) than the crystalline Cur formulations with an FPF at 56.3% (with 50% L-leucine, w/w). In conclusion, with a high concentration of L-leucine (35% or above) in the formulations, amorphous Cur would exhibit higher aerosolization efficiency than crystalline Cur. However, with a low concentration of L-leucine (20% or less) in the formulations, crystalline Cur would be preferred for more enhanced consideration.

Effect of Copolymer Properties on the Phase Behavior of Ibuprofen–PLA/PLGA Mixtures

Prediction of compatibility of the active pharmaceutical ingredient (API) with the polymeric carrier plays an essential role in designing drug delivery systems and estimating their long-term physical stability. A key element in deducing API-polymer compatibility is knowledge of a complete phase diagram, i.e., the solubility of crystalline API in polymer and mutual miscibility of API and polymer. In this work, the phase behavior of ibuprofen (IBU) with different grades of poly(D,L-lactide-co-glycolide) (PLGA) and polylactide (PLA), varying in composition of PLGA and molecular weight of PLGA and PLA, was investigated experimentally using calorimetry and computationally by the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EOS). The phase diagrams constructed based on a PC-SAFT EOS modeling optimized using the solubility data demonstrated low solubility at typical storage temperature (25 °C) and limited miscibility (i.e., presence of the amorphous-amorphous phase separation region) of IBU with all polymers studied. The ability of PC-SAFT EOS to capture the experimentally observed trends in the phase behavior of IBU-PLA/PLGA systems with respect to copolymer composition and molecular weight was thoroughly investigated and evaluated.

Ionic Liquids-Based Drug Delivery: a Perspective.

Ionic liquids (ILs) recently draw attention for addressing unmet needs in biomedicines. By converting solidsinto liquids, ILs are emerging as novel platforms to overcome some critical drawbacks associated with theapplication of solid or crystalline active pharmaceutical ingredients (APIs). ILs have shown promise in liquidizing orsolubilizing APIs, or as green solvents, novel permeation enhancers or active ingredients, alone or synergisticallywith APIs. Meanwhile, challenges turn up in company with the deepening understanding of ILs as drug deliverycarrier systems. This perspective aims to provide a sketchy overview on the status quo with specific attention paidto new problems arising from the utilization of ILs-based technologies in drug delivery.

Adding a New Dimension to the Amorphous Solid Dispersion Phase Diagram: Studying Dissolution Kinetics of Crystalline Drugs in a Polymer Matrix Using Temperature Dependent XRPD and DSC

Hot-melt-extrusion (HME) is an enabling technology used for poorly soluble active pharmaceutical ingredients (APIs) to increase the bioavailability by embedding the drug in a water soluble and often amorphous carrier such as a polymer. Knowledge of the most critical factors impacting the dissolution rate of crystalline API in the polymer during manufacturing will provide useful insight for process improvement. In this study, crystalline APIs (Acetaminophen, APAP and Indomethacin, IMC) were analyzed in a polymeric matrix (Copovidone, PVP-VA64) via X-Ray Powder Diffraction (XRPD) and Differential Scanning Calorimetry (DSC) to follow the dissolution process under various conditions in a down-scaled static laboratory system. The combination of in-situ XRPD measurements and a kinetic model based on DSC data proved to be a suitable tool to investigate the dissolution process and can be applied to various APIs and polymers to avoid residual crystallinity and thermal degradation. Thus, the temperature-composition phase diagram in a thermodynamic equilibrium is augmented by the kinetic component as new dimension. The obtained findings set the foundation for investigating the dissolution kinetics and enable the transition from a static to a dynamic system.

Intelligent Mechanochemical Design of Co-Amorphous Mixtures

Mechanochemistry is a green preparation method that uses mechanical forces to prompt chemical reactions. This technique has shown its potential as an efficient alternative for several solvent-based processes (e.g., synthesis of co-crystals, metal complexes, or polymers); however, predicting its reactivity remains a challenge. In this study, a machine learning model was developed to gain insights into this process and predict the formation of co-amorphous mixtures. Co-amorphous mixtures are produced when the molecular arrangement of a crystalline active pharmaceutical ingredient is disrupted and maintained at “random” by the synergistic presence of a secondary structure. Co-amorphous mixtures can be designed as multicomponent drugs and often display an enhanced solubility and bioavailability. In this work, we generated a database of 418 in-house amorphization experiments, novel to current literature, and informed data analysis (i.e., gradient boosting and neural networks) for predictive purposes and to extrapolate fundamental insights. By using 2066 chemical descriptors to train a gradient boost model, a predictive accuracy of >73% was achieved. This model was further used to predict and synthesize six novel co-amorphous mixtures. We expect that this novel database and the predictive model will aid at designing novel pharmaceuticals and advancing sustainable solvent-free processes.

Controlled nucleation of crystallization process as an efficient tool to tune the properties of corticosteroid API

Crystallization as one of the final steps in the industrial production of active pharmaceutical ingredients (APIs) significantly influences their physicochemical and rheological properties. Different crystallization procedures including antisolvent crystallization, seeding crystallization, crystallization with templates and sonocrystallization were utilized for the production of corticosteroid APIs—fluticasone propionate. The final crystalline APIs obtained by individual crystallization procedures were characterized by a wide range of characterization techniques. We show that nucleation is a critical step that significantly affects APIs' properties. Controlled nucleation thus represents an easy method for managing these properties. Well-designed nucleation yields to crystalline products, which does not necessitate any post-processing including, e.g., micronization. These findings can be widely applied to the production of API with targeted properties.

Development of Composite, Reinforced, Highly Drug-Loaded Pharmaceutical Printlets Manufactured by Selective Laser Sintering-In Search of Relevant Excipients for Pharmaceutical 3D Printing.

3D printing by selective laser sintering (SLS) of high-dose drug delivery systems using pure brittle crystalline active pharmaceutical ingredients (API) is possible but impractical. Currently used pharmaceutical grade excipients, including polymers, are primarily designed for powder compression, ensuring good mechanical properties. Using these excipients for SLS usually leads to poor mechanical properties of printed tablets (printlets). Composite printlets consisting of sintered carbon-stained polyamide (PA12) and metronidazole (Met) were manufactured by SLS to overcome the issue. The printlets were characterized using DSC and IR spectroscopy together with an assessment of mechanical properties. Functional properties of the printlets, i.e., drug release in USP3 and USP4 apparatus together with flotation assessment, were evaluated. The printlets contained 80 to 90% of Met (therapeutic dose ca. 600 mg), had hardness above 40 N (comparable with compressed tablets) and were of good quality with internal porous structure, which assured flotation. The thermal stability of the composite material and the identity of its constituents were confirmed. Elastic PA12 mesh maintained the shape and structure of the printlets during drug dissolution and flotation. Laser speed and the addition of an osmotic agent in low content influenced drug release virtually not changing composition of the printlet; time to release 80% of Met varied from 0.5 to 5 h. Composite printlets consisting of elastic insoluble PA12 mesh filled with high content of crystalline Met were manufactured by 3D SLS printing. Dissolution modification by the addition of an osmotic agent was demonstrated. The study shows the need to define the requirements for excipients dedicated to 3D printing and to search for appropriate materials for this purpose.

Solids Turn into Liquids-Liquid Eutectic Systems of Pharmaceutics to Improve Drug Solubility.

The low solubility of active pharmaceutical ingredients (APIs) is a problem in pharmaceutical development. Several methodologies can be used to improve API solubility, including the use of eutectic systems in which one of the constituents is the API. This class of compounds is commonly called Therapeutic Deep Eutectic Systems (THEDES). THEDES has been gaining attention due to their properties such as non-toxicity, biodegradability, and being non-expensive and easy to prepare. Since the knowledge of the solid liquid diagram of the mixture and the ideal eutectic point is necessary to ascertain if a mixture is a deep eutectic or just a eutectic mixture that is liquid at ambient temperature, the systems studied in this work are called Therapeutic Liquid Eutectic Systems (THELES). Therefore, the strategy proposed in this work is to improve the solubility of chlorpropamide and tolbutamide by preparing THELES. Both APIs are sulfonylurea compounds used for the treatment of type 2 diabetes mellitus and have low solubility in water. To prepare the THELES, several coformers were tested, namely, tromethamine, L(+)-arginine, L-tryptophan, citric acid, malic acid, ascorbic acid, and p-aminobenzoic acid, in molar ratios of 1:1 and 1:2. To improve viscosity, water was added in different molar ratios to all systems. THELES were characterized by mid-infrared spectroscopy (MIR), and differential scanning calorimetry. Their viscosity, solubility, and permeability were also determined. Their stability at room temperature and 40 °C was accessed by MIR. Cytocompatibility was performed by metabolic activity and cell lysis evaluation, according to ISO10993-5:2009, and compared with the crystalline APIs. THELES with TRIS were successfully synthesized for both APIs. Results showed an increased solubility without a decrease in the permeability of the APIs in the THELES when compared with the pure APIs. The THELES were also considered stable for 8 weeks at ambient temperature. The cells studied showed that the THELES were not toxic for the cell lines used.

Hydrogel Microparticle-Templated Anti-Solvent Crystallization of Small-Molecule Drugs.

Conventional formulation strategies for hydrophobic small-molecule drug products frequently include mechanical milling to decrease active pharmaceutical ingredient (API) crystal size and subsequent granulation processes to produce an easily handled powder. A hydrogel-templated anti-solvent crystallization method is presented for the facile fabrication of microparticles containing dispersed nanocrystals of poorly soluble API. Direct crystallization within a porous hydrogel particle template yields core-shell structures in which the hydrogel core containing API nanocrystals is encased by a crystalline API shell. The process of controllable loading (up to 64% w/w) is demonstrated, and tailored dissolution profiles are achieved by simply altering the template particle size. API release is well described by a shrinking core model. Overall, the approach is a simple, scalable and potentially generalizable method that enables novel means of independently controlling both API crystallization and excipient characteristics, offering a "designer" drug particle system.

Detection and Analysis of Drug Crystals in Medical Transdermal Patches by Using X-ray Diffraction Measurement

The crystallization of active pharmaceutical ingredients (APIs) in matrix-type transdermal patches has implications for the rate of drug absorption through the skin and patch adhesion strength. Therefore, the presence or absence and the degree of API crystallinity must be controlled to guarantee the quality of patches. In this study, the utility of laboratory-level X-ray diffractometers for the detection and analysis of crystalline APIs in transdermal patches was investigated using medical patches of tulobuterol and isosorbide dinitrate. Several matrix-type patches employ a controlled drug delivery system containing intentionally crystallized API. Both benchtop and high-resolution laboratory X-ray diffractometers can detect several characteristic peaks of the APIs in these patches even if the patches are wrapped in an outer bag, although a benchtop model provides peak heights one-seventh to one-fifth that of a high-resolution instrument. An isosorbide dinitrate patch containing an unintentionally crystallized spot was wrapped in an outer bag, followed by measurements using both X-ray diffractometers. For both instruments, several isosorbide dinitrate-derived peaks were detected only at the crystallized spot, although the signal-to-noise ratio was poorer for the benchtop model. These results show that a high-resolution X-ray diffractometer is advantageous for high-detection sensitivity and offers a high degree of freedom of the measurement position on the sample. It was concluded that a laboratory-level high-resolution X-ray diffractometer can be used to examine the crystalline state of APIs in patches inside an unopened outer bag.

Ball milling and hot-melt extrusion of indomethacin–l-arginine–vinylpyrrolidone-vinyl acetate copolymer: Solid-state properties and dissolution performance

Commonly applied approaches to enhance the dissolution properties of low water-soluble crystalline active pharmaceutical ingredients (APIs) include their amorphization by incorporation into a polymeric matrix and the formation of amorphous solid dispersions, or blending APIs with low-molecular-weight excipients and the formation of a co-amorphous system. This study focused on the preparation and characterization of binary (consisting of indomethacin (IND) and polymer – copovidone (PVP VA 64), as a carrier, or amino acid – L-arginine (ARG), as a co-former) and ternary (comprising the same API, polymer, and amino acid) formulations. Formulations were produced by ball milling (BM) and/or hot-melt extrusion (HME), and extensive physicochemical characterization was performed. Specifically, the physicochemical and solid-state properties of a model IND–ARG system incorporated into a polymeric matrix of PVP VA 64 by HME and BM as well as by combined BM/HME method together with the impact of the preparation strategy on the dissolution profiles and long-term physical stability were investigated. Ball-milled binary and ternary formulations were found to be amorphous. The residual crystals corresponding to IND–ARG salt were identified in the ternary formulations produced via HME. Despite the presence of a crystalline phase, dissolution tests showed that ternary systems prepared by HME exhibited improved IND solubility when compared to pure crystalline IND and their corresponding physical mixture. None of the binary and ternary formulations that were initially fully amorphous did undergo recrystallization during the entire period of preservation (minimum of 12 months) in dry conditions at 25 °C.

Drug-Polymer Interactions in Acetaminophen/Hydroxypropylmethylcellulose Acetyl Succinate Amorphous Solid Dispersions Revealed by Multidimensional Multinuclear Solid-State NMR Spectroscopy.

The bioavailability of insoluble crystalline active pharmaceutical ingredients (APIs) can be enhanced by formulation as amorphous solid dispersions (ASDs). One of the key factors of ASD stabilization is the formation of drug–polymer interactions at the molecular level. Here, we used a range of multidimensional and multinuclear nuclear magnetic resonance (NMR) experiments to identify these interactions in amorphous acetaminophen (paracetamol)/hydroxypropylmethylcellulose acetyl succinate (HPMC-AS) ASDs at various drug loadings. At low drug loading (<20 wt %), we showed that 1H–13C through-space heteronuclear correlation experiments identify proximity between aromatic protons in acetaminophen with cellulose backbone protons in HPMC-AS. We also show that 14N–1H heteronuclear multiple quantum coherence (HMQC) experiments are a powerful approach in probing spatial interactions in amorphous materials and establish the presence of hydrogen bonds (H-bond) between the amide nitrogen of acetaminophen with the cellulose ring methyl protons in these ASDs. In contrast, at higher drug loading (40 wt %), no acetaminophen/HPMC-AS spatial proximity was identified and domains of recrystallization of amorphous acetaminophen into its crystalline form I, the most thermodynamically stable polymorph, and form II are identified. These results provide atomic scale understanding of the interactions in the acetaminophen/HPMC-AS ASD occurring via H-bond interactions.

Solubilizing temperature of crystalline drug in polymer carrier: A rheological investigation on a posaconazole-copovidone system with low drug load

Measuring the solubility of a crystalline active pharmaceutical ingredient (API) in a polymer-rich system is challenging due to the high viscosity of the polymer which kinetically impedes reaching the solubility equilibrium. In this study, a rheological approach of determining the solubilizing temperature of a crystalline API in a polymeric carrier has been developed. To validate the method, a model physical mixture of crystalline posaconazole and copovidone with a relatively low API load (25 wt%) was utilized. First, a comparison between conventional differential scanning calorimetry (DSC) and a rheological temperature ramp was conducted to illustrate that the rheological method could capture the melting point depression behavior similarly to the more well-known DSC technique. Second, to further understand the dissolution process of the crystalline posaconazole into the copovidone carrier and precisely measure the solubilizing temperature, a series of isothermal rheological time sweeps were carried out at various temperatures selected based on the rheological temperature sweep. Because the dissolved API molecule imparted a plasticizing effect to the polymeric carrier, the complex viscosity of the API-polymer system decreased gradually over time and correlated well to an exponential decay function. Moreover, dependent on the applied temperature, the API-polymer system eventually accomplished distinct equilibrium states (complex viscosities) within different time frames. The obtained time constants at different temperatures were fitted to the Arrhenius equation, allowing the determination of the activation energy of the mixing process. The results indicated that once the processing temperature exceeded a critical point below the melting point of the crystalline API, the API-polymer solubilization process switched from a surface dominated dispersive mechanism to a molecular-level solubilization mode, manifested by the significantly increased activation energy. To the best of our knowledge, the currently developed rheological approach was the first successful measurement of the solubilizing temperature of a crystalline drug in a polymer-rich system.

Diagnosis of Agglomeration and Crystallinity of Active Pharmaceutical Ingredients in Over the Counter Headache Medication by Electrospray Laser Desorption Ionization Mass Spectrometry Imaging.

Agglomeration of active pharmaceutical ingredients (API) in tablets can lead to decreased bioavailability in some enabling formulations. In a previous study, we determined that crystalline APIs can be detected as agglomeration in tablets formulated with amorphous acetaminophen tablets. Multiple method advancements are presented to better resolve agglomeration caused by crystallinity in standard tablets. In this study, we also evaluate three “budget” over-the-counter headache medications (subsequently labeled as brands A, B, and C) for agglomeration of the three APIs in the formulation: Acetaminophen, aspirin, and caffeine. Electrospray laser desorption ionization mass spectrometry imaging (ELDI-MSI) was used to diagnose agglomeration in the tablets by creating molecular images and observing the spatial distributions of the APIs. Brand A had virtually no agglomeration or clustering of the active ingredients. Brand B had extensive clustering of aspirin and caffeine, but acetaminophen was observed in near equal abundance across the tablet. Brand C also had extensive clustering of aspirin and caffeine, and minor clustering of acetaminophen. These results show that agglomeration with active ingredients in over-the-counter tablets can be simultaneously detected using ELDI-MS imaging.