Stabilization of the amorphous state of pharmaceuticals in nanopores

Rengarajan, Gopalakrishnan Trichy; Enke, Dirk; Steinhart, Martin; Beiner, Mario

doi:10.1039/b804266g

Cited by 135 publications

(129 citation statements)

References 24 publications

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“…Dissolution parameters are given in Table 2, and the curves can be fitted for both the power law and Higuchi model, supporting a diffusion-based mechanism of release of ATV from NFM-1 particles. [27,28] Our in vitro results are consistent with their model of suppression of crystallization, where below a certain critical pore diameter (d*), the surface energy contributions are larger than the energetic gain upon crystallization. This thermodynamic effect increases with decreasing pore size, according to Equation (1): [27][28][29][30] …”

supporting

confidence: 92%

In vivo Enhancement in Bioavailability of Atazanavir in the Presence of Proton‐Pump Inhibitors using Mesoporous Materials

et al. 2011

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supporting

confidence: 92%

In vivo Enhancement in Bioavailability of Atazanavir in the Presence of Proton‐Pump Inhibitors using Mesoporous Materials

et al. 2011

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“…Most early studies used liquid phase guests, and the experiments were performed at temperature below 0°C (37,38,42). Recently, organic guest compounds with several polymorphs under nanoconfinement were also studied in different systems, in which pore size effect and kinetic factors were discussed (43)(44)(45). These reports noted that pore size, guest-host interactions, and surface properties of the pore wall are crucial factors to determine the final guest phases.…”

Section: Discussionmentioning

confidence: 99%

Guest–host interactions of a rigid organic molecule in porous silica frameworks

Hwang

Zones

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Molecular-level interactions at organic-inorganic interfaces play crucial roles in many fields including catalysis, drug delivery, and geological mineral precipitation in the presence of organic matter. To seek insights into organic-inorganic interactions in porous framework materials, we investigated the phase evolution and energetics of confinement of a rigid organic guest, N,N,N-trimethyl-1-adamantammonium iodide (TMAAI), in inorganic porous silica frameworks as a function of pore size (0.8 nm to 20.0 nm). We used hydrofluoric acid solution calorimetry to obtain the enthalpies of interaction between silica framework materials and TMAAI, and the values range from −56 to −177 kJ per mole of TMAAI. The phase evolution as a function of pore size was investigated by X-ray diffraction, IR, thermogravimetric differential scanning calorimetry, and solid-state NMR. The results suggest the existence of three types of inclusion depending on the pore size of the framework: single-molecule confinement in a small pore, multiple-molecule confinement/adsorption of an amorphous and possibly mobile assemblage of molecules near the pore walls, and nanocrystal confinement in the pore interior. These changes in structure probably represent equilibrium and minimize the free energy of the system for each pore size, as indicated by trends in the enthalpy of interaction and differential scanning calorimetry profiles, as well as the reversible changes in structure and mobility seen by variable temperature NMR.mesoporous silica | thermodynamics | porous materials K nowing both the structure and molecular mobility of guest matter in nanosized pores and channels, which often differ from those in the bulk unconfined material or solution, is essential for fundamental understanding of processes in both science and technology, with applications including natural processes such as biomineralization (1-3) and membrane transport (4, 5), engineering processes such as oil recovery (6-8), CO 2 sequestration (9-11), catalysis (12-14), and biomedical processes including diagnostics and drug delivery (15-17). Most of the pioneering research has used soft matter as guests, including gas and liquid phases, low-melting point organic solids, and longchain polymers (18)(19)(20).In our earlier studies, various calorimetric methods have been designed to investigate guest-host interactions. Piccione et al.(21) developed a novel system for hydrofluoric acid (HF) solution calorimetry to study the interactions of four different silica zeolite frameworks with several quaternary ammonium structure-directing agents (SDAs). The enthalpies of interaction were measured to be −32.0 to −181.0 kJ per mole of SDA. Slightly stronger interactions were found by Trofymluk et al. (22) for mesoporous silica phases containing long-chain molecules. Recently, Wu et al. (23) measured the enthalpy of interaction of various small molecules with mesoprous silicas using immersion calorimetry. The hydration enthalpies of a series of cation exchanged aluminosilicate or gallosilicate ze...

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“…Owing to the small clusters of acetaminophen, no inhomogeneities in the surface and vibrations between the paracetamol molecules could be induced, and the glassy liquid free energy was thus in equilibrium, precluding nucleation. Additionally, the clusters that did form are very uniform due to the uniform pore size distribution [159] .…”

Section: Applications Of Nanoporous Materials In Sorption and Drug Dementioning

confidence: 99%

Why is the nanoscale special (or not)? Fundamental properties and how it relates to the design of nano-enabled drug delivery systems

Otto

Villiers

2013

Nanotechnology Reviews

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Why is the nanoscale special (or not) ?Fundamental properties and how it relates to the design of nano-enabled drug delivery systems Abstract: Nanoscience studies describe natural phenomena at the submicron scale. Below a critical nanoscale limit, the physical, chemical, and biological properties of materials show a marked departure in their behavior compared to the bulk. At the nanoscale, energy conversion is dominated by phonons, whereas at larger scales, electrons determine the process. The surface-to-volume ratio at the nanoscale is immense, and interfacial interactions are markedly more important than at the macroscopic level, where the majority of the material is shielded from the surface. These properties render the nanoparticles to be significantly different from their larger counterparts. Nano-enabled drug delivery systems have resulted from multidisciplinary cooperation aimed at improving drug delivery. Significant improvements in the thermodynamic and delivery properties are seen due to nanotechnology. Hybrid nanodelivery systems, i.e., membranes with nanopores that can gate stimuli-responsive drug release could be a future development. Nanotechnology will improve current drug delivery and create novel future delivery systems. The fundamental properties and challenges of nanodelivery systems are discussed in this review.

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Stabilization of the amorphous state of pharmaceuticals in nanopores

Abstract: Confinement in nanoporous host systems with strongly interacting pore walls is shown to be a powerful approach to increase the lifetime of amorphous drugs based on changes in thermodynamics and crystallization kinetics in nano-sized systems.

Cited by 135 publications

References 24 publications

In vivo Enhancement in Bioavailability of Atazanavir in the Presence of Proton‐Pump Inhibitors using Mesoporous Materials

In vivo Enhancement in Bioavailability of Atazanavir in the Presence of Proton‐Pump Inhibitors using Mesoporous Materials

Guest–host interactions of a rigid organic molecule in porous silica frameworks

Why is the nanoscale special (or not)? Fundamental properties and how it relates to the design of nano-enabled drug delivery systems

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