scholarly journals Crystallisation Behaviour of Pharmaceutical Compounds Confined within Mesoporous Silicon

Pharmaceutics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 214 ◽  
Author(s):  
Eleanor C. L. Jones ◽  
Luis M. Bimbo
Keyword(s):  
Pore Size ◽  
Mesoporous Materials ◽  
Amorphous State ◽  
Aqueous Solubility ◽  
Pharmaceutical Compounds ◽  
Substrate Material ◽  
Mesoporous Silicon ◽  
Crystallisation Behaviour ◽  
Conventional Analysis ◽  
Drug Compounds

The poor aqueous solubility of new and existing drug compounds represents a significant challenge in pharmaceutical development, with numerous strategies currently being pursued to address this issue. Amorphous solids lack the repeating array of atoms in the structure and present greater free energy than their crystalline counterparts, which in turn enhances the solubility of the compound. The loading of drug compounds into porous materials has been described as a promising approach for the stabilisation of the amorphous state but is dependent on many factors, including pore size and surface chemistry of the substrate material. This review looks at the applications of mesoporous materials in the confinement of pharmaceutical compounds to increase their dissolution rate or modify their release and the influence of varying pore size to crystallise metastable polymorphs. We focus our attention on mesoporous silicon, due to the ability of its surface to be easily modified, enabling it to be stabilised and functionalised for the loading of various drug compounds. The use of neutron and synchrotron X-ray to examine compounds and the mesoporous materials in which they are confined is also discussed, moving away from the conventional analysis methods.

Pore size distribution in mesoporous materials as studied by 1H NMR

2001 ◽  
Vol 3 (15) ◽  
pp. 3203-3207 ◽  
Author(s):  
D. W. Aksnes ◽  
K. Førland ◽  
L. Kimtys
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
1H Nmr ◽  
Mesoporous Materials

scholarly journals Development of a Ternary Solid Dispersion Formulation of LW6 to Improve the In Vivo Activity as a BCRP Inhibitor: Preparation and In Vitro/In Vivo Characterization

Pharmaceutics ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 206 ◽  
Author(s):  
Rajiv Bajracharya ◽  
Sang Hoon Lee ◽  
Jae Geun Song ◽  
Minkyoung Kim ◽  
Kyeong Lee ◽  
...  
Keyword(s):  
Solid Dispersion ◽  
Amorphous State ◽  
Weight Ratio ◽  
Acid Methyl Ester ◽  
Systemic Exposure ◽  
Aqueous Solubility ◽  
Poloxamer 407 ◽  
Cancer Resistance ◽  
Ternary Solid Dispersion

LW6 (3-[2-(4-adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-benzoic acid methyl ester) is a potent inhibitor of drug efflux by the breast cancer resistance protein (BCRP). However, its poor aqueous solubility leads to low bioavailability, which currently limits in vivo applications. Therefore, the present study aimed to develop ternary solid dispersion (SD) formulations in order to enhance the aqueous solubility and dissolution rate of LW6. Various SDs of LW6 were prepared using a solvent evaporation method with different drug/excipient ratios. The solubility and dissolution profiles of LW6 in different SDs were examined, and F8-SD which is composed of LW6, poloxamer 407, and povidone K30 at a weight ratio of 1:5:8 was selected as the optimal SD. The structural characteristics of F8-SD were also examined using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM). In the acidic to neutral pH range, F8-SD achieved rapid dissolution with a drug release of 76–81% within 20 min, while the dissolution of pure LW6 was negligible. The XRPD patterns indicated that F8-SD probably enhanced the solubility and dissolution of LW6 by changing the drug crystallinity to an amorphous state, in addition to the solubilizing effect of the hydrophilic carriers. Furthermore, F8-SD significantly improved the oral bioavailability of topotecan, which is a BCRP substrate, in rats. The systemic exposure of topotecan was enhanced approximately 10-fold by the concurrent use of F8-SD. In conclusion, the ternary SD formulation of LW6 with povidone K30 and poloxamer 407 appeared to be effective at improving the dissolution and in vivo effects of LW6 as a BCRP inhibitor.

scholarly journals Mechanically Robust Gastroretentive Drug-Delivery Systems Capable of Controlling Dissolution Behaviors of Coground β-Lapachone

Pharmaceutics ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 271 ◽  
Author(s):  
Hyeongmin Kim ◽  
Chung-Lyol Lee ◽  
Seohyun Lee ◽  
Tae Jin Lee ◽  
Iqra Haleem ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Amorphous State ◽  
Aqueous Solubility ◽  
Gastric Fluid ◽  
Simulated Gastric Fluid ◽  
Dissolution Behavior ◽  
Matrix Tablet ◽  
Freeze Thaw ◽  
Physically Crosslinked

In this study, we aimed to design a highly swellable and mechanically robust matrix tablet (SMT) as a gastroretentive drug-delivery system (GRDDS) capable of improving the dissolution behavior of β-lapachone with low aqueous solubility. For the preparation of SMTs, the cogrinding technique and freeze–thaw method were used to disperse β-lapachone in SMTs in an amorphous state and to enhance the swelling and mechanical properties of SMTs, respectively. As a result, the crystallinity of coground β-lapachone incorporated in the SMTs was found to be considerably decreased; thereby, the dissolution rates of the drug in a simulated gastric fluid could be substantially increased. The SMTs of β-lapachone also demonstrated significantly enhanced swelling and mechanical properties compared to those of a marketed product. The reason for this might be because the physically crosslinked polymeric networks with a porous structure that were formed in SMTs through the freeze–thaw method. In addition, β-lapachone was gradually released from the SMTs in 6 h. Therefore, SMTs of β-lapachone developed in this study could be used as GRDDS with appropriate swelling and mechanical properties for improving the dissolution behavior of hydrophobic drugs such as β-lapachone.

scholarly journals Design and Characterization of Phosphatidylcholine-Based Solid Dispersions of Aprepitant for Enhanced Solubility and Dissolution

Pharmaceutics ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 407
Author(s):  
Sooho Yeo ◽  
Jieun An ◽  
Changhee Park ◽  
Dohyun Kim ◽  
Jaehwi Lee
Keyword(s):  
Solid Dispersion ◽  
Solid Dispersions ◽  
Amorphous State ◽  
Aqueous Solubility ◽  
Water Soluble ◽  
Scanning Calorimetry ◽  
Promising Alternative ◽  
Dispersion System ◽  
Enhanced Solubility ◽  
Water Soluble Drugs

This study aimed to improve the solubility and dissolution of aprepitant, a drug with poor aqueous solubility, using a phosphatidylcholine (PC)-based solid dispersion system. When fabricating the PC-based solid dispersion, we employed mesoporous microparticles, as an adsorbent, and disintegrants to improve the sticky nature of PC and dissolution of aprepitant, respectively. The solid dispersions were prepared by a solvent evaporation technique and characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry, and X-ray powder diffraction. The FTIR results showed that aprepitant interacted with the PC carrier by both hydrogen bonds and van der Waals forces that can also be observed in the interaction between aprepitant and polymer carriers. The solid dispersions fabricated with only PC were not sufficient to convert the crystallinity of aprepitant to an amorphous state, whereas the formulations that included adsorbent and disintegrant successfully changed that of aprepitant to an amorphous state. Both the solubility and dissolution of aprepitant were considerably enhanced in the PC-based solid dispersions containing adsorbent and disintegrant compared with those of pure aprepitant and polymer-based solid dispersions. Therefore, these results suggest that our PC-based solid dispersion system is a promising alternative to conventional formulations for poorly water-soluble drugs, such as aprepitant.

Preparation of SiC Nanoporous Membrane for Hydrogen Separation at High Temperature

2006 ◽  
Vol 510-511 ◽  
pp. 926-929 ◽  
Author(s):  
Y. Kim ◽  
Soo Ryong Kim ◽  
Kun Hang Cho ◽  
Seong Youl Bae ◽  
Woo Teck Kwon
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Porous Alumina ◽  
Amorphous State ◽  
Hydrogen Separation ◽  
Preceramic Polymer ◽  
Preceramic Polymers ◽  
Coating Method ◽  
Ft Ir

Nanoporous SiC membrane was developed on the porous alumina plate for the hydrogen separation using preceramic polymers such as polyphenylcarbosilane. The prepared preceramic polymers were characterized with FT-IR, TGA, GPC and XRD. Nanoporous SiC membrane was derived from the preceramic polymer using a spin coating method. The SiC membrane spin coated using 20 wt.% of polyphenylcarbosilane solution in cyclohexane does not show any cracks on the surface after heat treatment at 800oC. The average thickness of the SiC membrane is about 1µm. SiC coated porous alumina possesses asymmetric pore size distribution. There are micropores that originated from porous alumina substrate, and nanopores that derived from amorphous state of SiC membranes. The pore size distribution measurement showed that the sample contains 1-3 nm sized nano pores.

Pore size engineering of mesoporous silicon nitride materials

2002 ◽  
Vol 4 (9) ◽  
pp. 1675-1681 ◽  
Author(s):  
Stefan Kaskel ◽  
Klaus Schlichte ◽  
Bodo Zibrowius
Keyword(s):  
Silicon Nitride ◽  
Pore Size ◽  
Mesoporous Silicon

Investigations of the Mechanical and Hydrothermal Stabilities of SBA-15 and Al-SBA-15 Mesoporous Materials

MRS Advances ◽  
2016 ◽  
Vol 1 (35) ◽  
pp. 2453-2458 ◽  
Author(s):  
Dayton G. Kizzire ◽  
James Thomas ◽  
Sonal Dey ◽  
Hayley Osman ◽  
Robert A. Mayanovic ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Pore Size ◽  
Mesoporous Materials ◽  
High Surface ◽  
Md Simulations ◽  
High Energy ◽  
Hydrothermal Stability ◽  
Synchrotron Source ◽  
Stability Properties

ABSTRACTPeriodic mesoporous materials possess high surface to volume ratio and nano-scale sized pores, making them potential candidates for heterogeneous catalysis, ion exchange, gas sensing and other applications. In this study, we use in situ small angle x-ray scattering (SAXS) and molecular dynamics (MD) simulations to investigate the mechanical and hydrothermal stability properties of periodic mesoporous SBA-15 silica and SBA-15 type aluminosilica (Al-SBA-15) to extreme conditions. The mesoporous SBA-15 silica and Al-SBA-15 aluminosilica possess amorphous frameworks and have similar pore size distribution (pore size ∼9-10 nm). The in situ SAXS measurements were made at the B1 beamline, at the Cornell High Energy Synchrotron Source (CHESS). The mesoporous SBA-15 silica and Al-SBA-15 aluminosilica specimens were loaded in a diamond anvil cell (DAC) for pressure measurements, and, separately, with water in the DAC for hydrothermal measurements to high P-T conditions (to 255 °C and ∼ 114 MPa). Analyses of the pressure-dependent SAXS data show that the mesoporous Al-SBA-15 aluminosilica is substantially more mechanically stable than the SBA-15 silica. Hydrothermal measurements show a small net swelling of the framework at elevated P-T conditions, due to dissolution of water into the pore walls. Under elevated P-T conditions, the Al-SBA-15 aluminosilica shows significantly greater hydrothermal stability than the SBA-15 silica. Our MD simulations show that the bulk modulus value of periodic mesoporous SBA-15 silica varies exponentially with percentage porosity. Molecular dynamics simulations are being made in order to better understand how the pore architecture and the chemical composition of the host structure govern the stability properties of the mesoporous materials.

Synthesis of tailored bimodal mesoporous materials with independent control of the dual pore size distribution

2001 ◽  
pp. 2670-2671 ◽  
Author(s):  
Jihong Sun ◽  
Zhiping Shan ◽  
Thomas Maschmeyer ◽  
Jacob A. Moulijn ◽  
Marc-Olivier Coppens
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Mesoporous Materials ◽  
Independent Control

scholarly journals Measurement of pore sized microporous-mesoporous materials by time-domain nuclear magnetic resonance

BioResources ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1407-1418
Author(s):  
Zhi-hong Zhao ◽  
Ming-hui Zhang ◽  
Wen-Jing Liu ◽  
Quan-teng Li
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Rate ◽  
Porous Materials ◽  
Pore Size ◽  
Mesoporous Materials ◽  
Time Domain ◽  
Surface Relaxation ◽  
Pore Surface ◽  
Anodized Aluminum

Time-domain nuclear magnetic resonance (TD NMR) technology has been used for pore detection in porous materials for a long time, but there are few pore detection methods for microporous-mesoporous materials. The surface of different materials is obtained by pore detection of known pore materials. Relaxation rate, which obtains aperture information, has an important practical significance for the application of time-domain NMR technology in the characterization of porous materials. In this study, the T2 peaks of pores of known pore size materials, namely zeolite molecular sieves (0.3 nm and 1 nm) and anodized aluminum porous membranes (30 nm and 90 nm), were used to calculate the pore surface relaxation of zeolite molecular sieve with 0.3 nm pore size and 1 nm pore size. The ratio of the rate of the surface is 3.379; the ratio of the pore surface relaxation ratio of the 30 nm and 90 nm apertures of the anodized aluminum porous film is 3.031. This result is very close to the pore size ratio, indicating that the surface relaxation rate of the same material is directly related to the pore size, while the T2 peak can qualitatively measure the pore size.

Sign in / Sign up

Export Citation Format

Share Document