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On February 23, 2018, PubMed Central Canada (PMC Canada) will be taken offline permanently. No author manuscripts will be deleted, and the approximately 2,900 manuscripts authored by Canadian Institutes of Health Research (CIHR)-funded researchers currently in the archive will be copied to the National Research Council’s (NRC) Digital Repository over the coming months. These manuscripts along with all other content will also remain publicly searchable on PubMed Central (US) and Europe PubMed Central, meaning such manuscripts will continue to be compliant with the Tri-Agency Open Access Policy on Publications.

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1.  Application of Nanosize Zeolite Molecular Sieves for Medical Oxygen Concentration 
Nanomaterials  2017;7(8):195.
The development of a portable oxygen concentrator is of prime significance for patients with respiratory problems. This paper presents a portable concentrator prototype design using the pressure/vacuum swing adsorption (PVSA) cycle with a deep evacuation step (−0.82 barg) instead of desorption with purge flow to simplify the oxygen production process. The output of the oxygen concentrator is a ~90 vol % enriched oxygen stream in a continuous adsorption and desorption cycle (cycle time ~90 s). The size of the adsorption column is 3 cm in diameter and 20 cm in length. A Li+ exchanged 13X nanosize zeolite is used as the adsorbent to selectively adsorb nitrogen from air. A dynamic model of the pressure and vacuum swing adsorption units was developed to study the pressurization and depressurization process inside the microporous area of nanosized zeolites. The describing equations were solved using COMSOL Multiphysics Chemical Engineering module. The output flow rate and oxygen concentration results from the simulation model were compared with the experimental data. Velocity and concentration profiles were obtained to study the adsorption process and optimize the operational parameters.
PMCID: PMC5575677  PMID: 28757586
nanosize zeolite; microporous adsorption; bidisperison dynamic model; portable oxygen concentrator; COMSOL Multiphysics
2.  Crystal structure of (R)-N-benzyl-1-phenylethanaminium (R)-4-chloro­mandelate 
The absolute configuration of the title mol­ecular salt, C15H18N+·C8H6ClO3 −, has been confirmed by resonant scattering. In the (R)-N-benzyl-1-phenyl-ethyl­ammonium cation, the phenyl rings are inclined to one another by 44.65 (7)°. In the crystal, the (R)-4-chloro­mandelate anions are linked via O—H⋯O hydrogen bonds and bridged by N—H⋯O hydrogen bonds involving the cations, forming chains along [010]. There are C—H⋯O hydrogen bonds present within the chains, which are linked via C—H⋯π inter­actions and a short Cl⋯Cl inter­action [3.193 (1) Å] forming a three-dimensional framework. The structure was refined as a two-component inversion twin giving a Flack parameter of 0.05 (4).
PMCID: PMC4257388  PMID: 25553012
Crystal structure; 4-chloro­mandelate; diastereomeric salt; resolution; absolute structure; resonant scattering; hydrogen bonding; C—H⋯π inter­actions; Cl⋯Cl inter­action
3.  Cubic Magnetically Guided Nanoaggregates for Inhalable Drug Delivery: In Vitro Magnetic Aerosol Deposition Study 
AAPS PharmSciTech  2013;14(3):977-993.
The present work describes the in vitro aerosol deposition and enhanced deaggregation behavior of superparamagnetic iron oxide nanoaggregates (SPIONs). SPIONs were surface-coated with amine functionalized polyrotaxane and were proposed as a carrier for inhalation dry powders. Polyrotaxane is primarily composed of beta cyclodextrin rings which are spontaneously threaded on the block copolymer, poly(propylene glycol) bis(2-aminopropylether). Variable concentrations of surface coating polymers showed controlled manipulation of the crystal size and morphology. Magnetic nanoaggregates fabricated with low concentration of polyrotaxane showed cubic crystal morphology. However, these nanoaggregates exhibited rhombic dodecahedron crystal structure upon increasing the coating polymer concentration. In comparison to the spherical uncoated magnetic nanoparticles, cubic phase magnetic nanoaggregates demonstrated an enhanced in vitro aerosol deposition using magnetic field alignment. This enhancement can be accomplished at low inhalation flow rates (15 and 30 L/min). However, transformation to the cubic crystal structure was observed to be associated with a reduction in the powder geometric standard deviation. Using a mathematical modeling approach, we noted significant enhancement in the deaggregation behavior of inhalation dry powders; that can be achieved with small amounts of magnetic nanoaggregates. Aggregates of cubic nanoparticles showed promise for targeted pulmonary deposition of anticancer drugs.
FigureCubic magnetic nanoaggregates for systemic pulmonary drug delivery
Electronic supplementary material
The online version of this article (doi:10.1208/s12249-013-9980-y) contains supplementary material, which is available to authorized users.
PMCID: PMC3755173  PMID: 23765453
in vitro aerosol deposition; magnetic nanoaggregates; magnetic next generation impinger; polyrotaxane; saturation magnetization
4.  Controlled release of 5-fluorouracil and progesterone from magnetic nanoaggregates 
The potential use of magnetic nanoparticles in biomedical applications has witnessed an exponential growth in recent years.
In this study, we used nanoaggregates of magnetic nanoparticles as carriers for controlled drug delivery. The nanoaggregates are formed due to the presence of the block copolymer of polyethylene oxide-polypropylene oxide (Pluronic F-68) and beta-cyclodextrin that surround the magnetic core of the nanoparticles. The administration of the drug carriers occurs by inhalation, and the drug is delivered systemically via the pulmonary route. We tested the delivery of 5-fluorouracil and progesterone, which are used as models of hydrophilic and hydrophobic drugs, respectively.
The estimated nanoaggregates’ diameters are between 293 nm ± 14.65 nm and 90.2 nm ± 4.51 nm, respectively. In-situ and post-synthesis techniques are two approaches for drug loading. The polymer composition of nanoaggregates and initial drug concentration showed a significant effect on both the drug entrapment efficiency and release kinetics. Average drug entrapment efficiencies ranged between 16.11% and 83.25%. In-situ loaded samples showed significantly slower release rates. The drug release mechanism is investigated by mathematical curve fitting to different drug release kinetics models. In most cases, the Peppas model has shown good correlations (coefficients of correlation, R2, between 0.85 and 0.99) with the examined release profiles. The estimated release indices are below 0.5, which indicates the Fickian diffusion mechanism. For samples with an initial burst effect, the modified Peppas model can provide a better understanding of the drug release mechanism, both in the samples loaded with progesterone, or those high polymer concentrations.
Our work showed prolonged delivery of drugs (5-fluorouracil and progesterone) by diffusion from nanoaggregates, with the potential to reduce dose-related adverse effects.
PMCID: PMC3396392  PMID: 22802683
Nanoaggregates; 5-fluorouracil; progesterone; release kinetics; Fickian diffusion
5.  In Situ Focused Beam Reflectance Measurement (FBRM), Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Raman Characterization of the Polymorphic Transformation of Carbamazepine 
Pharmaceutics  2012;4(1):164-178.
The objective of this work was to study the polymorphic transformation of carbamazepine from Form II to Form III in 1-propanol during seeded isothermal batch crystallization. First, the pure Form II and Form III were obtained and characterized. Then their solubilities and metastable zone limits were measured by in-situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and focused beam reflectance measurement (FBRM). A transition temperature at about 34.2 °C was deduced suggesting the enantiotropic nature of this compound over the studied temperature range. To quantify the polymorph ratio during the transformation process, a new in-situ quantitative method was developed to measure the fraction of Form II by Raman spectroscopy. Successful tracking of the nucleation of the stable form and the transformation from Form II to Form III during isothermal crystallization was achieved by Raman spectroscopy and FBRM. The results from these three in-situ techniques, FBRM, FTIR and Raman were consistent with each other. The results showed a strong dependency on the amount of seeds added during isothermal crystallization.
PMCID: PMC3834901  PMID: 24300186
carbamazepine; polymorph transformation; in-situ quantitative method; in-situ analytical techniques
6.  (R)-1-Phenyl­ethanaminium (S)-4-chloro­mandelate 
The absolute configuration of the title complex, C8H12N+·C8H6ClO3 − or [R-C6H5C(H)CH3NH3][S-4-ClC6H4C(H)(OH)CO2], has been confirmed by the structure determination. In the crystal structure, inter­molecular O—H⋯O and N—H⋯O hydrogen bonds form a two-dimensional network perpendicular to the c axis.
PMCID: PMC2960855  PMID: 21201902

Results 1-6 (6)