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1.
Colloids Surf B Biointerfaces ; 167: 483-491, 2018 Jul 01.
Article in English | MEDLINE | ID: mdl-29727835

ABSTRACT

The low aqueous solubility of curcumin (CUR) had greatly limited the clinical efficacy of CUR therapy despite its well-known potent therapeutic activities. Previously, we developed amorphous nanoparticle complex (nanoplex) of CUR and chitosan (CHI) as a solubility enhancement strategy of CUR by electrostatically-driven drug-polyelectrolyte complexation. The CUR-CHI nanoplex, however, (1) lacked a built-in ability to produce prolonged high apparent solubility of CUR in the absence of crystallization-inhibiting agents, and (2) exhibited poor physical stability during long-term storage. For this reason, herein we developed amorphous ternary nanoplex of CUR, CHI, and hypromellose (HPMC) where HPMC functioned as the crystallization inhibitor. The effects of incorporating HPMC on the (1) physical characteristics and (2) preparation efficiency of the CUR-CHI-HPMC nanoplex produced were investigated. Compared to the CUR-CHI nanoplex, the HPMC inclusion led to larger nanoplex (≈300-500 nm) having lower zeta potential (≈1-15 mV) and lower CUR payload (≈40-80%), albeit with higher CUR utilization rates (≈100%) attributed to the CUR interactions with both CHI and HPMC. The CUR-CHI-HPMC nanoplex's physical characteristics could be controlled by varying the HPMC to CHI ratio in the feed. Subsequently, the CUR-CHI-HPMC and CUR-CHI nanoplexes were examined in terms of their (1) storage stability, (2) dissolution characteristics in simulated gastrointestinal fluids, and (3) in vitro solubility enhancement. The results showed that the CUR-CHI-HPMC nanoplex exhibited superior (i) amorphous state stability after twelve-month storage, (ii) dissolution characteristics, and (iii) solubility enhancement in simulated gastrointestinal fluids, with minimal cytotoxicity towards human gastric epithelial cells.


Subject(s)
Chitosan/chemistry , Curcumin/chemistry , Hypromellose Derivatives/chemistry , Nanoparticles/chemistry , Antineoplastic Agents/pharmacology , Cell Survival/drug effects , Cells, Cultured , Curcumin/pharmacology , Drug Carriers/chemistry , Epithelial Cells/drug effects , Gastric Mucosa/cytology , Humans , Microscopy, Electron, Scanning/methods , Nanoparticles/ultrastructure , Particle Size , Solubility
2.
Eur J Pharm Sci ; 114: 356-363, 2018 Mar 01.
Article in English | MEDLINE | ID: mdl-29309874

ABSTRACT

The numerous health benefits of curcumin (CUR) have not been fully realized due to its low aqueous solubility, resulting in poor bioavailability. While amorphization of CUR via amorphous solid dispersion (ASD) represents a well-established CUR solubility enhancement strategy, simultaneous amorphization and nanonization of CUR via amorphous CUR nanoparticles (or nano-CUR in short) have emerged only recently as the plausibly superior alternative to ASD. Herein we examined for the first time the amorphous nano-CUR versus the ASD of CUR in terms of their (1) in vitro solubility enhancement capability and (2) long-term physical stability. The ASD of CUR was prepared by spray drying with hydroxypropylmethylcellulose (HPMC) acting as crystallization inhibitor. The amorphous nano-CUR was investigated in both its (i) aqueous suspension and (ii) dry-powder forms in which the latter was prepared by spray drying with adjuvants (i.e. HPMC, trehalose, and soy lecithin). The results showed that the amorphous nano-CUR (in both its aqueous suspension and dry-powder forms) exhibited superior solubility enhancement to the ASD of CUR attributed to its faster dissolution rates. This was despite the ASD formulation contained a larger amount of HPMC. The superior solubility enhancement, however, came at the expense of low physical stability, where the amorphous nano-CUR showed signs of transformation to crystalline after three-month accelerated storage, which was not observed with the ASD. Thus, despite its inferior solubility enhancement, the conventional ASD of CUR was found to represent the more feasible CUR solubility enhancement strategy.


Subject(s)
Chemistry, Pharmaceutical/methods , Curcumin/chemical synthesis , Curcumin/metabolism , Nanoparticles/chemistry , Nanoparticles/metabolism , Crystallization , Drug Stability , Solubility
3.
J Neurosci Methods ; 173(2): 259-70, 2008 Aug 30.
Article in English | MEDLINE | ID: mdl-18634822

ABSTRACT

Two-photon microscopy offers the promise of monitoring brain activity at multiple locations within intact tissue. However, serial sampling of voxels has been difficult to reconcile with millisecond timescales characteristic of neuronal activity. This is due to the conflicting constraints of scanning speed and signal amplitude. The recent use of acousto-optic deflector scanning to implement random-access multiphoton microscopy (RAMP) potentially allows to preserve long illumination dwell times while sampling multiple points-of-interest at high rates. However, the real-life abilities of RAMP microscopy regarding sensitivity and phototoxicity issues, which have so far impeded prolonged optical recordings at high frame rates, have not been assessed. Here, we describe the design, implementation and characterisation of an optimised RAMP microscope. We demonstrate the application of the microscope by monitoring calcium transients in Purkinje cells and cortical pyramidal cell dendrites and spines. We quantify the illumination constraints imposed by phototoxicity and show that stable continuous high-rate recordings can be obtained. During these recordings the fluorescence signal is large enough to detect spikes with a temporal resolution limited only by the calcium dye dynamics, improving upon previous techniques by at least an order of magnitude.


Subject(s)
Action Potentials/physiology , Brain/physiology , Microscopy, Fluorescence, Multiphoton/methods , Neurons/physiology , Neurophysiology/methods , Optics and Photonics/instrumentation , Animals , Brain/cytology , Calcium Signaling/physiology , Cerebellar Cortex/cytology , Cerebellar Cortex/physiology , Cerebral Cortex/cytology , Cerebral Cortex/physiology , Dendritic Spines/physiology , Dendritic Spines/ultrastructure , Fluorescent Dyes/standards , Image Cytometry/instrumentation , Image Cytometry/methods , Microscopy, Fluorescence, Multiphoton/instrumentation , Neurons/cytology , Neurophysiology/instrumentation , Organ Culture Techniques , Purkinje Cells/cytology , Purkinje Cells/physiology , Pyramidal Cells/cytology , Pyramidal Cells/physiology , Rats , Rats, Wistar , Staining and Labeling/methods , Synaptic Transmission/physiology
4.
J Can Chiropr Assoc ; 50(4): 249-54, 2006 Dec.
Article in English | MEDLINE | ID: mdl-17549185

ABSTRACT

OBJECTIVE: To detail the progress of a patient with unresolved symptoms of Trigger thumb who underwent a treatment plan featuring Active Release Technique (ART) and Graston Technique. CLINICAL FEATURES: The most important feature is painful snapping or restriction of movement, most notably in actively extending or flexing the digit. The cause of this flexor tendinopathy is believed to be multi-factorial including anatomical variations of the pulley system and biomechanical etiologies such as exposure to shear forces and unaccustomed activity. Conventional treatment aims at decreasing inflammation through corticosteroid injection or surgically removing imposing tissue. INTERVENTION AND OUTCOME: The conservative treatment approach utilized in this case involved Active Release Technique (ART) and Graston Technique (GT). An activity specific rehabilitation protocol was employed to re-establish thumb extensor strength and ice was used to control pain and any residual inflammation. Outcome measures included subjective pain ratings with range of motion and motion palpation of the first right phalangeal joint. Objective measures were made by assessing range of motion. CONCLUSION: A patient with trigger thumb appeared to be relieved of his pain and disability after a treatment plan of GT and ART.

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