In situ ophthalmic gel of ciprofloxacin hydrochloride for once a day sustained delivery.
ABSTRACT This article focuses on preparation and evaluation of a once a day ophthalmic delivery system for ciprofloxacin hydrochloride based on the concept of pH-triggered in situ gelation. The in situ gelling system involves the use of polyacrylic acid (Carbopol 980NF) as a phase transition polymer, hydroxypropyl methylcellulose (Methocel K100LV) as a release retardant, and ion exchange resin as a complexing agent. Ciprofloxacin hydrochloride was complexed with ion exchange resin to avoid incompatibility between drug and polyacrylic acid. The developed formulation was stable, and nonirritant to rabbit eyes and in vitro drug release was found to be around 98% over a period of 24 hours.
Conference Paper: Thermoelectric properties in single crystals of Ca-Co-O system[Show abstract] [Hide abstract]
ABSTRACT: Single crystals of Co-based layered oxide, Ca<sub>3</sub>Co<sub>4</sub>O<sub>9</sub> (Co349), were grown using a flux method and their electrical and thermal properties were investigated. Values of thermoelectric power S are quite large above 773 K and reach almost 250 μV·K<sup>-1</sup> at 973 K, and their thermal conductivity κ is nearly 3 W·m<sup>-1</sup>·K<sup>-1</sup>, as determined by mathematical extrapolation. The relatively low κ is likely the result of a misfit structure between the CoO<sub>2</sub> layers and the Ca<sub>2</sub>CoO<sub>3</sub> slabs. The figure of merit for (Ca,Sr,Bi)<sub>2</sub>Co<sub>2</sub>O<sub>5+0</sub> with Co349 structure can be estimated as greater than 1.1. Co349 should be a promising material for thermoelectric power generation.Thermoelectrics, 2002. Proceedings ICT '02. Twenty-First International Conference on; 09/2002
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ABSTRACT: Lactobacillus strains that accumulated γ-aminobutyric acid (GABA) in culture medium were screened to determine strains with high GABA-producing ability. One strain, NFRI 7415, which was isolated from a Japanese traditional fermented fish (funa-sushi), showed the highest GABA-producing ability among the screened strains. Identification tests (i.e., 16S rDNA sequencing and sugar assimilation ability) indicated that NFRI 7415 belongs to Lb. paracasei. The GABA production was further improved by the addition of pyridoxal phosphate to the culture medium and pH regulation of culture medium at pH 5.0. Under optimal cultivation conditions, strain NFRI 7415 produced GABA at a concentration of 302 mm when the glutamate concentration in the culture medium was 500 mm.Food Microbiology 12/2005; 22(6-22):497-504. DOI:10.1016/j.fm.2005.01.002 · 3.37 Impact Factor
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ABSTRACT: This study focused on preparation and evaluation of a thermosensitive and mucoadhesive in situ gelling ophthalmic system of azithromycin (ATM). Poloxamer 407 (P407) and poloxamer 188 (P188) were used as gelling agents. Addition of Carbopol 974P (CP 974P) to the gelling systems could increase the solubility of ATM by salt effect and enhance the mucoadhesive property of the systems. Gelation temperature of these systems ranged from 31.21-36.31 degrees C depending on the ratio of P407 and P188. Mucoadhesion force of the system composed of P407/P188/CP 974P (21/5/0.3%, w/v) was 2.3-fold that without carbopol 974P. Viscosity of the formulation was in a suitable range at 25 degrees C and pseudoplastic behavior was observed at 35 degrees C. The formulation exhibited a 24-h sustained release of ATM. In vivo resident experiments showed AUC(0-12) of ATM in rabbit tears increased by 1.78-fold for in situ gel compared with eye drop. At 12 h, tear concentrations exceeded minimum inhibitory concentration (MIC) breakpoint for the most common causative pathogens of bacterial conjunctivitis by 2.8-fold. Results in vitro and in vivo indicated that this droppable gel performed better than ATM eye drop did.Drug Delivery 10/2010; 17(7):500-7. DOI:10.3109/10717544.2010.483255 · 2.20 Impact Factor