PubMed · 5863131
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I Benes, J Cífka. 1965. [Methionine].. https://pubmed.ncbi.nlm.nih.gov/5863131/
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The purpose of this study was to develop constants for the log-linear cosolvent model, thereby allowing accurate prediction of solubilization in the most common pharmaceutical cosolvents: propylene glycol, ethanol, polyethylene glycol 400, and glycerin. The solubilization power (sigma) of each cosolvent was determined for a large number of organic compounds from the slope of their log-solubility vs. cosolvent volume fraction plots. The solubilization data at room temperature were either experimentally determined or obtained from the literature. The slopes of the nearly linear relationship between solubilization power and solute hydrophobicity (logK(ow)) were obtained by linear regression analysis for each considered cosolvent. Thus, knowing or calculating a compound's partition coefficient is all that is needed to predict solubilization.
A hydrolyzable crosslinker (N,O-dimethacryloylhydroxylamine (MANHOMA)) was synthesized by a modified method and was characterized using 1H-NMR, FTIR, and melting point determination. Naltrexone-loaded nanoparticles were prepared by copolymerization of poly(ethylene glycol)1000 monomethyl ether mono methacrylate (PEO-MA), methyl methacrylate (MMA) and N,O-dimethacryloylhydroxylamine (MANHOMA) in 0.4% poly(vinyl alcohol) aqueous solution. The nanoparticles were characterized by FTIR, particle size determination and transmission electron microscope (TEM). The TEM photomicrographs of the nanoparticles show a crosslinked core surrounded by a ring formed by the polyethylene glycol tail of PEO-MA. The loading efficiency of the nanoparticles and in vitro drug availability from the nanoparticles were investigated. The naltrexone-loaded hydrolyzable crosslinked nanoparticles were able to sustain the release of naltrexone for different periods of time, depending on the monomer feed composition.
Dispersions of bicontinuous cubic monoglyceride-water phases, so-called 'cubosomes', have been proposed as parenteral sustained release delivery systems. For the present study, dispersions of monoolein-rich monoglycerides (MO), with or without purified soya phospholipids (PL), were prepared by equilibration of a MO/(PL)/water cubic phase, subsequent fragmentation with a poloxamer 407 (P407) solution, sonication and homogenization. This yielded systems of very different macroscopic appearance: Almost transparent dispersions, slightly turbid systems, opaque dispersions or milky emulsions. The mean z-average particle diameters ranged from 80 nm to well above 350 nm. Considerable particle growth could be detected in most systems during storage at room temperature. Storage at 5 degrees C resulted in the formation of ointment-like gels, which may be attributed to the crystallization of MO. Freeze-fracture transmission electron micrographs of MO dispersions revealed predominantly spherical particles with a low fracturing tendency. Synchrotron radiation X-ray diffraction indicated that high energy input during disintegration of the cubic phase leads to very complex systems in which particles with a cubic structure and MO/(PL) vesicles may coexist. The characteristic reflections of cubic systems were absent in the diffraction patterns of almost transparent or slightly turbid dispersions. The results indicate a strong dependence of ultrastructure of the dispersions on the preparation parameters.