PubMed · 14047862
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D SWARTZ, S ISRAELS. 1963. PRIMARY HYPEROXALURIA.. https://doi.org/10.1016/s0022-5347(17)64368-4
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The aim of the study was to investigate isotropic mono- and diglyceride (MCMDG)/oil/water systems as vehicles for combinations of hydrophilic and lipophilic drugs. For two-component systems, MCMDG was mixed with various masses of water. For MCMDG/oily vehicles/water systems, mixtures were prepared by mixing oil and MCMDG prior to the addition of the appropriate masses of water. The isotropic region was examined by visual inspection and confirmed using polarized light microscopy. Viscosities of the systems were determined. Solubilities of hydrophilic (levamisole HCl) and lipopohilic (abamectin) drugs were determined in the isotropic formulations by HPLC analysis. The isotropic regions in the two-component and three-component systems had water contents of up to 18% at 25 degrees C. The isotropic formulations exhibited Newtonion flow. The viscosity of formulations having the same percentage of water increased with increasing ratio of MCMDG to oil in three-component systems. The solubilities of the levamisole HCl and abamectin were higher in the isotropic MCMDG/sesame oil/water formulations than in equivalent MCMDG/water formulations. In some formulations, the solubility of levamisole HCl was higher in the absence of abamectin than in combination with abamectin. Isotropic MCMDG/oil/water systems were obtained without the use of co-surfactants. Increasing water content in the system did not proportionally increase the solubility of hydrophilic drug. Solubilization of hydrophilic drug was affected by lipophilic drug in the presence or absence of SO and lipophilic drug solubility was affected by hydrophilic drug in the absence of SO. These systems are suitable vehicles to deliver both hydrophilic and lipophilic drugs and could be of interest for pharmaceutical formulations.
A GC-MS method was developed for the determination of various flavonoids and phenolic and benzoic acids in human plasma. The procedure involved the extraction of flavonoids and phenolic and benzoic acids with ethyl acetate, followed by the derivatization of the phenolic and benzoic compounds with BSTFA (N,O-bis(trimethylsilyl) trifluoroacetamide) + TMCS (trimethylchlorosilane) reagent. The trimethylsilyl derivatives formed were separated and quantitated using GC-MS. Twenty flavonoids and phenolic and benzoic compounds have been well separated in the spiked human plasma without any interference. The average recovery was 79.3%. Several phenolic acids such as o-hydroxybenzoic, p-hydroxyphenylacetic, 2,3-dihydroxybenzoic, 2,4-dihydroxybenzoic, ferulic, sinapic, and benzoic acid were identified and quantified in human plasma after consumption of a cranberry juice. This developed method provides a simple, specific, and sensitive technique for the simultaneous determination of flavonoids and phenolic and benzoic acids in human plasma and is suitable for bioavailability and pharmacokinetic studies.
Twenty two p-substituted benzoic acid derivates were used to prepare salts of N-methylbenzylamine (II) and N,N-dimethylbenzylamine (III), respectively. Only five salts of (II) and two salts of (III) were obtained in a crystalline state. The solubility of these salts was orders of magnitude higher than those reported for the corresponding salts of benzylamine (I). Thermal analysis indicated that the increased solubility was caused by reduced crystal lattice energy, which was most likely due to the reduced number of strong hydrogen bonds of the salt of (II) and (III). X-ray crystallographic analysis of p-hydroxybenzoic acid salt of (I), (II) and (III) suggested that the reduced number of hydrogen bonds caused the apparent higher solubility. Further analyses of seven salts of (I) were performed. It was not possible to identify any relationship between the number of hydrogen bonds and the corresponding solubility of the salts.