Jankowski, et al.: Dermal and Transdermal Delivery from SemisolidsThe selection of a semisolid base type (hydrophobic, hydrophilic or emulsion) has an essential influence on the skin and transdermal delivery of active substances. The cutaneous and percutaneous absorption may be influenced by interactions occurring between base components and skin on the one hand and interactions between base components and the active ingredient on the other hand. The present article discusses the utility of different types of semisolid bases as carriers of active substances and summarizes results of studies comparing delivery of active substances from different semisolid bases.
COCs containing EE markedly inhibit hepatic microsomal function. This phenomenon must be taken into consideration when interpreting results of (13)C-MBT.
The main objective of the presented study was to characterize the high (HAS) and low anity (LAS) binding sites of ketoprofen (KP) in human serum albumin (HSA) structure with the use of spectrouorescence and proton nuclear magnetic resonance spectroscopy. In vitro uorescence analysis was used to estimate the eect of KP on the HSA uorescence. The association constants Ka [M −1 ] of KP-HSA complex in the HAS were determined with the use of Scatchard, Klotz, and Hill analysis. The quenching KQ [M −1 ] constants were determined on the basis of the SternVolmer equation. Binding of ketoprofen to plasma protein was also studied with the use of 8-anilinonapthalene-1-sulfonic acid (ANS) and 5-dimethylaminonaphthalene-1-sulfonic acid (DNSA) as the uorescence probes in IIIA and IIA subdomains of HSA, respectively. To estimate the cooperativeness in proteins Hill's coecient nH was used. The analysis of proton nuclear magnetic resonance spectra of KP in the presence of HSA allows us to observe the interactions between aromatic rings of the drug and the rings of amino acids located in the hydrophobic subdomains of the protein on the basis of the changes of chemical shifts ∆σ [ppm]
The proper choice of the solvent added to the semisolid base is crucial for enhanced skin delivery of the tested flavonoids. PG is more efficient absorption promoter than PEG 400 of both chrysin and quercetin.
Release of selected amino acids from zinc carriersThe paper deals with the results of an investigation of the release of selected amino acids (histidine, tryptophan, tyrosine) from model suspensions prepared by co-precipitation with zinc chloride. It has been proven that the influence of the Zn(II)/amino acid molar ratio on dissolution profiles of the tested amino acids and dissolution half-life (t 1/2 ) of histidine or tryptophan is significant. The amount of amino acid in the dispersed phase (supporting dose) is a determinant of the amino acid release profile. There is a minimal supporting dose (30.0 μmol of histidine or 17.4 μmol of tryptophan) that provides release of similar amounts of amino acid (4.1-4.6 μmol of histidine or 8.7-9.9 μmol of tryptophan) after the same time intervals. The tyrosine release profiles follow first order kinetics since the supporting dose (0.9-11.2 μmol) is limited by the tyrosine low solubility in water.
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