In this paper,it was investigated that the effect of parameters such as the ionic strength,pH.counter-ion type of release medium,particle size.and cross linkage of cation exchange resin on the release of model drug pseudoephedrine hydrochloride(PE) from uncoated drug-resin complex.The drug-resin complex was pepared by the reaction of PE with strongly acidic cation exchange resin(001×4,001×7,001×14） .The result showed that the loading of PE increased with the increase of temperatures.The release of PE from drug-resin complex at 37℃ was monitored in vitro.From the experiments,it was found that the release rate of PE depends on the pH.comosition of the releasing media,increased at lower pH media or with increase of ionic strength of media.Moreover,the release rate of PE was inversely proportional to the cross-linkage and particle size of the cation exchange resin. 相似文献
In this paper, a sensitive accurate method for the determination of heterocyclic aromatic amines (HAAs) in cigarette smoke has been developed and validated using solid-phase extraction coupled with liquid chromatography–tandem mass spectrometry. A calibration curve was obtained with representative cigarette smoke using the standard addition method to compensate for matrix effects because the smoke of different cigarettes shows similar matrix effects. With this method, the accuracy of the method can be improved using a common analog of HAAs, which will greatly reduce the expense of using an isotope-labeled internal standard. Validation results showed that the method has high sensitivity (quantification limits of 0.08–0.56 ng cig−1), good reproducibility (RSD 6.37–9.31 %) and satisfactory recoveries (81.0–111 %). With this method, the emissions of HAAs in 30 commercial cigarette samples were analyzed and compared.
