Transport of quercetin di-sodium salt in the human intestinal epithelial Caco-2 cell monolayer 139.

Quercetin di-sodium salt (QDS), a water-soluble derivative of quercetin (Q), is a potent free radical scavenger. The aim of this study was to examine the in vitro intestinal transport of QDS compared to that of Q using the Caco-2 human intestinal epithelial cell line. The apical (A) to basolateral (B) transport of QDS was found to be higher than the B to A transport of this compound. This polarized transport involved the presence of a carrier protein system. The involvement of the sodium/glucose transporter-1 (SGLT-1) was shown by using phloridzin, a selective inhibitor of this conveyor system. However, the transport of Q was not affected by this inhibitor. Moreover, the influx of QDS was pH-sensitive and decreased at pH 5.5 compared with that observed at pH 7.4 and 6.5. The permeability of QDS was 10-fold higher than that of Q. This could be explained by the involvement of SLGT-1 and the absence of an active efflux pump in the absorption of QDS in comparison with Q. This finding was supported by comparing the solubility of Q with that of QDS. This study indicates that both the higher solubility of QDS and its dependence on the SGLT-1 transport system resulted in more efficient permeability compared to Q.

Permeability and swelling studies on free films containing inulin in combination with different polymethacrylates aimed for colonic drug delivery.

The aim of this study was to assess some permeability and swelling characteristics of free films prepared by combination of inulin as a bacterially degradable system and time- or pH-dependent polymers as a coating formulation for colonic drug delivery. Different free films were prepared by casting and solvent evaporation method. Formulations containing inulin with Eudragit RS, Eudragit RL, Eudragit RS-Eudragit RL, Eudragit FS and Eudragit RS-Eudragit S with different ratios of inulin were prepared. After preparation, free films were evaluated by water vapor transmission test, swelling experiment and permeability to indomethacin and theophylline in different media. Formulations containing Eudragit FS had high resistance to water vapor permeation; but were unable to protect premature swelling and drug release in simulated small intestine media. Also, combination of Eudragit RS and Eudragit S had no suitable characteristics for colon delivery. However, Eudragit RS and Eudragit RL in combination with inulin made free films which had more swelling and permeation of drug in the colonic medium rather than the other media. It was shown that formulations containing sustained release polymethacrylates in combination with inulin have more potential as a coating system for specific colon delivery compared with pH-dependent polymers.

Physico-mechanical properties of poly (epsilon-caprolactone) for the construction of rumino-reticulum devices for grazing animals.

The solid-state degradation of poly(epsilon-caprolactone) in the rumen of fistulated cattle was investigated. The degradation process was studied by measurement of changes in weight loss, crystallinity, Young's modulus, molecular weight by size exclusion chromatography and by intrinsic viscosity. In vitro degradation studies were conducted at 39 degrees C in aqueous solutions with a pH and ionic strength as near as possible to those encountered in vivo. Such studies demonstrated that the poly (epsilon-caprolactone) degraded more rapidly in vivo than in vitro. In vivo, chain scission is associated with an increase in crystallinity. The faster degradation in vivo was attributed to fatty acids and bacteria that are present in the rumen, the first portion of the stomach of the grazing animals.

Quantitation of levamisole in plasma using high performance liquid chromatography.

A rapid and sensitive procedure is described for the quantitation of levamisole in plasma using high-performance liquid chromatography (HPLC). The procedure involves sample preparation using a reverse-phase C18 cartridge prior to chromatography and quantitation using peak area ratios (UV absorbance detection, 225 nm) of levamisole to the internal standard, quinine. The limit of detection was 21 ng/ml and the limit of quantification was 72 ng/ml, both contained in 1 ml of plasma. The recoveries were sufficiently high (73.1%) and overall coefficient of variation of the procedure was 0.25%. This procedure has been used to determine levamisole levels in human and cattle plasma. A comparison of using two C18 columns (Nova-pak, Puresil) was also studied and discussed.

Niosomes as carriers of radiopaque contrast agents for X-ray imaging.

Non-ionic surfactant vesicles (niosomes) are considered as carriers of iobitridol, a diagnostic agent used for X-ray imaging. The niosomes, with a diameter between 150 and 175 nm, are prepared using the film-hydration method followed by sonication. These vesicles were obtained with appropriate mixtures of D-alpha tocopheryl polyethylene glycol 1000 succinate, polyoxyethylene glycol 4000 stearate, sorbitan monostearate, cholesterol and dicetylphosphate. Methods allowing the increase of the rate of encapsulation and the stability of the vesicles were carried out. In addition to the study of the formulation of the vesicles, the physico-chemical and morphological properties of the vesicles have been studied.