Purpose: Fenretinide [N-(4-hydroxyphenyl)retinamide (4-HPR)] is a cytotoxic retinoid that suffers from a wide interpatient variation in bioavailability when delivered orally in a corn oil capsule. The poor bioavailability of the capsule formulation may have limited responses in clinical trials, and the large capsules are not suitable for young children. To support the hypothesis that a novel organized lipid matrix, LYM-X-SORB, can increase the oral bioavailability of fenretinide, fenretinide in LYM-X-SORB matrix and in a powderized LYM-X-SORB formulation was delivered to mice. Experimental Design: Fenretinide was delivered orally to mice as the contents of the corn oil capsule, in LYM-X-SORB matrix (4-HPR/LYM-X-SORB matrix) or in a LYM-X-SORB matrix powderized with sugar and flour (4-HPR/LYM-X-SORB oral powder). Levels of 4-HPR, and its principal metabolite, N-(4-methoxyphenyl)retinamide, were assayed in plasma and tissues. Results: In a dose-responsive manner, from 120 to 360 mg/kg/d, delivery to mice of 4-HPR in LYM-X-SORB matrix, or as 4-HPR/LYM-X-SORB oral powder, increased 4-HPR plasma levels up to 4-fold (P < 0.01) and increased tissue levels up to 7-fold (P < 0.01) compared with similar doses of 4-HPR delivered using capsule contents. Metabolite [N-(4-methoxyphenyl)retinamide] levels mirrored 4-HPR levels. Two human neuroblastoma murine xenograft models showed increased survival (P < 0.03), when treated with 4-HPR/LYM-X-SORB oral powder, confirming the bioactivity of the formulation. Conclusions: 4-HPR/LYM-X-SORB oral powder is a novel, oral drug delivery formulation, suitable for pediatric use, which warrants further development for the delivery of fenretinide in the treatment of cancer. A phase I clinical trial in pediatric neuroblastoma is in progress.

Abstract:A planar amperometric glucose microsensor based on glucose oxidase immobilized by chitosan film on Prussian Blue layer has been developed. The experimental results show that the optimum detection potential is 50 mV (versus Ag/AgCl) and the optimum pH is 6.5. Under the selective conditions the sensor exhibits excellent sensitivity of 98 nA/M and a linear range of 0.1-6.0 mM. The apparent Michanelis-Menten constant of the sensor is 21 mM. The response time is less than 60 seconds. No apparent change in the response to glucose was observed during one month. Foremost, the interference of ascorbic and uric acids can be avoided due to selective permeability of chitosan film and electrocatalysis of PB layer to H 2 O 2 . The sensor has been applied to detect glucose in human blood serum.

A simple and sensitive colorimetric detection method for hexavalent chromium (Cr(VI)) was described based on ascorbic acid (AA)-capped silver nanoparticles (AgNPs). The cross-linking between AA and Cr(III), the reductive product of Cr(VI), resulted in the aggregation of AA-capped AgNPs, and the color change from yellow to red. Control experiments with the addition of over 15 other metal ions (Cr 3+ , Pb 2+ , Zn 2+ , Hg 2+ , Cd 2+ , Co 2+ , Cu 2+ , Al 3+ , Ni 2+ , Ag + , Mn 2+ , Ba 2+ , Fe 3+ , Na + , K + , Ca 2+ , Mg 2+ ) did not result in a distinct change in the color or in the spectrum of the suspension, indicating that these ions do not interfere with the colorimetric determination of Cr(VI). The detection concentration of Cr(VI) ranged from 7.0 Â 10 À8 to 1.84 Â 10 À6 M, and the detection limit was 5 Â 10 À8 M (3d). The performance of the sensor was successfully evaluated with water samples spiked with Cr(VI), indicating that this convenient and sensitive technique offers great promise for onsite environmental monitoring of Cr(VI).

A convenient and environmentally friendly method of fabricating glucose biosensors is proposed. Glucose oxidase (GOD) was immobilized on electrochemically reduced graphene oxide (ERGO) which was adsorbed on the poly-L-lysine (PLL) modified glassy carbon electrode after being immersed in GO solution for 4 h. The electrochemical behaviors of GOD/ERGO/PLL/GC electrode have been investigated by cyclic voltammetry. Direct electron transfer between GOD immobilized with ERGO/PLL and GC electrode was observed. Moreover, the GOD/ERGO/PLL/GC electrode exhibited excellent electrocatalytic activity for the detection of glucose with a linear range from 0.25 to 5 mmol L(-1).

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Cysteine-modifed gold wire electrode was used for the first time to examine the promoted electron transfer process of superoxide dismutase. Electrochemical Quartz Crystal Microbalance technique was combined with cyclic voltammetric study for the understanding of coupled adsorption/desorption process of different states of SOD molecules.

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