E. Moustafa

Modified gold nanoparticles for intracellular delivery of anti-liver cancer siRNA.

To overcome the rapid enzymatic degradation and low transfection efficiency of siRNA, the delivery carriers for siRNA is a therapeutic demand to increase its stability. Gold nanoparticles (AuNPs) modified by branched polyethyleneimine (bPEI) were developed as an efficient and safe intracellular delivery carriers for siRNA. The current study implied that siRNA designed against an oncogene c-Myc could be delivered by a modified AuNPs complex without significant cytotoxicity. The comparative semi-quantitative and quantitative real time PCR were used to measure the c-Myc gene expression after transfection with naked siRNA and siRNA/bPEI/AuNPs, but AuNPs interfered with PCR. However, the c-Myc protein translation was successfully detected in the transfected HuH7 cells with naked siRNA and siRNA/bPEI/AuNPs and it was found to be inhibited by siRNA/bPEI/AuNPs more than naked siRNA. The results validate the successful silencing of c-Myc gene. Accordingly, it may confirm the promising and effective delivery of siRNA by bPEI/AuNPs. The complex enhances the cellular uptake of siRNA without significant cytotoxicity and confirms that bPEI modified AuNPs could be used as a good candidate for safe cellular delivery of siRNA.

Spectrophotometric Determination of Some Fluoroquinolone Derivatives in Dosage Forms and Biological Fluids Using Ion‐Pair Complex Formation

Abstract A simple, rapid, sensitive, and reproducible procedure for assaying norfloxacin (NOR), ciprofloxacin (CIP), and ofloxacin (OFL) was investigated. The procedure is based on the reaction of selected drugs with Sudan II (I), Congo red (II), and Gentian violet (III) in universal buffer to give soluble ion‐pair complexes. The effects of various parameters have been studied. Beers law plots were obeyed in the concentration ranges 0.5–11 µg ml−1, whereas Ringbom optimum ranges were 0.7–9.5 µg ml−1. The apparent molar absorptivity (6.4×104 L mol−1 cm−1), Sandell sensitivity (4.99 ng cm−2), detection (0.13 µg ml−1), and quantification (0.44 µg ml−1) limits were calculated. The relative standard deviation for ten determinations, for samples containing 4.0 µg ml−1, was found to be 1.40%. The influence of commonly employed excipients in the determination of the studied drugs was examined. There was no interference from degradate product results from thermal and hydrolytic treatments. The results obtained by the proposed procedure were statistically validated. The developed procedure was successfully applied to the determination of the studied drugs in dosage forms and biological fluids.

SELECTIVE SPECTROPHOTOMETRIC DETERMINATION OF COBALT(II) IN SYNTHETIC MIXTURES AND PHARMACEUTICAL FORMULATES WITH 5-[o-CARBOXYPHENYLAZO]2,4-DIHYDROXYBENZOIC ACID

The present work describes a selective, rapid and economical method for the determination of cobalt(II) using 5-[o-carboxyphenylazo] 2,4-dihydroxybenzoic acid [CPDB] as a spectrophotometric reagent without heating or extraction. The CPDB reacts with Co(II) in presence of Tween 80 surfactant forming a pink complex of a stoichiometric ratio 1:2 absorbed maximally at 555 nm with stability constant amounting to 10.33. Beers law is obeyed for a concentration of at least 3.50 μg ml−1 with Sandell sensitivity of 3.6 ng cm−2and molar absorptivity of 1.64×104 l mol−1cm−1. The relative standard deviation for six replicate sample of 2.0 μg ml−1 is 1.11%. A selective procedure is proposed for cobalt determination in presence of different metal ions in synthetic mixtures and in pharmaceutical formulations with more accurate results.