Zinc-ion-mediated self-assembly of forky peptides for prostate cancer-specific drug delivery.

A novel forky peptide was designed and synthesized. The peptide self-assembled into supramolecular hydrogels triggered by zinc ions (ZIs). The hydrogels were designed for a drug delivery system (DDS), loaded with docetaxel and applied for the therapy of prostate cancer. In this research, we have discussed the response mechanism and evaluated the anticancer effect of the DDS.

Quantitative analysis of binary polymorphs mixtures of fusidic acid by diffuse reflectance FTIR spectroscopy, diffuse reflectance FT-NIR spectroscopy, Raman spectroscopy and multivariate calibration.

Vibrational spectroscopic techniques such as infrared, near-infrared and Raman spectroscopy have become popular in detecting and quantifying polymorphism of pharmaceutics since they are fast and non-destructive. This study assessed the ability of three vibrational spectroscopy combined with multivariate analysis to quantify a low-content undesired polymorph within a binary polymorphic mixture. Partial least squares (PLS) regression and support vector machine (SVM) regression were employed to build quantitative models. Fusidic acid, a steroidal antibiotic, was used as the model compound. It was found that PLS regression performed slightly better than SVM regression in all the three spectroscopic techniques. Root mean square errors of prediction (RMSEP) were ranging from 0.48% to 1.17% for diffuse reflectance FTIR spectroscopy and 1.60-1.93% for diffuse reflectance FT-NIR spectroscopy and 1.62-2.31% for Raman spectroscopy. The results indicate that diffuse reflectance FTIR spectroscopy offers significant advantages in providing accurate measurement of polymorphic content in the fusidic acid binary mixtures, while Raman spectroscopy is the least accurate technique for quantitative analysis of polymorphs.

[Analysis of 3',5' reversed-sequence oligonucleotide isomers by reversed-phase ion-pair chromatography].

3', 5' Reversed-sequence oligonucleotides are isomers with the same length and base composition, except with reversed base sequence. In the current work, 6 oligonucleotide model samples were designed to study chromatographic behaviour of 3',5' reversed-sequence isomers by optimizing effects on retention and separation. The retention factor and resolution of isomers were investigated under triethylamine-acetic acid (TEAA) concentrations of 0.025 - 0.15 mol/L, pH values of 5.0 - 6.8, temperatures of 25 - 45 degrees C and flow rates of 0.3 - 0.7 mL/min by reversed-phase ion-pair chromatography (RP-IPC). The best resolution was observed under TEAA concentration of 0.05 mol/L, pH 6.8 and flow rate of 0.4 mL/min. While the effect of temperature on the separation was not apparent, effect of initial organic strength was stronger than that of the elution gradient. The retention and separation trends of the model samples were different, and weak retention of the samples on the solid phase contributes to good separation. It is concluded that 5' end of oligonucleotide sequence showed stronger interactions with the stationary phase than the 3' end did. This research might help to understand the retention mechanism of oligonucleotides by RP-IPC.

Determination of amantadine sulfate in sodium chloride injection by capillary gas chromatography.

This paper describes a new method to determine amantadine sulfate in sodium chloride injection by capillary gas chromatography. The chromatographic conditions of the methods employed a SGE BP-1 capillary column (30 m x 0.53 mm i.d., 1.0-microm film thickness); isothermal elution with N2 at a pressure of 100 KPa; injector, oven, and detector temperatures at 220 degrees C, 110 degrees C, and 220 degrees C, respectively; a split-less mode; and a 1-microL injection volume. Naphthalene was used as the internal standard. Peak purity testing with a Varian Saturn 2200 capillary gas chromatography- mass spectrometry system (Varian, Inc.) equipped with a DB-5 capillary column (30 m x 0.25 mm i.d., 0.25-microm film thickness) was performed for the investigation of specificity. There was a linear relationship between peak area ratios of analyte to the internal standard and concentration of analyte over the concentration range 0.1-2.0 mg/mL. The recovery was 97.8 approximately 100.7%. The relative standard deviation (%) of intermediate precision was less than 0.8. The limits of detection and quantitation were 0.2 microg/mL with a signal-to-noise ratio of 3, and 0.7 microg/mL with a signal-to-noise ratio of 10, respectively. The results of determination were similar to the titration method.

Single-based resolution for oligodeoxynucleotides and their phosphorothioate modifications by replaceable capillary gel electrophoresis.

A replaceable capillary gel electrophoretic (replaceable CGE) method was developed for the separation of two sets of model compounds of single-stranded oligodeoxynucleotide mixtures (18-20 mers), phosphodiester oligodeoxynucleotides (PO-ODNs) and their phosphorothioate modifications (PS-ODNs), with equal sequences differing in a single base. Polyethylene glycol (PEG) 35000 was chosen as the sieving matrix. It was confirmed that PEG polymer solution less influenced resolutions of the PS-ODNs compared with those of the PO-ODNs, while acetonitrile used as an additive in the system improved the separation significantly. It was also noticed that the effect of temperature on separation was much larger than that of denaturant urea.