Shruti Chopra

Effect of solvents quality on determination of particle size and polydispersity of nanoparticles

Nanotechnology is of great interest to researchers and industrialists and nanocolloidal carrier systems for drug delivery have been studied in great detail, but while much research has been carried out on the preparation of nanoparticles using a variety of techniques employing various solvents, no attention has been given to the quality of solvents used in the process of nanoparticles characterization. The present investigation aimed to study the effect of solvents quality on the chitosan nanoparticles characterization for average particle size (Z) and polydispersity index (P.I.). Particle size distribution study showed that the number of particles contributed by solvents significantly affects both the Z and P.I. of the nanoparticulate suspensions leading to ambiguous results. While the Z decreases upon dilution with organic solvents, the phosphate buffer and water causes a net increase in Z because of the introduction of larger extraneous nanoparticles. The P.I. was found to increase with dilution because of the differences in the size of the polymeric nanoparticles and the nanoparticles introduced by the solvent upon dilution. The study thus recommends use of the highest quality of solvents in nanoparticles manufacturing and characterization process to avoid the generation of erroneous results.

Quantitative Determination and Stress Degradation Studies on a Biomarker Trigonelline by a Validated Stability‐Indicating HPTLC Method

Abstract The present study describes stress degradation studies on a biomarker, trigonelline following the International Conference on Harmonization (ICH) guidelines under different stress conditions and establishment of a stability‐indicating HPTLC assay method. Analysis of trigonelline was performed on TLC aluminium plates precoated with silica gel 60F‐254 and mobile phase consisting of n‐propanol‐methanol‐water (4:1:4 v/v/v). Spectrodensitometric scanning was carried out in absorbance mode at 269 nm for trigonelline (Rf=0.46±0.02). Trigonelline was subjected to acid and alkali hydrolysis, oxidation, dry heat, wet heat treatment, and photodegradation. Statistical analysis proves that the developed HPTLC method is reproducible and selective. As the method could effectively separate the drug from its degradation products, it can be employed as a stability‐indicating one. Moreover, the method was utilized to investigate the kinetics of the acidic and alkaline degradation processes at different temperatures and to study degradation in constant ionic strength buffer solutions within the pH range 1–11.