RP-HPLC method validation for fast extraction and quantification of Levonorgestrel drug from silicone based intrauterine device intended for in-process and finished formulation.

BACKGROUND: To develop and validate a simple and consistent reversed phase high performance liquid chromatography (RP-HPLC) method for the estimation of Levonorgestrel (LNG) drug from silicone based intrauterine device. METHODS: Sample solution was prepared using tetrahydrofuran (THF) as solvent for the drug extraction, and RP-HPLC analysis was performed using Luna C18 analytical column (150 × 4.6 mm, 5 µm, 100 Å - Phenomenex), with a mobile phase consisting of a mixture of acetonitrile and water (50:50, v/v) at a flow rate of 1.0 ml/min and injection volume of 20 µl. Detection was carried out at 241 nm in PDA detector, with a total run time of 15 min. The method was validated in accordance with ICH guidelines. Method applicability was tested for optimizing formulation using quality-by-design approach, to check the stability and content uniformity of levonorgestrel-silicone mixture (core blend), and quantifying the amount of LNG from commercially available silicone based formulation. RESULTS: The retention time for LNG drug was obtained at 8.5 min (± 0.3 min). A linear relationship was observed over the concentration range of 2.6-15.6 µg/ml with the correlation coefficient (r) value 0.9999. The method was found to be precise within the acceptable limit (RSD < 2%) and the drug recovery from the intrauterine device was found in the range 99.78-100.0%. Content uniformity for different prototypes developed was observed in the range of 91.6-101.4%, and assay of optimized core blend was in the range of 97.78-106.79% during the 10 days of retention period for stability studies. CONCLUSION: The validated method is found to be a simple, accurate, precise, reproducible, and hence can be used for the routine analysis of LNG such as in-process, quality control and stability assays of silicone based intrauterine devices by RP-HPLC.

Physicochemical and in vitro biocompatibility evaluation of water-soluble CdSe/ZnS core/shell.

Group II-VI semiconductor quantum dots (Q-dots) have found various applications in biomedical field during last decade. In this study, we have synthesized CdSe Q-dots and CdSe/ZnS core/shell (CS) by wet chemical route and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FT-IR) and Photoluminescence (PL) spectroscopy. CS formation was confirmed by red shift as well as enhancement in the luminescence peak compared to bare Q-dots. Processing parameters such as core and sulfur concentrations were optimized at maximum luminescence efficiency during the shell preparation. Effects of dialysis, aging and cell culture medium on the properties of the Q-dots and CS were also studied by luminescence and DLS techniques. DLS data showed Q-dots and CS to be stable, and there was no effect on the integrity of the Q-dots and CS after various modifications. CS was found to be hemocompatible and cytocompatible for human umbilical vein endothelial cells even at a high concentration of 0.1 mg/ml up to 48 h indicating high potential for CS in various biomedical applications.

Mercaptoethanol capped CdSe quantum dots and CdSe/ZnS core/shell: synthesis, characterization and cytotoxicity evaluation.

CdSe Quantum dots (Q-dots) and CdSe/ZnS core/shell have been synthesized by wet chemical route using mercaptoethanol (ME) as cappant. The synthesized Q-dots and core/shell were characterized using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDS), Dynamic Light Scattering (DLS), Optical absorption and luminescence spectroscopy. The core/shell formation was confirmed by both XRD and TEM analysis. The luminescence was shown to be considerably enhanced in the core/shell sample. Effect of dialysis process on the optical properties of the Q-dots and core/shell has also been discussed. Cytotoxicity studies have been carried out for Q-dots and core/shell. CdSe/ZnS core/shell was found to be non-cytotoxic as compared to CdSe Q-dots up to a certain concentration range. Polyethylene glycol (PEG) coating enhances the non-cytotoxic nature of CdSe/ZnS core/shell when compared with bare core/shell.