DEVELOPMENT AND VALIDATION OF STABILITY-INDICATING REVERSE-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR THE ESTIMATION OF LEDIPASVIR IN BULK AND TABLET DOSAGE FORM

Objective: The objective of this study was to develop a stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC) method for the estimation of ledipasvir (LDP) in bulk and tablet formulation. Methods: Stability-indicating RP-HPLC method was developed and validated for the estimation of LDP in bulk and tablet formulation. RP-HPLC was carried out on HiQ SiL C18 columns (250 mm × 4.6 mm, 5 μ particle size) using mobile phase acetonitrile:1 mM ammonium acetate buffer in the ratio of 90:10 v/v at a flow rate of 1 ml/min. The analytes were monitored using MD 2010 PDA detector at 333 nm. Results: The retention time was found to be 3.843 min. The proposed method was found to be having linearity in the concentration range of 5–30 μg/ml. The number of theoretical plates obtained was 4236.50 which indicate the efficient performance of the column. The limit of detection was 0.305 μg/ml and limit of quantification was 0.923 μg/ml, which indicate the sensitivity of the method; the high percentage recovery indicates that the proposed method is highly accurate. The developed method has been validated according to the ICH guidelines and found to be simple, specific, precise, and accurate. Conclusion: The proposed method is precise, accurate, and stability indicating. Therefore, the proposed method can be used for routine quality control and analysis of LDP during stability studies in bulk samples and tablet dosage forms

Dielectric spectroscopy and hydrogen bonding studies of 1-chloropropane–ethanol mixture using TDR technique

The time-domain reflectometry technique was exercised to assess the complex permittivities of 1-chloropropane and ethanol along with their binary mixture in the frequency range of 10MHz–50GHz and in the temperature range of 10–25∘C. Dielectric parameters like static dielectric permittivity (ε0) and relaxation time (τ) have been acquired by the least-square-fit method. The obtained assessments of static permittivity and relaxation time were used to compute various dielectric parameters like excess dielectric constant, excess relaxation time, Kirkwood correlation factor and thermodynamic parameters. The experimental outcome illustrates the nonlinear variations in dielectric permittivity, relaxation time and authenticates the structural formation due to intermolecular interaction between 1-chloropropane and ethanol. Molecular rotary motion and dipole reorientation movements of these complex systems are presented in agreement with the molar entropy and enthalpy

Photocatalytic and Superhydrophilic TiO2-SiO2 Coatings on Marble for Self-Cleaning Applications

The application of photocatalytic and self-cleaning titanium dioxide (TiO2) nanomaterials coating on the stone of architectural heritage (particularly on marble) can be used to preserve their aesthetic qualities. The present work describes the effect of dipping time on the wetting property of coatings and the effect of UV irradiation on the coating in terms of hydrophilicity. The suspension of TiO2-SiO2 is prepared by adding 30–50 nm in size TiO2 particles in the sol–gel processed SiO2 solution. The water contact angle (WCA) decreases with increasing dipping time of piece of marble in TiO2 – SiO2 suspension. Also the hydrophilicity of coating increases with increasing UV illumination time. The 2D and 3D laser microscope analysis revealed surface structure and stable surface roughness of 1.0 µm. Such type of superhydrophilic TiO2 – SiO2 coating may be used to protect architectural heritage and buildings.Scopu