Whatman membrane filters ptfe pore size 0.5 μm

In a stoppered tube, nanosponges equivalent to 10 mg lornoxicam were taken and the drug was extracted with 50 ml of phosphate buffer solution (PBS) pH 6.8. The extracts were filtered using (Whatman® membrane filters PTFE pore size 0.5 μm) and transferred to 100 ml of a volumetric flask and the volume was completed with PBS pH 6.8 [20] . The solutions were subjected to further dilution with the buffer and measured spectrophotometrically at 378 nm.
A calibration curve was plotted for lornoxicam in PBS (pH 6.8) in the range of 0.005-0.03 mg/ml at 378 nm. A good linear relationship was observed between the concentration of lornoxicam and its absorbance (R 2 = 0.998). The specificity of the analytical method was performed using a blank formula which was prepared from all the used excipients except drug to check if any component of the formulation or the dissolution medium could interfere with the absorbance of lornoxicam at the selected wavelength.

Formulation of LX-loaded nanosponges was based on emulsion solvent evaporation [19] . Various amounts of ethyl cellulose and polyvinyl alcohol were utilized to prepare nanosponges (LS1-LS4). Dispersed phase was consisted of LX and EC and dissolved in 25 ml of dichloromethane. It was added in portions to 150 ml of an aqueous continuous phase containing a definite quantity of PVA. At that point, the blend was agitated at 1000 rpm for 2 h on an overhead stirrer (VELP, DLS stirrer, Italy). The formed nanosponges were exposed to filtration using Whatman® membrane filters PTFE pore size 0.5 μm) and dried in a hot oven for 2 h at 40 °C to remove any residual solvent. Nansponges were then kept in a vacuum desiccator. Table 1 shows the composition of LX loaded nanosponges formulations.