Using static method to measure tolmetin solubility at different pressures and temperatures in supercritical carbon dioxide

Tolmetin is a non-steroidal anti-inflammatory drug being used to decrease the level of hormones which are the reasons for pain, swelling, tiredness, and stiffness for osteoarthritis and rheumatoid arthritis cases. We evaluated its solubility in supercritical carbon dioxide (SC-CO2) with the aim of drug nanonization, considering temperature and pressure variations between 120 and 400 bar and 308–338 K, in the experiments. In this way, a PVT solubility cell based on static solubility approach coupled with a simple gravimetric procedure was utilized to evaluate the solubility of tolmetin. The solubility values between 5.00 × 10−5 and 2.59 × 10−3 mol fraction were obtained for tolmetin depending on the pressure and temperature of the cell. The measured data demonstrated a direct correlation between pressure and solubility of tolmetin, while the effect of temperature was a dual effect depending on the crossover pressure (160 bar). The calculated solubility data were modeled using several semi-empirical correlations, and the fitting parameters were calculated using the experimental data via appropriate optimization method. The correlated solubility data revealed that the KJ model was the most accurate one with an average absolute relative deviation percent (AARD%) of 6.9. Moreover, the carried out self-consistency analysis utilizing these correlations illustrated great potential of these models to extrapolate the solubility of tolmetin beyond the measured conditions.

Development of Cotton Nonwoven Composite Fabric for Toxic Chemical Decontamination and Characterization of its Adsorption Capabilities

Because of the current threat of toxic chemicals and chemical warfare agents, personal protection is important for soldiers and first responders, as well as the civilian population. This paper describes the development of a cotton non-particulate nonwoven composite fabric and the evaluation of its adsorption capability for protection against toxic chemical ingress which can be harmful or lethal. In addition, this paper focuses on the evaluation of toxic chemical adsorption capabilities of various chemical protective substrates that have the potential to be used in military applications. The development of a three-layered cotton based decontamination wipe and its adsorption of 0.1 % w/v pinacolyl methylphosphonate in butanol, is presented. Adsorption is quantified using a modified gravimetric procedure developed using a thermogravimetric analyzer. The results demonstrate the adsorption performance of a new cotton-based, non-particulate flexible composite that has a high potential to be used as a portable decontamination wipe. This research is unique in the area of individual protection and addresses the requirements of the U.S. Department of Defense (DoD) for seeking and evaluating highly efficient, non-particulate, and skin-friendly materials that provide necessary chemical protection while minimizing any discomfort or irritation.

Comparation of fundamental analytical methods for quantitative determination of copper(II)ion

Copper is a ductile metal with excellent electrical conductivity, and finds extensive use as an electrical conductor, heat conductor, as a building material, and as a component of various alloys. In this work accuracy of methods for quantitative determination (gravimetric and titrimetric methods of analysis) of copper(II) ion was studied. Gravimetric methods do not require a calibration or standardization step (as all other analytical procedures except coulometry do) because the results are calculated directly from the experimental data and molar masses. Thus, when only one or two samples are to be analyzed, a gravimetric procedure may be the method of choice because it involves less time and effort than a procedure that requires preparation of standards and calibration. In this work in gravimetric analysis the concentration of copper(II) ion is established through the measurement of a mass of CuSCN and CuO. Titrimetric methods is a process in which a standard reagent is added to a solution of an analyze until the reaction between the analyze and reagent is judged to be complete. In this work in titrimetric analysis the concentration of copper(II) ion is established through the measurement of a volume of different standard reagents: Km, Na2S2O3 and AgNO3. Results were discussed individually and mutually with the aspect of exactility, reproductivity and rapidity. Relative error was calculated for all methods.

Titrimetric and gravimetric determination of the specific pore volume of microparticulate silica gels

The titrimetric and gravimetric methods of determination of the specific pore volume were studied unmodified and modified chromatographic silica gels of mean particle size above 5 μm. The apparatus and titrimetric procedure suggested elsewhere were adapted so that the relative standard deviation of measurement did not exceed 2%. Water, n-octane, and methanol were used as titrants, and methanol was found to suit best from the point of view of accuracy and rapidity of analysis and versatility of use. This solvent is also suitable for the gravimetric measurements, which can be carried out without thermostatting and at barometric pressure. The titrimetric procedure is less time consuming than the gravimetric procedure which, on the other hand, is less tedious and less instrumentation-demanding.