The conductance was measured subsequent to each addition of the reagent solution and after thorough stirring for 2 min. A graph of the corrected conductance recordings versus the volume of click here the added titrant was constructed, and the drug–titrant stoichiometric ratio is then determined from the intercept of the two linear segments of the graph. For analysis of Triton tablets (100 mg TB/tablet), tablets were powdered and an accurately weighed portion equivalent to 0.387 g TB was taken and dissolved in 75 mL water. For Imodium capsules (2 mg LOP.HCl/capsule), capsules were accurately weighed
portion equivalent to 0.513 g were mixed with 75 mL water, for both tablets and capsules, shake in a mechanical shaker for about 30 min, and filtered into a 100 mL volumetric flask. The solution was completed to the mark with bi-distilled water and shaken. Different volumes of the solution (1.0–10.0 mL) were taken, and subjected to the conductimetric determination as mentioned above. A series of solutions of molar concentrations
(C) 10−2 mol L−1 selleck kinase inhibitor was prepared for each of LOP.HCl and TB and PTA. The conductances of these solutions were measured at 25 °C, and the specific conductivities (λo) (corrected for the effect of dilution) were calculated and used to obtain the equivalent conductivities (λ) of these solutions. Straight line plots of λ versus √c were all constructed and (λo)LOP, (λo)TB and (λo)PTA were determined from the intercept of the respective line with the λ-axis. The activity coefficients of the ions employed were taken as unity because all the solutions were sufficiently dilute, the values of λo(LOP-PT) and λo(TB-PT) were calculated using Kohlrausch’s law of independent migration of ions. 28The solubility (S) and solubility product (Ksp) values of the ion-associates were calculated using the following equations: S = KS × 1000/λo (ion-associate), Ksp = S2 for 1:1 ion-pairs Ksp = 4
S3 for 1:2 ion-associates Ksp = 27 S4 for 1:3 ion-associates, and Ksp = 256 S5 for 1:4 ion-associateswhere, KS is the specific conductivity of the saturated solution of the ion associate, determined at 25 °C and corrected for the effect of dilution. Such saturated solution was made by stirring a suspension of the solid precipitate in distilled water for 2 h, and then leaving it for 24 h at 25 °C before measuring the conductivities. Conductometric measurements are used, successfully, for the equivalent point determination in titration of systems in which the conductance of the solution varies before, and after the end point. One of the valuable features of the conductance method of titration is that it permits the analysis of the components of a precipitation reaction. In this case, the formation of a precipitate alters the number of ions present in the solution and consequently the conductance varies.