Mastering Ideal, Intrinsic, and Regular Solubilities

[@betheone8911]

Sir your videos are really helpful as my research surrounds these topics. Thanks a lot

[@virion-a]

Thanks a lot. those are very confusing concepts. After your explaination, It became crystal clear.

[@virion-a]

Could you please also explain what is kinetic solubility which was often mentioned in some of JMC paper?

[@PharmaDrama]

When a material can dissolve very fast (say, if it's amorphous) the molecules will go into solution rapidly and the concentration of the solution may exceed the thermodynamic (equilibrium) solubility. When this happens the solution is supersaturated and sometimes the term kinetic solubility is used. Over time any molecules dissolved in excess of solubility will precipitate, but if this process takes a bit of time (say a few hours) then kinetic solubility is useful for medicines, because a higher concentration of drug will be achieved in the GI tract.

[@virion-a]

@@PharmaDrama thanks

[@virion-a]

@@PharmaDrama In the drug discovery industry, some contract research organizations (CRO) offer the service to measure the kinetic solubility of compounds. If you read the experiment method how they measure the so-called “kinetic solubility” (labtesting.wuxiapptec.com/dmpk-services/kinetic-thermodynamic-solubility-testing/), you will conclude that solubility that they measure with DMSO solution of compound is actually an equilibrium solubility which more related to enthalpy of mixing (further related to Log D of compound). It is not kinetic solubility which you mentioned. Kinetic solubility should be used when describing that a certain form of solid API rapidly dissolves into a solvent with the maximum concentration (supersaturated, exceed the equilibrium solubility) for certain periods of time (a few hours). Is my understanding correct?

[@virion-a]

@@PharmaDrama There is so much confusion when people use those concepts. I suggest that you should make a video to explain what kinetic solubility and thermodynamic solubility are. Is thermodynamic solubility equal to equilibrium solubility? I think, in some solid form, they are, but not always.