For the purpose of drug dissolution testing, one has to demonstrate that if the drug is in solution then the analytical method is capable of measuring it accurately and reliably. Therefore, for validation of such methods, one needs to add the drug (“spiking”) in solution form to a dissolution testing apparatus . vessel containing required volume of medium maintained at 37 ºC and spindle rotating. Samples are withdrawn and processed exactly as if these were from a product (filtration, dilution/concentration, extraction etc) and responses are measured accordingly. If responses and concentrations are as one would expect (as explained above), then that dissolution method has been validated.