Fundamentals of diffusion and dissolution: dissolution testing of pharmaceuticals

Abstract Disintegration and dissolution are the in vitro performance test procedures for a drug to be developed and its formulation to be selected for in vivo studies, specifically for orally administered drugs except for solution dosage forms. Further, these procedures also provide an alternative for in vivo bioequivalence studies with sufficient in vitro–in vivo correlation and comparable evaluation of change in products before and after their manufacturing or formulation. Understanding diffusion mechanisms is imperative because it allows us to clarify some doubts in the innovation research such as what mechanisms influence adopters at a given time, how do mechanisms interact given different population structures, or how mechanisms work for different types of innovation. To judge the quality of different products of the solid dosage form, dissolution testing is a standard official test prescribed in pharmacopeias. This test, which is strictly controlled, allows monitoring the quality of products from series to series and diminishes errors during manufacturing. The test has to be performed with different apparatus in different pharmacopeia monographs for the same dosage forms.