The data validation shows that the AAS method is accurate, robust and possesses excellent linearity and precision characteristics. The direct dilution method presented here requires less than 2 min per sample. This method can be successfully used for the quantification of zinc as active substance, in dissolution studies and in liquid dosage forms. The dissolution data are reliable and precise. This approach is valid not only for the zinc, but also for other liquid dosage forms, therefore, contributing for the establishment of procedures to assure the quality, safety and efficacy of the developed drug product. This method is cheap and can be used in each laboratory. On the other hand, studies are still going on about its application to auto analytic equipment and routine use.