Stress tests of corn Silk dry extract as an element of the pharmaceutical quality system
Stability tests of drug are an integral part of pharmaceutical development. Of particular importance is given to testing the stability of the galenic preparations, due to the multiplicity of biologically active substances in the composition and variability of quality indicators. This group of drugs includes corn silk dry extract with hepatoprotective activity. The aim of the study is to establish the optimal storage conditions for corn silk dry extract and the need to control climatic parameters in the manufacture of dosage forms based on it. The following stress factors were studied: air humidity, natural and artificial daylight, and UV irradiation. The design of the experiments was formed on the basis of the ICH guidelines (Q1A, Q1B). As a control, the samples of the extract that were not degraded were used. The decomposition of corn silk dry extract was evaluated by HPLC by changing the composition of flavonoids and phenolic acids. In addition, changes were established in the amount of these groups of biologically active substances. The quantitative determination of flavonoids in the samples was carried out by the method of differential spectrophotometry, based on the complexation reaction of flavonoids with aluminum chloride, in terms of luteolin. The content of phenolic acids was determined by direct spectrophotometry using the Fjordt method, taking into account the content of flavonoids in terms of chlorogenic acid. It has been established that increased air humidity (60-65%) and artificial daylight do not lead to significant changes in the composition of the active ingredients of the extract. Under the action of other light sources, significant changes in the qualitative composition and content of flavonoids and phenolic acids occur. Consequently, a prerequisite for the storage of corn silk dry extract is a light protected place. However, there is no need to protect the extract from high humidity and lighting in the production areas, due to the short-term effects of these factors on the extract in the process.