[Influence of manufacturing procedure on stability of Unguentum contra perniones preparations].

BACKGROUND: Application of various technological procedures for the manufacture of officinal preparation ointment against chilblains (Unguentum contra perniones) produce essential variations in the quality and stability of the final product. Changing the sequence of admixing active substances into the ointment base indicated the presence of incompatibility between the active substances, as well as between the active substances and the ointment base components. The aim was to examine the influence of various technological manufacturing procedures on quality and stability of the preparation.

METHODS: Changes in the samples of ointments and aqueous solutions of active substances were analysed microscopically.

RESULTS: Microscopic analysis of hydrosoluble active substance solutions demonstrated destruction of ichthammol, induced by an acidic medium due to the dissolution of tannin and resorcinol, which is well known from the literature. It also demonstrated the destruction of tannin and resorcinol in aqueous solution, which had not been described in the literature. Application of the prescribed procedure for the manufacturing of ointment against chilblains, conceals the incompatibility reactions due to a slow dissolution of the tannin suspended in the officinal ointment base Unguentum cera lanae. Admixture of an ready-made aqueous solution of tannin caused an instant contact between ichthammol and the acidic medium, which caused the destruction or the complete absence of the formation of emulsion droplets. The problem of incompatibility reactions between lanolin alcohols in the ointment base and ichthammol and resorcinol, as well as the reaction between Peruvian balsam and sulfur from the ichthammol sulfate ion was observed. Numerous incompatibility reactions of ointment against chilblains, components indicated that it was necessary to introduce alterations in both the qualitative and quantitative composition of the preparation.

CONCLUSION: Excipient preparation procedure, as well as the technological procedure for incorporation of active ingredients can cause the incompatibilities and therefore the formulation stability problems.