[Biological availability of ophthalmic drugs. 1. Increasing drug permeability in the cornea]. / Biologická dostupnost ocních léku. 1. Zvýsení prostupnosti léciva rohovkou.

Most eye diseases are treated by topical administration of ophthalmic preparations. Low ophthalmic bioavailability is due to a number of physiological and physicochemical factors. The main obstacle to the penetration of active ingredients to the eye is the layered character of the cornea. Formulation of ophthalmic preparations enabling easier penetration of this biological barrier thus ranks among the most effective ways of improving bioavailability. Penetrability of the cornea can be increased by the following methods: a) adjustment of the actual acidity in such a way that pH of the preparation makes it possible to produce the optimal portion of non-ionized particles; b) incorporation of absorption enhancers (non-ionic tensides, salts of bile acids, some antimicrobial substances, EDTA, cyclodextrins, etc.) into the composition of the preparation, and c) production of prodrugs or ionic pairs.

[Selection of an extraction agent and development of the technology for producing an extract with sedative effects]. / Výber vyluhovadla a vypracování technologie výroby extraktu s uklidnujícím úcinkem.

The drugs Valerinae radix, Crataegi fructus, Leonuri herba and Melissae folium were used to produce a liquid plant extract. The experiment revealed that the extraction with 70% ethanol achieved the highest concentration of extractable active principles. The optimal conditions for obtaining a sedative extract are established when the method of repercolation is used, and in the production itself the batch of the drug is divided into equally large doses and a pre-prepared mixture of plant drugs is extracted. The extract prepared by this manner remains stable for the whole period of storage, i.e., 24 months.