Alkaloids in the pharmaceutical industry: Structure, isolation and application

By the end of the 18th and the beginning of the 19th century a new era began in medicine, pharmaceutics and chemistry that was strongly connected with alkaloids and alkaloid drugs. Even before that it was known that certain drugs administered in limited doses were medicines, and toxic if taken in larger doses (opium, coke leaves, belladonna roots, monkshood tubers crocus or hemlock seeds). However, the identification, isolation and structural characterization of the active ingredients of the alkaloid drugs was only possible in the mid 20th century by the use of modern extraction equipment and instrumental methods (NMR, X-ray diffraction and others).In spite of continuing use over a long time, there is still great interest in investigating new drugs, potential raw materials for the pharmaceutical industry, as well as the more detailed investigation and definition of bio-active components and the indication of their activity range, and the partial synthesis of new alkaloid molecules based on natural alkaloids. The scope of these investigations, especially in the field of semi-synthesis is to make better use of the bio-active ingredients of alkaloid drugs, i.e. to improve the pharmacological effect (stronger and prolonged effect of the medicine, decreased toxicity and side effects), or to extend or change the applications. A combined classification of alkaloids was used, based on the chemical structure and origin, i.e. the source of their isolation to study alkaloid structure. For practical reasons, the following classification of alkaloids was used: ergot alkaloids, poppy alkaloids, tropanic alkaloids purine derivative alkaloids, carbon-cyclic alkaloids, and other alkaloids. The second part of this report presents a table of general procedures for alkaloid isolation from plant drugs (extraction by water non-miscible solvents, extraction by water-miscible solvents and extraction by diluted acid solutions). Also, methods for obtaining chelidonine and glaucine as hydrochloride bases and salts were presented in more details. Data from leading world pharmacopoeias (Ph. Eur. Ill/s 2000, DAB 1996, USP 23, JP XIII, BP 1993, Ph. Jug. IV) were used in the study of application of the pure alkaloids in pharmaceutical forms with predetermined doses. A comparative study of these data shows that a great number of preparations are produced worldwide based on alkaloids and alkaloids with modified structure. These medicines have found use in modern therapeutic practice in many countries. Most products are produced on the basis of caffeine, theophylline, ephedrine, atropine, scopolamine, reserpine and pilocarpine.