Sources Of Drugs Derivation And Storage.
The five main sources of drugs used in treating diseases; they are:
Seeds, roots, leaves and the bark of trees are used in various forms, example; digitalis is made from the leaf of the foxglove, quinine from the bark of the cinchona tree.
Salts of minerals are used in many compounds. example; sulphur in the sulphonamides, iron in iron tonics.
Extracts from certain glands of animals are used, example; insulin from the pancreas and thyroxin from the thyroid gland.
Vaccines, toxoids and sera. These drugs are made by the controlled use of micro-organisms either with or without the use of experimental animals. In B.C.G.(Bacille Calmette-Guerin) vaccination a suspension of tubercle bacilli, which have been attennuated by years of growth outside the body (that is , in the laboratory) is used. On the other hand, the serum used in the treatment of diphtheria is acquired from immunised animals and contains antitoxin.
Antibiotic drugs. Antibiotic drugs were initially obtained and in some cases still are obtained from the growth of moulds (a form of higher bacteria). The mould is collected and the active principle extracted. This is the method by which penicillin is prepared.
When the chemical structure of a drug obtained by one of the above methods is identified, chemists proceed to try to produce the pure substance in the laboratory. Drugs such as methylpenicillin, pethedine and digoxin are laboratory preparations. Some of the advantages of synthetic production are:
1. The elimination of harmful biological impurities
2. Very accurate measurement and control of the quality and quantity of the drugs.
THE STORAGE AND CARE OF DRUGS
Certain precautionary measures must be taken in hospitals to prevent the occurrence of accidents due to the mishandling of drugs; the greatest care must therefore be taken in the labelling and storing of these substances. Three cupboards are usually used for their storage and all cupboards as far as possible should be outside the actual ward and should be kept locked.
First cupboard : For external use only.
Second cupboard: For internal use only.
Third cupboard : For drugs which are classified as Dangerous drugs.
FIRST CUPBOARD: For external use only
Examples of these substances are Hibitane, Roccal and Dettol; these are disinfectants and are not usually applied to the body. Examples of other substances which may be applied externally to the body are calamine lotion, methylated spirit and methylated ether. If the drugs contains poisonous substances, they should be sent from the pharmaceutical department to the ward in the followin ways:
1. In a special distinctive bottles. These bottles are usually deeply coloured, either dark green, blue or brown.
2. The bottles should have a distinctive label marked clearly for external use only.
3. The bottle should have a ridged surface.
4. They should also have a red label marked poison.
SECOND CUPBOARD: drugs for internal use only
Many mixtures , pills, cachets and tablets are kept in this cupboard and some of these substances may be controlled by law.
1. In the hospitals, they must be kept locked cupboards. Drugs controlled by law are subjected to certain restrictions.
2. They should be clearly and distinctly labelled.
3. They can only be obtained by the public with a written medical prescription.
THIRD CUPBOARD: dangerous drugs
In other to control the illicit use of the drugs of addiction, that is; habit forming drugs, a number of drugs have been designated dangerous. Their use is controlled by law and new additions to the list are made from time to time. Such drugs includes:
1. Opium and its preparation
2. Amidone (physeptone)
3. Phenadoxone (heptalgin)
4. Morphine and its derivatives
5. Cocaine and its derivatives
6. Pethedine and its salt