Storage and Preservation of Drugs are Important
The proper methods of storage and preservation of drugs and their preparations are of very great importance for maintenance of their potency. These methods must be strictly observed by the manufactures and retail pharmacists.
The following factors may affect the drug and may lower the original potency as moisture, light, heat, air, age, chemicals, insect and bacteria and fungal growth.
It is a major cause for drugs like powder and tablets etc, Deliquescent preparations like zinc chloride,ephedrine, digitalis preparations, ergot preparations must be preserved from moisture in air tight containers with dehydrating agents. Pharmacist must take proper care of them in their stores during rainy season by keeping them in dry places.
Direct sun light destroys the activity of drugs. Bismuth subcarbonate and ephedrine decomposes slowly in light. Tannic acid, bismuth salts, quinine and aminopyrine, change their color with light. These drugs should be stored in amber or dark colored bottles. Drugs contained in the colored bottles must be protected from light by keeping them in dark place in the pharmacy.
Biological drugs are damaged even at room temperature. They must be stored at a temperature between 2-10°C. Small pox vaccine should be kept even below O°C, because of their losing of potency very rapidly in room temperature. Biological products, antibiotics, ethyl nitrite and insulin must be kept in refrigerators (2— 15°C) in the Drug Stores and Pharmacies and maintenance of constant low temperature should be checked.
Air due to 02, CO2, and moisture may cause deterioration of the drugs. Arsphenamine, chloral hydrate, calcium lactate, Caffeine, codeine sulphate, Castor oil, cinnamon, ferrous sulphate, lead sub-acetate, hydantoin sodium, etc. will be damaged when exposed to air. Thyroid and other glandular products will be damaged by air also due to the growth of bacteria, mold and fungus. Containers of these drugs should be repeatedly checked against leakages.
Arsenic preparations like neoarsphnamine, procaine solutions, many tinctures, fluid extracts deteriorate with age in spite of best preservations. Biological drugs and antibiotics also lose their potency with time. These drugs should not be sold after the expiration date. These drugs should be stored separately and constant watch on the expiry dates of these drugs should be made by the pharmacists.
5. Bacterial and Fungal growth:
The growth of these plants commonly occur in carbohydrate containing drugs like syrups and mucilage and also in plant and animal extracts, and other pharmaceutical preparations like mixtures, emulsions, ointments, creams,sterile solutions, injections and biological products.These preparations may be protected against these growth by adding 0.2% of benzoic acid Or sodium benzoate and 0.5 % of chlorbutol, cresol, phenol, sodium bisulphite, sulphur dioxide, or glycerin, or methyl-paraben ( 0.05-0.25•/• Or phenyl mercuric nitrate ( 0.005*/. ) etc. Pharmacist should store them separately and keep a constant watch against such growth.
6. Chemical Stabilizers:
Many drugs which are highly oxidizable such as vitamin C, adrenaline, phenylephrene, fats and oils are protected by the use of chemical stabilizers like anti-oxidants such as sodium bisulphite, sodium meta-bi sulphite maleic acid, or sulphur di-oxide. pH sensitive drugs are stabilized by using buffer solutions. Acetanilide acts as a negative catalyst in hydrogen peroxide. Sugars are used to prevent decomposition of ferrous iron in solution.
7. Glass containers:
Glass may also cause deterioration of some drugs.The hard glass containers contain silicon dioxide which is more resistant but the soft glass contains sodium and calcium oxides.The soft glass containers containing solution under high temperature dissolves the oxides and produces alkaline hydroxides and increase the pH of the solution and may affect the stability of the pH sensitive substances.
It is important to store your medicines properly. Guidelines for proper storage include:
- Keep out of the reach of children.
- Keep medicines in their original containers.
- Store away from heat and direct light.
- Do not store capsules or tablets in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down. Also, do not leave the cotton plug in a medicine container that has been opened, since it may draw moisture into the container.
- Keep liquid medicines from freezing.
- Do not store medicines in the refrigerator unless directed to do so.
- Do not leave your medicines in an automobile for long periods of time.
- Do not keep outdated medicine or medicine that is no longer needed. Be sure that any discarded medicine is out of the reach of children.