Stabilization of drugs in pharmaceutical preparations

ABSTRACT

Drug substances may undergo chemical degradation which may result in the loss of potency and therapeutic activity. Drugs are often sensitive to environmental and chemical factors such as oxygen, temperature, humidity, light, pH, ionic strength, solvent, buffers and excipients. The degraded products may produce undesirable effects as well as toxic effects on the body. The delivery of stabilized formulated products is a necessary requirement for the optimum efficacy of the active drug. The drugs are usually stabilized by chelating agents, complexing agents, bio-polymers, naturally occurring protectors, encapsulation of drugs and use of antioxidants. It has been found that hydrolytic and oxidative degradation are the main routes of loss of active ingredients. Solid preparations are usually stabilized by complex formation while in some liquid and semi-solid preparations there is a need to consider other factors such as pH, solvents for the stabilization of the drugs