Prolonged Action Pharmaceuticals

Pharmaceutical drugs are those medications used for specific purposes according to the patient, and their dosage relies on the condition of the patient. Pharmaceutical drugs are capable of sustaining their effects for a longer duration in the body and slowly releasing the drug. Such effects of releasing drugs gradually are known as prolonged action pharmaceuticals and are technically termed pharmacokinetics. As per the prolonged action dosage form definition, the action of drugs depends upon the number of active components present in the composition of the pharmaceutical product. There are various methods to prolong the duration of drug action that will be discussed later in the upcoming section. 

Factors on which drug action depends  

The action of a drug depends on numerous factors: preparation of pharmaceuticals, half-life of the drug, slope of the concentration and response curve, reversible action of the drug, activities of the metabolites and the drug’s influence on the elimination of the diseases. Experts have suggested that drugs with prolonged effects must be given twice a day for their better effects.  

Equipped Methods to prolong duration of drug action

There are various artificial methods to prolong the duration of drug action: 

 1. By controlling the frequency of administration

• By oral

For controlling the gradual release of the drug into the body, the drug particles present inside the capsules and tablets are required to be coat with a plastic material or other substances like resin. Another method is the implementation of a semipermeable membrane for controlling the gradual release of the drugs. With these effects, the prolonged action of the drug can last from 4 to 8 hours.  

• By parenteral 

The insoluble form of drugs like benzathine penicillin, lente insulin, and oily solution like depot progestins are injected into the body for sustaining them for several months to a year. In this way, the medicine will remain inside the patient for a longer duration.

• By a system of transdermal drug delivery

Another distinct way of administering the drugs into the body is to impregnate the drug via adhesive strips or patches that can be applied on the skin of the body externally. This method is different from others as the drug is not internally administered into the patient’s body. 

 2. By enhancing the binding of plasma protein

Another scientific way of controlling the release of the drug into the body is by binding the drug with the protein so that the drug will be released slowly into the body. These prepared drugs bound together with the plasma protein are termed drug congeners. 

 3. By controlling the rate of metabolism

Despite other methods for prolonging the drug action, the rate of metabolism of the drug is controlled by modifying the chemical composition of the drug, without undergoing any distinctive changes in the biological aspect of the drug. This can be achieved by the addition of the ethinyl groups to estradiol to sustain it for a longer duration. This drug is consumed by the human body orally. Along with that certain examples of enzymes are also inhibited for prolonged action pharmaceuticals. An example is the inhibition of cilastatin for the protection of imipenem drug from its degradation in the kidney. Physostigmine inhibition prolongs the drug action of acetylcholine by retarding its metabolism. 

 4. By retarding the renal excretion

The tubular section of the drug enhances the activity of the active component present in the composition of the pharmaceutical drugs. Therefore, for sustaining it for a longer duration in the body, the structure of the drug is suppressed by another competing substance. For example, the duration of drug action of penicillin and ampicillin is prolonged by probenecid.

Conclusion

There are numerous methods to prolong the duration of drug action such as by controlling the frequency of drug administration whether done orally or  by injecting it through the body or by adhesive strips, by controlling the rate of metabolism, by enhancing the plasma protein binding and by retarding the renal excretion. Several factors affect the prolonged action of drug action: preparation of pharmaceuticals, the half-life of the drug, slope of the concentration and response curve, reversible action of the drug, activities of the metabolites and the influence of the drug on the elimination of the diseases.