Advantages and Disadvantages of Controlled Drug Delivery

The primary objectives of controlled drug delivery are to ensure safety and to improve the efficacy of drugs as well as patient compliance. For conventional dosage forms, only the dose and dosing interval can vary, and for each drug, there exists a therapeutic window of plasma concentration below which the therapeutic effect is insufficient and above which undesirable or toxic side effects are elicited. This is often defined as "the ratio of median lethal dose (LD₅₀) to median effective dose (ED₅₀)".

ADVANTAGES OF CONTROLLED DRUG DELIVERY

1. Maintenance of drug levels within a desired range.
2. Delivery of "difficult" drugs: slow release of water-soluble drugs, fast release of low-solubility drugs.
3. Less dosing and increased patient compliance.
4. Eliminate overdosing or underdosing.
5. Prevention of side effects.
6. Reduction in healthcare costs.
7. Improved efficiency in treatment.
8. Reduction in adverse side effects and improvement in tolerability.

DISADVANTAGES OF CONTROLLED DRUG DELIVERY

1. Dumping is a major disadvantage of CRDDS, which refers to the rapid release of a relatively large quantity of drug from a controlled-release formulation. This phenomenon becomes hazardous with potent drugs.
2. Poor in-vivo and in-vitro correlations.
3. Difficult to optimise the accurate dose and dosing interval.
4. Patient variability affects the release rate, like GI emptying rate, residence time, fasting or non-fasting condition, etc.