Bioavailability And Bioequivalence (BABE) Studies: Making The Best Science Accessible To The Masses

Bioequivalence and bioavailability (BABE) studies evaluate pharmaceutical test samples with a reference item.  

Bioavailability is the study that showcases the rate and extent of drug available at the site of action or the absorption region. Any drug consumed orally passes through the gastrointestinal tract before reaching the target site. The compound enters the system’s blood circulation to reach the site of action. Measurement of bioavailability of drugs is identified using Active Ingredient or API concentration of the drug and its metabolites.

When the bioavailability of two drugs is similar, the drug products are known as bioequivalent. A bioequivalence study identifies clinical differences present between two marked drugs. A plasma concentration-time curve is employed to assess the rate of drug absorption at the targeted site. The study is performed under conditions that the two drugs get administered at the same molar dose and under similar experimental conditions. The dosage can be single or multiple doses.

The main objective of conducting BABE studies is to avail safe therapeutic products to the masses. A compound with low bioavailability does not reach the therapeutic level in the circulation and requires a high dose to show effectiveness. The high dosage is expensive and can cause side-effects. Hence, the drug undergoes a chemical change, and the compound with a positive bioavailability value is selected for the development.

Bioequivalence Studies Endpoints

Implementation of the BE studies takes place in generic drug samples. The studies determine whether two different formulations provide the same efficacy and an equal amount of API to the body. 

There are two sections studied under bioequivalence which is very important to know. They are- 

• Pharmacokinetic Studies- The principal method in assessing bioequivalence measures the concentration of API in circulation by blood or urine studies. The rate of an active moiety at the targeted site emphasizes pharmacokinetic measures to identify the release of drugs into the circulation. Cmax and Tmax are the two feature which evaluates the rate of drug absorption at a specific site. The purpose of BE studies is to gauge drug levels and systemic exposure. 

• Pharmacodynamic Studies- The PD study estimate the dose-response relationship of the drug. It also assesses the pathophysiological process after the consumption of two drugs. Pharmacodynamics studies come into importance when analysis of safety and accuracy is not sufficient.

Bioavailability and Bioequivalence Testing

The testing for BABE studies takes place for new drugs and the commercially marketed drug. The bioequivalence testing is carried out in plasma and urine samples of healthy individuals and occasionally in patients—The plasma sample studies aid in determining pharmacokinetic parameters such as AUC, absorption time lag, etc. 

Conclusion

The application of bioavailability and bioequivalence studies in the pharmaceutical industry and has been adopted two decades ago. The protocols followed by the regulatory bodies are modified along with the estimation of pharmacokinetic attributes to achieve accurate, high-quality, and affordable drugs.

Continuous attempts are made worldwide to develop bioequivalence services and identify scientific approaches to determine bioavailability and bioequivalence studies for various concentrations of a drug product.