In vitro tests to evaluate potential biological activity in natural substances

Bioequivalence studies are crucial in evaluating whether new drugs can match an approved one regarding pharmacological effects and clinical performance. These studies test if drugs, despite different dosage forms, share identical plasma concentration-time profiles. Three types of equivalence are central to these studies: chemical, pharmaceutical, and therapeutic. Chemical equivalence indicates that two or more drug products contain identical active ingredients in equal amounts. Pharmaceutical...

In vitro dissolution and drug release tests assess how quickly and how much of a drug is released from its dosage form into an aqueous medium under standardized laboratory conditions. These tests are essential tools in pharmaceutical development and quality assurance, offering insight into the drug's performance before clinical use.During formulation development, dissolution testing identifies incomplete or inconsistent drug release issues. It also supports decisions on selecting the optimal...

In certain scenarios, in vitro dissolution tests can replace in vivo bioequivalence studies. This is particularly true when a drug product, though available in varying strengths, maintains proportional similarity in its active and inactive ingredients. In such cases, the need for in vivo bioequivalence studies for lower strength variants may be waived, provided dissolution tests and in vivo studies on the highest strength yield satisfactory results.Bioequivalence can be indicated through...

In vitro experiments are crucial for understanding the transport and absorption of drugs through biological materials. These studies employ varied methods such as the diffusion cell method, the everted sac technique, and the everted ring technique.
The diffusion cell method uses a two-compartment cell, including a donor compartment with the drug solution, which simulates the environment where the drug is applied, and a receptor compartment with a buffer solution, which simulates the environment...

Toxicity tests in animals are grounded on two main assumptions: first, the effects observed in laboratory animals can be extrapolated to humans, especially when adjusted for body surface area; second, high-dose exposure in animals is essential to identify potential human hazards from lower doses. This is based on the quantal dose-response concept, which faces the challenge of extrapolating results from relatively few test animals to much larger human populations. For example, a 0.01% incidence...

Preclinical development consists of a series of tests that ensure the safety and efficacy of a new therapeutic compound before it is tested in humans. There are four main phases to this process. First, safety pharmacology tests are conducted to ensure the drug does not produce any acutely harmful effects. These tests examine parameters such as bronchoconstriction, cardiac dysrhythmias, blood pressure changes, and ataxia. Next, preliminary toxicological testing is performed to determine the...