Question

What does it mean for a system to be under sink conditions? Explain sink conditions in terms of in vitro and in vivo drug release testing.

Answer 1

When we fall ill, we take a medicine or drug in the form of syrup or tablets. When the drug entered into the body metabolic system it should be completely absorb[through intestine and blood]. Otherwise it will excrete from body with urine as a waste . The power of dissolution of drug in our body should require a test which is called dissolution testing and sink condition.

If any drug is under proper sink condition means has the good dissolution ability and maximum drug absorb in side the body system.

scintifically the answer is :-

•“Sink condition”:- One of the requirements to conduct an appropriate drug dissolution test is to use a sufficient volume of dissolution medium, which should be able to dissolve the expected amount of drug released from a product. This ability of the medium to dissolve the expected amount of drug is known as a “sink condition”.

• Dissolution is the process in which a substance forms a solution. Dissolution testing measures the extent and rate of solution formation from a dosage form, such as tablet, capsule, ointment, etc. The dissolution of a drug is important for its bioavailability and therapeutic effectiveness.

•In the pharmaceutical industry, drug dissolution testing is routinely used to provide critical in vitro drug release information for both quality control purposes, i.e., to assess batch-to-batch consistency of solid oral dosage forms such as tablets, and drug development, i.e., to predict in vivo drug release profiles.

•In vitro sink condition is a testing of dissolution rate in artificial [biological] system, by using sufficient dissolution medium, which should be a checking that the expected amount of drug released from a product and dissolve in medium.

•In vivo sink condition is a living body system with dissolution medium in the form of body fluids. The drug is continuously absorbed into blood, metabolised and eliminated, which provides a very efficient mechanism for providing a high solubility equivalent.

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