Biopharmaceutics Classification System

Short description: System to differentiate drugs on the basis of their solubility and permeability

The Biopharmaceutics Classification System (BCS) is a system to differentiate drugs on the basis of their solubility and permeability.[1]

This system restricts the prediction using the parameters solubility and intestinal permeability. The solubility classification is based on a United States Pharmacopoeia (USP) aperture. The intestinal permeability classification is based on a comparison to the intravenous injection. All those factors are highly important because 85% of the most sold drugs in the United States and Europe are orally administered [citation needed].

## Contents

* 1 BCS classes
* 2 Definitions
* 3 See also
* 4 References
* 5 Further reading
* 6 External links

## BCS classes

BCS classes

According to the biopharmaceutics Classification System (BCS) drug substances are classified to four classes upon their solubility and permeability:[1]

* Class I - high permeability, high solubility
* Example: metoprolol, paracetamol[2]
* Those compounds are well absorbed and their absorption rate is usually higher than excretion.
* Class II - high permeability, low solubility
* Example: glibenclamide, bicalutamide, ezetimibe, aceclofenac
* The bioavailability of those products is limited by their solvation rate. A correlation between the in vivo bioavailability and the in vitro solvation can be found.
* Class III - low permeability, high solubility
* Example: cimetidine
* The absorption is limited by the permeation rate but the drug is solvated very fast. If the formulation does not change the permeability or gastro-intestinal duration time, then class I criteria can be applied.
* Class IV - low permeability, low solubility
* Example: Bifonazole
* Those compounds have a poor bioavailability. Usually they are not well absorbed over the intestinal mucosa and a high variability is expected.

## Definitions

The drugs are classified in BCS on the basis of solubility, permeability, and dissolution.

Solubility class boundaries are based on the highest dose strength of an immediate release product. A drug is considered highly soluble when the highest dose strength is soluble in 250 ml or less of aqueous media over the pH range of 1 to 7.5. The volume estimate of 250 ml is derived from typical bioequivalence study protocols that prescribe administration of a drug product to fasting human volunteers with a glass of water.

Permeability class boundaries are based indirectly on the extent of absorption of a drug substance in humans and directly on the measurement of rates of mass transfer across human intestinal membrane. Alternatively non-human systems capable of predicting drug absorption in humans can be used (such as in-vitro culture methods). A drug substance is considered highly permeable when the extent of absorption in humans is determined to be 90% or more of the administered dose based on a mass-balance determination or in comparison to an intravenous dose.

For dissolution class boundaries, an immediate release product is considered rapidly dissolving when no less than 85% of the labeled amount of the drug substance dissolves within 15 minutes using USP Dissolution Apparatus 1 at 100 RPM or Apparatus 2 at 50 RPM in a volume of 900 ml or less in the following media: 0.1 M HCl or simulated gastric fluid or pH 4.5 buffer and pH 6.8 buffer or simulated intestinal fluid.

## See also

* ADME
* Partition coefficient
* Bioavailability
* Drug metabolism
* First pass effect
* Polar surface area
* IVIVC

## References

1. ↑ 1.0 1.1 Mehta, Mehul (2016). Biopharmaceutics Classification System (BCS): Development, Implementation, and Growth. Wiley. ISBN 978-1-118-47661-1.
2. ↑ "Draft agreement" (PDF). 22 June 2017. https://www.ema.europa.eu/documents/scientific-guideline/draft-paracetamol-oral-use-immediate-release-formulations-product-specific-bioequivalence-guidance_en.pdf.

## Further reading

* Folkers, Gerd; van de Waterbeemd, Han; Lennernäs, Hans; Artursson, Per; Mannhold, Raimund; Kubinyi, Hugo (2003). Drug Bioavailability: Estimation of Solubility, Permeability, Absorption and Bioavailability (Methods and Principles in Medicinal Chemistry). Weinheim: Wiley-VCH. ISBN 3-527-30438-X. https://archive.org/details/drugbioavailabil0000unse.
* "A theoretical basis for a biopharmaceutic drug classification: the correlation of in vitro drug product dissolution and in vivo bioavailability". Pharm. Res. 12 (3): 413–20. March 1995. PMID 7617530.

## External links

* BCS guidance of the U.S. Food and Drug Administration

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Biopharmaceutics Classification System. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Medicine:Biopharmaceutics_Classification_System&oldid=288606"