Biopharmaceutics Classification System
The Biopharmaceutics Classification System is a system to differentiate the drugs on the basis of their solubility and permeability. It is a guide for predicting the intestinal drug absorption provided by the U.S. Food and Drug Administration[1]. The fundamental basis for the BCS was established by Gordon Amidon, who was presented with a Distinguished Science Award at the August 2006 International Pharmaceutical Federation (FIP) congress in Salvador, Brazil.[citation needed]
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.
BCS classes
According to the Biopharmaceutics Classification System, drug substances are classified as follows:
- Class I - high permeability, high solubility
- Example: metoprolol
- Those compounds are well absorbed and their absorption rate is usually higher than excretion.
- Class II - high permeability, low solubility
- Example: glibenclamide, bicalutamide, ezetimibe,phenytoin
- 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: hydrochlorothiazide, Bifonazole
- Those compounds have a poor bioavailability. Usually they are not well absorbed over the intestinal mucosa and a high variability is expected.
The drugs are classified in BCS on the basis of following parameters:
1. Solubility
2. Permeability
3. Dissolution
The class boundaries for these parameters are:
1. Solubility class boundaries- It is 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.
2. Permeability class boundaries- It is 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.
3. 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 N HCl or simulated gastric fluid or pH 4.5 buffer and pH 6.8 buffer or simulated intestinal fluid.
4.programe for bcs classification in c++.
#include <cstdlib>
#include <iostream>
#include<conio.h>
using namespace std;
int main(int argc, char *argv[])
{
cout<<" PROGRAM TO CLASSIFY THE DRUG ACCORDING TO BIOPHARMACEUTICAL CLASSIFICATION SYSTEM"<<endl<<endl;
float V, P, n;
int i;
cout<<"Enter the number of drugs = ";
cin>>n;
cout<<endl;
for ( i=1;i<=n;i++)
{
cout<<endl;
cout<<" Enter the permeability constant of the drug "<<i<<" = ";
cin>>P;
cout<<" Enter the Volime of water required to dissolve the highest dose of drug "<<i<<" = ";
cin>>V;
if ((P>=1 && P<=10) && (V>=1 && V<=500))
{
cout<<" The drug belongs to BCS class 1 "<<endl;
cout<<" It shows high permeability and high solubility "<<endl;
}
else if ((P>=1 && P<=10) && (V>=500 && V<=100000))
{
cout<<" The drug belongs to BCS class 2 "<<endl;
cout<<" It shows high permeability and low solubility "<<endl;
}
else if ((P>=0.01 && P<=1) && (V>=1 && V<=500))
{
cout<<" The drug belongs to BCS class 3 "<<endl;
cout<<" It shows low permeability and high solubility "<<endl;
}
else if ((P>=0.01 && P<=1) && (V>=500 && V<=100000))
{
cout<<" The drug belongs to BCS class 4 "<<endl;
cout<<" It shows low permeability and low solubility "<<endl;
}
else
{
cout<<" invalid entry" <<endl;
}
}
system("PAUSE");
return EXIT_SUCCESS;
}
See also
References
- Gerd Folkers; Waterbeemd, Han van de; Lennernäs, Hans; Per Artursson; Raimund Mannhold; Hugo Kubinyi (2003). Drug Bioavailability : Estimation of Solubility, Permeability, Absorption and Bioavailability (Methods and Principles in Medicinal Chemistry). Weinheim: Wiley-VCH. ISBN 3-527-30438-X.
{{cite book}}: CS1 maint: multiple names: authors list (link) - Amidon GL, Lennernäs H, Shah VP, Crison JR (March 1995). "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. PMID 7617530.
{{cite journal}}: CS1 maint: multiple names: authors list (link)