Biopharmaceutical Classification System Case Study
When a particular medicine is swallowed (tablets, capsules, etc). The absorption or uptake of the drug into the body mainly depend on two factors.
1. How well does the drug dissolves in stomach and gastrointestinal(GI) fluids (solubility of drug)
2. How readily does the drug passes through the intestinal wall into the blood (drug permeability)
To find out how a drug is likely to be taken up when it is swallowed. The Biopharmaceutical Classification System (BCS) was introduced by Gordon L. Amidon in 1995. The BCS is a systematic way of classifying drugs into four categories according to their aqueous solubility and permeability. The need for the classification system is due to its application in drug development and change of product …show more content…
Determination of permeability
Methods range from simple oil/water partition coefficient to absolute bioavailability studies. These include human studies, in vivo intestinal perfusion in a suitable animal model, in vitro permeability methods using excised intestinal tissues and monolayers of suitable epithelial cells.
Solubility enhancements or improvement methods are generally divided into physical, chemical modifications. Miscellaneous methods are anything other than that.
1. Physical Modifications
Particle size reduction like micronation and nanosuspension, modification of the crystal habit, polymorphs, amorphous form and crystallization, drug dispersion in carriers like eutectic mixtures, solid dispersions, solid solutions, cryogenic techniques and …show more content…
The conventional approach to produce ultrafine drug particles can be divided into top-down and bottom-up technologies. Examples of top-down technologies are jet-milling, pearl/ball milling and high-pressure homogenization. the bulk drugs with the size of several hundred microns are comminuted into micro or nano-sized range by the use of mechanical force. However milling technologies such as wet milling can cause contamination of products because of the abrasion between the grinding beads, leading to broad size distribution with only a fraction of the particles below 1μm.The major disadvantage of high pressure homogenization is that the crystal structure of drugs may vary in some cases due to the high pressure, which may result in instability and cause quality control problems. Next includes the bottom-up technologies such as precipitation, spray freezing into liquid, supercritical fluid (SCF) technology and so on. These technologies have been employed to prepare several drugs in micro- or nano-scale, such as cephradine, cefuroxime axetil, danazol and