Formulation Of Bcs Class 2 Drugs

6/6/20196/6/2019

Formulation Of Bcs Class 2 Drugs
Formulation Of Bcs Class 2 Drugs Dissolution

Dec 22, 2017 FDA has issued a final guidance entitled Waiver of In-vivo Bioavailability and Bioequivalence Studies for Immediate Release Solid Oral Dosage Forms Based on a Biopharmaceutics Classification System.
BCS Class 2 Immediate Release (IR) Dissolution in Two-Phase Media Richard (Rik) Lostritto, Ph.D. Summing up the issues for BCS class 2 Dissolution • Formulation strategies to increase solubility may be. Low a volume for maintaining sink conditions for most BCS class 2 drugs. • Non biologically relevant surfactants in dissolution.

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

Samples of structurally di erent drugs includ- ed in the Class II of the Biopharmaceutics classi cation system (BCS) were obtained, namely Griseofulvin, Glib- enclamide, Carbamazepine, Haloperidol, Itraconazol, Triclosan, Praziquantel and Rifaximin, for testing of maximal saturation in formulations prepared from com- mercially available excipients. Program flowchart examples.

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]}.

BCS classes[edit]

According to the Biopharmaceutical 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[edit]

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

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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 N HCl or simulated gastric fluid or pH 4.5 buffer and pH 6.8 buffer or simulated intestinal fluid.

References[edit]

^ ^a^bMehta M (2016). Biopharmaceutics Classification System (BCS): Development, Implementation, and Growth. Wiley. ISBN978-1-118-47661-1.
^https://www.ema.europa.eu/documents/scientific-guideline/draft-paracetamol-oral-use-immediate-release-formulations-product-specific-bioequivalence-guidance_en.pdf

External links[edit]