Biopharmaceutics Classification System

The BCS classification system is used to categorize drugs and serves to help anticipate whether drugs will have bioavailability/ bioequivalence problems. BCS classifies drugs according to their solubility and permeability. A drug is considered to have high solubility if drug substance at the highest dose strength for an immediate release formulation can be dissolved in < 250 mL of water over a pH range of 1-7.5. A high permeability drug is one that has either complete intestinal absorption (fa > 90%) or exhibits rapid movement through intestinal epithelia cells in vitro. BCS classifies all drugs into four categories as shown in Table 3.3.

Table 3.3. Biopharmaceutics classification system

BCS CLASS I High solubility High permeability

BCS CLASS III High solubility Low permeability

BCS CLASS II Low solubility High permeability

BCS CLASS IV Low solubility Low permeability

BCS class I compounds (high solubility and permeability) are unlikely to show bioavailability/bioequivalence issues. Therefore, for BCS class I drugs, in vitro dissolution studies are thought to provide sufficient information to assure in vivo product performance making full in vivo bioavailability/bioequivalence studies unnecessary. BCS class II and III drugs are not eligible for biowavers due to anticipated formulation differences in oral exposure. BCS class IV compounds, in general, are problematic with both poor solubility and permeability. The following tables (see Tables 3.4-3.7) contain lists of drugs that are categorized as BCS classes I to IV.

Table 3.4. BCS class I compounds (high solubility, high permeability)

Abacavir

Diazepam

Ketorolac

Phenobarbital

Acetaminophen

Diltiazem

Ketoprofen

Phenylalanine

Acyclovir

Diphenhydramine

Labetolol

Prednisolone

Amiloride

Disopyramide

Levodopa

Primaquine

Amitryptyline

Doxepin

Levofloxacin

Promazine

Antipyrine

Doxycycline

Lidocaine

Propranolol

Atropine

Enalapril

Lomefloxacin

Quinidine

Buspirone

Ephedrine

Meperidine

Rosiglitazone

Caffeine

Ergonovine

Metoprolol

Salicylic acid

Captopril

Ethambutol

Metronidazole

Theophylline

Chloroquine

Ethinyl estradiol

Midazolam

Valproic acid

Chlorpheniramine

Fluoxetine

Minocycline

Verapamil

Cyclophosphamide

Glucose

Misoprostol

Zidovudine

Desipramine

Imipramine

Nifedipine

Adapted from Wu and Benet (2005)

Adapted from Wu and Benet (2005)

Table 3.5. BCS class II compounds (low solubility, high permeability)

Amiodarone

Diclofenac

Itraconazole

Piroxicam

Atorvastatin

Diflunisal

Ketoconazole

Raloxifene

Azithromycin

Digoxin

Lansoprazole

Ritonavir

Carbamazepine

Erythromycin

Lovastatin

Saquinavir

Carvedilol

Flurbiprofen

Mebendazole

Sirolimus

Chlorpromazine

Glipizide

Naproxen

Spironolactone

Cisapride

Glyburide

Nelfinavir

Tacrolimus

Ciprofloxacin

Griseofulvin

Ofloxacin

Talinolol

Cyclosporine

Ibuprofen

Oxaprozin

Tamoxifen

Danazol

Indinavir

Phenazopyridine

Terfenadine

Dapsone

Indomethacin

Phenytoin

Warfarin

Adapted from Wu and Benet (2005)

Adapted from Wu and Benet (2005)

Table 3.6. BCS class III compounds (high solubility, low permeability)

Acyclovir

Amiloride

Amoxicillin

Atenolol

Atropine

Bisphosphonates

Bidisomide

Captopril

Cefazolin

Cetirizine

Cimetidine

Ciprofloxacin

Cloxacillin

Dicloxacillin

Erythromycin

Famotidine

Fexofenadine

Folinic acid

Furosemide

Ganciclovir

Hydrochlorothiazide

Lisinopril

Metformin

Methotrexate

Nadolol

Pravastatin

Penicillins

Ranitidine

Tetracycline

Trimethoprim

Valsartan

Zalcitabine

Adapted from Wu and Benet (2005)

Table 3.7. BCS class IV compounds (low solubility, low permeability)

Amphotericin B

Furosemide

Chlorthalidone

Hydrochlorothiazide

Chlorothiazide

Mebendazole

Colistin

Methotrexate

Ciprofloxacin

Neomycin

Adapted from Wu and Benet (2005)

Adapted from Wu and Benet (2005)

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  • mattalic
    Is cetirizine a bcs class 1 or 3?
    1 month ago

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