Brinzolamide

Brinzolamide
Clinical data
Pronunciation	brin ZOH la mide
Trade names	Azopt
AHFS/Drugs.com	Monograph
MedlinePlus	a601233
License data	US DailyMed: Brinzolamide;
Pregnancy; category	AU: B3; ;
Routes of; administration	Ophthalmic
ATC code	S01EC04 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); US: ℞-only; EU: Rx-only;
Pharmacokinetic data
Bioavailability	Absorbed systemically, but below detectable levels (less than 10 ng/mL)
Protein binding	~60%
Elimination half-life	111 days
Excretion	Kidney (60%)
Identifiers
	IUPAC name (5R)-5-ethylamino-3-(3-methoxypropyl)-; 2,2-dioxo-2λ6,9-dithia-; 3-azabicyclo[4.3.0]nona-7,10-diene-; 8-sulfonamide;
CAS Number	138890-62-7 ;
PubChem CID	68844;
IUPHAR/BPS	6797;
DrugBank	DB01194 ;
ChemSpider	62077 ;
UNII	9451Z89515;
KEGG	D00652 ;
ChEBI	CHEBI:3176 ;
ChEMBL	ChEMBL220491 ;
CompTox Dashboard (EPA)	DTXSID6045531 ;
ECHA InfoCard	100.149.376
Chemical and physical data
Formula	C12H21N3O5S3
Molar mass	383.50 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O=S(=O)(c1sc2c(c1)[C@@H](NCC)CN(CCCOC)S2(=O)=O)N;
	InChI InChI=1S/C12H21N3O5S3/c1-3-14-10-8-15(5-4-6-20-2)23(18,19)12-9(10)7-11(21-12)22(13,16)17/h7,10,14H,3-6,8H2,1-2H3,(H2,13,16,17)/t10-/m0/s1 ; Key:HCRKCZRJWPKOAR-JTQLQIEISA-N ;
	(verify)

Brinzolamide (trade name Azopt) is a carbonic anhydrase inhibitor used to lower intraocular pressure in patients with open-angle glaucoma or ocular hypertension.

Brinzolamide was approved as a generic medication in the United States in November 2020.^[2]

Chemistry

Brinzolamide is a carbonic anhydrase inhibitor (specifically, carbonic anhydrase II). Carbonic anhydrase is found primarily in erythrocytes (but also in other tissues including the eye). It exists as a number of isoenzymes, the most active of which is carbonic anhydrase II (CA-II).

Indications

Use for the treatment of open-angle glaucoma and raised intraocular pressure due to either excess aqueous humor production or inadequate drainage of the humor via the trabecular meshwork.

Pharmacodynamics

Inhibition of carbonic anhydrase in the ciliary processes of the eye decreases aqueous humor secretion and thus lowers the intraocular pressure in the anterior chamber, presumably by reducing the rate of formation of bicarbonate ions with subsequent reduction in sodium and fluid transport; this may alleviate the effects of open-angle glaucoma.

Pharmacokinetics

Absorption

The recommended frequency for topical application is two times per day. Following ocular instillation, the suspension is systemically absorbed to some degree; however the plasma concentrations are low and generally below the limits of detection (less than 10 ng/mL) due to extensive binding by tissues and erythrocytes. Oral administration is less-favored due to variable absorption from the stomach mucosa and an increased side-effect profile versus ophthalmic administration.

Distribution

The compound is fairly well protein-bound (60%), but adheres extensively to the carbonic anhydrase-containing erythrocytes. Due to the abundance of readily-bound erythrocytes and minimal known metabolism, Brinzolamide's whole blood half-life is very long (111 days).

Metabolism

While definitive sites of metabolism have not been firmly established, there are several metabolites worthy of note. N-Desethylbrinzolamide is an active metabolite of the parent compound, and thus exhibits carbonic anhydrase inhibitory activity (largely carbonic anhydrase-I, when in the presence of Brinzolamide) and also accumulates in the erythrocytes. However, Brinzolamide's other known metabolites (N-Desmethoxypropylbrinzolamide and O-Desmethylbrinzolamide) either have no activity or their activity is currently unknown.

Excretion

Brinzolamide is excreted primarily unchanged (60%) in the urine, although the renal clearance rate has not been definitively determined. N-Desethylbrinzolamide is also found in the urine along with lower concentrations of the inactive metabolites, N-Desmethoxypropylbrinzolamide and O-Desmethylbrinzolamide; exact levels have not been definitively determined.

Cautions

Side effects

Common, but mild: blurred vision; bitter, sour, or unusual taste; itching, pain, watering, or dryness of the eyes; feeling that something is in the eye; headache; runny nose
Rare, but serious: fast or irregular heartbeat; fainting; skin rash, hives, or itching; severe eye irritation, redness, or swelling; swelling in the face, lips, or throat; wheezing or trouble breathing

Precautions

Hypersensitivity to other sulfonamides
Acute angle-closure glaucoma
Concomitant administration of oral carbonic anhydrase inhibitors
Moderate-to-severe chronic kidney disease or liver disease

Combinations

With timolol

The combination of brinzolamide with timolol is marketed under the trade name Azarga. This combination may be more effective than either medication alone.^[3]

With brimonidine

The combination of brinzolamide with brimonidine is marketed under the trade name Simbrinza.^[4]^[5] This combination may be more effective than either medication alone.^[4]^[5]

References

^ "Brinzolamide ophthalmic (Azopt) Use During Pregnancy". Drugs.com. 16 May 2019. Retrieved 17 August 2020.
^ "First Generic Drug Approvals". U.S. Food and Drug Administration (FDA). Retrieved 13 February 2021.
^ Croxtall JD, Scott LJ (2009). "Brinzolamide/timolol: in open-angle glaucoma and ocular hypertension". Drugs & Aging. 26 (5): 437–46. doi:10.2165/00002512-200926050-00007. PMID 19552495.
^ ^a ^b "Simbrinza EPAR". European Medicines Agency. Retrieved 11 June 2020.
^ ^a ^b "Simbrinza- brinzolamide/brimonidine tartrate suspension/ drops". DailyMed. 9 September 2019. Retrieved 11 June 2020.