In normotensive NZW rabbits, brinzolamide (7.5 mg or 12 mg) implanted in a silicone matrix is incredibly well tolerated, resulting in prolonged release of the drug and a notable drop in intraocular pressure (IOP) for up to 28 days[2]. No negative effects or toxic symptoms are observed. The parameters of Brinzolamide's pharmacokinetics in rabbits[1]. Topical Administration (500 mg) Topical Administration (500 mg) PK Parameters Aqueous Humor Iris-Ciliary Body Aqueous Humor Iris-Ciliary Body Tmax (h) 0.08 0.5 1 0.25 Cmax (ng/mL, ng/g) 11,050 1964 408 1245 Terminal t1/2 (h) 3.4 13 2 13.6 AUC0-24h (h*ng/mL, h*ng/g) 17,780 7725 1896 11414 AUC0-∞ (h*ng/mL, h*ng/g) 17,836 8839 1955 16628 Dose-normalized AUC0-∞ (h*/mL, h*/g) 4 2 0.004 0.03

Animal/Disease Models: Rabbits [2]
Doses: 7.5 mg, 12 mg
Route of Administration: Brinzolamide silicone matrix implant placed in the episcleral space
Experimental Results: Resulted in a significant IOP reduction of 4.6 mmHg on days 10-28, with concentrations of 12 mg.

Absorption, Distribution and Excretion
Brinzolamide is absorbed through the cornea following topical ocular administration. The substance is also absorbed into the systemic circulation where it binds strongly to carbonic anhydrase in red blood cells (RBCs). Plasma concentrations are very low.
Brinzolamide is eliminated predominantly in the urine as unchanged drug.N-Desethyl brinzolamide is also found in the urine along with lower concentrations of the N-desmethoxypropyl and O-desmethyl metabolites.

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Metabolism / Metabolites
Brinzolamide is metabolized by hepatic cytochrome P450 isozymes, specifically CYP3A4, CYP2A6, CYP2B6, CYP2C8 and CYP2C9. The primary metabolite is N-desethylbrinzolamide followed by the N-desmethoxypropyl and O-desmethyl metabolites as well as an N-propionic acid analog formed by oxidation of the N-propyl side chain of O-desmethyl brinzolamide. Brinzolamide and N-desethylbrinzolamide do not inhibit cytochrome P450 isozymes at concentrations at least 100-fold above maximum systemic levels. Brimonidine is extensively metabolized by hepatic aldehyde oxidase with the formation of 2-oxobrimonidine, 3-oxobrimonidine, and 2,3-dioxobrimonidine being the major metabolites. Oxidative cleavage of the imidazoline ring to 5-bromo-6-guanidinoquinoxaline is also observed.

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Biological Half-Life
Due to its affinity for CAII, brinzolamide distributes extensively into the red blood cells (RBCs) and exhibits a long half-life in whole blood (approximately 111 days).

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
No information is available on the use of brinzolamide ophthalmic drops during breastfeeding. French guidelines recommend ophthalmic carbonic anhydrase inhibitor drops such as brinzolamide as a preferred therapy for glaucoma during breastfeeding. To substantially diminish the amount of drug that reaches the breastmilk after using eye drops, place pressure over the tear duct by the corner of the eye for 1 minute or more, then remove the excess solution with an absorbent tissue.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Protein Binding
Binding to plasma proteins is approximately 60%.

[1]. Comprehensive Ocular and Systemic Pharmacokinetics of Brinzolamide in Rabbits After Intracameral, Topical, and Intravenous Administration. J Pharm Sci. 2021 Jan;110(1):529-535.

[2]. Tolerability, pharmacokinetics, and pharmacodynamics of a brinzolamide episcleral sustained release implant in normotensive New Zealand white rabbits,Journal of Drug Delivery Science and Technology,Volume 61,2021,102123,ISSN 1773-224.

Brinzolamide is a sulfonamide and a thienothiazine. It has a role as an antiglaucoma drug and an EC 4.2.1.1 (carbonic anhydrase) inhibitor.
Brinzolamide is a highly specific, non-competitive, reversible carbonic anhydrase II (CA-II) inhibitor indicated to reduce ocular pressure in patients with ocular hypertension or open-angle glaucoma. Although the exact pathophysiology of glaucoma is still unknown, one of the main hallmarks of this disease is vascular dysregulation and abnormalities. The resulting vascular resistance increases intraocular pressure, thus impairing ocular perfusion. Although systemic anti-carbonic anhydrase (CA) therapy has been used for almost 50 years with varying degrees of success, systemic administration results in an increase in incidences of adverse effects. Brinzolamide was developed as a topical solution to the systemic side effects and [dorzolamide], the first-ever approved topical CA inhibitor with contrasting results and evidence. Unlike [dorzolamide], brinzolamide has a higher lipophilicity to facilitate diffusion across the blood-retinal barrier. Brinzolamide was approved by the FDA in 1998 as a standalone product and in 2013 as a combination product with brimonidine tartrate. In Europe, it was also approved as a combination product with timolol in 2008.
Brinzolamide is a Carbonic Anhydrase Inhibitor. The mechanism of action of brinzolamide is as a Carbonic Anhydrase Inhibitor.
Brinzolamide is a sulfonamide and carbonic anhydrase inhibitor with specific affinity for carbonic anhydrase II. Following topical ocular administration, brinzolamide inhibits carbonic anhydrase II, an enzyme that is responsible for the movement of sodium and fluid transport in the eye. This inhibition leads to a decrease in aqueous humor secretion, probably by slowing the formation of bicarbonate ions, and results in a reduction in intraocular pressure. Brinzolamide is used to treat increased pressure in the eye caused by open-angle glaucoma.
See also: Brimonidine Tartrate; Brinzolamide (component of).

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Drug Indication
Brinzolamide, either as a standalone agent or in combination with brimonidine, is approved by the FDA for the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma. Brinzolamide is also approved in Europe to be used in combination with timolol to treat the same conditions.
FDA Label
Azopt is indicated to decrease elevated intraocular pressure in: ocular hypertension; open-angle glaucomaas monotherapy in adult patients unresponsive to beta-blockers or in adult patients in whom beta-blockers are contraindicated, or as adjunctive therapy to beta-blockers or prostaglandin analogues.

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Mechanism of Action
Brinzolamide is a highly specific, reversible, non-competitive inhibitor of carbonic anhydrases (CA), the enzymes catalyzing the reversible reaction of water and carbon dioxide (CO2) to form bicarbonate ions. Although there are 7 isoforms of CA in human tissues, brinzolamide has the highest affinity to CA II. Brinzolamide and its active metabolites were not found to displace any known ligands in vitro from their respective receptors or enzymes commonly involved in producing side effects or ancillary pharmacology, thus explaining brinzolamide's high order of safety.

C12H21N3O5S3

383.51

383.064

138890-62-7

Brinzolamide hydrochloride;150937-43-2;Brinzolamide-d5;1217651-02-9

68844

Light yellow to yellow solid powder

1.5±0.1 g/cm3

586.0±60.0 °C at 760 mmHg

308.2±32.9 °C

0.0±1.6 mmHg at 25°C

1.626

-0.65

2

9

7

23

598

1

CCN[C@H]1CN(S(=O)(=O)C2=C1C=C(S2)S(=O)(=O)N)CCCOC

HCRKCZRJWPKOAR-JTQLQIEISA-N

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

(4R)-4-(ethylamino)-2-(3-methoxypropyl)-1,1-dioxo-3,4-dihydrothieno[3,2-e]thiazine-6-sulfonamide

AL 4862; Brinzolamide; trade names Azopt, Alcon Laboratories, Befardin, Fardi Medicals; AL-4862; AL4862

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.75 mg/mL (7.17 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 27.5 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.75 mg/mL (7.17 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 27.5 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.75 mg/mL (7.17 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 27.5 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)