HIV protease (Ki = 2.66 nM)

Atazanavir has an IC50 of approximately 47 nM for the proteolytic cleavage of the viral gag precursor p55 polyprotein in H9 cells infected with the virus. With an EC50 of 3.89 nM in RF/MT-2 strains, atazanavir demonstrates strong antiviral activity.[1] It is demonstrated that atazanavir inhibits bilirubin glucuronidation with an IC50 of 2.4 μM. Atazanavir has a Ki of 1.9 μM, which inhibits recombinant UGT1A1.[2] In U251, T98G, and LN229 glioblastoma cell lines, atazanavir inhibits cell growth with notably elevated levels of GRP78 and CHOP protein. In U251 glioblastoma cells, atazanavir induces a significant upregulation of polyubiquitinated proteins of diverse sizes.[3] With an IC50 of 26 μM, atazanavir also inhibits the human 20S proteasome. In HepG2 cells, atazanavir (30 μM) modifies the levels of ER stress and UPR gene expression.[4] In LS180V cells, atazanavir (30 mM) results in a 2.5-fold increase in immunoreactive P-gp expression and a decrease in intracellular Rh123.[5]

Purified HIV-1 RF wild-type Prt (2.5 nM) is incubated at 37 °C with 1 μM to 15 μM fluorogenic substrate in reaction buffer (1 M NaCl, 1 mM EDTA, 0.1 M sodium acetate [pH 5.5], 0.1% polyethylene glycol 8000) with or without atazanavir in order to calculate the inhibition constants (Ki) for each Prt inhibitor. Using a Cytofluor 4000, cleavage of the substrate is measured as an increase in fluorescent emission at 490 nM following excitation at 340 nM. In five different concentrations of Atazanavir (1.25 nM to 25 nM), reactions are conducted with substrate that is 1.36 μM, 1.66 μM, 2.1 μM, 3.0 μM, 5.0 μM, or 15 μM. During a half-hour, the substrate cleavage is observed every five minutes. Then, at early stages of the reaction, cleavage rates are calculated for each sample, and Ki values are ascertained from the slopes of the ensuing Michaelis-Menten plots.

In order to assess cytotoxicity, host cells are cultured for six days with serially diluted Atazanavir. Cell viability is then measured using the XTT[2,3-bis(2-methoxy-4-nitro-5-sulfophenyl-2H-tetrazolium-5-carboxanilide)] assay, which yields the 50% cytotoxic concentrations (CC50s). In order to evaluate how human serum proteins affect antiviral activity, 40% adult human serum or 1 mg of α1-acid glycoprotein/mL is added to the 10% fetal calf serum that is typically used for assays.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Amounts of atazanavir in milk appear to be low based on limited data. The combination product, which also contains the CYP3A inhibitor cobicistat, has not been studied during breastfeeding, but would be expected to have similar or greater levels of atazanavir in milk. Achieving and maintaining viral suppression with antiretroviral therapy decreases breastfeeding transmission risk to less than 1%, but not zero. Individuals with HIV who are on antiretroviral therapy with a sustained undetectable viral load and who choose to breastfeed should be supported in this decision. If a viral load is not suppressed, banked pasteurized donor milk or formula is recommended.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Gynecomastia has been reported among men receiving highly active antiretroviral therapy. Gynecomastia is unilateral initially, but progresses to bilateral in about half of cases. No alterations in serum prolactin were noted and spontaneous resolution usually occurred within one year, even with continuation of the regimen. Some case reports and in vitro studies have suggested that protease inhibitors might cause hyperprolactinemia and galactorrhea in some male patients, although this has been disputed. The relevance of these findings to nursing mothers is not known. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

[1]. Antimicrob Agents Chemother . 2000 Aug;44(8):2093-9.

[2]. Drug Metab Dispos . 2005 Nov;33(11):1729-39.

[3]. Cancer Res . 2007 Nov 15;67(22):10920-8.

[4]. Mol Pharmacol . 2005 Jun;67(6):1909-19.

[5]. Drug Metab Dispos . 2005 Jun;33(6):764-70.

Atazanavir (brand name: Reyataz) is a prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of HIV infection in adults and children. Atazanavir comes in two different dosage forms: capsules and oral powder.
Atazanavir capsules are approved for use in adults and children 6 years of age and older who weigh at least 33 lb (15 kg). Atazanavir capsules may be used with a pharmacokinetic enhancer (boosting agent) – either ritonavir (brand name: Norvir) or cobicistat (brand name: Tybost). (A fixed-dose combination tablet containing atazanavir and cobicistat [brand name: Evotaz] is also available.)
Atazanavir oral powder is approved for use in children 3 months of age and older who weigh at least 11 lb (5 kg) and must be used with the boosting agent ritonavir.
Atazanavir is always used in combination with other HIV medicines.
Atazanavir Sulfate is a sulfate salt form of atazanavir, an aza-dipeptide analogue with a bis-aryl substituent on the (hydroxethyl)hydrazine moiety with activity against both wild type and mutant forms of HIV protease. Atazanavir does not elevate serum lipids, a common problem with other protease inhibitors.
An azapeptide and HIV-PROTEASE INHIBITOR that is used in the treatment of HIV INFECTIONS and AIDS in combination with other ANTI-HIV AGENTS.
See also: Atazanavir (has active moiety); Atazanavir sulfate; ritonavir (component of); Atazanavir sulfate; cobicistat (component of) ... View More ...

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Drug Indication
Reyataz capsules, co-administered with low dose ritonavir, are indicated for the treatment of HIV-1 infected adults and paediatric patients 6 years of age and older in combination with other antiretroviral medicinal products (see section 4. 2). Based on available virological and clinical data from adult patients, no benefit is expected in patients with strains resistant to multiple protease inhibitors (≥ 4 PI mutations). The choice of Reyataz in treatment experienced adult and paediatric patients should be based on individual viral resistance testing and the patient's treatment history (see sections 4. 4 and 5. 1). Reyataz oral powder, co-administered with low dose ritonavir, is indicated in combination with other antiretroviral medicinal products for the treatment of HIV-1 infected paediatric patients at least 3 months of age and weighing at least 5 kg (see section 4. 2). Based on available virological and clinical data from adult patients, no benefit is expected in patients with strains resistant to multiple protease inhibitors ( 4 PI mutations). The choice of Reyataz in treatment experienced adult and paediatric patients should be based on individual viral resistance testing and the patient's treatment history (see sections 4. 4 and 5. 1).
Treatment of human immunodeficiency virus (HIV-1) infection

C38H54N6O11S

802.93

802.357

C, 56.84; H, 6.78; N, 10.47; O, 21.92; S, 3.99

229975-97-7

Atazanavir;198904-31-3

158550

White to light yellow solid powder

1.164g/cm3

995.5ºC at 760 mmHg

195.0°, or acetone; mp 198-199° (dec)

555.8ºC

0mmHg at 25°C

6.203

7

13

18

56

1190

4

S(=O)(=O)(O[H])O[H].O([H])[C@@]([H])(C([H])([H])N(C([H])([H])C1C([H])=C([H])C(C2=C([H])C([H])=C([H])C([H])=N2)=C([H])C=1[H])N([H])C([C@]([H])(C(C([H])([H])[H])(C([H])([H])[H])C([H])([H])[H])N([H])C(=O)OC([H])([H])[H])=O)[C@]([H])(C([H])([H])C1C([H])=C([H])C([H])=C([H])C=1[H])N([H])C([C@]([H])(C(C([H])([H])[H])(C([H])([H])[H])C([H])([H])[H])N([H])C(=O)OC([H])([H])[H])=O

DQSGVVGOPRWTKI-QVFAWCHISA-N

InChI=1S/C38H52N6O7.H2O4S/c1-37(2,3)31(41-35(48)50-7)33(46)40-29(22-25-14-10-9-11-15-25)30(45)24-44(43-34(47)32(38(4,5)6)42-36(49)51-8)23-26-17-19-27(20-18-26)28-16-12-13-21-39-28;1-5(2,3)4/h9-21,29-32,45H,22-24H2,1-8H3,(H,40,46)(H,41,48)(H,42,49)(H,43,47);(H2,1,2,3,4)/t29-,30-,31+,32+;/m0./s1

methyl N-[(2S)-1-[2-[(2S,3S)-2-hydroxy-3-[[(2S)-2-(methoxycarbonylamino)-3,3-dimethylbutanoyl]amino]-4-phenylbutyl]-2-[(4-pyridin-2-ylphenyl)methyl]hydrazinyl]-3,3-dimethyl-1-oxobutan-2-yl]carbamate;sulfuric acid

Atazanavir sulfate; BMS-232632; BMS 232632; BMS232632

2934.99.03.00

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

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: ≥ 2.5 mg/mL (3.11 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 25.0 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: ≥ 2.5 mg/mL (3.11 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 25.0 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: ≥ 2.5 mg/mL (3.11 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 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: ≥ 2.5 mg/mL (3.11 mM) (saturation unknown) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
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 5: ≥ 2.5 mg/mL (3.11 mM) (saturation unknown) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
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 6: 30% PEG400+0.5% Tween80+5% propylene glycol: 30 mg/mL

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