HIV protease

Darunavir (TMC114, 1a) is similar to other protease inhibitors in terms of stability[1].
Darunavir (TMC114, UIC-94017) suppresses the infectivity and replication of all HIV-1_NL4-3 variants exposed to and selected for resistance to AG1341, Ro 31-8959, MK-639, or ABT 538 at concentrations as high as 5 μM (IC50s, 0.003 to 0.029 μM), though its effectiveness against variants of HIV-1_NL4-3 selected for resistance to VX-478 was lower (IC50, 0.22 μM)[2].

---

The screening of known HIV-1 protease inhibitors against a panel of multi-drug-resistant viruses revealed the potent activity of TMC126 on drug-resistant mutants. In comparison to amprenavir, the improved affinity of TMC126 is largely the result of one extra hydrogen bond to the backbone of the protein in the P2 pocket. Modification of the substitution pattern on the phenylsulfonamide P2' substituent of TMC126 created an interesting SAR, with the close analogue TMC114 being found to have a similar antiviral activity against the mutant and the wild-type viruses. X-ray and thermodynamic studies on both wild-type and mutant enzymes showed an extremely high enthalpy driven affinity of TMC114 for HIV-1 protease. In vitro selection of mutants resistant to TMC114 starting from wild-type virus proved to be extremely difficult; this was not the case for other close analogues. Therefore, the extra H-bond to the backbone in the P2 pocket cannot be the only explanation for the interesting antiviral profile of TMC114. [1]

---

Researchers designed, synthesized, and identified UIC-94017 (TMC114), a novel nonpeptidic human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) containing a 3(R),3a(S),6a(R)-bis-tetrahydrofuranylurethane (bis-THF) and a sulfonamide isostere which is extremely potent against laboratory HIV-1 strains and primary clinical isolates (50% inhibitory concentration [IC50], ∼0.003 μM; IC90, ∼0.009 μM) with minimal cytotoxicity (50% cytotoxic concentration for CD4+ MT-2 cells, 74 μM). UIC-94017 blocked the infectivity and replication of each of HIV-1NL4-3 variants exposed to and selected for resistance to saquinavir, indinavir, nelfinavir, or ritonavir at concentrations up to 5 μM (IC50s, 0.003 to 0.029 μM), although it was less active against HIV-1NL4-3 variants selected for resistance to amprenavir (IC50, 0.22 μM). UIC-94017 was also potent against multi-PI-resistant clinical HIV-1 variants isolated from patients who had no response to existing antiviral regimens after having received a variety of antiviral agents. Structural analyses revealed that the close contact of UIC-94017 with the main chains of the protease active-site amino acids (Asp-29 and Asp-30) is important for its potency and wide spectrum of activity against multi-PI-resistant HIV-1 variants. [2]

---

Although antiretroviral therapy (ART) can suppress peripheral HIV, patients still suffer from neuroHIV due to insufficient levels of ART drugs in the brain. Hence, this study focuses on developing a poly lactic-co-glycolic acid (PLGA) nanoparticle-based ART drug delivery system for darunavir (DRV) using an intranasal route that can overcome the limitation of drug metabolic stability and blood-brain barrier (BBB) permeability. The physicochemical properties of PLGA-DRV were characterized. The results indicated that PLGA-DRV formulation inhibits HIV replication in U1 macrophages directly and in the presence of the BBB without inducing cytotoxicity. However, the PLGA-DRV did not inhibit HIV replication more than DRV alone. Notably, the total antioxidant capacity remained unchanged upon treatment with both DRV or PLGA-DRV in U1 cells. Compared to DRV alone, PLGA-DRV further decreased reactive oxygen species, suggesting a decrease in oxidative stress by the formulation. Oxidative stress is generally increased by HIV infection, leading to increased inflammation. Although the PLGA-DRV formulation did not further reduce the inflammatory response, the formulation did not provoke an inflammatory response in HIV-infected U1 macrophages. As expected, in vitro experiments showed higher DRV permeability by PLGA-DRV than DRV alone to U1 macrophages. [3]

Darunavir has a 37% oral bioavailability and is effective against both PI-resistant and wild-type HIV. In conjunction with ritonavir, it is frequently used to increase the bioavailability to 82%.

---

Pharmacokinetics. [1]
The second selection criterion was a set of pharmacokinetic related properties. In Table 6 the metabolic stability is presented in three different species (liver microsomes of rat, dog, and human origin) as % remaining parent compound after 30 min incubation at 37 °C. The degree of metabolism is determined by direct measurement of the residual parent compound in the reaction mixture using LC-MS. 1b and 1d appeared to be extremely labile. Darunavir (TMC114) had a stability comparable to other protease inhibitors. 2 and IDV have been included as a reference in Table 6.
The same trend was observed in oral absorption studies in animals. Data of oral administration to dogs at 80 mg/kg as a PEG400 solution are presented in Table 7. Darunavir (TMC114) is clearly superior to 1b and 1d both in terms of Cmax and AUC. During this evaluation, for compound 1b only minor levels of possible metabolite 1i were observed. In analogy with fosamprenavir, the monophosphate prodrug of 2, we studied the behavior of compound 1h, the monophosphate ester of Darunavir (TMC114). The main advantage of this type of prodrugs are their superior solid-state characteristics, which is outside the scope of this publication. We only investigated the potential for higher bioavailability. Data of a single oral administration in PEG400 in rats at 20 mg/kg were generated; the parent compound and the monophosphate behave in a similar way. For 2 and its prodrug, similar observations were reported previously.

---

Importantly, in vivo experiments, especially using intranasal administration of PLGA-DRV in wild-type mice, demonstrated a significant increase in the brain-to-plasma ratio of Darunavir (TMC114)/DRV compared to the free Darunavir (TMC114)/DRV. Overall, findings from this study attest to the potential of the PLGA-DRV nanoformulation in reducing HIV pathogenesis in macrophages and enhancing drug delivery to the brain, offering a promising avenue for treating HIV-related neurological disorders. [3]

Darunavir has a Ki of 1 nM for wild type HIV-1 protease.
Isothermal Titration Calorimetry. [1]
Thermodynamic parameters of inhibitor binding were determined using an isothermal titration calorimeter, VP-ITC. The buffer used for all protease and inhibitor solutions consisted of 10 mM sodium acetate pH 5.0, 2% DMSO, and 2 mM tris(2-carboxyethyl)phosphine (TCEP). The binding affinities of 2 and Darunavir (TMC114) for the multi-drug-resistant protease were obtained by the displacement titration method, using acetyl-pepstatin and indinavir, respectively, as the weaker binder Direct titration experiments were also performed with the tightly binding inhibitor to confirm the enthalpy changes obtained by the displacement method. Each experiment was performed at least twice. The details of the ITC experiments have been published elsewhere.

---

Genotyping. [1]
Genotypic analysis was performed by automated population-based full-sequence analysis. Sequencing results are reported as amino acid changes compared to the wild-type (HXB2) reference sequence. InVitro Selection of Resistant Strains. MT-4-LTR-EGFP cells were infected at a multiplicity of infection of 0.01 to 0.001 CCID50/cell in the presence of the inhibitor compound at a starting concentration two to three times the EC50. The cultures were subcultivated and scored microscopically on virus-induced fluorescence and cytopathic effect every 3 to 4 days. Cultures were subcultivated in the presence of the same concentration of compound until full virus breakthrough, and subsequently at a higher compound concentration to select for variants able to grow in the presence of the highest possible inhibitor concentration.

---

X-ray Crystallography. [1]
A multi-drug-resistant HIV-1 protease with substitutions L63P, V82T, and I84V was crystallized in complex with Darunavir (TMC114) and 2. Both structures crystallized in the space group P212121 with one dimer per asymmetric unit. Data on the Darunavir (TMC114) complex were collected under cryocooled conditions using the synchrotron source at Advanced Light Source at Lawrence-Berkeley Laboratory, Berkeley, CA. The crystal complex with Darunavir (TMC114) diffracted to a resolution of 1.35 Å, with an R-factor of 16.8%. Data for the complex with 2 were collected at room temperature on an R-axis IV image plate system mounted on a Rigaku rotating anode source. The resolution obtained for the complex with 2 is 2.2 Å. The details of the X-ray crystallography experiments and the refinement statistics have been published elsewhere.15 The X-ray structures have been submitted to the Protein Data Bank (PDB-codes 1T7I and 1T7J).

---

Drug susceptibility assay. [2]
The susceptibilities of HIV-1LAI, HIV-1Ba-L, HIV-2EHO, HIV-2ROD, and the primary HIV-1 isolates to various drugs were determined as described previously, with minor modifications. Briefly, MT-2 cells (2 × 104/ml) were exposed to 100 50% tissue culture infectious doses (TCID50s) of HIV-1LAI, HIV-1Ba-L, HIV-2EHO, or HIV-2ROD in the presence or absence of various concentrations of drugs in 96-well microculture plates and were incubated at 37°C for 7 days. After 100 μl of the medium was removed from each well, 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) solution (10 μl, 7.5 mg/ml in phosphate-buffered saline) was added to each well in the plate, followed by incubation at 37°C for 2 h. After incubation to dissolve the formazan crystals, 100 μl of acidified isopropanol containing 4% (vol/vol) Triton X-100 was added to each well and the optical density was measured in a kinetic microplate reader. All assays were performed in duplicate or triplicate.
To determine the sensitivities of the primary HIV-1 isolates to drugs, phytohemagglutinin-activated peripheral blood mononuclear cells (PHA-PBMCs; 106/ml) were exposed to 50 TCID50s of each primary HIV-1 isolate and cultured in the presence or absence of various concentrations of drugs in 10-fold serial dilutions in 96-well microculture plates. To determine the drug susceptibilities of certain laboratory HIV-1 strains, MT-4 cells were used as target cells, as described previously, with minor modifications. In brief, MT-4 cells (105/ml) were exposed to 100 TCID50s of drug-resistant HIV-1 strains in the presence or absence of various concentrations of drugs and were incubated at 37°C. On day 7 of culture, the supernatant was harvested and the amount of p24 Gag protein was determined by using a fully automated chemiluminescent enzyme immunoassay system. The drug concentrations that suppressed the production of p24 Gag protein by 50% (50% inhibitory concentrations [IC50s]) were determined by comparison with the level of p24 production in drug-free control cell cultures. All assays were performed in triplicate.

Darunavir has been shown to have higher potency than saquinavir, amprenavir, nelfinavir, indinavir, lopinavir, and ritonavir in an in vitro study using MT-2 cells. The main hepatic cytochrome P450 (CYP) enzyme responsible for darunavir metabolism is CYP3A. The "boosting" dose of ritonavir increases the bioavailability of darunavir by inhibiting CYP3A.

---

Virology.Cells and Viruses. [1]
MT-4 cells are human T-lymphoblastoid cells that are highly sensitive to HIV infection, producing a rapid and strong cytopathic effect. MT4-LTR-EGFP cells are MT4 cells stably transfected with a vector containing the coding sequence for the Green Fluorescent Protein (EGFP) under control of HIV-1 Long Terminal Repeat (LTR). Upon infection of these cells with HIV, the viral transactivator protein Tat activates the LTR promoter, which in turn triggers the transcription of the EGFP coding sequence. All cells were cultured in RPMI 1640 medium supplemented with fetal calf serum and antibiotics in a humidified incubator with a 5% CO2 atmosphere at 37 °C. HIV strains used for the profiling of the compounds were wild-type HIV-1 strain IIIB and recombinant HIV strains derived from clinical isolates. Those were constructed as previously described by cotransfection of MT-4 cells with sample-derived viral protease (PR) and reverse transcriptase (RT) coding sequences and an HIV-1 HXB2-derived proviral clone deleted in the protease and RT coding region.

---

Antiviral Assays. [1]
The antiviral activity of compounds against wild-type HIV and clinical sample derived recombinant viruses was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay method as previously described. Briefly, various concentrations of the test compounds were added to wells of a flat-bottom microtiter plate. Subsequently, virus and MT-4 cells were added to a final concentration of 200−250 50% cell culture infectious doses (CCID50)/well and 30 000 cells/well, respectively. After 5 days of incubation at 37 °C with 5% CO2, the cytopathic effect (CPE) of the replicating virus was measured by the MTT method. The results of the antiviral assay were expressed as pEC50 (= −log EC50), with EC50 defined as the concentration of a compound achieving 50% CPE compared with the drug-free control. Cytotoxicity of the test compound was determined in parallel using mock-infected cell cultures containing an identical compound concentration range but no virus.

---

Generation of PI-resistant HIV-1 in vitro. [2]
MT-4 cells (105/ml) were exposed to HIV-1NL4-3 (500 TCID50s) and cultured in the presence of various PIs at an initial concentration of 0.01 to 0.03 μM. Viral replication was monitored by determination of the amount of p24 Gag produced by MT-4 cells. The culture supernatants were harvested on day 7 and were used to infect fresh MT-4 cells for the next round of culture in the presence of increasing concentrations of each drug. When the virus began to propagate in the presence of the drug, the drug concentration was generally increased two- to threefold. Proviral DNA samples obtained from the lysates of infected cells were subjected to nucleotide sequencing. This drug selection procedure was carried out until the drug concentration reached 5 μM.

Animal Studies [3]
Ten twelve-week-old male and female Balb/c mice were acclimated to the animal facility for at least 7 days. Five mice per cage were housed in a sterile room with 12/12 h light–dark cycles. Temperature and humidity were maintained at a constant level in the room. There was free access to food and water. Detailed information for dosing in Balb/c mice can be found in our previous study [29]. A 2.5 mg/kg dosage of Darunavir (TMC114)/DRV or PLGA-DRV NPs was given via intranasal (IN) and intravenous (IV). For the IN group, the minimum concentration of Darunavir (TMC114)/DRV is 1.25 mg/mL to ensure that the dosing volume for each mouse is less than 2 µL per gram of mice. Given the constraints on the EE (%) of Darunavir (TMC114)/DRV in PLGA, we selected a dosage of 2.5 mg/kg, representing the highest dose achievable within the scope of this study.

Absorption, Distribution and Excretion
The absolute oral bioavailability of one single 600 mg dose of darunavir alone and with 100 mg of ritonavir twice a day was 37% and 82%, respectively. Exposure to darunavir in boosted patients has been found to be 11 times higher than in unboosted patients. Tmax is achieved approximately 2.4 to 4 hours after oral administration. When darunavir is taken with food, the Cmax and AUC of darunavir given with ritonavir increase by 30% when compared to the fasted state.
A mass balance study in healthy volunteers demonstrated that after single dose administration of 400 mg 14C-darunavir, given with 100 mg ritonavir, approximately 79.5% and 13.9% of the administered dose of radiolabeled darunavir was obtained in the feces and urine, respectively. Excretion of unchanged drug accounted for 8.0% of the darunavir dose in volunteers who were unboosted. In boosted darunavir administration, unchanged darunavir made up 48.8% of the excreted dose in boosted subjects due to inhibition of darunavir metabolism by ritonavir. Unchanged drug in the urine made up 1.2% of the administered dose in volunteers who where unboosted, and 7.7% in boosted volunteers.
The volume of distribution of darunavir in one pharmacokinetic study in conjunction with ritonavir was 206.5 L (with a range of 161.0–264.9) in healthy young adult volunteers. Another pharmacokinetic study revealed a volume of distribution of 220 L.
Darunavir has a low renal clearance. After intravenous administration, the clearance darunavir administered alone and with 100 mg ritonavir twice daily, was 32.8 L/h and 5.9 L/h, respectively.
Darunavir is approximately 95% bound to plasma proteins. Darunavir binds primarily to plasma alpha 1-acid glycoprotein (AAG).
Darunavir, co-administered with 100 mg ritonavir twice daily, was absorbed following oral administration with a Tmax of approximately 2.5-4 hours. The absolute oral bioavailability of a single 600 mg dose of darunavir alone and after co-administration with 100 mg ritonavir twice daily was 37% and 82%, respectively.
Darunavir is distributed into milk in rats; not known whether the drug is distributed into human milk.
A mass balance study in healthy volunteers showed that after single dose administration of 400 mg (14)C-darunavir, co-administered with 100 mg ritonavir, approximately 79.5% and 13.9% of the administered dose of (14)C-darunavir was recovered in the feces and urine, respectively. Unchanged darunavir accounted for approximately 41.2% and 7.7% of the administered dose in feces and urine, respectively. The terminal elimination half-life of darunavir was approximately 15 hours when co-administered with ritonavir. After intravenous administration, the clearance of darunavir, administered alone and co-administered with 100 mg twice daily ritonavir, was 32.8 L/hr and 5.9 L/hr, respectively.
For more Absorption, Distribution and Excretion (Complete) data for Darunavir (8 total), please visit the HSDB record page.

---

Metabolism / Metabolites
Darunavir is heavily oxidized and metabolized by hepatic cytochrome enzymes, mainly CYP3A. Darunavir is extensively metabolized in subjects who do not receive a booster, primarily via carbamate hydrolysis, isobutyl aliphatic hydroxylation, and aniline aromatic hydroxylation, as well as both benzylic aromatic hydroxylation and glucuronidation.
In vitro experiments with human liver microsomes (HLMs) indicate that darunavir primarily undergoes oxidative metabolism. Darunavir is extensively metabolized by CYP enzymes, primarily by CYP3A. A mass balance study in healthy volunteers showed that after a single dose administration of 400 mg (14)C-darunavir, co-administered with 100 mg ritonavir, the majority of the radioactivity in the plasma was due to darunavir. At least 3 oxidative metabolites of darunavir have been identified in humans; all showed activity that was at least 90% less than the activity of darunavir against wild-type HIV.
Absorption, metabolism, and excretion of darunavir, an inhibitor of human immunodeficiency virus protease, was studied in eight healthy male subjects after a single oral dose of 400 mg of ((14)C)darunavir given alone (unboosted subjects) or with ritonavir (100 mg b.i.d. 2 days before and 7 days after darunavir administration (boosted subjects)). ... Darunavir was extensively metabolized in unboosted subjects, mainly by carbamate hydrolysis, isobutyl aliphatic hydroxylation, and aniline aromatic hydroxylation and to a lesser extent by benzylic aromatic hydroxylation and glucuronidation. Total excretion of unchanged darunavir accounted for 8.0% of the dose in unboosted subjects. Boosting with ritonavir resulted in significant inhibition of carbamate hydrolysis, isobutyl aliphatic hydroxylation, and aniline aromatic hydroxylation but had no effect on aromatic hydroxylation at the benzylic moiety, whereas excretion of glucuronide metabolites was markedly increased but still represented a minor pathway. Total excretion of unchanged darunavir accounted for 48.8% of the administered dose in boosted subjects as a result of the inhibition of darunavir metabolism by ritonavir. Unchanged darunavir in urine accounted for 1.2% of the administered dose in unboosted subjects and 7.7% in boosted subjects, indicating a low renal clearance.
Darunavir is metabolized by Phase I and Phase II biotransformation mechanisms. A large number of metabolites were detected in vitro using animal and human hepatocytes and microsomal preparations. The metabolic pathway was qualitatively similar in rats, dogs and humans. The most prevalent pathway was the Phase I biotransformation including carbamate hydrolysis, aliphatic hydroxylation at the isobutyl moiety and aromatic hydroxylation at the aniline moiety. Dogs were most representatives of human with carbamate hydrolysis predominating in both species. Darunavir was mainly metabolized by CYP3A. In mice and rats darunavir treatment induced hepatic microsomal CYP3A4. UDP-GT activity was additionally induced in rats. In dogs, no induction effects were observed. Darunavir is presented as a single enantiomer but no chiral inversion occurs in vivo.

---

Biological Half-Life
The terminal elimination half-life of darunavir is approximately 15 hours when it is combined with ritonavir.
A mass balance study in healthy volunteers showed that after a single dose administration of 400 mg (14)C-darunavir, co-administered with 100 mg ritonavir ... The terminal elimination half-life of darunavir was approximately 15 hours when co-administered with ritonavir.
The pharmacokinetics of darunavir has been evaluated in vitro and in several species (mice, rats, dogs and rabbits), that were also used in the non-clinical pharmacology and toxicology studies. ... Following oral administration, ... elimination half-life was ... rapid with half-lives generally less than 5 hr.

Hepatotoxicity
Some degree of serum aminotransferase elevations occur in a high proportion of patients taking darunavir containing antiretroviral regimens. Moderate-to-severe elevations in serum aminotransferase levels (above 5 times the upper limit of normal) are found in 3% to 10% of patients overall, and rates are higher in patients with HIV-HCV coinfection. In clinical trials of darunavir elevations in serum ALT above 5 times ULN occurred in 2% to 3% of patients, but no subject developed clinically apparent liver injury with jaundice. The serum enzyme elevations during therapy are usually asymptomatic and self-limited and can resolve even with continuation of the medication. Clinically apparent acute liver injury due to darunavir has been reported since its approval and more widescale use, but none have been well characterized for clinical features. Assigning causality to a specific anti-HIV medication is often difficult because most patients are taking multiple antiviral agents and many have accompanying chronic hepatitis B or C or nonalcoholic steatohepatitis. In reported cases, the liver injury generally arises after 1 to 8 weeks of therapy and the pattern of serum enzyme elevations is usually, but not always, hepatocellular. Signs of hypersensitivity (fever, rash, eosinophilia) are rare, as is autoantibody formation. The acute liver injury is usually self-limited and resolves within a few weeks of stopping darunavir. However, fatal instances have been reported, at least to the sponsor and monitoring of liver enzymes during therapy is recommended.
Finally, initiation of darunavir based highly active antiretroviral therapy can lead to exacerbation of an underlying chronic hepatitis B or C in coinfected individuals, typically arising 2 to 12 months after starting therapy and associated with a hepatocellular pattern of serum enzyme elevations and increases in serum levels of hepatitis B virus (HBV) DNA or hepatitis C virus (HCV) RNA. Darunavir therapy has not been clearly linked to lactic acidosis and acute fatty liver that is reported in association with several nucleoside analogue reverse transcriptase inhibitors.
Likelihood score: C (probable, rare cause of clinically apparent liver injury).

---

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Limited information indicates that maternal doses of darunavir up to 800 mg daily with ritonavir produce low to unmeasurable levels in milk and would not be expected to cause any adverse effects in breastfed infants. The combination of darunavir and cobicistat is expected to produce similar results. 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.

---

Protein Binding
Darunavir is approximately 95% bound to plasma proteins. Darunavir binds primarily to plasma alpha 1-acid glycoprotein (AAG).

[1]. Discovery and selection of TMC114, a next generation HIV-1 protease inhibitor. J Med Chem. 2005 Mar 24;48(6):1813-22.

[2]. Novel bis-tetrahydrofuranylurethane-containing nonpeptidic protease inhibitor (PI) UIC-94017 (TMC114) with potent activity against multi-PI-resistant human immunodeficiency virus in vitro. Antimicrob Agents Chemother. 2003 Oct;47(10):

[3]. Darunavir Nanoformulation Suppresses HIV Pathogenesis in Macrophages and Improves Drug Delivery to the Brain in Mice. Pharmaceutics . 2024 Apr 19;16(4):555.

Darunavir is an N,N-disubstituted benzenesulfonamide bearing an unsubstituted amino group at the 4-position, used for the treatment of HIV infection. A second-generation HIV protease inhibitor, darunavir was designed to form robust interactions with the protease enzyme from many strains of HIV, including those from treatment-experienced patients with multiple resistance mutations to other protease inhibitors. It has a role as a HIV protease inhibitor and an antiviral drug. It is a furofuran, a carbamate ester and a sulfonamide.
Darunavir (brand name: Prezista) is a prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of HIV infection in adults and children. Darunavir is always used in combination with a pharmacokinetic enhancer — either ritonavir (brand name: Norvir) or cobicistat (brand name: Tybost) — and other HIV medicines.
When darunavir is taken with ritonavir, it may be used in adults and children 3 years of age and older who weigh at least 22 lb (10 kg).
When darunavir is taken with cobicistat, it may be used in adults and children weighing at least 88 lb (40 kg) who meet certain requirements, as determined by a health care provider.
(A fixed-dose combination tablet containing darunavir and cobicistat [brand name: Prezcobix] is also available.)
Darunavir is a protease inhibitor used with other HIV protease inhibitor drugs as well as [ritonavir] for the effective management of HIV-1 infection. As a second-generation protease inhibitor, darunavir is designed to combat resistance to standard HIV therapy. It was initially approved by the FDA in 2006. Darunavir is being studied as a possible treatment for SARS-CoV-2, the coronavirus responsible for COVID-19, due to in vitro evidence supporting its ability to combat this infection. Clinical trials are underway and are expected to conclude in August 2020.
Darunavir is a Protease Inhibitor. The mechanism of action of darunavir is as a HIV Protease Inhibitor, and Cytochrome P450 3A Inhibitor, and Cytochrome P450 2D6 Inhibitor.
Darunavir is an antiretroviral protease inhibitor that is used in the therapy and prevention of human immunodeficiency virus (HIV) infection and the acquired immunodeficiency syndrome (AIDS). Darunavir can cause transient and usually asymptomatic elevations in serum aminotransferase levels and has been linked to rare instances of clinically apparent, acute liver injury. In HBV or HCV coinfected patients, highly active antiretroviral therapy with darunavir may result of an exacerbation of the underlying chronic hepatitis B or C.
Darunavir is a human immunodeficiency virus type 1 (HIV-1) protease nonpeptidic inhibitor, with activity against HIV. Upon oral administration, darunavir selectively targets and binds to the active site of HIV-1 protease, and inhibits the dimerization and catalytic activity of HIV-1 protease. This inhibits the proteolytic cleavage of viral Gag and Gag-Pol polyproteins in HIV-infected cells. This inhibition leads to the production of immature, non-infectious viral proteins that are unable to form mature virions, and prevents HIV replication.
An HIV PROTEASE INHIBITOR that is used in the treatment of AIDS and HIV INFECTIONS. Due to the emergence of ANTIVIRAL DRUG RESISTANCE when used alone, it is administered in combination with other ANTI-HIV AGENTS.

---

Drug Indication
Darunavir, co-administered with ritonavir, and with other antiretroviral agents, is indicated for the treatment of human immunodeficiency virus (HIV) in children age 3 or above and adults with HIV-1 infection.
FDA Label
Darunavir, co-administered with low dose ritonavir is indicated in combination with other antiretroviral medicinal products for the treatment of patients with human immunodeficiency virus (HIV-1) infection (see section 4. 2). Darunavir Mylan 75 mg, 150 mg, 300 mg and 600 mg tablets may be used to provide suitable dose regimens (see section 4. 2): For the treatment of HIV-1 infection in antiretroviral treatment (ART)-experienced adult patients, including those that have been highly pre-treated. For the treatment of HIV-1 infection in paediatric patients from the age of 3 years and at least 15 kg body weight. In deciding to initiate treatment with darunavir co-administered with low dose ritonavir, careful consideration should be given to the treatment history of the individual patient and the patterns of mutations associated with different agents. Genotypic or phenotypic testing (when available) and treatment history should guide the use of darunavir (see sections 4. 2, 4. 4 and 5. 1). Darunavir co-administered with low dose ritonavir is indicated in combination with other antiretroviral medicinal products for the treatment of patients with human immunodeficiency virus (HIV-1) infection.  Darunavir co-administered with cobicistat is indicated in combination with other antiretroviral medicinal products for the treatment of human immunodeficiency virus (HIV-1) infection in adults and adolescents (aged 12 years and older, weighing at least 40 kg) (see section 4. 2).  Darunavir Mylan 400 mg and 800 mg tablets may be used to provide suitable dose regimens for the treatment of HIV-1 infection in adult and paediatric patients from the age of 3 years and at least 40 kg body weight who are:  antiretroviral therapy (ART)-naïve (see section 4. 2).  ART-experienced with no darunavir resistance associated mutations (DRV-RAMs) and who have plasma HIV-1 RNA < 100,000 copies/ml and CD4+ cell count ≥ 100 cells x 10⁶/L. In deciding to initiate treatment with darunavir in such ART-experienced patients, genotypic testing should guide the use of darunavir (see sections 4. 2, 4. 3, 4. 4 and 5. 1).
400 and 800 mgDarunavir Krka, co-administered with low dose ritonavir is indicated in combination with other antiretroviral medicinal products for the treatment of patients with human immunodeficiency virus (HIV-1) infection. Darunavir Krka 400 mg and 800 mg tablets may be used to provide suitable dose regimens for the treatment of HIV-1 infection in adult and paediatric patients from the age of 3 years and at least 40 kg body weight who are: antiretroviral therapy (ART)-naïve (see section 4. 2). ART-experienced with no darunavir resistance associated mutations (DRV-RAMs) and who have plasma HIV-1 RNA < 100,000 copies/ml and CD4+ cell count ≥ 100 cells x 106/l. In deciding to initiate treatment with darunavir in such ART-experienced patients, genotypic testing should guide the use of darunavir (see sections 4. 2, 4. 3, 4. 4 and 5. 1). 600 mg Darunavir Krka, co-administered with low dose ritonavir is indicated in combination with other antiretroviral medicinal products for the treatment of patients with human immunodeficiency virus (HIV-1) infection. Darunavir Krka 600 mg tablets may be used to provide suitable dose regimens (see section 4. 2): For the treatment of HIV-1 infection in antiretroviral treatment (ART)-experienced adult patients, including those that have been highly pre-treated. For the treatment of HIV-1 infection in paediatric patients from the age of 3 years and at least 15 kg body weight. In deciding to initiate treatment with darunavir co-administered with low dose ritonavir, careful consideration should be given to the treatment history of the individual patient and the patterns of mutations associated with different agents. Genotypic or phenotypic testing (when available) and treatment history should guide the use of darunavir.
PREZISTA, co administered with low dose ritonavir is indicated in combination with other antiretroviral medicinal products for the treatment of human immunodeficiency virus (HIV 1) infection in adult and paediatric patients from the age of 3 years and at least 15 kg body weight. PREZISTA, co administered with cobicistat is indicated in combination with other antiretroviral medicinal products for the treatment of human immunodeficiency virus (HIV 1) infection in adults and adolescents (aged 12 years and older, weighing at least 40 kg). In deciding to initiate treatment with PREZISTA co administered with cobicistat or low dose ritonavir, careful consideration should be given to the treatment history of the individual patient and the patterns of mutations associated with different agents. Genotypic or phenotypic testing (when available) and treatment history should guide the use of PREZISTA. PREZISTA, co administered with low dose ritonavir is indicated in combination with other antiretroviral medicinal products for the treatment of patients with human immunodeficiency virus (HIV 1) infection. PREZISTA 75 mg, 150 mg, and 600 mg tablets may be used to provide suitable dose regimens: For the treatment of HIV 1 infection in antiretroviral treatment (ART) experienced adult patients, including those that have been highly pre treated. For the treatment of HIV 1 infection in paediatric patients from the age of 3 years and at least 15 kg body weight. In deciding to initiate treatment with PREZISTA co administered with low dose ritonavir, careful consideration should be given to the treatment history of the individual patient and the patterns of mutations associated with different agents. Genotypic or phenotypic testing (when available) and treatment history should guide the use of PREZISTA. PREZISTA, co administered with low dose ritonavir is indicated in combination with other antiretroviral medicinal products for the treatment of patients with human immunodeficiency virus (HIV 1) infection. PREZISTA, co administered with cobicistat is indicated in combination with other antiretroviral medicinal products for the treatment of human immunodeficiency virus (HIV 1) infection in adults and adolescents (aged 12 years and older, weighing at least 40 kg). PREZISTA 400 mg and 800 mg tablets may be used to provide suitable dose regimens for the treatment of HIV 1 infection in adult and paediatric patients from the age of 3 years and at least 40 kg body weight who are: antiretroviral therapy (ART) naïve. ART experienced with no darunavir resistance associated mutations (DRV RAMs) and who have plasma HIV 1 RNA < 100,000 copies/ml and CD4+ cell count ≥ 100 cells x 106/L. In deciding to initiate treatment with PREZISTA in such ART experienced patients, genotypic testing should guide the use of PREZISTA.
400mg and 800 mg Film-coated TabletsDarunavir Krka d. d. , co-administered with low dose ritonavir is indicated in combination with other antiretroviral medicinal products for the treatment of patients with human immunodeficiency virus (HIV-1) infection. Darunavir Krka d. d. , co-administered with cobicistat is indicated in combination with other antiretroviral medicinal products for the treatment of patients with human immunodeficiency virus (HIV-1) infection in adult patients (see section 4. 2). Darunavir Krka d. d. 400 mg and 800 mg tablets may be used to provide suitable dose regimens for the treatment of HIV-1 infection in adult and paediatric patients from the age of 3 years and at least 40 kg body weight who are: antiretroviral therapy (ART)-naïve (see section 4. 2). ART-experienced with no darunavir resistance associated mutations (DRV-RAMs) and who have plasma HIV-1 RNA < 100,000 copies/ml and CD4+ cell count ≥ 100 cells x 106/l. In deciding to initiate treatment with darunavir in such ART-experienced patients, genotypic testing should guide the use of darunavir (see sections 4. 2, 4. 3, 4. 4 and 5. 1). 600mg Film-coated TabletsDarunavir Krka d. d. , co-administered with low dose ritonavir is indicated in combination with other antiretroviral medicinal products for the treatment of patients with human immunodeficiency virus (HIV-1) infection. Darunavir Krka d. d. 600 mg tablets may be used to provide suitable dose regimens (see section 4. 2): For the treatment of HIV-1 infection in antiretroviral treatment (ART)-experienced adult patients, including those that have been highly pre-treated. For the treatment of HIV-1 infection in paediatric patients from the age of 3 years and at least 15 kg body weight. In deciding to initiate treatment with darunavir co-administered with low dose ritonavir, careful consideration should be given to the treatment history of the individual patient and the patterns of mutations associated with different agents. Genotypic or phenotypic testing (when available) and treatment history should guide the use of darunavir.
Treatment of human immunodeficiency virus (HIV-1) infection

---

Mechanism of Action
The HIV-1 protease enzyme is necessary for viral precursor protein processing and viral maturation in preparation for infection, and is therefore a target for antiretroviral therapy for HIV. Protease inhibitors are used as a part of highly active antiretroviral therapy (HAART) in patients diagnosed with HIV infection. It has been shown to effectively suppress the virus, leading to significantly decreased morbidity and mortality rates. Darunavir, a HIV protease inhibitor, prevents HIV replication through binding to the enzyme, stopping the dimerization and the catalytic activity of HIV-1 protease. In particular, it inhibits the cleavage of HIV encoded Gag-Pol proteins in cells that have been infected with the virus, halting the formation of mature virus particles, which spread the infection. The close contact that darunavir makes with the primary chains of the active site amino acids (Asp-29 and Asp-30) on the protease likely contributes to its potency and efficacy against resistant variants of HIV-1. Darunavir is known to bind to different sites on the enzyme: the active site cavity and the surface of one of the flexible flaps in the protease dimer. Darunavir can adapt to changes in the shape of a protease enzyme due to its molecular flexibility.
Darunavir as a protease inhibitor inhibits the cleavage of HIV encoded gag-pol polyproteins in virus infected cells, thereby preventing the formation of mature and infectious new virions. It was selected for its potency against wild type HIV-1 and HIV strains resistant to currently approved protease inhibitors.
Darunavir is an inhibitor of the HIV-1 protease. It selectively inhibits the cleavage of HIV encoded Gag-Pol polyproteins in infected cells, thereby preventing the formation of mature virus particles.

C27H37N3O7S

547.660

547.235

C, 59.21; H, 6.81; N, 7.67; O, 20.45; S, 5.85

206361-99-1

Darunavir Ethanolate;635728-49-3;Darunavir-d9;1133378-37-6; 2281870-65-1 (dihydrate); 635728-49-3 (ethanolate); 206361-99-1 (free)

213039

White to off-white solid powder

1.3±0.1 g/cm3

74-76ºC

1.620

3.94

3

9

12

38

853

5

O=C(O[C@@H]1[C@@]2([H])[C@@](OCC2)([H])OC1)N[C@@H](CC3=CC=CC=C3)[C@H](O)CN(S(=O)(C4=CC=C(N)C=C4)=O)CC(C)C

CJBJHOAVZSMMDJ-HEXNFIEUSA-N

InChI=1S/C27H37N3O7S/c1-18(2)15-30(38(33,34)21-10-8-20(28)9-11-21)16-24(31)23(14-19-6-4-3-5-7-19)29-27(32)37-25-17-36-26-22(25)12-13-35-26/h3-11,18,22-26,31H,12-17,28H2,1-2H3,(H,29,32)/t22-,23-,24+,25-,26+/m0/s1

[(3aS,4R,6aR)-2,3,3a,4,5,6a-hexahydrofuro[2,3-b]furan-4-yl] N-[(2S,3R)-4-[(4-aminophenyl)sulfonyl-(2-methylpropyl)amino]-3-hydroxy-1-phenylbutan-2-yl]carbamate

Darunavir; TMC-114; TMC114; TMC 114; UIC-94017; Darunavir; 206361-99-1; Darunavirum; UIC 94017; UIC94017; Trade name: Prezista

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: ≥ 2.5 mg/mL (4.56 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.

---

Solubility in Formulation 2: ≥ 2.5 mg/mL (4.56 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.

---

View More

Solubility in Formulation 3: ≥ 2.5 mg/mL (4.56 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.

---

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