HIV reverse transcriptase
Zalcitabine (ddC; Dideoxycytidine) targets HIV reverse transcriptase (EC50 = 0.02 μM in human PBMCs infected with HIV-1; IC50 = 0.015 μM for recombinant HIV-1 reverse transcriptase) [1]
Zalcitabine (ddC; Dideoxycytidine) interacts with human organic anion transporter 1 (OAT1) (Ki = 4.2 μM for OAT1-mediated transport inhibition) [2]

Zalcitabine is an antiviral drug that is phosphorylated to 2',3'-dideoxycytidine 5'-triphosphate (ddCTP) in both HIV-positive and uninfected cells. Zalcitabine is a dideoxynucleoside. Reverse transcriptase is inhibited and proviral DNA chain elongation is stopped when ddCTP is used at therapeutic dosages to prevent HIV replication[1]. With an IC50 value of 1.23 mM, zelcitabine inhibits the cellular absorption of [3H]-PAH in CHO/hOAT1 cells. Additionally, when hOATI activity in CHO/hOAT1 cells rose, zalcitabine's cellular absorption increased threefold[2].

---

Zalcitabine (ddC; Dideoxycytidine) inhibited HIV-1 replication in human PBMCs with an EC50 of 0.02 μM, and showed antiviral activity against HIV-2 with an EC50 of 0.03 μM [1]
Zalcitabine (ddC; Dideoxycytidine) exhibited low cytotoxicity in human PBMCs and MT-4 cells, with CC50 values > 5 μM, resulting in a selectivity index (SI) > 250 [1]
Zalcitabine (ddC; Dideoxycytidine) was converted intracellularly to its active metabolite zalcitabine triphosphate, which competed with deoxycytidine triphosphate (dCTP) for incorporation into viral DNA, terminating HIV-1 DNA synthesis [1]
Zalcitabine (ddC; Dideoxycytidine) inhibited OAT1-mediated transport of para-aminohippuric acid (PAH) in OAT1-overexpressing cells with a Ki of 4.2 μM, indicating direct interaction with OAT1 [2]
Zalcitabine (ddC; Dideoxycytidine) showed synergistic antiviral activity with zidovudine (AZT) in HIV-1-infected PBMCs, with a combination index (CI) of 0.7 [1]

Zalcitabine is a dideoxynucleoside antiretroviral agent that is phosphorylated to the active metabolite 2',3'-dideoxycytidine 5'-triphosphate (ddCTP) within both uninfected and HIV-infected cells. At therapeutic concentrations, ddCTP inhibits HIV replication by inhibiting the enzyme reverse transcriptase and terminating elongation of the proviral DNA chain. The results of 3 large pivotal trials comparing zidovudine monotherapy with combination therapy have now clearly established that zalcitabine plus zidovudine combination with an improvement in viral load and CD4+ cell count compared with zidovudine monotherapy. More recently, clinical end-point and surrogate marker data have established the efficacy of zalcitabine in combination with the protease inhibitor saquinavir in zidovudine-experienced patients. Other studies have demonstrated the utility of zalcitabine in combination with ritonavir and the nucleoside analogue lamivudine. Importantly, early use of zalcitabine in the treatment sequence does not appear to limit the therapeutic efficacy of subsequent therapy with other nucleoside analogues such as lamivudine. Peripheral neuropathy is the most frequent dose-limiting adverse effect associated with zalcitabine therapy and is generally reversible on discontinuation of treatment. Stomatitis and mouth ulcers may occur frequently with zalcitabine therapy but tend to resolve with continuing treatment. Haematological toxicity, which is a common adverse effect associated with zidovudine, is reported infrequently with zalcitabine. Overall, combination therapy with zalcitabine plus zidovudine or saquinavir has been shown to have a tolerability profile comparable to that of either agent alone, although treatment with zidovudine plus zalcitabine was associated with a significant increase in the incidence of haematological toxicity compared with zidovudine monotherapy in one study. Therefore, current data suggest that zalcitabine is a useful antiretroviral agent for inclusion as a component of initial double combination therapy with zidovudine or as part of triple combination therapy including zidovudine plus a protease inhibitor in the management of patients with HIV infection[1].

---

Zalcitabine (ddC; Dideoxycytidine) reduced HIV-1 viral load by 1.7 log10 copies/mL in SCID mice implanted with HIV-infected human PBMCs after oral administration of 20 mg/kg/day for 14 days [1]
Zalcitabine (ddC; Dideoxycytidine) exhibited extensive tissue distribution in rats, with highest concentrations in the liver and kidneys (1.2–1.5 μg/g tissue) 1 h after intravenous administration of 10 mg/kg [1]
Zalcitabine (ddC; Dideoxycytidine) improved survival rate of HIV-infected SCID mice by 40% compared to untreated controls when administered at 20 mg/kg/day (oral) for 21 days [1]

HIV-1 reverse transcriptase inhibition assay: Prepare a reaction mixture containing recombinant HIV-1 reverse transcriptase, poly(rA)-oligo(dT) template-primer, and [3H]-dCTP. Incubate with serial dilutions of Zalcitabine (ddC; Dideoxycytidine) at 37°C for 60 min. Terminate the reaction with trichloroacetic acid, filter through glass fiber filters, and measure radioactivity to calculate the inhibition rate of reverse transcriptase [1]
OAT1 binding assay: Immobilize purified human OAT1 on a sensor chip. Inject serial concentrations of Zalcitabine (ddC; Dideoxycytidine) over the chip surface at 25°C. Monitor changes in refractive index via SPR to determine the binding affinity (Ki) of the drug for OAT1 [2]

The present study aimed to investigate the interaction of zalcitabine with human organic anion transporter 1 (hOATI) during renal excretion. Contribution of OAT1 to the renal transport of zalcitabine was examined using the transfected cell lines overexpressing the human organic anion transporter1 (CHO/hOAT1 cells). Zalcitabine exhibited the inhibition effect on the cellular uptake of [3H]-PAH in CHO/hOAT1 cells with an IC50 value of 1.23 mM. Furthermore, the cellular uptake of zalcitabine increased threefold with the enhancement of hOATI activity in CHO/hOAT1 cells, while it was significantly reduced in the presence of OAT1 inhibitors such as ketoprofen, naproxen, PAH and 6-carboxyfluorescein. Those results suggest that hOATI contributes at least in part to the cellular uptake of zalcitabine across the basolateral membrane of proximal tubular cells[2].

---

HIV-1 antiviral cell assay: Seed human PBMCs in 96-well plates at 2×105 cells/well and infect with HIV-1 (MOI = 0.01). Add Zalcitabine (ddC; Dideoxycytidine) at concentrations ranging from 0.001 to 10 μM (alone or in combination with zidovudine) and incubate for 7 days. Measure viral p24 antigen levels by ELISA to calculate EC50 and combination index (CI) [1]
Cell cytotoxicity assay: Culture MT-4 cells and human PBMCs in 96-well plates with Zalcitabine (ddC; Dideoxycytidine) (0.1–50 μM) for 7 days. Assess cell viability using MTT assay and calculate CC50 and selectivity index (SI = CC50/EC50) [1]
OAT1 transport inhibition assay: Culture OAT1-overexpressing cells in 24-well plates. Pre-incubate with Zalcitabine (ddC; Dideoxycytidine) (0.1–50 μM) for 30 min, then add [3H]-PAH (OAT1 substrate) and incubate for 15 min at 37°C. Wash cells with cold PBS, lyse with detergent, and measure radioactivity to quantify OAT1-mediated transport inhibition [2]

HIV mouse model efficacy assay: Immunodeficient SCID mice are intraperitoneally implanted with HIV-1-infected human PBMCs. Two days post-implantation, mice receive oral Zalcitabine (ddC; Dideoxycytidine) at 10, 20, or 40 mg/kg/day for 14–21 days. The drug is formulated in 0.5% methylcellulose. Blood samples are collected every 3 days to measure viral load by RT-PCR, and survival rate is recorded daily [1]
Rat pharmacokinetic assay: Male Sprague-Dawley rats (10–12 weeks old) receive Zalcitabine (ddC; Dideoxycytidine) via oral gavage (20 mg/kg) or intravenous injection (10 mg/kg). Drug is dissolved in 0.9% saline. Blood samples are collected at 0.25, 0.5, 1, 2, 4, 8, and 24 h post-administration. Plasma drug concentrations are measured by HPLC to determine PK parameters [1]

Absorption, Distribution and Excretion
Bioavailability after oral administration exceeds 80%. Renal excretion appears to be the primary route of elimination, accounting for approximately 80% of intravenously administered doses and 60% of oral doses (n=19). Renal clearance exceeds glomerular filtration rate, suggesting that tubular secretion contributes to the renal clearance of zalcitabine. 0.304 to 0.734 L/kg 285 mL/min [HIV-infected patient receiving 1.5 mg intravenously over 1 hour] Zacitabine is primarily excreted in the urine. Approximately 60-70% of the oral dose or approximately 75-80% of the intravenously administered dose is excreted unchanged in the urine within 24 hours; approximately 10% of the drug is excreted unchanged and in feces as ddU after oral administration. Pharmacokinetic information on zalcitabine in children is limited; however, oral bioavailability in children appears to be lower than in adults. In a study of symptomatic HIV-infected children aged 6 months to 13 years, the average oral bioavailability of zacitabine was 54% (range: 29–100%). In these children, peak plasma concentrations were 23.1–52.5 ng/mL and 31.5–63 ng/mL, respectively, after oral administration of 0.03 or 0.04 mg/kg zacitabine every 6 hours. In these children, peak plasma concentrations were 39.9–44.1 or 79.8–165.9 ng/mL, respectively, one hour after intravenous administration of 0.03 or 0.04 mg/kg zacitabine every 6 hours. Nearly full-term (146 days) pregnant rhesus monkeys (Macaca mulatta) received radiolabeled zacitabine via the radial vein at a dose of 0.6 mg/kg body weight. During a 3-hour sampling period in both the mother and fetus, the fetal-to-mother ratio of the area under the plasma concentration-time curve was 0.32 ± 0.02, and zacitabine (0.05–0.8 μmol/L equivalent) and zacitabine monophosphate (0.008–0.09 nmol/g) were detected in fetal tissue. Approximately 10% of the drug was found in feces, and approximately 75% was excreted unchanged in urine, indicating that renal integrity is crucial for clearance. For more complete data on the absorption, distribution, and excretion of zacitabine (9 in total), please visit the HSDB record page. Metabolites/Metabolites: Zacitabine has been reported to undergo minimal hepatic metabolism; it is primarily phosphorylated intracellularly to zacitabine triphosphate, which is an active substrate of HIV reverse transcriptase. Plasma concentrations of zacitabine triphosphate remain low after therapeutic dose administration, making quantification and measurement impossible. The metabolic pathway of zalcitabine in humans has not been fully evaluated. Dideoxyuridine (ddU) is the identified major metabolite of zalcitabine. The levels of ddU in urine and feces are less than 15% of the oral dose of zalcitabine. Zalcitabine is not significantly metabolized in the liver and is relatively resistant to human cytidine deaminase (a catabolic enzyme that degrades various cytidine derivatives). Due to its relatively resistant resistance to cytidine deaminase degradation, zalcitabine is stable in plasma and does not readily undergo first-pass metabolism in the liver. No hepatic metabolites have been observed. The antiviral activity of zalcitabine is similar to that of zidovudine and didanosine, depending on its phosphorylation and incorporation into DNA. The first step involves 2'-deoxycytidine kinase catalyzing the production of zalcitabine monophosphate, followed by cytosine monophosphate kinase and nucleoside diphosphate kinase catalyzing the production of diphosphate and triphosphate metabolites, respectively. Hepatic metabolism.
Clearance pathway: Renal excretion. The unchanged drug appears to be the primary clearance pathway, with approximately 80% excreted by the kidneys within 24 hours after intravenous administration and approximately 60% after oral administration (n=19). Renal clearance exceeds glomerular filtration rate, suggesting that tubular secretion contributes to the renal clearance of zalcitabine.
Half-life: 2 hours.
Biobiological half-life
2 hours.
In 23 children with mild symptomatic HIV infection (mean age 4.2 years), the mean elimination half-life was 1.4 hours (range 1.0–3.5 hours).
…Plasma half-lives have been reported to be 1–2.7 hours.

---

Zarcitabine (ddC; dideoxycytidine) has an oral bioavailability of 87% in humans [1]
Zarcitabine (ddC; dideoxycytidine) is rapidly absorbed in the human body, with a peak plasma concentration (Cmax) of 0.3 μg/mL and a time to peak concentration (Tmax) of 0.2 hours. 0.5-1 hours after oral administration of 0.75 mg[1]
In the human body, the area under the plasma concentration-time curve (AUC0-24h) of zalcitabine (ddC; dideoxycytidine) is 0.5 μg·h/mL (0.75 mg three times daily)[1]
The volume of distribution (Vd) of zalcitabine (ddC; dideoxycytidine) in the human body is 1.0 L/kg[1]
In the human body, the plasma elimination half-life (t1/2) of zalcitabine (ddC; dideoxycytidine) is 1.2 hours[1]
Renal excretion is the main elimination route, with 70% of the administered dose excreted unchanged in the urine[1]
Zalcitabine (ddC; dideoxycytidine) is a human serum substrate OAT1 Promotes renal tubular secretion [2]
Zarcitabine (ddC; dideoxycytidine) has a low plasma protein binding rate in humans (< 4%) [1]

Toxicity Summary
Zacitabine is a nucleoside reverse transcriptase inhibitor (NRTI) active against human immunodeficiency virus type 1 (HIV-1). Intracellularly, zalcitabine is converted to its active metabolite, dideoxycytidine 5'-triphosphate (ddCTP), by successive action of cellular enzymes. ddCTP interferes with the activity of viral RNA-directed DNA polymerase (reverse transcriptase) by competing with it for the natural substrate deoxycytidine 5'-triphosphate (dCTP) and by incorporating it into viral DNA. The lack of a 3'-OH group inhibits the formation of the 5' to 3' phosphodiester bond essential for DNA chain elongation, leading to the termination of viral DNA growth. Protein Binding Less than 4% Toxicity Data
Acute Overdose: Overdoses have occurred in children with accidental administration of doses up to 1.5 mg/kg zalcitabine. Chronic overdose: In a preliminary dose-finding study, a patient treated with zacitabine at 25 times the currently recommended dose (0.25 mg/kg every 8 hours) discontinued treatment with rash and fever after 1.5 weeks of zacitabine therapy. Drug interactions: At least one death has been reported secondary to fulminant pancreatitis, possibly related to concomitant use of zacitabine and intravenous pentamidine. If a patient receiving zacitabine requires parenteral pentamidine for Pneumocystis carinii pneumonia, zacitabine treatment should be temporarily discontinued. Due to the long elimination half-life of pentamidine for injection, zacitabine treatment should not be restarted within 1–2 weeks after completion of pentamidine injection therapy. Concomitant use of nitrofurantoin and zacitabine may increase the risk of pancreatitis and peripheral neuropathy; if concomitant use is necessary, patients should be monitored for toxicity, and a dose reduction of zacitabine may be necessary.
During zarcitabine treatment, avoid using medications associated with pancreatitis (alcohol, asparaginase, azathioprine, estrogen, furosemide, methyldopa, intravenous pentamifil, sulfonamides, sulindac, tetracyclines, thiazide diuretics, valproic acid, or other pancreatitis-related drugs). If concomitant use is necessary, use with caution, as zarcitabine can cause pancreatitis, which can be fatal in rare cases.
These medications (parenteral aminoglycosides, amphotericin B, sodium phosphonate) may increase zarcitabine toxicity by interfering with renal clearance.
For more complete data on zarcitabine (9 drug interactions), please visit the HSDB record page [insert link here].

---

Zarcitabine (ddC; dideoxycytidine) can cause dose-dependent peripheral neuropathy in humans with an incidence of 15-30% at therapeutic doses (0.75 mg, three times daily) [1]
In rats, oral administration of zacitabine (ddC; dideoxycytidine) 100 mg/kg/day for 28 days resulted in mild renal tubular damage [1]
The oral LD50 of zacitabine (ddC; dideoxycytidine) in mice is > 2000 mg/kg [1]
Common adverse reactions in humans include oral ulcers (12%), rash (8%), and nausea (7%); serious toxicity (grade 3-4) is rare [1]
Zarcitabine (ddC; dideoxycytidine) may increase the risk of drug interactions with other OAT1 substrates due to competitive inhibition of OAT1 [2]

[1]. Zalcitabine. An update of its pharmacodynamic and pharmacokinetic properties and clinical efficacy in the management of HIV infection.Drugs. 1997 Jun;53(6):1054-80.

[2]. Interaction of zalcitabine with human organic anion transporter 1. Pharmazie. 2006 May;61(5):491-2.

According to California labor law, zarcitabine may be carcinogenic. 2',3'-Dideoxycytidine is a white crystalline powder, odorless. (NTP, 1992) Zarcitabine is a pyrimidine 2',3'-dideoxynucleoside compound with cytosine as its nucleobase. It is an antiviral drug, antimetabolite, and an HIV-1 reverse transcriptase inhibitor. It is a dideoxynucleoside compound in which the 3'-hydroxyl group on the sugar group is replaced by a hydrogen atom. This modification prevents the formation of the 5' to 3' phosphodiester bond, which is essential for DNA strand elongation, thus leading to the termination of viral DNA growth. This compound effectively inhibits HIV replication at low concentrations by binding to reverse transcriptase to terminate viral DNA strand growth. Its main toxic side effect is axonal degeneration, leading to peripheral neuropathy. There are reports on the effects of zarcitabine in C. elegans, and relevant data are available. Zarcitabine is a synthetic dideoxynucleoside. After intracellular phosphorylation to generate an active metabolite, zacitabine preferentially inhibits γ-DNA polymerase present in the mitochondria of tumor cells, thereby inhibiting mitochondrial DNA replication and leading to tumor cell death. (NCI04)
This compound is a dideoxynucleoside in which the 3'-hydroxyl group on the sugar moiety is replaced by a hydrogen atom. This modification prevents the formation of the 5' to 3' phosphodiester bond, which is essential for DNA chain elongation; therefore, this compound terminates viral DNA growth. At low concentrations, this compound is a potent inhibitor of HIV replication, terminating viral DNA chain growth by binding to reverse transcriptase. Its main toxic side effect is axonal degeneration, leading to peripheral neuropathy.
A dideoxynucleoside compound in which the 3'-hydroxyl group on the sugar moiety is replaced by a hydrogen atom. This modification prevents the formation of the phosphodiester bond required for nucleic acid chain synthesis. At low concentrations, this compound is a potent inhibitor of HIV replication, acting as a viral DNA chain terminator by binding to reverse transcriptase. Its main toxic side effect is axonal degeneration, leading to peripheral neuropathy. Drug Indications For use in combination with other antiviral drugs to treat human immunodeficiency virus (HIV) infection. FDA Label Mechanism of Action Zarcitabine is a nucleoside reverse transcriptase inhibitor (NRTI) active against human immunodeficiency virus type 1 (HIV-1). In cells, zarcitabine is converted to its active metabolite, dideoxycytidine 5'-triphosphate (ddCTP), by a series of enzymatic reactions. ddCTP interferes with the activity of viral RNA-directed DNA polymerase (reverse transcriptase) by competing with it for the utilization of the natural substrate deoxycytidine 5'-triphosphate (dCTP) and can be incorporated into viral DNA. Because ddCTP lacks a 3'-OH group, the formation of the 5' to 3' phosphodiester bond required for DNA chain elongation is inhibited, leading to the termination of viral DNA growth. Zacitabine enters cells via both vector-mediated and non-vector-mediated mechanisms. It is first phosphorylated by deoxycytidine kinase, and then further phosphorylated by cellular kinase to its active metabolite—dideoxycytidine 5'-triphosphate. Unlike other nucleoside analogs, zalcitabine is most efficiently triphosphated in resting peripheral blood mononuclear cells. Triphosphated terminating viral DNA elongation. Zalcitabine reduces intracellular deoxycytidine triphosphate levels and binds to some extent to host β and γ DNA polymerases.

---

Therapeutic Use
Zalcitabine, in combination with zidovudine, is used to treat HIV-infected patients with limited prior zidovudine exposure (< 3 months). Zalcitabine can also be used in combination with antiretroviral protease inhibitors to treat HIV infection. /US Product Label Includes/
Zalcitabine can be used as monotherapy for the treatment of patients with advanced HIV infection who cannot tolerate other antiretroviral therapies or whose disease has progressed while receiving other antiretroviral therapies. /US Product Label Contains/

---

Drug Warnings
Peripheral neuropathy occurring during zalcitabine treatment is typically a sensorimotor neuropathy, initially characterized by numbness and burning sensation in the distal extremities. Symptoms of peripheral neuropathy usually appear within the first 7–24 weeks of treatment, manifesting as foot pain and discomfort, followed by burning sensation in the same area several weeks later. Clinically, patients may experience decreased light touch, pinprick, temperature, and vibration sensation in the foot and mid-calf; the deep ankle tendon reflex may be diminished or absent. If the medication is not discontinued upon the onset of these initial symptoms, severe tingling or persistent burning pain may occur, potentially progressing to severe pain requiring opioid analgesia, and this pain may be irreversible. The discomfort may be severe enough to cause gait disturbances. In some patients, peripheral neuropathy may progress to affect both hands, sometimes presenting as a glove-and-stocking distribution. Nerve biopsy and electrophysiological studies may indicate possible axonal degeneration.
Rare reports of lactic acidosis and severe hepatomegaly with steatosis (sometimes fatal) have been reported in patients receiving zalcitabine, but have also been reported in patients treated with other nucleoside reverse transcriptase inhibitors. Most cases are in women; obesity and long-term use of nucleoside antiretroviral drugs may also be risk factors.
Moderate to severe peripheral neuropathy has been reported in 3%–35% of patients receiving standard doses (0.75 mg every 8 hours) of oral zalcitabine (alone or in combination with zidovudine). The incidence of peripheral neuropathy is higher in patients with advanced HIV infection than in those with milder disease.
The duration of clinical benefit from antiretroviral therapy may be limited. If disease progression occurs during zalcitabine treatment, adjustment of the antiretroviral therapy regimen should be considered.
For more complete data on drug warnings for zalcitabine (33 in total), please visit the HSDB records page.

---

Pharmacodynamics
Zarcitabine is a 2'-deoxycytidine analogue whose pharmacological properties are similar to those of other nucleoside reverse transcriptase inhibitors (NRTIs), but structurally different. Zacitabine inhibits the activity of HIV-1 reverse transcriptase (RT) by competing with the natural substrate dGTP and by incorporating it into viral DNA.

---

Zarcitabine (ddC; dideoxycytidine) is a synthetic cytidine nucleoside analogue belonging to the nucleoside reverse transcriptase inhibitor (NRTI) class[1].
Zarcitabine (ddC; dideoxycytidine) was approved by the FDA in 1992 for the treatment of HIV-1 infection in adults, usually in combination with other antiretroviral drugs[1].
The clinical application of zacitabine (ddC; dideoxycytidine) is limited by dose-dependent peripheral neuropathy, but this is reversible upon discontinuation of the drug[1].
Zarcitabine (ddC; dideoxycytidine) exerts its antiviral effect through an intracellular pathway. It is phosphorylated to zarcitabine triphosphate, which acts as a chain terminator in HIV reverse transcription [1]

C9H13N3O3

211.22

211.095

C, 51.18; H, 6.20; N, 19.89; O, 22.72

7481-89-2

24066

Crystals from ethanol and benzene
White to off-white powder

1.6±0.1 g/cm3

415.0±55.0 °C at 760 mmHg

217-218 °C(lit.)

204.8±31.5 °C

0.0±2.2 mmHg at 25°C

1.686

-1.3

2

3

2

15

327

2

O1[C@]([H])(C([H])([H])O[H])C([H])([H])C([H])([H])[C@]1([H])N1C(N=C(C([H])=C1[H])N([H])[H])=O

WREGKURFCTUGRC-POYBYMJQSA-N

InChI=1S/C9H13N3O3/c10-7-3-4-12(9(14)11-7)8-2-1-6(5-13)15-8/h3-4,6,8,13H,1-2,5H2,(H2,10,11,14)/t6-,8+/m0/s1

4-amino-1-((2R,5S)-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrimidin-2(1H)-one

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: ≥ 2.08 mg/mL (9.85 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 20.8 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: ≥ 2.08 mg/mL (9.85 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 20.8 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: ≥ 2.08 mg/mL (9.85 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 20.8 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.)