VEGFR1 (IC50 = 10 nM); VEGFR2 (IC50 = 30 nM); VEGFR3 (IC50 = 47 nM); PDGFRβ (IC50 = 84 nM); FGFR1 (IC50 = 140 nM); c-Kit (IC50 = 74 nM); c-Fms (IC50 = 146 nM)

Comparing the tumor burden of the mice treated with 30 mg/kg or 100 mg/kg of Pazopanib to the mice treated with vehicle or 10 mg/kg of Pazopanib, a significant reduction was observed. There is no discernible variation in the mice's body weight within each group despite the well-tolerated Pazopanib treatment.[2]

In 384-well microtiter plates, homogeneous time-resolved fluorescence (HTRF) VEGFR enzyme assays for VEGGR1, VEGFR2, and VEGFR3 are conducted using a purified, baculovirus-expressed glutathione-S-transferase (GST) fusion protein that encodes the catalytic c-terminus of human VEGFR receptor kinases 1, 2, or 3. The reactions commence with the addition of 10 μL of activated VEGFR2 kinase solution [final concentration: 1 nM enzyme in 0.1 M HEPES, pH 7.5, containing 0.1 mg/mL bovine serum albumin (BSA), 300 μM dithiothreitol (DTT)] to 10 μL of substrate solution [final concentration: 360 nM peptide, (biotin-aminohexyl-EEEEYFELVAKKKK-NH2), 75 μM ATP, 10 μM MgCl₂], and 1 μL of titrated Pazopanib in DMSO]. After incubating the plates for 60 minutes at room temperature, 20 μL of 100 mM ethylene diamine tetraacetic acid (EDTA) is added to quench the reaction. Following the quenching process, 20 μL of HTRF reagents (final concentration: 15 nM Streptavidin-linked allophycocyanin, 1 nM antiphosphotyrosine antibody labeled in 0.1 mg/mL BSA, 0.1 M HEPES, pH 7.5) are added, and the plates are then incubated for a minimum of 10 minutes. With a 50 μs time delay, the fluorescence at 665 nM is measured using a Wallac Victor plate reader.

Using commercially available kits, the 5-bromo-2-deoxyuridine (BrdU) incorporation method is used to measure the impact of Pazopanib on cell proliferation. In 96-well plates coated with type 1 collagen, HUVEC are seeded in a medium containing 5% fetal bovine serum (FBS) and incubated for an entire night at 37°C with 5% CO₂. After the medium is removed from the cells, each well is filled with different concentrations of Pazopanib in serum-free medium. Either VEGF (10 ng/mL) or bFGF (0.3 ng/mL) is added to the wells after 30 minutes. After an extra 72 hours of incubation, cells receive an addition of BrdU (10 μM) for the final 18 to 24 hours of incubation. ELISA is used to measure the amount of BrdU incorporated into cells at the end of incubation. A curve that fits the data is given by the formula y=V_max(1−(x/(K+x))), where K is the IC50.

Mice: In 8–12 week old nude mice, tumors are started by injecting tumor cell suspension. After tumors grow to a volume of 100–200 mm³, mice are randomly assigned to eight-groups. Pazopanib is given at 10, 30, or 100 mg/kg once or twice a day. When the study is over, the animals are put to death by breathing in CO₂. Tumor volume (mm³) = (length×width²)/2 is the equation used to measure tumor volume twice a week using calipers. % inhibition=1−(average growth of the drug-treated population/average growth of the vehicle-treated control population) is a common way to report results.
Rats: Brown man from Norway Prior to any experimental procedure, 200–250 g pigmented rats, or BN rats, are acclimatized for at least two days. An intraperitoneal injection of 30 mg/mL streptozotocin solution in 10 mM citrate buffer (pH 4.5) is given (60 mg/kg body weight) to induce diabetes after an overnight fasting period of 12–16 hours. The animals are fed a regular diet after receiving a streptozotocin injection for 3–4 hours, and a blood sample (5–10 μL) is drawn via a tail vein 24 hours later. A glucose monitor is used to measure the blood glucose levels in the animals. Animals classified as diabetics have blood glucose levels higher than 250 mg/dL. Three groupings of animals are created. Group 1: Healthy (n = 12), Group 2: Diabetic (n = 12), and Group 3: Diabetic+Treatment (n = 12). Upon induction of diabetes, treatment is initiated promptly. On day 31, 16–17 hours after the last dose on day 30, animals in all groups are sacrificed. Both eyes are dosed twice daily for 30 days with 0.5% w/v Pazopanib suspension (10 μL volume in each eye).

Absorption, Distribution and Excretion
Absorption of pazopanib in cancer patients is slow and incomplete. In patients with solid tumour, over a dose range of 50-2000 mg, absorption is nonlinear. Significant accumulation of pazopanib can also be observed in patients receiving 800 mg once daily for 22 days. Crushing tablets may increase exposure (increase in Cmax and AUC, while Tmax decreases by 2 hours). Bioavailability, oral tablet 800 mg, cancer patient = 21%; Bioavailability may be low due to incomplete absorption from the gastrointestinal tract. The major circulating component of the drug in the systemic is pazopanib, and not its metabolites. Mean maximum plasma concentration= 58.1 µg/mL; Mean AUC= 1037 µg · h/mL;
Primarily excreted via feces (82.2%) and to a negligible extent via urine (<4%) in cancer patients. Most of the administered dose is excreted unchanged. Approximately 10% of dose are oxidative metabolites and are mostly eliminated via the feces.
Vd steady state, IV administration 5 mg, cancer patient = 11.1 L (range of 9.15 - 13.4)
CL, cancer patient, IV administration 5 mg = 4mL/min Half of the absorbed dose is cleared via oxidative metabolism.
Systemic exposure to pazopanib is increased when administered with food. Administration of pazopanib with a high-fat or low-fat meal results in an approximately 2 fold increase in AUC and Cmax. Therefore, pazopanib should be administered at least 1 hour before or 2 hours after a meal.
Pazopanib is absorbed orally with median time to achieve peak concentrations of 2 to 4 hours after the dose. Daily dosing at 800 mg results in geometric mean AUC and Cmax of 1,037 ug hr/mL and 58.1 ug/mL (equivalent to 132 uM), respectively. There was no consistent increase in AUC or Cmax at pazopanib doses above 800 mg.
Elimination is primarily via feces with renal elimination accounting for <4% of the administered dose.
Binding of pazopanib to human plasma protein in vivo was greater than 99% with no concentration dependence over the range of 10 to 100 ug/mL.
For more Absorption, Distribution and Excretion (Complete) data for Pazopanib (8 total), please visit the HSDB record page.

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Metabolism / Metabolites
Metabolized by CYP3A4 and to a lesser extent by CYP1A2 and CYP2C8. Metabolites are less active than pazopanib (10 to 20-fold less active). Three of its metabolites can be observed in the systemic and account for <10% of plasma radioactivity.
In vitro studies demonstrated that pazopanib is metabolized by CYP3A4 with a minor contribution from CYP1A2 and CYP2C8.
Pazopanib (Votrient) is an oral tyrosine kinase inhibitor that was recently approved for the treatment of renal cell carcinoma and soft tissue sarcoma. In this two-part study, ... the metabolism, disposition of (14)C-pazopanib, and the oral bioavailability of pazopanib tablets in patients with advanced cancer /was investigated. In part A, three men each received a single oral dose of (14)C-pazopanib in suspension (400 mg, 70 uCi). Two metabolites derived from hydroxylation and one from N-demethylation were ,,, circulating, but were minor, each accounting for <5% of plasma radioactivity. ...
The routes of metabolism observed in human liver microsomes and hepatocytes were monooxygenation, di-oxygenation, and possibly oxidation to a carboxylic acid. Glucuronidation of a monooxygenated metabolite was also detected in human hepatocytes. There were no unique human phase I metabolites observed in either liver microsomal or hepatocyte incubations. However, a phase II metabolite, i.e., a glucuronide potentially derived from a carboxylic acid metabolite, was observed only in human hepatocytes. Its presumed precursor was identified in vivo as a significant component (<19%) in bile from bile duct cannulated monkeys. In conclusion, the combined in vitro and in vivo metabolic data indicated no major species differences in metabolism.
The extent of metabolism of pazopanib was low in human liver microsomal and hepatocyte incubations as well as in most of the preclinical species. Pazopanib was more extensively metabolized by rabbit and dog hepatocytes than by those from the other species studied. Following PO administration, unchanged pazopanib was the predominant component in feces from all species including humans.
Pazopanib (Votrient) is an oral tyrosine kinase inhibitor that was recently approved for the treatment of renal cell carcinoma and soft tissue sarcoma. In this two-part study, ... the metabolism, disposition of (14)C-pazopanib, and the oral bioavailability of pazopanib tablets in patients with advanced cancer /was investigated. In part A, three men each received a single oral dose of (14)C-pazopanib in suspension (400 mg, 70 uCi). Pazopanib was the predominant drug-related component in circulation. Two metabolites derived from hydroxylation and one from N-demethylation were also circulating, but were minor, each accounting for <5% of plasma radioactivity. ...

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Biological Half-Life
35 hours. Oral absorption is not the rate limiting step of elimination from the plasma.
The pharmacokinetics of pazopanib and/or its dihydrochloride salt has been studied in several animal species. The terminal elimination half-life was comparable among the animal species (half life = 2-6 hr) but significantly lower than observed in humans (half life = 21-51 hr).
Pazopanib has a mean half-life of 30.9 hours after administration of the recommended dose of 800 mg.

Toxicity Summary
IDENTIFICATION AND USE: Pazopanib is a white to slightly yellow solid formulated into film-coated tablets. Pazopanib, an inhibitor of multiple receptor tyrosine kinases, is an antineoplastic agent. It is used for the treatment of advanced renal cell carcinoma and for patients with advanced soft tissue sarcoma who have received prior chemotherapy. HUMAN EXPOSURE AND TOXICITY: Severe or fatal hepatotoxicity, manifested as increases in serum concentrations of aminotransferases and bilirubin, has been reported in patients receiving pazopanib. If hepatotoxicity occurs, pazopanib dosage should be reduced, or therapy should be interrupted or permanently discontinued. Woman should avoid the use of pazopanib during pregnancy. While there are no adequate and well-controlled studies in pregnant women, pazopanib has been shown to be teratogenic, embryotoxic, fetotoxic, and abortifacient in animal studies. If used during pregnancy or if the patient becomes pregnant while receiving pazopanib, the patient should be apprised of the potential fetal hazard. Prolongation of the QT interval and torsades de pointes and severe and sometimes fatal hemorrhage events have been reported in patients receiving pazopanib. Finally, GI perforation or fistula which can be fatal has also been associated with the use of pazopanib. ANIMAL STUDIES: While carcinogenicity studies with pazopanib have not been conducted, in a 13-week study in mice, proliferative lesions in the liver including eosinophilic foci occurred in 2 females and a single case of adenoma in another female was observed at a dose of 1000 mg/kg/day. Pazopanib produced fetal teratogenic effects (including cardiovascular malformations and delayed ossification), reduced fetal body weight, and embryo lethality in rats at a dose level as low as 3 mg/kg/day. In rabbits, maternal toxicity (body weight loss, reduced food consumption, and abortion) was observed at doses as low as 30 mg/kg/day, while fetal weight was reduced at doses as low as 3 mg/kg/day. Pazopanib also reduced fertility in female rats at a dose of 300 mg/kg. Increased pre- and post-implantation loss and early resorptions were noted at doses as low as 10 mg/kg/day. Decreased corpora lutea were observed in monkeys and mice and ovarian atrophy was noted in rats. While pazopanib did not affect mating or fertility in male rats, reductions in sperm production rates, sperm motility, and epididymal and testicular sperm concentration was observed at doses as low as 100 mg/kg/day for 15 weeks. Following 26 weeks of dosing, male rats given doses of 30 mg/kg/day or greater exhibited decreased testicular and epididymal weights, atrophy and degeneration of the testes with aspermia, hypospermia and cribriform change in the epididymis. In toxicology studies in rats, there were effects in a variety of tissues (bone, teeth, bone marrow, nail beds, reproductive organs, hematological tissues, kidney, adrenal glands, lymph node, pituitary, and pancreas) consistent with vascular endothelial growth factor receptor (VEGFR) inhibition and/or disruption of VEGF signaling pathways with some effects occurring at doses of 3 mg/kg/day. Pazopanib was tested in a standard battery of genotoxicity studies. Pazopanib was found to be nonmutagenic and non-clastogenic when tested in a bacterial cell (Ames) assay, human peripheral lymphocyte chromosome aberration assay and rat micronucleus assay.

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Hepatotoxicity
In large clinical trials, abnormalities in routine liver tests were common in patients treated with pazopanib, with serum aminotransferase elevations occurring in up to half of patients and total serum bilirubin in approximately one-third. ALT and AST values greater than 5 times the upper limit of normal (ULN) occurred in 8% of patients and combinations of ALT and bilirubin elevations in 1% to 2%. In preliminary trials of pazopanib in various solid tumors, there were rare reports of hepatitis with jaundice in
Likelihood score: C (probable cause of clinically apparent liver injury).

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
No information is available on the clinical use of pazopanib during breastfeeding. Because pazopanib is more than 99% bound to plasma proteins, the amount in milk is likely to be low. However, its half-life is about 31 hours and it might accumulate in the infant. The manufacturer recommends that breastfeeding be discontinued during pazopanib therapy and for 2 weeks after the final dose.
◉ 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
>99% protein bound, independent of concentrations over a range of 10-100 μg/mL.

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Interactions
Votrient is not indicated for use in combination with other /cancer therapy/ agents. Clinical trials of Votrient in combination with pemetrexed and lapatinib were terminated early due to concerns over increased toxicity and mortality. The fatal toxicities observed included pulmonary hemorrhage, gastrointestinal hemorrhage, and sudden death. A safe and effective combination dose has not been established with these regimens.
In vitro studies suggested that pazopanib is a substrate of P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP). Therefore, absorption and subsequent elimination of pazopanib may be influenced by products that affect Pgp and BCRP. Concomitant treatment with strong inhibitors of Pgp or breast cancer resistance protein (BCRP) should be avoided due to risk of increased exposure to pazopanib. Selection of alternative concomitant medicinal products with no or minimal potential to inhibit Pgp or BCRP should be considered.
Inhibitors of CYP3A4: Pharmacokinetic interaction (increased peak plasma concentrations and area under the plasma concentration-time curve (AUC) of pazopanib) observed during concomitant use of pazopanib ophthalmic solution with ketoconazole (a potent inhibitor of CYP3A4 and an inhibitor of Pgp) or during concomitant use of pazopanib oral tablets with lapatinib (a substrate and weak inhibitor of CYP3A4, Pgp, and BCRP). Concomitant use of pazopanib with a potent CYP3A4 inhibitor (e.g., clarithromycin, ketoconazole, ritonavir) should be avoided; if concomitant use cannot be avoided, pazopanib dosage should be reduced. The manufacturer states that concomitant use with grapefruit or grapefruit juice also should be avoided.
Concomitant use of Votrient and simvastatin increases the incidence of ALT elevations. Across monotherapy studies with Votrient, ALT >3 X ULN was reported in 126/895 (14%) of patients who did not use statins, compared with 11/41 (27%) of patients who had concomitant use of simvastatin. If a patient receiving concomitant simvastatin develops ALT elevations, follow dosing guidelines for Votrient or consider alternatives to Votrient. Alternatively, consider discontinuing simvastatin. Insufficient data are available to assess the risk of concomitant administration of alternative statins and Votrient.
For more Interactions (Complete) data for Pazopanib (13 total), please visit the HSDB record page.

[1]. J Med Chem . 2008 Aug 14;51(15):4632-40.

[2]. J Orthop Res . 2012 Sep;30(9):1493-8.

[3]. Retina . 2012 Sep;32(8):1652-63.

Therapeutic Uses
Votrient is indicated for the treatment of patients with advanced renal cell carcinoma (RCC). /Included in US product label/
Votrient is indicated for the treatment of patients with advanced soft tissue sarcoma (STS) who have received prior chemotherapy. /Included in US product label/
Limitation of Use: The efficacy of Votrient for the treatment of patients with adipocytic soft tissue sarcoma (STS) or gastrointestinal stromal tumors has not been demonstrated.
EXPL THER Pazopanib was evaluated for its ability to inhibit the growth of a variety of human tumor cell lines, HT-29 (colon), MDA-MB-468 (breast), PC3 (prostate), and A375P (melanoma) and normal human fibroblasts (HFF) growing in serum containing media. Pazopanib inhibited proliferation of HFF with an IC50 of 1.01 uM and had no effect on the proliferation of the 4 tumor cell lines at the highest concentration tested (30 uM). To further investigate whether pazopanib can directly modulate the proliferation of tumour cells, the compound was tested in a cell proliferation assay in a panel of 282 human cell lines. Of these, 281 were tumor cell lines derived from various tissue types, and 1 was a non-transformed breast cell line. IC50 values across the cell panel ranged from 0.01 to >10 uM. Only 7 cell lines showed an IC50 <1 uM: GDM1 (AML); ARH-77 (myeloma); NCI-H716 (colon carcinoma); G402 (kidney leiomyoblastoma); CGTH-W-1 (thyroid carcinoma); A204 (rhabdomyosarcoma) and CML-T1 (CML). Hence, pazopanib is a weak or inactive inhibitor of proliferation in the majority of human cell lines tested in vitro. The antitumor activity of pazopanib is, therefore, most likely derived from its anti-proliferative effect on endothelial cells.

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Drug Warnings
/BOXED WARNING/ WARNING: HEPATOTOXICITY. Severe and fatal hepatotoxicity has been observed in clinical trials. Monitor hepatic function and interrupt, reduce, or discontinue dosing as recommended.
Severe or fatal hepatotoxicity, manifested as increases in serum concentrations of aminotransferases (ALT (SGPT), AST (SGOT)) and bilirubin, has been reported in patients receiving pazopanib. Most (92.5%) cases of aminotransferase elevations (of any grade) occurred during the first 18 weeks of therapy. In the randomized, placebo-controlled study (VEG105192) in patients with renal cell carcinoma, increases in ALT concentrations exceeding 3 or 10 times the upper limit of normal (ULN) were reported in approximately 18 or 4%, respectively, of patients receiving pazopanib. Concurrent increases in concentrations of ALT (exceeding 3 times the ULN) and bilirubin (exceeding twice the ULN) in the absence of substantial (exceeding 3 times the ULN) increases in alkaline phosphatase concentrations were reported in approximately 2% of patients receiving pazopanib. In an analysis of data from 11 studies involving 977 patients who received pazopanib as a single agent for a variety of tumor types (including 586 patients with renal cell carcinoma), death (resulting from disease progression and hepatic failure) occurred in approximately 0.2% of patients receiving pazopanib. Because pazopanib inhibits uridine diphosphate-glucuronosyltransferase (UGT) 1A1 (an enzyme that catalyzes the glucuronidation of bilirubin for elimination), mild elevations in indirect (unconjugated) bilirubin may occur in patients with deficient glucuronidation of bilirubin (i.e., Gilbert's syndrome). Liver function tests should be performed prior to initiation of pazopanib, at least once every 4 weeks for at least the first 4 months of therapy or as clinically indicated, and periodically thereafter. If hepatotoxicity occurs, pazopanib dosage should be reduced, or therapy should be interrupted or permanently discontinued.
FDA Pregnancy Risk Category: D /POSITIVE EVIDENCE OF RISK. Studies in humans, or investigational or post-marketing data, have demonstrated fetal risk. Nevertheless, potential benefits from the use of the drug may outweigh the potential risk. For example, the drug may be acceptable if needed in a life-threatening situation or serious disease for which safer drugs cannot be used or are ineffective./
Prolongation of the QT interval and torsades de pointes have been reported in patients receiving pazopanib. In the VEG105192 study, prolongation of the QT interval (500-549 msec) was reported in approximately 1 or 0% of patients receiving pazopanib or placebo, respectively. In an analysis of pooled data from 3 studies involving 55815 patients with renal cell carcinoma, prolongation of the QT interval (500 msec or greater) or torsades de pointes was reported in approximately 2% or less than 1%, respectively, of patients receiving pazopanib. Pazopanib should be used with caution in patients with a history of prolongation of the QT interval, in patients receiving antiarrhythmic agents or other drugs that cause prolongation of the QT interval, and in patients with relevant preexisting cardiac disease. ECG should be monitored prior to initiation of pazopanib and periodically during treatment; serum electrolytes (e.g., calcium, magnesium, potassium) should be maintained within the normal range.
For more Drug Warnings (Complete) data for Pazopanib (23 total), please visit the HSDB record page.

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Pharmacodynamics
Pazopanib is a synthetic indazolylpyrimidine and reaches steady state concentrations of >15 μg/ml. This concentration is high enough to observe maximal inhibition of VEGFR2 phosphorylation and some anti-tumour activity (concentration required to inhibit receptors is 0.01 - 0.084 μmol/L). A reduction in tumour blood flow, increased tumour apoptosis, inhibition of tumour growth, reduction in tumour interstitial fluid pressure, and hypoxia in cancer cells can be observed in patients receiving treatment.

C21H23N7O2S

437.52

437.163

C, 57.65; H, 5.30; N, 22.41; O, 7.31; S, 7.33

444731-52-6

Pazopanib Hydrochloride;635702-64-6;Pazopanib-d6;1219592-01-4;Pazopanib-13C,d3;1261734-88-6

10113978

white solid powder

1.4±0.1 g/cm3

728.8±70.0 °C at 760 mmHg

285-289°C (dec.)

394.6±35.7 °C

0.0±2.4 mmHg at 25°C

1.702

1.98

2

8

5

31

717

0

S(C1C([H])=C(C([H])=C([H])C=1C([H])([H])[H])N([H])C1=NC([H])=C([H])C(=N1)N(C([H])([H])[H])C1C([H])=C([H])C2=C(C([H])([H])[H])N(C([H])([H])[H])N=C2C=1[H])(N([H])[H])(=O)=O

CUIHSIWYWATEQL-UHFFFAOYSA-N

InChI=1S/C21H23N7O2S/c1-13-5-6-15(11-19(13)31(22,29)30)24-21-23-10-9-20(25-21)27(3)16-7-8-17-14(2)28(4)26-18(17)12-16/h5-12H,1-4H3,(H2,22,29,30)(H,23,24,25)

5-[[4-[(2,3-dimethylindazol-6-yl)-methylamino]pyrimidin-2-yl]amino]-2-methylbenzenesulfonamide

GW-78603; GW78603; GW 78603; GW-786034; GW786034; GW 786034; Pazopanib; trade name: Votrient

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 (5.71 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 2: ≥ 2.5 mg/mL (5.71 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 3: ≥ 0.43 mg/mL (0.98 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 4: ≥ 0.43 mg/mL (0.98 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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 (Please use freshly prepared in vivo formulations for optimal results.)