By influencing TNF-α and IL-6 levels, sinapultide microbubble preparation (2 μg/mL, 5 μg/mL; 24 h) in conjunction with ultrasound (0.5 MHz, 40 s) may significantly aid in the functional recovery of injured AT II cells[2].

Microbubbles (MBs) loaded with sinapultide (0.1 mg; nasal application; collected at 3, 6, 12, and 24 hours after LPS) alleviate lung injury's pulmonary edema and increase lung weight relative to lung diameter in mice with ALI caused by LPS[2].

Absorption, Distribution and Excretion
This product is administered directly to the lungs, and its biophysical effects occur in the terminal airways and on the alveolar surface. Human pharmacokinetic studies have not yet been conducted to describe the absorption, distribution, metabolism, or excretion of this product.

[1]. Braide-Moncoeur O, et al. Peptide-based synthetic pulmonary surfactant for the treatment of respiratory distress disorders. Curr Opin Chem Biol. 2016 Jun;32:22-8.
[2]. Liu D, et al. Sinapultide-Loaded Microbubbles Combined with Ultrasound to Attenuate Lipopolysaccharide-Induced Acute Lung Injury in Mice. Drug Des Devel Ther. 2020 Dec 22;14:5611-5622.

Sinapultide (also known as KL4 peptide) is a synthetic protein used to mimic human pulmonary surfactant protein B. The protein has a molecular weight of 2469.40. Sinapultide is a peptide composed of 21 amino acid residues, consisting of lysine (K) and leucine (L), with the sequence KLLLLKLLLLKLLLLKLLLLK (KL4). This peptide is dispersed in an aqueous phase and mixed with phospholipids DPPC (dispalmitoylphosphatidylcholine), POPG (palmitoyloleoylphosphatidylglycerol), and palmitic acid to form the drug [lucinactant]. This product was initially developed by the Scripps Research Institute and later licensed to Windtree Therapeutics. Windtree Therapeutics planned to conduct a Phase III clinical trial for respiratory distress syndrome (RDS) in 2018. RDS is a leading cause of death and morbidity in premature infants. Surfactant replacement therapy has been widely used for the prevention and treatment of neonatal RDS and has become a standard treatment. First-generation synthetic surfactants, such as Exosurf, did not contain any surfactant proteins. This major drawback was later overcome by animal-derived surfactant products, which contained specific proteins, but in limited quantities and had to be derived from animals. This prompted the development of novel synthetic surfactants, such as lucinactant (Surfaxin), which contains sinapultide. Phase III clinical trials of Surfaxin showed encouraging results, demonstrating efficacy similar to animal-derived surfactants while avoiding the use of animal-derived products. Windtree is currently developing nebulized KL4 surfactant for the treatment of respiratory distress syndrome (RDS) in preterm infants and plans to apply it to multiple indications in neonates, children, and adult intensive care patients in the future.

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Drug Indications
Infant Respiratory Distress Syndrome

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Mechanism of Action
Endogenous lung surfactants reduce the surface tension of the air-liquid interface on the alveolar surface during respiration and stabilize the alveoli under resting transpulmonary pressure, preventing their collapse. Lung surfactant deficiency in preterm infants leads to RDS.
Endogenous lung surfactants reduce the surface tension of the air-liquid interface on the alveolar surface during respiration and stabilize the alveoli under resting transpulmonary pressure, preventing their collapse.
Surfaxin, a drug containing this protein, can compensate for surfactant deficiency and restore the surface activity of infant lungs. To investigate the protective mechanism of sinatropin against respiratory distress syndrome (RDS), we conducted in vitro experiments using human and mouse endothelial cell monolayers and studied the transendothelial migration of polymorphonuclear leukocytes (PMNs) with and without KL(4)-surfactant or lipid controls. Based on morphology, histopathology, white blood cell count, PMN percentage, and protein concentration in bronchoalveolar lavage fluid, the results showed that KL(4)-surfactant can block neutrophil infiltration into the alveoli, thereby preventing lung injury. Furthermore, in vitro experiments also confirmed that KL(4)-surfactant can reduce neutrophil transendothelial migration at the endothelial cell level. In two mouse lung injury models, KL(4)-surfactant reduced the inflammatory response and decreased lung permeability compared to the control group. Evidence suggests that the anti-inflammatory mechanism of KL(4) peptide is achieved by inhibiting the transendothelial migration of polymorphonuclear leukocytes (PMNs).

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Pharmacodynamics
Windtree's KL4 surfactant technology produces a synthetic surfactant with a structure similar to human lung surfactant, containing a proprietary synthetic peptide, KL4 (sinapultide), a 21-amino acid peptide formulated to mimic the basic properties of human lung surfactant protein B (SP-B). SP-B is one of four surfactant proteins essential for normal respiratory function. Windtree has demonstrated in preclinical studies that KL4 surfactant may possess other beneficial properties, including alteration of inflammatory processes, antibacterial properties, and non-immunogenicity.

C126H238N26O22

2467.83

138531-07-4

Sinapultide TFA;2828433-25-4

16132243

White to off-white solid powder

1.1±0.1 g/cm3

2047.1±65.0 °C at 760 mmHg

1191.9±34.3 °C

0.0±0.6 mmHg at 25°C

1.514

14.95

27

28

93

174

4880

21

O=C([C@H](CC(C)C)NC(=O)[C@@H](NC([C@H](CC(C)C)NC(=O)[C@H](CC(C)C)NC([C@@H](NC(=O)[C@@H](NC(=O)[C@@H](N)CCCCN)CC(C)C)CC(C)C)=O)=O)CCCCN)N[C@@H](CC(C)C)C(N[C@H](C(=O)N[C@H](C(=O)N[C@H](C(=O)N[C@H](C(N[C@@H](CC(C)C)C(N[C@@H](CC(C)C)C(N[C@H](C(N[C@@H](CCCCN)C(N[C@@H](CC(C)C)C(=O)N[C@H](C(=O)N[C@@H](CC(C)C)C(N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(=O)O)=O)CC(C)C)=O)=O)CC(C)C)=O)=O)=O)CC(C)C)CCCCN)CC(C)C)CC(C)C)=O

QSIRXSYRKZHJHX-TWXHAJHVSA-N

InChI=1S/C126H238N26O22/c1-69(2)53-90(137-106(153)85(132)43-33-38-48-127)114(161)145-98(61-77(17)18)122(169)149-99(62-78(19)20)118(165)141-91(54-70(3)4)110(157)133-86(44-34-39-49-128)107(154)138-95(58-74(11)12)115(162)146-103(66-82(27)28)123(170)150-100(63-79(21)22)119(166)142-92(55-71(5)6)111(158)134-87(45-35-40-50-129)108(155)139-96(59-75(13)14)116(163)147-104(67-83(29)30)124(171)151-101(64-80(23)24)120(167)143-93(56-72(7)8)112(159)135-88(46-36-41-51-130)109(156)140-97(60-76(15)16)117(164)148-105(68-84(31)32)125(172)152-102(65-81(25)26)121(168)144-94(57-73(9)10)113(160)136-89(126(173)174)47-37-42-52-131/h69-105H,33-68,127-132H2,1-32H3,(H,133,157)(H,134,158)(H,135,159)(H,136,160)(H,137,153)(H,138,154)(H,139,155)(H,140,156)(H,141,165)(H,142,166)(H,143,167)(H,144,168)(H,145,161)(H,146,162)(H,147,163)(H,148,164)(H,149,169)(H,150,170)(H,151,171)(H,152,172)(H,173,174)/t85-,86-,87-,88-,89-,90-,91-,92-,93-,94-,95-,96-,97-,98-,99-,100-,101-,102-,103-,104-,105-/m0/s1

(2S)-6-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-6-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-6-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-6-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2,6-diaminohexanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]hexanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]hexanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]hexanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]hexanoic acid

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)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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