Compstatin TFA is a 13-residue cyclic peptide that is a potent inhibitor of complement system C3 and is species-specific. Compstatin TFA binds to baboon C3 and is resistant to proteolytic cleavage in baboon blood (similar to humans). Compstatin TFA inhibits activation of the primate complement system only. The IC50s of Compstatin TFA for the classical and alternative pathways of complement are 63 μM and 12 μM, respectively.

Physicochemical Properties

Molecular Formula	C68H100F3N23O19S2
Molecular Weight	1664.79
Related CAS #	Compstatin;206645-99-0
Appearance	White to off-white solid powder
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	In vitro, compstatin has a half-life of roughly two hours in human blood[2]. Compstatin creates a hydrophobic cluster in solution by producing a β-turn at residues Gln-5–Gly-8, Ile–1–Val–4, and Thr–13, along with the disulfide bridge Cys-2–Cys12[3].
ln Vivo	When administered as a bolus injection plus infusion, compstatin (21 mg/kg) results in total suppression. Compstatin completely prevents complement activation generated by heparin and prostamine in vivo, however without changing heart rate or pulmonary, central venous, or systemic artery pressures [1]. In baboon plasma, compstatin is stable for more than 24 hours[1]. The group that received Compstatin perfusion had a considerably longer survival rate for pig xenografts than the control group [2].
Animal Protocol	Animal/Disease Models: Juvenile baboons (P. Anubis) weighing 10.5-28.8 kg[1]. Doses: 50, 25 mg/kg 60 min after heparin and 2 min before protamine. Route of Administration: A bolus injection. Experimental Results: Completely inhibited complement activation induced by heparin–protamine complexes.
References	[1]. Inhibition of heparin/protamine complex-induced complement activation by Compstatin in baboons. Clin Immunol. 2000 Sep;96(3):212-21. [2]. Compstatin, a peptide inhibitor of C3, prolongs survival of ex vivo perfused pig xenografts. Xenotransplantation. 1999 Feb;6(1):52-65. [3]. Structure of compstatin in complex with complement component C3c reveals a new mechanism of complement inhibition. J Biol Chem. 2007 Oct 5;282(40):29241-7. [4]. Inhibition of human complement by a C3-binding peptide isolated from a phage-displayed random peptide library. J Immunol. 1996 Jul 15;157(2):884-91.

Solubility Data

Solubility (In Vitro)

DMSO :~100 mg/mL (~60.07 mM) H2O :~50 mg/mL (~30.03 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.75 mg/mL (1.65 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 27.5 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: ≥ 2.75 mg/mL (1.65 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 27.5 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. Solubility in Formulation 3: ≥ 2.75 mg/mL (1.65 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 27.5 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.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	0.6007 mL	3.0034 mL	6.0068 mL
	5 mM	0.1201 mL	0.6007 mL	1.2014 mL
	10 mM	0.0601 mL	0.3003 mL	0.6007 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.