Prostaglandin E1

Outline

Prostaglandin E1 (Prostaglandin E1), also known as alprostadil. Prostaglandin E1 is widely present in the body of biologically active substances, as one of the prostaglandin family, it is a recognized endogenous physiologically active substances. Prostaglandin E1 acts directly on vascular smooth muscle, dilates blood vessels, increases blood flow, improves microcirculation perfusion; and inhibits platelet aggregation and thromboxane A2 production, inhibits atherosclerosis, lipid plaque and immune complex formation; it also owns following effects: the expansion of the periphery small blood vessels and coronary arteries, reduction of peripheral vascular resistance and blood pressure, protection platelet membrane against thrombosis; protection the ischemic myocardium, reducing myocardial infarct size; anti-heart failure; renal vascular dilation, increased renal blood flow, removal of non-protein nitrogen, regulating sodium and water balance, with a diuretic and renal-protecting function. t1/2 is 5~10min. 68% is excreted by renal after hepatic metabolism . Clinical usage includes angina pectoris, myocardial infarction, pulmonary hypertension, chronic arterial occlusion.
The above information is edited by the chemicalbook of Tian Ye.

Pharmacological effects

1. It dilates blood vessels, inhibits platelet aggregation.
2. It improves liver circulation, increases the oxygen supply, promotes liver metabolism and detoxification.
3. It stabilizes liver cell membrane, inhibits of inflammatory cytokines and promotes regeneration.

Preparation Process

Sheep seminal vesicles → (KCl, EDTA-Na2, pH8) → Enzyme suspensions →incubated (hydroquinone, glutathione, two high-γ-linolenic acid) → the reaction liquid →extraction (acetone, diethyl ether, methylene chloride )→ prostaglandin crude → prostaglandin E1 crude (separation, silica gel).

Content determination

1. Chromatographic conditions
Detection wavelength: 214nm; flow rate: 1.0mL/min; mobile phase: acetonitrile: 0.02 mol/L potassium dihydrogen phosphate (pH = 4.9 ± 0.5) = 30:70; Column: Dumas C18 (200mm × 4.6mm, 5μm); injection volume: 10μL; the number of theoretical plates: prostaglandin E1 peak should not be less than 2000.
2. Preparation of the reference solution
Exactly weighing reference substance PGE1 0.5mg, exactly adding 25% ethanol solution 5mL, 0.1mg/mLPGE1 solution was made. Exactly drawing 0.5mL to 5mL volumetric flask, add 25% ethanol solution to the given mark, thought 0.22μm microporous membrane.
3. Preparation of the test solution
Exactly weighing homemade PGE crude 0.1mg, exactly adding ethanol solution 1mL, through 0.22μm microporous membrane.
4. The method for the content determination
Exactly amounting the test solution 10μL, into the liquid chromatograph, pressing "1" under the conditions of operation, the peak area values of prostaglandin E1 absorption peak is measured, calculate the content of prostaglandin E1.

Structure and Pharmacokinetics

The basic structure of PGE1 is a fatty acid with twenty unsaturated carbon hydrocarbon, a five-carbon ring and the two hydrocarbon chains, there is a double bond in the side chain.
The precursor of the body's synthesis of prostaglandins is arachidonic acid, which produces prostaglandins (such as PGD2, PGE1, PEG2, PGF2α, PGI2) and thromboxane synthase via epoxidation and lipid oxidation enzyme catalysis. PGE1 is biological instability in vivo, lung is the main place of synthesis and metabolism. When PGE1 passes through the pulmonary circulation for the first time , about 60%-90% is metabolized, its biotransformation products have almost no biological activity. PGE1 enters artery within 5min, it gets to the maximum and steady-state plasma concentrations in venous blood, the base plasma concentrations is restored after stopping input for 5minis . After β-oxidation and ω-oxidation, 88% of PGE1 metabolite excreted by urine within 72h, the remaining 12% in the faeces. Since PGE1 metabolism is quick, usually long time continuous infusion or a liposome preparation is prepared tomaintain efficacy .

Side effects

Adverse reactions of PGE1 may involve multiple body systems and organs, but the most common adverse reactions are at the injection site, mainly redness, itching, and vascular pain, vasculitis at the injection site, some patients skin can be a "red line" along the vein.
Adverse reactions for digestive system ,include nausea, vomiting, diarrhea, which may be related to PGE1 gastrointestinal smooth muscle contraction effects. Cardiovascular adverse reactions and nervous system adverse reactions are more common. In addition, erythema, pruritus, rash, and anaphylaxis, which may be caused by PGE1 binding directly with mast cell surface glycoprotein to be sensitized , and then to produce a variety of immediate hypersensitivity antigen binding and biological activity release, particularly histamine and other substances causing allergic reactions. In addition, PGE1 can cause dry eyes, blurred vision, dry mouth, low back pain, and reduce the total number of white blood cells and other rare adverse reactions, it should also lead to enough clinical attention. During the treatment, it should pay attention to check body temperature, blood pressure and white blood cells.

Medication precautions

Cautions should be paid to heart failure, glaucoma, peptic ulcers, interstitial pneumonia . Having a stimulating effect on the vein, there may be redness, swelling, heat, pain and other symptoms of inflammation, it can cause phlebitis. You should adjust the drip rate or stop drip for observation. Provisional equipped with, you can not use frozen drugs.

Contraindications

1. severe cardiac dysfunctions. 2. pregnant women. 3. Allergy

Clinical application

Used for clinical complications of diabetes, coronary heart disease, intractable heart failure, congenital heart disease with pulmonary hypertension, hypertension, cerebral infarction, chronic arterial occlusive disease, sudden deafness, retinal vein occlusion, viral hepatitis, chronic gastritis, duodenal ulcer, chronic renal insufficiency, pancreatitis, organ transplantation, erectile dysfunction, induction of labor and postpartum hemorrhage, necrosis of the femoral head, lumbar disc herniation, postherpetic neuralgia, bronchial asthma.

Dosage

Intravenous infusion: Usually a dose of 0.05~0.5μg/(kg · min), first dissolved in 2ml saline, angina 100μg/d in 5% glucose solution 250ml instillation; myocardial infarction 100~200μg/d added 250ml of 5% glucose solution infusion, severe available to 400μg/d. A course of treatment is 7~10d.

Chemical Properties

PG is a group of twenty-carbon straight-chain unsaturated fatty acid, arachidonic acid is usually the biosynthetic precursor, for prostate acid (prostanoic acid) is generated by enzymatic and non-enzymatic conversion , with an endogenous physiological skeleton active substance. In 1958 for the first time people obtained two pure PG crystallines from sheep seminal separation: PGE1 and PGF1α. Natural PG is classicified into three communities by structures (PG1, PG2, PG3), ten types (PGA, PGB, PGC, PGD, PGE, PGF, PGG, PGH, PGI, PGJ). E, F types in six natural PG, ie, PGE1, PGE2, PGE3 and PGF1α + PGF2α + PGF3α were earliest studied , the primary PG; A, B, C, D, G, H, I, J and other natural PG are called secondary PG. Various PG code names (such as E, F, etc.) are based on observations from the study during the early years. PG soluble in ether (ethyl) is represented by E, that is PGE, PG soluble in phosphate solution is represented by F (Swedish fosfate), namely PGF. PGA, PGB respectively are represented by PGE acid (acid) or base (base) processed end products.
It is white or pale yellow needle-like crystal. Mp115-116 ℃, specific rotation-61.6 ° (c = 0.56, THF). Prostaglandin E1 is a physiologically active substance with the expansion of blood vessels and inhibit platelet aggregation, and can inhibit vascular smooth muscle cells free Ca2 +, inhibite vascular sympathetic nerve endings, release norepinephrine for vascular smooth muscle relaxation, to decrease peripheral resistance , lower blood pressure, increase coronary blood flow, reduce myocardial oxygen consumption, thereby to relieve angina and reduce the incidence of myocardial infarction and reduced infarct size. It can improve heart failure, myocardial contractility, increased cardiovascular output, improve the coronary circulation, protect the ischemic myocardium. It can effectively inhibit cholesterol formation of additional immune damage caused by atherosclerosis. It can inhibit smooth muscle cell growth and reduce plaque. Expansion of renal vessels and increase renal blood flow, regulate sodium and water balance, resulting in diuresis.

Uses

Used for diabetic neuropathy, myocardial infarction, thrombotic vasculitis, arteriosclerosis obliterans, central retinal vein thrombosis.
It is used in the treatment of hepatitis cirrhosis, cerebral infarction, diabetes, impotence, respiratory diseases. Liver damage is not serious childA, class B patients, especially patients with antithrombin level childA China effect. For induction of labor, oxytocin, renal insufficiency, treatment mumps, pancreatitis. Injection of prostaglandin E1 is mainly applied to myocardial infarction, heart failure, thrombotic vasculitis, chronic arterial occlusive disease, central retinal vein thrombosis, platelet protection for extracorporeal circulation, arteriography, revascularization surgery.

Production method

Sheep seminal vesicles were uesd as raw material for the preparation of PGE crude , with enzyme preparation, incubation, organic solvent extraction, silica gel column separation.
The preparation of PGE crude: sheep seminal vesicles [KCl, EDTANa2, PH8] → enzyme suspension [hydroquinone, glutathione] → [arachidonic acid, O2] reaction solution [acetone, ether, methylene chloride] → PGS crude [Separation] → [silica gel] PGE crude Preparation PGE1 finished product: per 1g PGE crude product used 20g silica gel, 10 times the mass of PGE activated silver nitrate silica gel from 200-250 mesh was suspended in expansion agents including: V ethyl acetate : V acetic acid: V petroleum ether: V water = 220: 22.5: 125 : 5 (bp of petroleum ether is 90-120 ℃) , with wet packed column. A small amount of the crude product was dissolved in the same expansion agents, put in the column , eluted. PGE1 and PGE2 were collected . The PGE1 part was put below 35 ℃ to nitrogen concentrating until acetic acid odor was removed, ethyl acetate was added to dissolve, added acid to wash, pH4-5, saline was added to remove silver. The ethyl acetate solution was set in the refrigerator overnight to get finished PGE1 .

Description

Prostaglandin E1 is an endogenous prostaglandin with vasodilatory, anti-platelet, and anti-hypertensive activities. It is in clinical use for the treatment of erectile dysfunction and the emergency management of infants with patent ductus arteriosus. It has also been used in the treatment of peripheral arterial occlusive disease (PAD).

Chemical Properties

Crystalline Solid

Originator

Alprostadil,Schwarz Pharmacia

Uses

For use in cell culture applications for the study of prostaglandin regulated cell signaling and gene regulation.

Uses

Vasodilator;Prostaglandin receptor agonist

Uses

A primary Prostaglandin; easily crystallized from purified biological extracts. Vasodilator (peripheral)

Definition

ChEBI: Prostaglandin E1 is a prostaglandins E. It has a role as a platelet aggregation inhibitor, a vasodilator agent, an anticoagulant and a human metabolite. It is a conjugate acid of a prostaglandin E1(1-).

Indications

Alprostadil (prostaglandin E₁ [PGE₁]; Edex, Topiglan) exerts a number of effects, including systemic vasodilation, inhibition of platelet aggregation, and stimulation of intestinal motility. PGE₁ relaxes isolated smooth muscle cells contracted by norepinephrine. It has become widely used in the treatment of ED. Alprostadil binds with PGE receptors and results in a cyclic adenosine monophosphate (cAMP) mediated smooth muscle relaxation. Little is known about the pharmacokinetics of PGE₁, but it is believed that as much as 80% is metabolized in one pass through the lungs. Such rapid degradation probably accounts for its lack of significant cardiovascular side effects when administered intracavernosally. PGE₁ can also be metabolized in the penis.

brand name

Caverject (Pfizer); Caverject (Pharmacia & Upjohn); Edex (Schwarz Pharma); Muse (Vivus); Prostin (Pharmacia & Upjohn);Coverject;Minprog pad;Postivas;Prostadin;Prostalgin;Prostandin;Prostavasin;Prostin vr pediatric;Prostin-vr;Prostivas.

Therapeutic Function

Vasodilator, Abortifacient, Antihypertensive, Bronchodilator

World Health Organization (WHO)

Alprostadil, a prostaglandin with vasodilating and platelet antiaggregatory activity, was introduced in 1984 for the treatment of chronic arterial obstruction. Intravenous administration of the drug has been associated with adverse effects that have sometimes been severe. These include allergic reactions, pulmonary oedema and cardiac insufficiency. Interactions with antihypertensive agents, vasodilators, anticoagulants and inhibitors of platelet aggregation have also occurred. This has led the German agency to modify the approved product information of alprostadil preparations to warn against these adverse effects.

Biological Functions

Prostaglandin E1 is produced endogenously to relax vascular smooth muscle and cause vasodilation by activating the adenylate cyclase/cAMP pathway. Recent studies show that the cAMP is important in the PGE1 relaxation of penile erectile tissue and vasodilation of penile resistance arteries. Moreover, agents that stimulate the release of cAMP also crossactivate the NO/cGMP cascade.

General Description

PGE1, Alprostadil (Prostin VR Pediatric), is a naturally occurring prostaglandin that has found particular use in maintaining a patent (opened) ductus arteriosus in infants with congenital defects that restrict pulmonary or systemic blood flow.
Alprostadil must be administered intravenously continually at a rate of approximately 0.1 μg/kg/min to maintain the patency of the ductus arteriosus until corrective surgery can be performed. Up to 80% of circulating alprostadil may be metabolized in a single pass through the lungs. Because apnea has been observed in 10% to 12% of neonates with congenital heart defects, this product should be administered only when ventilatory assistance is immediately available. Other commonly observed side effects include decreased arterial blood pressure, which should be monitored during infusion; inhibited platelet aggregation, which might aggravate bleeding tendencies; and diarrhea.

Biological Activity

Prostaglandin with some selectivity for EP 3 and EP 4 receptors (K i values are 1.1, 2.1, 36, 10? and 33 nM for mouse EP 3 , EP 4 , EP 1 , EP 2 and IP receptors respectively). Inhibits platelet aggregation and is a vasodilator in vivo .

Biochem/physiol Actions

Prostaglandin E1?(PGE1) aids in the relaxation of corporal cavernosal tissue. It helps to preserve the patency of the ductus arteriosus. It is used to treat erectile dysfunction (ED).

Mechanism of action

PGE₁ is not orally effective. Its therapeutic success depends on its being injected intracavernosally or administered transurethrally or intraurethrally. PGE₁ has also been used in combination with other agents, such as papaverine. The injection does not appear to produce any long-term side effects on penile smooth muscle. Transurethral therapy with alprostadil, such as MUSE (alprostadil urethral suppository or medicated urethral system for erection) is also an effective therapeutic technique, and there may be a role for this form of administration in selected patients with ED.The intracavernosal injection of alprostadil (e.g., alprostadil alfadex; Edex, Viridal) is safe and effective in patients with ED when sildenafil is ineffective. Both of these delivery systems have been used in the treatment of ED. MUSE can also be used in conjunction with a penile constrictor device (e.g., ACTIS).

Clinical Use

Prostaglandin E1 (PGE1; Alprostadil) is approved for the intracavernosal (Caverject, Edex)or intraurethral suppository (Muse) treatment of ED. A three-drug combination of PGE1, papaverine, and phentolamine sometimes is used as an intracavernosal injection to achieve a synergistic action. Erectile dysfunction that is medication-induced or caused by endocrine problems, such as hypogonadism or hyper- or hypothyroidism, should be evaluated and appropriately treated before PGE1 treatment is considered.

Metabolism

The major route of excretion of PGE1 metabolites is via the kidney. Its elimination half-life is 5 to 10 minutes. If any alprostadil is systemically absorbed, it is metabolized by a single pass through the lungs. The onset of action is within 10 minutes, and the time to peak effect is less than 20 minutes. The duration of action is 1 to 3 hours for the intracavernosal injection and 30 to 60 minutes for the intraurethral suppository.

storage

Store at -20°C

References

1) Kirtland (1988) Prostaglandin E1: 1 review; Prostaglandins Leukot. Essent. Fatty Acids,?32 165 2) Schermuly et al. (2005) Prostanoids and Phosphodiesterase Inhibitors in Experimental Pulmonary Hypertension; Curr. Top. Dev. Biol. 67 251 3) Urciuoli et al (2004) Prostaglandin E1 for treatment of erectile dysfunction; Cochrane Database Syst. Rev. CD001784 4) Huang et al. (2013) Reappraisal of the prostaglandin E1 dose for early newborns with patent ductus arteriosus-dependent pulmonary circulation; Pediatr. Neonatol. 54 102 5) Schroer and Hohlfeld (2004) Mechanisms of anti-ischemic action of prostaglandin E1 in peripheral arterial occlusive disease; Vasa 33 119