The in vitro metabolism of ingenol mebutate was qualitatively similar in blood, skin homogenates and hepatocytes of rats, dogs, minipigs and humans. Ingenol mebutate was found to be relatively stable in blood and skin homogenates, and to undergo extensive metabolism in cryopreserved hepatocytes. The major pathway in rat, dog and minipig hepatocytes was hydrolysis to ingenol, whereas the major pathway in humans was hydroxylation of ingenol mebutate. In the skin of rats, dogs, minipigs and humans, rearrangement of ingenol mebutate was predominantly to PEP015 (approximately 26% to approximately 31%) and, to a much lesser extent, PEP025 (approximately 1% to approximately 2%); hydrolysis to ingenol was minimal (0% to 0.81%). However, after topical or IV administration of ingenol mebutate to rats and minipigs, PEP025 was not detected and PEP015 was less than 10% of the corresponding ingenol mebutate concentration in the blood.
IDENTIFICATION AND USE: Ingenol mebutate is a white to pale yellow crystalline powder. As the drug Picato, it is used as a gel for the topical treatment of actinic keratosis. HUMAN EXPOSURE AND TOXICITY: Results from three pharmacology studies in healthy volunteers indicate a favorable topical safety profile for ingenol mebutate gel, with no evidence seen of skin sensitization, photoirradiation, or photoallergic potential. However, topical overdosing could result in an increased incidence of local skin reactions. ANIMAL STUDIES: In rats given repeat IV dosing for 28 days, treatment-related effects included transient tachypnea, which was not dose-related, lethargy and/or subdued behavior and decreased food consumption. In mice dosed for 7 consecutive days, one animal receiving 60 ug/kg/day and all animals receiving >/= 80 ug/kg/day were killed prematurely after </= 4 days of dosing because of the severity of physical signs, which were dose-related. In mini-pigs, no deaths occurred at 5 ug/kg/day ingenol mebutate for 4 consecutive days or 3 ug/kg/day for 28 days. Treatment-related effects were limited to sporadic and transient subdued behavior, emesis and slightly reduced body weight gain post-dose at 2.5 ug/kg/day. An increase in embryo-fetal mortality as well as increased incidence of fetal visceral and skeletal variations was noted in pregnant rabbits exposed to ingenol mebutate intravenously. No treatment related effects on embryofetal toxicity or teratogenicity were noted after intravenous administration to pregnant rats. Ingenol mebutate was not mutagenic in an in vitro Ames test, mouse lymphoma assay, and in vivo rat micronucleus test. An in vitro Syrian hamster embryonic (SHE) cell transformation assay was positive. A 6-month repeat dose IV rat study in 154 rats found that one male and one female dosed twice weekly with 15 ug/kg had a kidney tubular adenoma and tubular hyperplasia of the kidney. A pituitary adenoma was also present in the female with the renal adenoma. At the 1-month recovery kill, one male had a thyroid follicular cell carcinoma.
/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/
/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/
来源:Hazardous Substances Data Bank (HSDB)
毒理性
解毒与急救
/SRP:/ 高级治疗:对于昏迷、严重肺水肿或严重呼吸困难的病人,考虑进行口咽或鼻咽气管插管以控制气道。使用气囊面罩装置的正压通气技术可能有益。考虑使用药物治疗肺水肿……。对于严重的支气管痉挛,考虑给予β激动剂,如沙丁胺醇……。监测心率和必要时治疗心律失常……。开始静脉输注D5W TKO /SRP: "保持开放",最低流量/。如果出现低血容量的迹象,使用0.9%生理盐水(NS)或乳酸钠林格氏液(LR)。对于伴有低血容量迹象的低血压,谨慎给予液体。注意液体过载的迹象……。用地西泮或劳拉西泮治疗癫痫……。使用丙美卡因氢氯化物协助眼部冲洗……。/毒物A和B/
/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W TKO /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/
/HUMAN EXPOSURE STUDIES/ Healthy volunteers were enrolled in single-center, randomized, controlled, within-subject comparison trials. PEP005-005 was designed as a repeat-insult patch test study. In PEP005-023, treatment areas were examined after irradiation for photoirritation potential; dermal reactions were evaluated. In PEP005-024, irradiation was performed to determine the photoallergic (photosensitizing) potential of the medication. All treatment areas were graded immediately prior to irradiation and 24, 48, and 72 hours following irradiation. In all studies, local tolerability was assessed visually using an ordinal scoring system at set intervals before and after medication application/irradiation. In PEP005-005 (n=238), a significant difference (p<0.001) was seen between ingenol mebutate and vehicle for mean and total cumulative irritation scores. In PEP005-023 (n=34), mild erythema in all irradiated treatment areas was as expected for the ultraviolet dose. There was no clinically significant irritation in response to ingenol mebutate or vehicle, irrespective of irradiation. In PEP005-024 (n=60), there was no significant irritation in response to either ingenol mebutate or vehicle at their irradiated treatment areas. Results from three pharmacology studies in healthy volunteers indicate a favorable topical safety profile for ingenol mebutate gel, with no evidence seen of skin sensitization, photoirritation, or photoallergic potential.
Plasma clearance and volume of distribution (steady-state) in humans were estimated using a simple allometric correlation based on body weight. Using a one-compartment model with first-order absorption and elimination kinetics, it was estimated that dermal administration of the maximum intended clinical dose of 2 ug/kg/day would produce levels of ingenol mebutate in the blood below the LLOQ of 0.1 ng/mL. Blood clearance and volume of distribution at steady-state were predicted to range from approximately 0.22 to 1.01 L/hr/kg and approximately 0.61 L/kg, respectively. The absorption rate constant and topical bioavailability was projected to be 0.0277 hours-1 and 0.21%, respectively. A human blood Tmax of 2 hours and Cmax of 0.107 pg/mL were predicted for a 2 ug/kg/day topical dose. A minimum topical dose of 2000 ug/kg/day to humans would be required produce detectable blood levels.
After IV administration, a high to very high blood clearance, moderate to high volume of distribution at steady-state and short half-life were observed in rats, rabbits, dogs and minipigs. Following IV administration of 3(H)-ingenol mebutate to rats, drug-related radioactivity was well distributed to the tissues and there were no gender differences in the organs exposed but elimination was faster in females. In vitro, ingenol mebutate and its isomers were shown to have high plasma protein binding in rats, dogs, minipigs and humans (>99%). In rats, the majority of an intravenous dose of 3(H)-ingenol mebutate was excreted via the biliary route, with urinary excretion as a minor pathway.
After in vitro applications of 0.01%, 0.1% or 0.05% PEP005 Gels to rat, mini-pig and human skin preparations, the percutaneous absorption was generally low, with a range of 0.04% (mini-pig) to 8.68% (rat) across animal species and 0.16% to 1.93% in humans. The absorbed doses of 3(H)-ingenol mebutate were in the order of WI rat > SD rat > human > mini-pig. After topical administration of PEP005 Gel to mini-pigs, blood levels of ingenol mebutate were generally not detected, and when detected, ranged up to 0.1 ng/mL. After topical administration of ingenol mebutate to rats, blood levels were consistently quantifiable only at doses of 300 ug/kg or greater, in which case the absolute bioavailability was 2% to 4%.
The systemic exposure to Picato gel, 0.05% was assessed in two studies in a total of 16 subjects with AK, following application of approximately 1 g of Picato gel, 0.05% to an area of 100 cm2 of the dorsal forearm once daily for two consecutive days. In these studies, the blood levels of ingenol mebutate and two of its metabolites (acyl isomers of ingenol mebutate) were measured. Blood levels of ingenol mebutate and the two metabolites were below the lower limit of quantification (0.1 ng/mL) in all the blood samples of the subjects evaluated.