Aminopterin

Signs and Symptoms of Aminopterin Exposure: Signs and symptoms of acute exposure to aminopterin may include nausea, vomiting, anorexia, stomatitis (inflammation of the oral mucosa), pharyngitis (inflammation of the pharynx), erythematous rashes (red rashes on the skin), hyperpigmentation (abnormally increased pigmentation), chills, fever, gastrointestinal hemorrhage, and renal failure (especially in high doses). May induce abortion in pregnant women.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

For emergency situations, wear a positive pressure, pressure-demand, full facepiece self-contained breathing apparatus (SCBA) or pressure- demand supplied air respirator with escape SCBA and a fully-encapsulating, chemical resistant suit. (EPA, 1998)

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 650(SRC), determined from a structure estimation method(2), indicates that aminopterin is expected to have low mobility in soil(SRC). A measured pKa of one of the carboxylic acid moieties of aminopterin is 5.5(3), indicates that this compound will primarily exist in anion form in the environment and anions do not volatilize from moist soil surfaces. Aminopterin is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.3X10-19 mm Hg(SRC), determined from a fragment constant method(4). Biodegradation data were not available(SRC, 2005).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 650(SRC), determined from a structure estimation method(2), indicates that aminopterin is expected to adsorb to suspended solids and sediment(SRC). A measured pKa of one of the carboxylic acid moieties of aminopterin is 5.5(3), indicate that this compound will primarily exist in anion form in the environment and anions do not volatilize from water surfaces and generally do not adsorb more strongly to suspended solids and sediment than their neutral counterparts(4). According to a classification scheme(5), an estimated BCF of 3.2(SRC), from an estimated log Kow of -1.82(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation data were not available(SRC, 2005).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), aminopterin, which has an estimated vapor pressure of 2,3X10-19 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase aminopterin may be removed from the air by wet and dry deposition(SRC). Aminopterin absorbs UV light >290 nm(3); therefore, aminopterin may be susceptible to photolysis by sunlight(SRC).

Aminopterin is an amino derivative of folic acid which binds competitively to the dihydrofolate reductase enzyme to block tetrahydrofolate synthesis. Tetrahydrofolate is essential in the production of purines and pyrimadines, thus it's deficiency results in a reduction of DNA, RNA and protein synthesis.

Using a structure estimation method based on molecular connectivity indices(1), the Koc for aminopterin can be estimated to be 650(SRC). According to a classification scheme(2), this estimated Koc value suggests that aminopterin is expected to have low mobility in soil. A pKa of one of the carboxylic acid moieties of aminopterin was reported as 5.5(3), indicating that this compound will primarily exist in the dissociated form in the environment and anions generally do not adsorb more strongly to organic carbon and clay than their neutral counterparts(4).

/SIGNS AND SYMPTOMS/ Effect of drug on fetus: ...Aminopterin syndrome: cranial dystosis, hydrocephalus, hypertelorism, anomalies of external ear, micrognathia, posterior cleft palate. /from table/

/SIGNS AND SYMPTOMS/ Overdosage with... aminopterin causes leukopenia, granulocytopenia, thrombocytopenia, hypoplasia of all elements of bone marrow, nausea and vomiting, and anorexia. ...Lymphopenia, fetal death or abnormalities, stomatitis /are also listed/.

/SIGNS AND SYMPTOMS/ Known effects of aminopterin in man that are well documented and conclusive (embryonic development in the first trimester of pregnancy): multiple anomalies, craniofacial anomalies, abortion, intrauterine growth retardation. /From table/

/SIGNS AND SYMPTOMS/ First trimester use of the folate antagonists, aminopterin and methotrexate, is known to cause spontaneous abortions and congenital abnormalities... however, normal pregnancy outcome has been reported after use in the second and third trimesters.

For more Human Toxicity Excerpts (Complete) data for AMINOPTERIN (7 total), please visit the HSDB record page.

Aminopterin's former production and use as a research drug for the treatment of leukemias(1) may have resulted in its release to the environment through various waste streams; its former(2) use as a rodenticide(3) resulted in its direct release to the environment(SRC).

An estimated BCF of 3 was calculated for aminopterin(SRC), using an estimated log Kow of -1.8(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

A measured pKa of one of the carboxylic acid moieties of aminopterin is 5.5(1), indicates that this compound will primarily exist in anion form in the environment and anions do not volatilize from water or moist soil surfaces(SRC). Aminopterin is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.3X10-19 mm Hg(SRC), determined from a fragment constant method(2).

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ ...Rats /were administered/ 0.1 mg/kg bw /of aminopterin/ on the 6th day and... defects of the eye, face, skull, brain, extremities, abdominal wall and tail /were observed/. A complete mitotic block was noted in the ectotrophoblast but not the embryoblast.

/ALTERNATIVE IN VITRO TESTS/ /Studies were performed/... of cultures... of eight-cell-blastomeres of rat embryos in Bigger's medium with the addition of 20% rat serum from animals treated with different doses of this drug (aminopterin). Retardation of cleavage rate, abnormalities of blastocyst formation and damage of inner cell mass was observed.

/OTHER TOXICITY INFORMATION/ A quite new approach to biological control /of pests/ is by means of chemosterilants. The sustained release of large numbers of sterilized males of specific insect species has yielded remarkable control of certain insect pests of domestic animals and crop plants. ...Sterilization can be effected in two ways; physically, by means of radiation, x-rays, or gamma rays or chemically, by feeding compounds of known chemosterilant activity, such as the folic acid antagonist aminopterin...

Aminopterin is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(1). Aminopterin absorbs UV light >290 nm(2); therefore, on soil surfaces, aminopterin may be susceptible to photolysis(SRC).

Occupational exposure to aminopterin may have occurred through inhalation and dermal contact with this compound at workplaces where aminopterin was produced or used. Exposure of the general population to this compound was limited to those receiving this drug in the treatment of certain leukemias. (SRC)

Releases of CERCLA hazardous substances are subject to the release reporting requirement of CERCLA section 103, codified at 40 CFR part 302, in addition to the requirements of 40 CFR part 355. Aminopterin is an extremely hazardous substance (EHS) subject to reporting requirements when stored in amounts in excess of its threshold planning quantity (TPQ) of 500 or 10,000 lbs. Extremely hazardous substances that are solids are subject to either of two threshold planning quantities ... The lower quantity applies only if the solid exists in powdered form and has a particle size less than 100 microns; or is handled in solution or in molten form; or meets the criteria for a National Fire Protection Association (NFPA) rating of 2, 3 or 4 for reactivity. If the solid does not meet any of these criteria, it is subject to the upper ... threshold planning quantity ... .