A toxicological assessment of spermidine trihydrochloride produced using an engineered strain of Saccharomyces cerevisiae.

Spermidine is a polyamine consumed in the diet, endogenously biosynthesized in most cells, and produced by the intestinal microbiome. A variety of foods contribute to intake of spermidine along with other polyamines. Spermidine trihydrochloride (spermidine-3HCl) of high purity can be produced using an engineered strain of Saccharomyces cerevisiae. Spermidine has a demonstrated history of safe use in the diet; however, limited information is available in the public literature to assess the potential toxicity of spermidine-3HCl. To support a safety assessment for this spermidine-3HCl as a dietary source of spermidine, authoritative guideline and good laboratory practice (GLP) compliant in vitro genotoxicity assays (bacterial reverse mutation and mammalian micronucleus assays) and a 90-day oral (dietary) toxicity study in rats were conducted with spermidine-3HCl. Spermidine-3HCl was non-genotoxic in the in vitro assays, and no adverse effects were reported in the 90-day oral toxicity study up to the highest dose tested, 12500 ppm, equivalent to 728 mg/kg bw/day for males and 829 mg/kg bw/day for females. The subchronic no observed adverse effect level (NOAEL) is 728 mg/kg bw/day.

D-10-camphorsulfonic acid: Safety evaluation.

The safety of D-10-camphorsulfonic acid (CSA) was evaluated by genotoxicity testing and in a subchronic 90-day study in rats. Ames test and in vitro micronucleus test results, either in the absence or the presence of metabolic activation, were negative. Administration of CSA to Wistar rats in the drinking water (0.05, 0.20, or 1.00 mg/mL), for 90 days caused neither test-item-related mortality nor adverse clinical signs. The only macroscopic change seen at necropsy was enlarged testes in the high-dose animals. The 0.20 mg/mL (25 mg/kg bw/day) dose level was considered to be the no observed adverse effect level (NOAEL). A total intake calculation for consumers was performed, based on the intended maximal amount of 0.5 ppm CSA in feed, published transfer factors, and conservative tissue consumption data, resulting in 0.29 µg/kg bw/day. Therefore, the NOAEL is approximately 80,000 × the maximum estimated human exposure, a margin that is more than adequate to ensure consumer safety.

Needle-free nasal delivery of glucagon for treatment of diabetes-related severe hypoglycemia: toxicology of polypropylene resin used in delivery device.

CONTEXT: The intranasal route is a promising route of administration for several emergency rescue drugs including naloxone and glucagon. Glucagon nasal powder (GNP) is a novel, needle-free delivery system for intranasal administration of glucagon for the treatment of severe hypoglycemia, an infrequent but serious complication of insulin use in patients with diabetes. The GNP delivery device is a compact, highly portable, single-use nasal powder dosing device constructed of polypropylene that allows for simple, single-step administration. OBJECTIVE: To evaluate the toxicological profile of the polypropylene resin used in the actuator part of the delivery device that will contact skin and nasal mucosal membranes of the patient, we performed an in vitro cytotoxicity study, a skin sensitization study and an irritation (intracutaneous reactivity) study in animal models. METHODS: Extracts of the actuator of the GNP device were generated from HAM F12 medium with 10% fetal bovine serum, 0.9% sodium chloride (NaCl) or sesame oil. The in vitro cytotoxicity test was performed in cultured L929 mouse fibroblasts. Skin sensitization analysis was performed in 10 guinea pigs according to the Magnusson-Kligman method, using a maximization method with Freund's Complete Adjuvant. Irritation following intracutaneous/intradermal treatment with device extracts (NaCl and sesame oil extractants) was assessed in three New Zealand White rabbits. RESULTS: In vitro cytotoxicity test: Both undiluted and diluted extract showed no toxicity (i.e. no abnormal morphology, cell death or cell lysis) toward L929 fibroblasts (cytotoxicity grade 0). Sensitization test in guinea pigs: Challenge with device extracts did not evoke positive responses in test animals previously induced with device extracts. The net response value represented an incidence rate of 0% and a net dermal irritation score value of 0.00. Irritation (intracutaneous/intradermal) test in New Zealand White rabbits: Device extracts and corresponding vehicle controls caused similar irritation reactions. The difference between the mean scores for the device extracts and the corresponding vehicle controls was less than 1.0. CONCLUSIONS: Extracts of the polypropylene resin of the GNP delivery device are not cytotoxic, do not result in dermal sensitization and do not cause irritation when applied topically or intracutaneously. Given the infrequent use and very short duration of exposure to the nasal mucosa during administration of GNP, the polypropylene resin of the GNP device actuator will likely not cause adverse dermal sensitization effects or irritation effects in humans and can, therefore, be considered for use as a delivery device in clinical trials assessing the efficacy and safety of GNP for the treatment of insulin-using patients experiencing episodes of severe hypoglycemia.

Safety assessment of a wheat bran extract containing arabinoxylan-oligosaccharides: mutagenicity, clastogenicity, and 90-day rat-feeding studies.

Wheat bran extract (WBE) is a food-grade preparation that is highly enriched in arabinoxylan-oligosaccharides. As part of the safety evaluation of WBE, its genotoxic potential was assessed in a bacterial reverse mutagenicity assay (Ames test) and a chromosome aberration assay on Chinese hamster lung fibroblast cells. These in vitro genotoxicity assays showed no evidence of mutagenic or clastogenic activity with WBE. The safety of WBE was furthermore evaluated in a subchronic toxicity study on rats that were fed a semisynthetic diet (AIN 93G) containing 0.3%, 1.5%, or 7.5% WBE for 13 weeks, corresponding to an average intake of 0.2, 0.9, and 4.4 g/kg body weight (bw) per day, with control groups receiving the unsupplemented AIN 93G, AIN 93G with 7.5% inulin, or AIN 93G with 7.5% wheat bran. Based on this rat-feeding study, the no-observed-adverse-effect level (NOAEL) for WBE was determined as 4.4 g/kg (bw)/d, the highest dose tested.

Safety evaluation of the phosphinothricin acetyltransferase proteins encoded by the pat and bar sequences that confer tolerance to glufosinate-ammonium herbicide in transgenic plants.

Transgenic plant varieties, which are tolerant to glufosinate-ammonium, were developed. The herbicide tolerance is based upon the presence of either the bar or the pat gene, which encode for two homologous phosphinothricin acetyltransferases (PAT), in the plant genome. Based on both a review of published literature and experimental studies, the safety assessment reviews the first step of a two-step-approach for the evaluation of the safety of the proteins expressed in plants. It can be used to support the safety of food or feed products derived from any crop that contains and expresses these PAT proteins. The safety evaluation supports the conclusion that the genes and the donor microorganisms (Streptomyces) are innocuous. The PAT enzymes are highly specific and do not possess the characteristics associated with food toxins or allergens, i.e., they have no sequence homology with any known allergens or toxins, they have no N-glycosylation sites, they are rapidly degraded in gastric and intestinal fluids, and they are devoid of adverse effects in mice after intravenous administration at a high dose level. In conclusion, there is a reasonable certainty of no harm resulting from the inclusion of the PAT proteins in human food or in animal feed.