Pyridostigmine Bromide and Potassium Iodate: Subacute Oral Toxicity and Stability

Subacute toxicity of pyridostigmine bromide (PB) and potassium iodate (PI) tablets upon forty five days administration were assessed by changes in body weight, hematology, serum biochemical parameters and histopathology of rat liver and kidney. LD50 of PB was estimated to be 66.9 mg/kg. At dose of 45 mg/kg/day showed decrease in body weight and liver weight with cytoplasmic acidophilic bodies and vesicular steatosis signifying hepatocellular injury. Kidney tissue developed neutrophil polymorph infiltration with inflammatory glomerulonephritis, protein casts and glomerulosclerosis. Serum SGOT, SGPT, ALP and lipid profile were elevated. The oral LD50 of PI was found to be 944.6 mg/kg. PI at 150 mg/kg dose showed anorexia and body weight loss. Serum SGOT, ALP, cholesterol and triglyceride level were elevated at 85 and 150 mg/kg dose and focal area of tubular injury and inflammatory cell infiltration occurred only at 150 mg/kg dose in kidney. The content of PB and PI has been found stable in accelerated (40 ± 2°C/75 ± 5% RH), intermediate (30 ± 2°C/65 ± 5% RH) and long term (30 ± 2°C/65 ± 5% RH) conditions. PB 30 mg/kg/day and PI 85 mg/kg/day doses are safe for rats, which are far in excess of human exposure levels.