Test standard for dissolution of plastic syringes

Plastic syringes are mainly used in filling and using dairy cow mastitis drugs. Qualified products need to pass strict testing. Dissolved matter testing is an important indicator in the detection of plastic syringes, which mainly includes four experiments: PH change value, heavy metal, easy oxide and non-volatile substance.

Dissolution content

Preparation of test solution: take the product (needle tube) with an internal surface area of 600cm2 (small pieces with a length of 5cm and a width of 0.3cm), place them in a tapered bottle, add appropriate amount of water, shake and wash the small pieces, discard the water, and repeat the operation twice. After drying at 30 ~ 40℃, soak 200ml of water (70℃±2℃) for 24 hours, then take out and cool to room temperature. Use the same batch of test solvent to supplement the original volume as the test solution. Use the same batch of water as the blank solution to conduct the following tests:

1. The pH change value

20ml of the sample solution and 20ml of the blank solution were added to potassium chloride solution (1→1000) 1.0ml, respectively, and determined in accordance with the law (general rule 0631, part ii, 2015 edition of veterinary pharmacopoeia of the People's Republic of China). The pH difference between the two was no more than 1.0.

2. The heavy metal

The test solution was accurately measured with 20ml of water and 2ml of acetate buffer (pH 3.5). It was determined in accordance with the law (general rule 0821, part ii, 2015 edition of veterinary pharmacopoeia of the People's Republic of China), and the content of heavy metal should not exceed one millionth.

3. Easy to oxide

Water was collected in a precise amount to provide 20ml of the test solution, and 20ml of potassium permanganate titrant (0.002mol/L) and 1ml of dilute sulfuric acid were precisely added, boiled for 3 minutes, and then cooled to room temperature rapidly. Add 0.1g potassium iodide and leave in the shade for 5 minutes. Titrate with sodium thiosulfate titrant (0.01mol/L). Add 5 drops of starch indicator solution and continue titrating until colorless. The difference in consumption of sodium thiosulfate titrant (0.01mol/L) between the two should not exceed 1.5ml.

4. No volatiles

The test liquid and the blank liquid were placed in the evaporating dish with constant weight, dried in water bath, and dried at 105℃ to the constant weight. The difference between the two should not exceed 12.0mg.