Heavy metals are metals with a specific gravity greater than 5 (generally speaking, metals with a density greater than 4.5 grams per cubic centimeter), including gold, silver, copper, iron, lead, and so on. The accumulation of heavy metals in the human body to a certain level can cause chronic poisoning.
Fig.1 Detection of heavy metals
Raw Material Drugs
One is that the drugs themselves contain heavy metals, such as mineral medicines like vermilion and strophanthus and their preparations. The other is the heavy metals that accumulate in the raw herbs due to the pollution of soil or water during the cultivation of herbs.
Excipients
Pharmaceutical excipients are excipients and additives used in the production of drugs and prescriptions; they are substances other than active ingredients that have been reasonably evaluated in terms of safety and are included in pharmaceutical preparations.
Pharmaceutical excipients in addition to excipients, act as carriers, improve stability, but also have solubilization, solubilization, slow and controlled release and other important functions, is an important component that may affect the quality, safety and efficacy of drugs. Excipients in excess of the heavy metal content will directly affect the final preparation of heavy metal content.
Formulation
Some heavy metal catalysts are often added in the synthesis process, but if there are residues of these catalysts it will eventually affect the quality of the formulation.
The professional team of CD Formulation has the expertise and equipment to test and analyze heavy metals in samples to determine whether the drug meets the specified requirements. Among many metals, lead is the most easily introduced heavy metal element, and it is very easy to accumulate in the body and cause toxic reactions, so lead is often the main object of testing. The heavy metal ions react with the chromogenic agent to produce insoluble heavy metal sulfide particles, and compare the color shades of the heavy metal sulfide particles generated by the test solution and the standard lead solution evenly mixed in the solution to determine whether the limit of heavy metals in the test product is in accordance with the regulations.
Notes for Heavy Metal Examination:
(1) In the weak acid conditions for determination, the pH should be strictly controlled at 3.0~3.5, because at this time the sulfide precipitation is complete, the acidity is too large or too small to make the color lighter.
(2) 10~20 μg Pb2+/25 mL turbidity is the best visual comparison range. When the standard lead sample size is around 20 μg, visual observation is applicable, such as less than 10 μg, the color is too light, such as up to 30 μg, the color is too dark, not using observation and distinction.
(3) If there is a trace of high iron ions present, it will affect the determination of the results. Vitamin C can be added to reduce to ferrous ions to eliminate interference.
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