Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1. Pharmacodynamic properties
Pharmacotherapeutic group: Pharyngeal preparations, antiseptics ATC code: R02AA15

Povidone-iodine is a complex of the polymer polyvinyl-pyrrolidone with iodine (povidone-iodine). The microbicidal effect is based on the content of free, non- complexed iodine released by the povidone-iodine complex during an equilibrium reaction. Thus, the povidone-iodine complex is an iodine depot slowly releasing elemental iodine over a prolonged period of time and maintaining a constant concentration of active free iodine.
Binding of iodine to the povidone complex largely reduces local irritating properties of alcoholic iodine preparations and is well tolerated by skin, mucous membranes and wounds.
Free iodine reacts with oxidizable SH- or OH-groups of amino acids in enzymes and structural proteins of microorganisms, which are thereby inactivated and killed. This process decolors the iodine. Therefore, the intensity of the brown color is an indicator for its efficacy. Decoloration requires an additional dosage. This relatively unspecific mode of action is the reason for the comprehensive efficacy of povidone-iodine against a wide spectrum of human pathogens: gram-positive, gram-negative, bacteria, Gardnerella vag., Mycoplasma, Treponema pallidum, Chlamydia, fungi (e. g. candida), viruses (including herpes and HIV), protozoa (e. g. trichomonas) as well as spores.
Resistance or development of secondary resistance with long-term use is not expected due to the mode of action.
Betadine Gargle is a therapeutic anti-infectious mouth rinse, which tastes good and prevents bad breath. Betadine Gargle is water-soluble and easy to rinse off.

Pharmacokinetic Properties

5.2. Pharmacokinetic properties
After use of Betadine Gargle the possibility of iodine resorption must be considered depending on the duration of use and the applied amount.
A significant amount of iodine may be absorbed with long-term use of Betadine Gargle on large wounds and burned areas as well as mucous membranes. The resulting increase in iodine levels in the blood is generally temporary (normalization within 7 to 14 days after discontinuation of the treatment).
In a healthy thyroid, the increased iodine levels do not lead to any clinical relevant changes in the hormone status of the thyroid.

Povidone:
Resorption and renal elimination of povidone depends on the (average) molecular weight (of the mixture). Retention mainly in the reticulo-endothelial system is expected above a molecular weight of 35,000 to 50,000 Dalton. However thesaurismosis and other changes observed after intravenous or subcutaneous administration of other povidone-containing medications were not observed for povidone-iodine.
Iodine:
The behavior of resorbed iodine or iodide in the organism corresponds to a great extent to that of otherwise absorbed iodine. The volume of distribution corresponds to about 38 % of the body weight in kg. The biological half life after vaginal administration was reported to be about 2 days. The normal value of total iodine in the serum is 3.8 to 6.0 µg/dl and of inorganic iodine 0.01 to 0.5 µg/dl.
Elimination occurs almost exclusively renally with a clearance rate of 15 to 60 ml plasma/min depending on the iodine level in serum and creatinine clearance (normal value: 100 - 300 µg iodide per 1 g of creatinine).