Technology

Povidone-iodine (or PVP-I) is the active ingredient in Nasodine® Nasal Spray and Firebrick’s other Nasodine brand products in development. Firebrick scientists are experts in the field of PVP-I and have filed numerous patents and assembled a reference library to more than 2,400 published papers relevant to the science and use of PVP-I.

PVP-I is a complex of iodine, a molecule with potent antimicrobial properties, and a polymer called polyvinylpyrrolidone (PVP).

Molecular iodine (I₂) is almost insoluble in water, making it difficult to use as a practical antiseptic.  PVP is water soluble and by combining it with iodine, it effectively makes the iodine water soluble, because the iodine can be held inside PVP’s coiled structure (‘complexed iodine’ in the image). This leaves a tiny fraction of the iodine (around 1/1000^th) present as free iodine to kill microorganisms. Fortunately, it only needs a minute amount (less than 20 ppm) of iodine to kill germs.

As free iodine is used up to kill germs, it is replenished from the iodine reserve held inside the PVP coils. This clever mechanism ensures that the amount of free iodine present at any time is more than enough to kill all germs (up to 20 ppm) while avoiding adverse effects on human tissue.

Since its invention in the US in the 1950s, PVP-I has been widely marketed under the “Betadine” brand and extensively used in hospitals as the antiseptic of choice for a range of uses. These hospital applications include eradication of germs on the skin of patients who are undergoing surgery, prevention of infection in wounds and burns, and hand disinfection by surgeons prior to surgery. Outside hospital use, PVP-I has been used as a wound antiseptic and for treatment of certain infections as well.

Notably, it has been used as a throat gargle to treat sore throats, which are mostly caused by viruses. In Australia, Betadine® Sore Throat Gargle has been a leader in the OTC (over-the-counter) market as a sore throat treatment for more than 40 years. By one estimate, more than 100 million sore throats have been treated over the years with Betadine gargle, just in Australia.

PVP-I is a remarkable and unique antimicrobial agent:

• It kills all microbes, including all viruses, at very low concentrations.
• Its effect is ‘virucidal’ and ‘bactericidal’ in that it causes a permanent loss of infectivity for viruses and cell death for bacteria.
• PVP-I has no apparent potential for viral (or bacterial) resistance, despite decades of use.
• Remarkably, the antimicrobial potency of a PVP-I solution is greater at 0.5% PVP-I than at 10% PVP-I concentration; this is due to the release of higher free iodine levels from the complex (with consequent reduced reserve iodine capacity) in the more dilute solution. This heightened activity at low concentration is important for its safe and effective use on mucous membranes where fast activity and low risk of adverse effects are important.
• Most respiratory viruses are inactivated in less than 60 seconds by 0.5% PVP-I solutions; interestingly, the viruses of greater clinical concern (coronaviruses, influenza virus, RSV and HMPV) are the most sensitive to PVP-I.

• Nasodine Nasal Spray comprises 0.5% PVP-I concentration in a patented formulation for nasal use; the formulation includes excipients designed to optimise nasal tolerability and stability over the full shelf life of the product.
• The concentration of 0.5% PVP-I was selected to optimise rapid antimicrobial action in the nose, as well as to minimise nasal sensitivity (related to PVP-I concentration) and minimise potential iodine absorption (also related to PVP-I concentration)
• The recommended dose of Nasodine Nasal Spray is 3-4 sprays per nostril. This is designed to be enough to cover entire surface of the nasal passages with a fine layer of Nasodine solution. Recommended dose frequency is 4 times daily, but it has been used safely up to 8 times daily in one study².
• Based on this dose and frequency, each 25mL bottle contains enough for 7 days of use.

• The world’s first nasal spray that kills all respiratory viruses and bacteria.
• Shown in vitro to kill all the viruses (and bacteria) that cause upper respiratory infections.
• No potential for viral or bacterial resistance; will not contribute to antimicrobial resistance which is a serious worldwide problem with antibiotics..
• First product that targets the microbial cause of upper respiratory infections, not just the symptoms.
• Proven safe in multiple independently-controlled clinical trials.
• Supported by peer-reviewed published studies.
• Backed by 10 years of R&D by Firebrick Pharma.
• Protected by multiple international patents.

• Nasodine is a nasal spray that kills all respiratory viruses (and bacteria); most respiratory illnesses are caused by viruses, but a small number (5%) are associated with bacterial infection as well.
• In vitro test results with Nasodine formulation are shown in the table below: