Type: Prelims Only

Why in the News?

Mumbai-based Entod Pharmaceuticals has announced that the Drug Controller General of India (DCGI) has approved its new eye drop, PresVu, aimed at reducing the dependency on reading glasses for individuals with presbyopia.

How does PresVu work? 

• The active ingredient in PresVu is pilocarpine, a compound that contracts the iris muscles, controlling the size of the pupil and helping individuals focus better on nearby objects.
• PresVu also uses an advanced dynamic buffer technology to adapt to the pH levels of tears, ensuring consistent efficacy and safety for extended use over the years.
• However, PresVu’s effects are temporary, typically lasting between four to six hours, and it is prescription-only.

• PresVu should not be used by individuals with iris inflammation.
• Regular use may lead to side effects such as:
  • Itching and redness
  • Eyebrow pain
  • Muscle spasms in the eyes

Is this a Novel Therapy?

• Although Entod claims PresVu is novel, the main compound, pilocarpine, has been available in India for decades and is commonly used as a first-line therapy for cataracts.
• Pilocarpine’s ability to temporarily improve the depth of focus has been explored in other countries, including the United States, where the FDA approved a pilocarpine eye drop for presbyopia in 2021.
• In India, the government regulates the ceiling price of pilocarpine in 4% and 2% concentrations, whereas PresVu contains 1.25%.

Why in the News?

Recent research reveals that FD&C Yellow 5, a common food dye, can temporarily make tissue transparent, with potential implications for cancer treatment and medical procedures.

About Yellow Food Dye 

• FD&C Yellow 5, also known as Tartrazine, is a widely used synthetic food dye found in various snacks, drinks, and processed foods.
• Approved by the FDA, it is commonly used to give products a vibrant yellow color.

How does it work?

• The dye has the ability to make tissue transparent is based on its interaction with light, specifically through the Kramers-Kronig relations, a principle in physics.
• It absorbs blue light, leaving only the red-orange spectrum visible.
• This alters the refractive index of water, causing it to match the refractive index of fats and proteins in tissue.
• When the refractive indices match, light can pass through tissue with less scattering, creating the appearance of transparency.

Potential Medical Applications of Yellow Food Dye

• Cancer Treatment: By making tissues transparent, FD&C Yellow 5 could enhance photodynamic and photothermal therapies, allowing laser light to reach deeper tissues and target cancerous cells more effectively.
• Vein Visibility: Transparent tissues could help make veins more visible, aiding in procedures like venepuncture for blood draws or injections, particularly in patients with hard-to-see veins.
• Non-invasive Diagnostics: The dye could allow doctors to visualize internal organs and structures without the need for invasive procedures like biopsies or expensive imaging technologies like CT scans or MRIs.