What preservative is used in Unique pH?

• A. Povidone iodine
• B. Polyquad
• C. Chlorhexidine/PAPB
• D. Polyhexanide

Answer: (B)

Polyquad (polyquaternium-1) is the preservative used in Unique pH. The idea behind this preservative choice is to keep the solution sterile without being harsh on the eye or the lens material. Polyquad is a polymeric quaternary ammonium compound, which means it stays gentler on corneal cells and much of the lens surface compared with older preservatives like benzalkonium chloride. This gentleness helps reduce irritation and staining, making it a good fit for daily use with common soft lenses and silicone hydrogel materials.

Povidone-iodine acts mainly as a broad antiseptic and is not typically used as a long-term preservative in standard contact lens solutions due to potential staining and ocular surface irritation. Chlorhexidine with PAPB and polyhexanide are other antiseptic options used in some products, but they can have higher cytotoxicity or compatibility concerns with lenses and the eye, which is why they’re not as commonly chosen for mainstream multipurpose solutions.