What preservative is located in Original Boston Formula Conditioning Solution?

• A. Chlorhexidine
• B. PAPB
• C. Chlorhexidine/PAPB
• D. Polyquad

Answer: (C)

Preservative systems in lens care solutions are designed to balance antimicrobial effectiveness with compatibility for lenses and the eye. Original Boston Formula Conditioning Solution uses a two-agent preservative system: chlorhexidine together with PAPB (polyaminopropyl biguanide). Chlorhexidine provides strong antimicrobial action, while PAPB adds additional protection and helps optimize the safety profile when used in combination. This pairing distinguishes the Boston Original Formula from solutions that rely on a single agent or on other preservatives like Polyquad. Polyquad is a different preservative used in other brands, and neither chlorhexidine alone nor PAPB alone describes the full preservative system used in this Boston formulation.