What water activity threshold defines an aqueous dosage form?

What water activity threshold defines an aqueous dosage form?

• A. ≤ 0.60
• B. 0.60
• C. > 0.60
• D. ≥ 0.60

Answer: (D)

Water activity measures how much water in a dosage form is free and available to participate in chemical reactions and microbial growth. In pharmaceutical thinking, an aqueous dosage form is defined by having enough free water that the water activity reaches 0.60 or higher. That means a value of 0.60 qualifies as aqueous, since the water is sufficiently available to act like water in solution or other aqueous media. If water activity is below 0.60, water is less available for reactions or growth, so the product is considered non-aqueous.

Water activity measures how much water in a dosage form is free and available to participate in chemical reactions and microbial growth. In pharmaceutical thinking, an aqueous dosage form is defined by having enough free water that the water activity reaches 0.60 or higher. That means a value of 0.60 qualifies as aqueous, since the water is sufficiently available to act like water in solution or other aqueous media. If water activity is below 0.60, water is less available for reactions or growth, so the product is considered non-aqueous.