The absorption site for buccal/sublingual administration has which pH?

The absorption site for buccal/sublingual administration has which pH?

• A. Neutral
• B. Alkaline
• C. Acidic
• D. Variable

Answer: (A)

The key idea is that buccal and sublingual absorption occurs across the oral mucosa, which is bathed by saliva at roughly physiologic, near-neutral pH. Saliva in the mouth is typically around 6.8–7.0, close to neutral, which favors diffusion of non-ionized drug forms across the mucous membranes. If the environment were strongly acidic or strongly alkaline, ionization would increase for many drugs and reduce their ability to diffuse across the membrane, slowing absorption. Although saliva pH can vary a bit with conditions, the typical absorption site pH is effectively neutral, so the best answer is neutral.

The key idea is that buccal and sublingual absorption occurs across the oral mucosa, which is bathed by saliva at roughly physiologic, near-neutral pH. Saliva in the mouth is typically around 6.8–7.0, close to neutral, which favors diffusion of non-ionized drug forms across the mucous membranes. If the environment were strongly acidic or strongly alkaline, ionization would increase for many drugs and reduce their ability to diffuse across the membrane, slowing absorption. Although saliva pH can vary a bit with conditions, the typical absorption site pH is effectively neutral, so the best answer is neutral.