Patent ID: 7785615

Claim:
A medical device for placement at a site in a patient's body and for maintaining pH levels at the site in the patient's body at neutral pH, the device comprising: one or more structural components made of a first biodegradable and/or bioabsorbable material which is a polymer of poly (alpha-hydroxy acid); a buffering agent; and at least one second biodegradable and/or bioabsorbable material encapsulating the buffering agent on or in the one or more structural components, said buffering agent being encapsulated by the second biodegradable and/or bioabsorbable material, the buffering agent being released from the second biodegradable and/or bioabsorbable material as the second biodegradable and/or bioabsorbable material degrades, in response to a reduction in the pH level at the site in the patient's body resulting from the hydrolysis of the first biodegradable and/or bioabsorbable material, wherein the device is configured so that upon exposure to an acidic environment, an amount of the second biodegradable and/or bioabsorbable material degrades and releases the encapsulated buffering agent in an amount that provides a stoichiometric balance between the amount of buffering agent released and the total amount of acid released from the device, such that the pH level is raised to a neutral pH level.