Sustained release drug delivery devices

A method for treating a mammalian organism for cytomegalovirus retinitis comprising:

• administering a sustained release drug delivery system to a mammalian organism in need of such treatment, said drug delivery system comprising;
• (1) an inner core or reservoir comprising an effective amount of ganciclovir effective to obtain a desired local or systemic physiological or pharmacological effect,
• (2) a first polymer coating layer, said first polymer coating layer essentially impermeable to the passage of said ganciclovir, and said first polymer coating layer covering at least a portion of the inner core, wherein at least a small portion of the inner core is not coated with said first polymer coating layer, and
• (3) a second polymer coating layer permeable to the passage of said ganciclovir, wherein said second polymer coating layer essentially completely covers said first polymer coating layer and the uncoated portion of the inner core, whereby said ganciclovir is able to pass through said second polymer coating layer in a controlled manner.

A method for treating a mammalian organism to obtain a desired physiological or pharmacological effect comprising:

• placing a sustained release drug delivery system in contact with or within an eye of a mammalian organism in need of such treatment, said drug delivery system comprising;
• (1) an inner core having an effective amount of an agent to obtain a desired local or systemic physiological or pharmacological effect and an inner polymer coating permeable to the passage of said agent covering at least a portion of said agent,
• (2) a first polymer coating essentially impermeable to the passage of said agent, said first polymer coating covering at least a portion but not the entire surface area of said inner polymer coating of said inner core, and
• (3) a second polymer coating permeable to the passage of said agent, wherein said second polymer coating essentially completely covers said first polymer coating and any uncoated portion of the inner core, whereby said agent is able to pass through said second polymer coating,
• wherein each of the polymers selected to make the device are essentially insoluble and inert in body fluids and compatible with eye tissues, and
• allowing said agent to pass through said second polymer coating to obtain a desired effect.

A sustained release drug delivery system suitable for placing in contact with or within the eye to provide a desired physiological or pharmacological effect comprising:

• (1) an inner core having an effective amount of an agent to obtain a desired local or systemic physiological or pharmacological effect and an inner polymer coating permeable to the passage of said agent covering at least a portion of said agent,
• (2) a first polymer coating essentially impermeable to the passage of said agent, said first polymer coating covering at least a portion but not the entire surface area of said inner polymer coating of said inner core, and
• (3) a second polymer coating permeable to the passage of said agent, wherein said second polymer coating essentially completely covers said first polymer coating and any uncoated portion of the inner core,
• wherein each of the polymers selected to make the device are essentially insoluble and inert in body fluids and compatible with eye tissues.

A method for providing controlled and sustained administration of an agent effective in obtaining a desired local or systemic physiological or pharmacological effect comprising:

• surgically implanting a sustained release drug delivery system at a desired location, said drug delivery system comprising;
• (1) an inner core or reservoir comprising an effective amount of an agent effective in obtaining a desired physiological or pharmacological effect,
• (2) a polymer coating layer which is essentially impermeable to the passage of said effective .mu.gent, said impermeable layer covering at least a portion or the inner core, wherein at least a small portion of the inner core is not coated with said impermeable polymer coating layer, and
• (3) a polymer coating layer which essentially completely covers the inner core and is permeable to the passage of said effective agent whereby said agent is able to pass through said polymer coating layer in a controlled manner.