Abstract: Compounds of the formula: are described wherein: A1 is ascorbic acid, dehydroascorbic acid, ascorbyl-2-phosphate, an analog thereof, or a salt thereof; L is a linking group coupled to A1 at the C5 or C6 position thereof; and B1 is an active agent such as an imaging agent or therapeutic agent (e.g. a bisphosphonate), along with pharmaceutically acceptable salts and prodrugs thereof. The compounds are useful for, among other things, improving cartilage uptake of active agents administered for joint diseases such as osteoarthritis and rheumatoid arthritis, and for improving gastrointestinal absorption of bisphosphonates.

Abstract: Compounds of the formula: are described wherein: A1 is ascorbic acid, dehydroascorbic acid, ascorbyl-2-phosphate, an analog thereof, or a salt thereof; L is a linking group coupled to A1 at the C5 or C6 position thereof; and B1 is an active agent such as an imaging agent or therapeutic agent (e.g. a bisphosphonate), along with pharmaceutically acceptable salts and prodrugs thereof. The compounds are useful for, among other things, improving cartilage uptake of active agents administered for joint diseases such as osteoarthritis and rheumatoid arthritis, and for improving gastrointestinal absorption of bisphosphonates.