Facilitated Transport of Bisphosphonates by Vitamin C

In a method of preferentially administering a compound of interest into chondrocytes of a subject, the improvement comprising administering said subject compound of Formula I:

• A1-L-B1 or A1-B1 (1)
• wherein:
• A1 is ascorbic acid, dehydroascorbic acid, ascorbyl-2-phosphate, or an analog thereof;
• L is a linking group coupled to said ascorbic acid, dehydroascorbic acid, ascorbyl-2-phosphate, salt derivatives or analogs thereof at the C5 or C6 position thereof;
• and
• B1 is said compound of interest;
• or a pharmaceutically acceptable salt or prodrug thereof.

In a method of enhancing uptake of a compound of interest (B1) into chondrocytes, the improvement comprising administering to said chondrocytes a compound of Formula I:

• A1-L-B1 or A1-B1 (1)
• wherein:
• A1 is ascorbic acid, dehydroascorbic acid, ascorbyl-2-phosphate, or an analog thereof;
• L is a linking group coupled to said ascorbic acid, dehydroascorbic acid, ascorbyl-2-phosphate, salt derivatives or analogs thereof at the C5 or C6 position thereof;
• and
• B1 is said compound of interest;
• or a pharmaceutically acceptable salt or prodrug thereof.