Abstract
Purpose. Macromolecular delivery systems have therapeutic uses because of their ability to deliver and release drugs to specific tissues. The uptake and localization of HPMA copolymers using Asp8 as the bone-targeting moiety was determined in aged, ovariectomized (ovx) rats. PGE1 was attached via a cathepsin K-sensitive linkage to HPMA copolymer-Asp8 conjugate and was tested to determine if it could promote bone formation. Materials and Methods. The uptake of FITC-labeled HPMA copolymer-Asp8 conjugate (P-Asp8-FITC) on bone surfaces was compared with the mineralization marker, tetracycline. Then a targeted PGE1-HPMA copolymer conjugate (P-Asp8-FITC-PGE1) was given as a single injection and its effects on bone formation were measured 4 weeks later. Results. P-Asp8-FITC preferentially deposited on resorption surfaces, unlike tetracycline. A single injection of P-Asp8-FITC-PGE 1 resulted in greater indices of bone formation in aged, ovx rats. Conclusions. HPMA copolymers can be targeted to bone surfaces using Asp 8, with preferential uptake on resorption surfaces. Additionally, PGE1 attached to the Asp8-targeted HPMA copolymers and given by a single injection resulted in greater bone formation measured 4 weeks later. This initial in vivo study suggests that macromolecular delivery systems targeted to bone may offer some therapeutic opportunities and advantages for the treatment of skeletal diseases.
Original language | English (US) |
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Pages (from-to) | 2889-2895 |
Number of pages | 7 |
Journal | Pharmaceutical Research |
Volume | 25 |
Issue number | 12 |
DOIs | |
State | Published - Dec 2008 |
Keywords
- Bone formation
- HPMA
- Macromolecular therapeutics
- Prostaglandin
- Rats
ASJC Scopus subject areas
- Biotechnology
- Molecular Medicine
- Pharmacology
- Pharmaceutical Science
- Organic Chemistry
- Pharmacology (medical)