Sustained release of ancillary amounts of testosterone and alendronate from PLGA coated pericard membranes and implants to improve bone healing

PLoS One. 2021 May 17;16(5):e0251864. doi: 10.1371/journal.pone.0251864. eCollection 2021.

Abstract

Testosterone and alendronate have been identified as two bone healing compounds which, when combined, synergistically stimulate bone regeneration. This study describes the development of a novel ultrasonic spray coating for sustained release of ancillary amounts of testosterone and alendronate encapsulated in PLGA 5004A as a carrier. Due to the low amounts of testosterone and alendronate used, sensitive in vitro assays were developed to determine in vitro release. The ultrasonic spray coating technology was optimized for coating titanium screws and pericardial collagen membranes, with the aim to improve osseo-integration and (guided) bone regeneration, respectively, without interfering with their primary mode of action. In vitro release analysis of collagen membranes and screws showed up to 21 days sustained release of the compounds without a burst release. Subsequent preclinical studies in rat and rabbit models indicated that testosterone and alendronate coated membranes and screws significantly improved bone regeneration in vivo. Coated membranes significantly improved the formation of new bone in a critical size calvarial defect model in rats (by 160% compared to controls). Coated screws implanted in rabbit femoral condyles significantly improved bone implant contact (69% vs 54% in controls), bone mineral density (121%) and bone volume (119%) up to 1.3 mm from the implant. Based on the results obtained, we suggest that implants or membranes enabled with local sustained delivery of ancillary amounts of testosterone and alendronate can be a promising system to stimulate local bone regeneration resulting in improved osseo-integration of implants and improved healing of bone defects and fractures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alendronate / pharmacology*
  • Animals
  • Bone Density / drug effects
  • Bone Density Conservation Agents / chemistry
  • Bone Density Conservation Agents / pharmacology
  • Bone Regeneration / drug effects*
  • Bone Regeneration / physiology
  • Coated Materials, Biocompatible / chemistry
  • Coated Materials, Biocompatible / pharmacology
  • Delayed-Action Preparations / pharmacology
  • Disease Models, Animal
  • Femur / growth & development
  • Femur / surgery
  • Humans
  • Male
  • Osseointegration / drug effects*
  • Osseointegration / physiology
  • Polylactic Acid-Polyglycolic Acid Copolymer / chemistry
  • Polylactic Acid-Polyglycolic Acid Copolymer / pharmacology
  • Prostheses and Implants
  • Rabbits
  • Rats
  • Testosterone / pharmacology*
  • Titanium / chemistry
  • Titanium / therapeutic use

Substances

  • Bone Density Conservation Agents
  • Coated Materials, Biocompatible
  • Delayed-Action Preparations
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Testosterone
  • Titanium
  • Alendronate

Grants and funding

This work was funded by Osteo-Pharma. The funder provided support in the form of salaries for authors [CvdV, EG, NB, DL, JG], and did have a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.