Biorelevant release testing of biodegradable microspheres intended for intra-articular administration

Giulia Magri, Francesca Selmin, Francesco Cilurzo, Nikoletta Fotaki

Research output: Contribution to journalArticlepeer-review

9 Citations (SciVal)
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Characterization of controlled release formulations used for intra-articular (IA) drug administration is challenging. Bio-relevant synovial fluids (BSF), containing physiologically relevant amounts of hyaluronic acid, phospholipids and proteins, were recently proposed to simulate healthy and osteoarthritic conditions. This work aims to evaluate the performance of different controlled release formulations of methylprednisolone (MP) for IA administration, under healthy and disease states simulated conditions. Microspheres differed in grade of poly(lactide-co-glycolide) and in the theoretical drug content (i.e. 23 or 30% w/w). Their performance was compared with the commercially available suspension of MP acetate (MPA). Under osteoarthritic state simulated condition, proteins increased the MPA release and reduced the MPA hydrolysis rate, over 48 h. Regarding microspheres, the release patterns over 40 days were significantly influenced by the composition of BSF. The pattern of the release mechanism and the amount released was affected by the presence of proteins. Protein concentration affected the release and the concentration used is critical, particularly given the relevance of the concentrations to target patient populations, i.e. patients with osteoarthritis.

Original languageEnglish
Pages (from-to)115-122
Number of pages8
JournalEuropean Journal of Pharmaceutics and Biopharmaceutics
Early online date21 Mar 2019
Publication statusPublished - 1 Jun 2019


  • Biorelevant synovial fluids
  • Corticosteroids
  • Hyaluronic acid
  • Intra-articular
  • Methylprednisolone
  • Microspheres
  • PLGA
  • Proteins
  • Release testing

ASJC Scopus subject areas

  • Biotechnology
  • Pharmaceutical Science


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