Poly(hydroxybutyrate-hydroxyvalerate) microspheres containing progesterone: preparation, morphology and release...

Area of Science:

• Polymer science
• Materials science
• Drug delivery systems

Background:

• Biodegradable polyesters such as poly(hydroxybutyrate) (PHB) and poly(hydroxybutyrate-hydroxyvalerate) (PHBV) are investigated for pharmaceutical applications.
• Sustained drug delivery systems are crucial for improving therapeutic efficacy and patient compliance.

Purpose of the Study:

• To evaluate PHB and PHBV as carriers for sustained delivery of progesterone.
• To characterize the microspheres prepared using an emulsion solvent-evaporation method.

Main Methods:

• Spherical drug-loaded microspheres were fabricated using poly(hydroxybutyrate) and poly(hydroxybutyrate-hydroxyvalerate) via emulsion solvent-evaporation.
• Methylene chloride and chloroform were used as polymer solvents, with gelatin as an emulsifier.
• Microsphere characteristics, including surface texture, residual solvent content, and drug release profiles, were analyzed.

Main Results:

• Methylene chloride produced smoother microspheres compared to chloroform.
• Increased drug loading beyond 5% w/w resulted in surface crystals.
• Residual solvent levels varied from 3.4 to 58.4 ppm, influenced by processing parameters.
• Microspheres composed of a copolymer with 9% hydroxyvalerate demonstrated the slowest in vitro drug release.
• The 9% hydroxyvalerate copolymer formed a less porous microsphere matrix.

Conclusions:

• Poly(hydroxybutyrate-hydroxyvalerate) copolymers are effective for sustained progesterone delivery.
• The composition of the PHBV copolymer significantly influences microsphere properties and drug release kinetics.
• Optimized processing conditions and polymer selection can yield desirable drug delivery characteristics.