A mathematical model for interpreting in vitro rhGH release from laminar implants

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Polymer Chemistry

Background:

• Recombinant human growth hormone (rhGH) therapy for growth hormone deficiency requires daily injections, impacting patient compliance.
• Controlled-release formulations can enhance treatment efficacy and patient quality of life by reducing injection frequency.
• Biodegradable implants present a viable alternative for sustained drug delivery, though they involve a minor surgical procedure.

Purpose of the Study:

• To develop and evaluate biodegradable implants for controlled release of rhGH.
• To investigate the correlation between polymer matrix degradation and rhGH release kinetics.
• To establish a mathematical model for predicting drug release from PLGA implants.

Main Methods:

• Three laminar implant formulations (F(1), F(2), F(3)) were fabricated using solvent-casting with poly(lactic-co-glycolic acid) (PLGA).
• In vitro studies assessed the relationship between PLGA polymer degradation and rhGH release rates.
• A mathematical model was developed and applied to analyze drug release mechanisms (diffusion vs. erosion).

Main Results:

• A direct correlation was observed between the degradation rate of the PLGA polymer matrix and the release kinetics of rhGH.
• The developed mathematical model successfully interpreted the drug release profiles for each formulation.
• Manufacturing parameters significantly influenced polymer structure and, consequently, the rhGH release characteristics.

Conclusions:

• Controlling the manufacturing process of PLGA implants is crucial for achieving desired rhGH release profiles.
• Understanding the interplay between polymer degradation and drug release allows for optimization of implants for growth hormone deficiency treatment.
• Biodegradable implants offer a promising approach for improving rhGH delivery and patient outcomes.