Critical attributes of formulation and of elaboration process of PLGA-protein microparticles

• Published in: International journal of pharmaceutics 2015-03, Vol.480 (1-2), p.27-36
• Main Authors: Martín-Sabroso, C., Fraguas-Sánchez, A.I., Aparicio-Blanco, J., Cano-Abad, M.F., Torres-Suárez, A.I.
• Format: Article
• Language: English
• Subjects: Albumin; Albumins - administration & dosage; Albumins - chemistry; Animals; Cell Proliferation - drug effects; Chemistry, Pharmaceutical - methods; Critical attributes; Delayed-Action Preparations; Drug Liberation; Hydrophobic and Hydrophilic Interactions; Lactic Acid - chemistry; Microparticles; Microspheres; Molecular Weight; PC12 Cells; Poly(lactic-co-glycolic) acid; Polyglycolic Acid - chemistry; Protein microencapsulation; Quality by design; Rats; Sodium Chloride - chemistry; Solvents - chemistry
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/j.ijpharm.2015.01.008

[Display omitted] Low drug loading, burst effect during release and drug inactivation account for the main drawbacks of protein microencapsulation in poly(d,l-lactic-co-glycolic) acid (PLGA) matrix by the water-in oil-in water (W/O/W) solvent evaporation method. Thus, the current study was set to invest the critical attributes of formulation and of elaboration process which determine protein loading into microparticles as well as its further release, using albumin as protein model. NaCl concentration in the external aqueous phase, poly(vinyl alcohol) (PVA) concentration and mostly viscosity of both the internal aqueous phase and the organic phase were critical attributes for improving drug loading, with polymer molecular weight and hydrophobicity likewise directly related to albumin loading. In such a way, when using 0.5% PVA as internal aqueous phase the highest albumin loading was achieved. Optimized microparticles exhibited a sustained in vitro release of albumin over 130 days. The influence of the microencapsulation process on albumin stability and biological activity was evaluated by carrying out cell proliferation assays on PC12 cells with albumin released from microparticles. Such assay demonstrated that the microencapsulation procedure optimized in this study did not affect the biological stability of the microencapsulated protein.