Active self-healing encapsulation of vaccine antigens in PLGA microspheres
Desai, KGH; Schwendeman, SP
| HERO ID | 1761627 |
|---|---|
| In Press | No |
| Year | 2013 |
| Title | Active self-healing encapsulation of vaccine antigens in PLGA microspheres |
| Authors | Desai, KGH; Schwendeman, SP |
| Journal | Journal of Controlled Release |
| Volume | 165 |
| Issue | 1 |
| Page Numbers | 62-74 |
| Abstract | Herein, we describe the detailed development of a simple and effective method to microencapsulate vaccine antigens in poly(lactic-co-glycolic acid) (PLGA) by simple mixing of preformed active self-microencapsulating (SM) PLGA microspheres in a low concentration aqueous antigen solution at modest temperature (10-38 °C). Co-encapsulating protein-sorbing vaccine adjuvants and polymer plasticizers were used to "actively" load the protein in the polymer pores and facilitate polymer self-healing at a temperature>the hydrated polymer glass transition temperature, respectively. The microsphere formulation parameters and loading conditions to provide optimal active self-healing microencapsulation of vaccine antigens in PLGA was investigated. Active self-healing encapsulation of two antigens, ovalbumin and tetanus toxoid (TT), in PLGA microspheres was adjusted by preparing blank microspheres containing different vaccine adjuvants (aluminum hydroxide (Al(OH)₃) or calcium phosphate). Active loading of vaccine antigen in Al(OH)₃-PLGA microspheres was found to: a) increase with an increasing loading of Al(OH)₃ (0.88-3 wt.%) and addition of porosigen, b) decrease when the inner Al(OH)₃/trehalose phase to 1 mL outer oil phase and size of microspheres was respectively >0.2 mL and 63 μm, and c) change negligibly by PLGA concentration and initial incubation (loading) temperature. Encapsulation of protein sorbing Al(OH)₃ in PLGA microspheres resulted in suppression of self-healing of PLGA pores, which was then overcome by improving polymer chain mobility, which in turn was accomplished by coincorporating hydrophobic plasticizers in PLGA. Active self-healing microencapsulation of manufacturing process-labile TT in PLGA was found to: a) obviate micronization- and organic solvent-induced TT degradation, b) improve antigen loading (1.4-1.8 wt.% TT) and encapsulation efficiency (~97%), c) provide nearly homogeneous distribution and stabilization of antigen in polymer, and d) provide improved in vitro controlled release of antigenic TT. |
| Doi | 10.1016/j.jconrel.2012.10.012 |
| Pmid | 23103983 |
| Wosid | WOS:000314107800009 |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Source: Web of Science WOS:000314107800009Scopus URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869862247&doi=10.1016%2fj.jconrel.2012.10.012&partnerID=40&md5=82abc728cb9f0fcbc13cf259149cb4a1 |
| Is Public | Yes |
| Language Text | English |
| Keyword | PLGA; Self-healing; Active loading; Encapsulation; Vaccine delivery; Controlled release |