Formulation aspects of biodegradable polymeric microspheres
for antigen delivery
Harjit Tamber
a,b
,P3l Johansen
a,c
, Hans P. Merkle
a
, Bruno Gander
a,
*
a
Institute of Pharmaceutical Sciences, ETH Zurich, ETH-Hoenggerberg, HCI, 8093 Zurich, Switzerland
b
Napp Pharmaceuticals Research Ltd., Cambridge Science Park, Milton Road, Cambridge, CB4 0GW, U.K.
c
Department Dermatology, University Hospital of Zurich, Gloriastrasse 31, 8091 Zurich, Switzerland
Received 31 March 2004; accepted 1 September 2004
Available online 30 September 2004
Abstract
Biodegradable microspheres (MS) have proven to be very useful antigen delivery systems that are ingested by
immunocompetent cells and provide prolonged antigen release and lasting immunity thanks to sustained release of the
microencapsulated material. This review provides an applicable summary of different formulation routes for the purpose of
producing safe, qualified and efficacious products of microencapsulated peptide and protein antigens. We have brought to
attention, with case examples, not only the most common means of improving the quality of microsphere formulations, i.e., the
use of stabilising additives, but also less commonly known and applied approaches, e.g., ion pairing, novel polymer systems,
solid-state and other innovative microencapsulation methods.
D 2004 Elsevier B.V. All rights reserved.
Keywords: PLGA microspheres; Antigen stability; Antigen microencapsulation; Antigen release
Contents
1. Introduction..................................................... 358
2. Biodegradable polymers and methods for antigen microencapsulation ....................... 359
2.1. PLGA as biodegradable matrix material .................................. 359
2.2. Commonly used microencapsulation techniques .............................. 359
3. The challenges of antigen release testing and stability ............................... 360
3.1. Antigen release from microspheres ..................................... 360
3.2. Antigen stability .............................................. 361
0169-409X/$ - see front matter D 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.addr.2004.09.002
* Corresponding author. Tel.: +41 44 633 7312; fax: +41 44 633 1314.
E-mail address: bruno.gander@pharma.ethz.ch (B. Gander).
Advanced Drug Delivery Reviews 57 (2005) 357 – 376
www.elsevier.com/locate/addr