Evaluation of critical formulation parameters influencing the bioactivity of ?-lactamases entrapped in pectin beads - Protein

Evaluation of critical formulation parameters influencing the bioactivity of ?-lactamases entrapped in pectin beads
Received 16 February 2006; revised 23 May 2006; accepted 25 May 2006. Available online 2 June 2006.
Sandrine Bourgeoisa, Muriel Gerneta, Dominique Pradeaub, Antoine Andremonta, c and Elias Fattala
International Journal of Pharmaceutics
Volume 324, Issue 1 , 31 October 2006
ScienceDirect
Copyright ? 2006 Elsevier B.V. All rights reserved.
aUMR CNRS 8612, Group of Targeting and Delivery of Poorly Stable Compounds, School of Pharmacy, Paris-Sud University, 5 Rue Jean Baptiste Cl?ment, 92296 Ch?tenay-Malabry, France
bAGEPS, Laboratoire de D?veloppement Analytique, Paris, France
cBichat-Claude Bernard Hospital, Laboratory of Microbiology, Paris, France
Abstract
The bioactivity of ?-lactamases upon entrapment in calcium-pectinate beads was evaluated. Non-amidated (NAP) and amidated pectin (AP) beads were prepared according to the ionotropic gelation method using calcium chloride (CaCl2) as gelling agent, washed and dried at 37 ?C in an oven for 2 h. Both enzyme activity and protein content were determined as well as bead calcium content. NAP allowed a better encapsulation of the protein than AP. Increasing both CaCl2 concentration and bead residence time in the gelation medium led to a significant loss of ?-lactamase activity. The drying process of beads also lowered the enzyme activity. Moreover, bead calcium content increased as the CaCl2 concentration augmented. Being very hygroscopic, the excess of CaCl2 correlates with an increase of moisture content in beads that affects enzyme activity. After elimination of free calcium from beads, it was shown that a small amount is needed to form the Ca-pectinate network and that the activity of ?-lactamases is preserved in these conditions. Therefore, the bioactivity of encapsulated ?-lactamases in pectin beads mainly depends on formulation parameters such as pectin type, CaCl2 concentration, washing and drying processes.
Keywords: Pectin beads; ?-Lactamases; Colonic drug delivery; Bioactivity; Peptide/protein delivery; Microencapsulation
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