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There is huge global concern surrounding the emergence of antimicrobial resistant bacteria and this is resulting in an inability to treat infectious diseases. This is due to a lack of new antimicrobials coming to the market and irresponsible use of traditional antibiotics. Bactofencin A, a novel antimicrobial peptide which shows potential as an antibiotic, is susceptible to enzyme degradation. To improve its solution stability and inherent activity, bactofencin A was loaded onto a traditional silica mesoporous matrix, SBA-15, and a periodic mesoporous organosilane, MSE. The loading of bactofencin A was considerably higher onto SBA-15 than MSE due to the hydrophilic nature of SBA-15. While there was no detectable peptide released from SBA-15 into phosphate buffered saline and only 20% of the peptide loaded onto MSE was released, the loaded matrices showed enhanced activity compared to the free peptide during in vitro antimicrobial assays. In addition, the mesoporous matrices were found to protect bactofencin A against enzymatic degradation where results showed that the SBA-15 and MSE with loaded bactofencin A exposed to trypsin inhibited the growth of S. aureus while a large decrease in activity was observed for free bactofencin upon exposure to trypsin. Thus, the activity and stability of bactofencin A can be enhanced using mesoporous matrices and these matrices may enable its potential development as a novel antibiotic. This work also shows that in silico studies looking at surface functional group and size complementarity between the peptide and the protective matrix could enable the systemic selection of a mesoporous matrix for individual bacteriocins with potential antimicrobial therapeutic properties., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Gallidermin (Gdm) loaded in anionic niosomes composed of Tween 61/CHL/DP (1:1:0.05 molar ratio) gave the highest entrapment efficiency (45.06%). This formulation gave antibacterial activity against Propionibacterium acnes and Staphylococcus aureus with the MIC and MBC of 3.75 and 7.5; 7.5 and 15 microg/microl, respectively. Gdm loaded in niosomes was more chemically stable than Gdm in aqueous solution of about 1.5 times. Gdm loaded and unloaded in niosomes were not found in the receiver solution investigated by vertical Franz diffusion cells at 37 degrees C for 6h. Gdm loaded in niosomes showed higher cumulative amounts in viable epidermis and dermis (VED) of rat skin of about 2 times more than unloaded Gdm. Gdm loaded in niosomes and incorporated in gel exhibited the highest cumulative amounts (82.42+/-9.28 microg cm(-2)) and fluxes (13.74+/-1.55 microg cm(-2)h(-1)) in stratum corneum (SC) and comparative cumulative amounts (183.16+/-30.32 microg cm(-2)) and fluxes (25.74+/-5.05 microg cm(-2)h(-1)) in VED to the unloaded Gdm incorporated in gel. This study has suggested that Gdm loaded in anionic niosomes and incorporated in gel is the superior topical antibacterial formulation because of the high accumulation in the skin with no risk of systemic effect., (Copyright 2010 Elsevier B.V. All rights reserved.)