Antibacterial activity of liposome-encapsulated antibiotics against Pseudomonas aeruginosa attached to the matrix of human dermis

Colistin- and amikacin-loaded lipid-based drug delivery systems for resistant gram-negative lung and wound bacterial infections

Antimicrobial resistance (AMR) is a global health issue, which needs to be tackled without further delay. The World Health Organization(WHO) has classified three gram-negative bacteria, Pseudomonas aeruginosa, Klebsiella pneumonia and Acinetobacter baumannii, as the principal responsible for AMR, mainly causing difficult to treat nosocomial lung and wound infections. In this regard, the need for colistin and amikacin, the re-emerged antibiotics of choice for resistant gram-negative infections, will be examined as well as their associated toxicity. Thus, current but ineffective clinical strategies designed to prevent toxicity related to colistin and amikacin will be reported, highlighting the importance of lipid-based drug delivery systems (LBDDSs), such as liposomes, solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), as efficient delivery strategies for reducing antibiotic toxicity. This review reveals that colistin- and amikacin-NLCs are promising carriers with greater potential than liposomes and SLNs to safely tackle AMR, especially for lung and wound infections.

Polypeptide Self-Assembled Nanoparticles as Delivery Systems for Polymyxins B and E

Polymyxins are peptide antibiotics that are highly efficient against many multidrug resistant pathogens. However, the poor stability of polymyxins in the bloodstream requires the administration of high drug doses that, in turn, can lead to polymyxin toxicity. Consequently, different delivery systems have been considered for polymyxins to overcome these obstacles. In this work, we report the development of polymyxin delivery systems based on nanoparticles obtained from the self-assembly of amphiphilic random poly(l-glutamic acid-co-d-phenylalanine). These P(Glu-co-dPhe) nanoparticles were characterized in terms of their size, surface charge, stability, cytotoxicity, and uptake by macrophages. The encapsulation efficiency and drug loading into P(Glu-co-dPhe) nanoparticles were determined for both polymyxin B and E. The release kinetics of polymyxins B and E from nanoformulations was studied and compared in buffer solution and human blood plasma. The release mechanisms were analyzed using a number of mathematical models. The minimal inhibitory concentrations of the nanoformulations were established and compared with those determined for the free antibiotics.

Cholesterol--a biological compound as a building block in bionanotechnology

Cholesterol is a molecule with many tasks in nature but also a long history in science. This feature article highlights the contribution of this small compound to bionanotechnology. We discuss relevant chemical aspects in this context followed by an overview of its self-assembly capabilities both as a free molecule and when conjugated to a polymer. Further, cholesterol in the context of liposomes is reviewed and its impact ranging from biosensing to drug delivery is outlined. Cholesterol is and will be an indispensable player in bionanotechnology, contributing to the progress of this potent field of research.

Preparation and comparative clinical evaluation of liposomal gel of benzoyl peroxide for acne

A novel topical benzovl peroxide (BP) gelformulation containing liposomal BP was shown to significantly reduce local irritation relative to its nonliposomal BP gel (plain BP gel) preparation and also to improve clinical efficacy (almost twofold) in the treatment of acne. BP liposomes were prepared, optimized, and formulated into a carbopol 934gel base. Drug release evaluated using dialysis membrane has repeatedly shown that a new topical gel formulation containing liposomal BP (liposomal BP gel) significantly reduced BP penetration. Clinical evaluation data were also compared with those obtained with liposomal tretinoin (TRE) gel in an earlier investigation of ours. The overall improvement in terms of percentage reduction in total number of skin lesions demonstrated almost similar results for both BP and TRE. However, variation was observed in the treatment of separate types of lesions in which liposomal TRE gel was found to be more effective in treating comedones and liposomal BP gel in treating papules and pustules. Also, the liposomal gel formulation of both the drugs significantly reduced the local adverse effects, thereby improving patient compliance.

Clinical assessment of the combination therapy with liposomal gels of tretinoin and benzoyl peroxide in acne

The findings of this investigation thus conclusively demonstrate the promising role of concomitant therapy of liposomal TRE and BP gels in treating acne patients. Allthough their use improved the therapeutic response, more benefits of the liposomal form of drugs were observed in terms of reduction in adverse effects of therapy, thus fostering better patient compliance. It can be concluded that this study underscores the potential utility of concomitant therapy with liposomal TRE and BP gels in the treatment of acne. However, the role of liposmal formulations may only be established after clinical evaluation of alarge number of patients, with a special focus on the adverse symptoms of therapy.