In vitro and in vivo activities of ticarcillin-loaded nanoliposomes with different surface charges against Pseudomonas aeruginosa (ATCC 29248)

Liposome-Based Antibacterial Delivery: An Emergent Approach to Combat Bacterial Infections

The continued emergence and spread of drug-resistant pathogens and the decline in the approval of new antimicrobial drugs pose a major threat to managing infectious diseases, resulting in high morbidity and mortality. Even though a significant variety of antibiotics can effectively cure many bacterial infectious diseases, microbial infections remain one of the biggest global health problems, which may be due to the traditional drug delivery system's shortcomings which lead to poor therapeutic index, low drug absorption, and numerous other drawbacks. Further, the use of traditional antibiotics to treat infectious diseases has always been accompanied by the emergence of multidrug resistance and adverse side effects. Despite developing numerous new antibiotics, nanomaterials, and various techniques to combat infectious diseases, they have persisted as major global health issues. Improving the current antibiotic delivery systems is a promising approach to solving many life-threatening infections. In this context, nanoliposomal systems have recently attracted much attention. Herein, we attempt to provide a concise summary of recent studies that have used liposomal nanoparticles as delivery systems for antibacterial medicines. The minireview also highlights the enormous potential of liposomal nanoparticles as antibiotic delivery systems. The future of these promising approaches lies in developing more efficient delivery systems by precisely targeting bacterial cells with antibiotics with minimum cytotoxicity and high bacterial combating efficacy.

Designer Liposomic Nanocarriers Are Effective Biofilm Eradicators

Drug delivery via nanovehicles is successfully employed in several clinical settings, yet bacterial infections, forming microbial communities in the form of biofilms, present a strong challenge to therapeutic treatment due to resistance to conventional antimicrobial therapies. Liposomes can provide a versatile drug-vector strategy for biofilm treatment, but are limited by the need to balance colloidal stability with biofilm penetration. We have discovered a liposomic functionalization strategy, using membrane-embedded moieties of poly[2-(methacryloyloxy)ethyl phosphorylcholine], pMPC, that overcomes this limitation. Such pMPCylation results in liposomic stability equivalent to current functionalization strategies (mostly PEGylation, the present gold-standard), but with strikingly improved cellular uptake and cargo conveyance. Fluorimetry, cryo-electron, and fluorescence microscopies reveal a far-enhanced antibiotic delivery to model Pseudomonas aeruginosa biofilms by pMPC-liposomes, followed by faster cytosolic cargo release, resulting in significantly greater biofilm eradication than either PEGylation or free drug. Moreover, this combination of techniques uncovers the molecular mechanism underlying the enhanced interaction with bacteria, indicating it arises from bridging by divalent ions of the zwitterionic groups on the pMPC moieties to the negatively charged lipopolysaccharide chains emanating from the bacterial membranes. Our results point to pMPCylation as a transformative strategy for liposomal functionalization, leading to next-generation delivery systems for biofilm treatment.

Experimental Design Supported Liposomal Aztreonam Delivery: In Vitro Studies

Purpose: The present study focuses on a systemic approach to develop liposomal aztreonam as a promising dosage form for inhalation therapy in the treatment of pneumonia and explores the in-vitro antimicrobial and cell uptake efficacy. Methods: Liposomes were prepared by ethanol injection method using the lipids - soya phosphatidylcholine (SP) and cholesterol (CH). A central composite design (CCD) was employed to optimize the lipid composition to evaluate the effect on vesicle size, zeta potential and entrapment efficiency of the formulation. A numerical and graphical optimization was carried out to predict the optimized blend. The optimized formulation was characterized for vesicle size, surface charge, encapsulation, surface morphology, differential scanning calorimetry (DSC), powder X Ray Diffraction (PXRD), thermogravimetric analysis (TGA), in vitro diffusion, accelerated stability studies, antimicrobial studies on Pseudomonas aeruginosa NCIM 2200 and in vitro cell uptake studies. Results: The optimized formulation was found to have a particle size of 144 nm, a surface charge of -35 mV, with satisfactory drug entrapment. The surface morphology study proved the formation of nanosized vesicles. The drug release from liposomal matrix was biphasic in nature. The solid-state study revealed the reason for good encapsulation of drug. The moisture retention capacity was found to be minimum. The anti-microbial study revealed the potential antibacterial activity of the optimized formulation over the pure drug. The formulation was found to be safe on the epithelial cells and showed a marked increase in cellular uptake of aztreonam in a lipid carrier. Conclusion: It can be concluded that the optimized liposomal aztreonam could be considered as a promising approach for the delivery of aztreonam through inhalation.

A brief overview on nano-sized materials used in the topical treatment of skin and soft tissue bacterial infections

Introduction: Skin and soft tissue infections are a significant clinical problem that can happen anywhere on the body. Bacteria are the most common cause of skin and soft tissue infections in humans. Despite the fact that there is a lot of antimicrobial agents and antibiotics for elucidating bacterial infections, the prevention and control of infectious diseases continue to be one of the greatest challenges for public health worldwide. At the present time, an alarming increase in multidrug resistance instantly requests to find suitable alternatives to current antibiotics. Therefore, drug resistance has been attempted to be resolved by the development of new classes of antimicrobial agents or targeted delivery systems for antibacterial drugs using nanotechnology.Area covered: The present review summarizes the emerging topical efforts to support the use of nano-sized materials as a new opportunity to combat today's skin infectious diseases.Expert opinion: Nano-sized materials can overcome the stratum corneum barrier and deliver drugs specifically to bacterial skin infections with trivial side effects. Depending on the physicochemical characteristics of nano-scaled materials, they can specifically be selected to target bacterial pathogens and also to get into the skin layers. These systems can overcome the antibiotic-resistance mechanisms and help us to the design of novel topical formulations that will make administration of antibacterial compounds safer, easier and more convenient.

Liposomal antibiotic formulations for targeting the lungs in the treatment of Pseudomonas aeruginosa

Pseudomonas aeruginosa is a Gram-negative bacterium that causes serious lung infections in cystic fibrosis, non-cystic fibrosis bronchiectasis, immunocompromised, and mechanically ventilated patients. The arsenal of conventional antipseudomonal antibiotic drugs include the extended-spectrum penicillins, cephalosporins, carbapenems, monobactams, polymyxins, fluoroquinolones, and aminoglycosides but their toxicity and/or increasing antibiotic resistance are of particular concern. Improvement of existing therapies against Pseudomonas aeruginosa infections involves the use of liposomes - artificial phospholipid vesicles that are biocompatible, biodegradable, and nontoxic and able to entrap and carry hydrophilic, hydrophobic, and amphiphilic molecules to the site of action. The goal of developing liposomal antibiotic formulations is to improve their therapeutic efficacy by reducing drug toxicity and/or by enhancing the delivery and retention of antibiotics at the site of infection. The focus of this review is to appraise the current progress of the development and application of liposomal antibiotic delivery systems for the treatment pulmonary infections caused by P. aeruginosa.

Nanoliposome-based antibacterial drug delivery

Although most bacterial infectious diseases can be treated successfully with the remarkable array of antibiotics, the microbial pathogens continue to be one of the most critical health challenges worldwide. One of the common efforts in addressing this issue lies in improving the existing antibacterial delivery systems since inefficient delivery can lead to poor therapeutic outcome of the administered drug. Recently, nanoliposomal systems have been widely used as promising strategies to overcome these challenges due to their unique set of properties. This article tries to briefly summarize the current studies that have taken advantage of liposomal nanoparticles as carriers to deliver antibacterial agents. The reviewed investigations demonstrate the immense potential of liposomal nanoparticles as carriers for antibiotic delivery and highlight the latent promise in this class of vehicles for treatment of bacterial infections. The future of these promising approaches lies in the development of more efficient techniques for preparing liposomal nanoparticles with great potential in effective and selective targeting of antibiotics to bacterial cells for eradication as well as the highest safety for human host.