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

Safety and usefulness of nebulized liposomal amphotericin B: Systematic scoping review

PURPOSE

Invasive fungal infections potentially result in fatal outcomes in immunocompromised hosts. Compared to intravenous administration, a nebulization therapy can achieve a high concentration of drug delivered in the respiratory tract, without a systematic absorption. We herein summarized the study findings on the safety and clinical utility of nebulized liposomal amphotericin B therapy.

METHODS

According to the PRISMA Extension for Scoping Reviews, we performed a search on MEDLINE and EMBASE for articles with relevant keywords, including "inhaled liposomal amphotericin B″, "nebulized liposomal amphotericin B″, or "aerosolized liposomal amphotericin B″, from the inception of these databases to August 31, 2022.

RESULTS

Of the 172 articles found, 27 articles, including 13 case reports, 11 observational studies, and 3 clinical trials, were selected. Generally, findings showed that nebulized liposomal amphotericin B treatment appeared to be safe and without severe adverse effects. We found an accumulated evidence for the safety, tolerability, and effectiveness of nebulized liposomal amphotericin B prophylaxis among lung transplantation recipients; however, a randomized controlled study has yet to be reported. Data on hemato-oncological patients are relatively scarce; however, a randomized controlled study suggested the prophylactic effect of nebulized liposomal amphotericin B on invasive pulmonary aspergillosis. Observational and randomized controlled studies to evaluate therapeutic efficacy of the nebulized liposomal amphotericin B therapy have not been performed.

CONCLUSION

In conclusion, we found increasing evidence for the effectiveness of the inhalation therapy among patients after lung transplantation and with hemato-oncological diseases.

Recent Advances in Pharmaceutical Approaches of Antimicrobial Agents for Selective Delivery in Various Administration Routes

Globally, the increase of pathogenic bacteria with antibiotic-resistant characteristics has become a critical challenge in medical treatment. The misuse of conventional antibiotics to treat an infectious disease often results in increased resistance and a scarcity of effective antimicrobials to be used in the future against the organisms. Here, we discuss the rise of antimicrobial resistance (AMR) and the need to combat it through the discovery of new synthetic or naturally occurring antibacterial compounds, as well as insights into the application of various drug delivery approaches delivered via various routes compared to conventional delivery systems. AMR-related infectious diseases are also discussed, as is the efficiency of various delivery systems. Future considerations in developing highly effective antimicrobial delivery devices to address antibiotic resistance are also presented here, especially on the smart delivery system of antibiotics.

Safety and Therapeutic Efficacy of Thymoquinone-Loaded Liposomes against Drug-Sensitive and Drug-Resistant Acinetobacter baumannii

In the present study, we investigated the activity of free thymoquinone (TQ) or liposomal thymoquinone (Lip-TQ) in comparison to standard antibiotic amoxicillin (AMX) against the drug-sensitive and drug-resistant Acinetobacter baumannii. A liposomal formulation of TQ was prepared and characterized and its toxicity was evaluated by analyzing the hematological, liver and kidney function parameters. TQ was effective against both drug-sensitive and drug-resistant A. baumannii as shown by the findings of drug susceptibility testing and time kill kinetics. Moreover, the therapeutic efficacy of TQ or Lip-TQ against A. baumannii was assessed by the survival rate and the bacterial load in the lung tissues of treated mice. The mice infected with drug-sensitive A. baumannii exhibited a 90% survival rate on day 30 post treatment with Lip-TQ at a dose of 10 mg/kg, whereas the mice treated with AMX (10 mg/kg) had a 100% survival rate. On the other hand, the mice infected with drug-resistant A. baumannii had a 70% survival rate in the group treated with Lip-TQ, whereas AMX was ineffective against drug-resistant A. baumannii and all the mice died within day 30 after the treatment. Moreover, Lip-TQ treatment effectively reduced the bacterial load in the lung tissues of the mice infected with the drug-sensitive and drug-resistant A. baumannii. Moreover, the blood of the mice treated with Lip-TQ had reduced levels of inflammation markers, leukocytes and neutrophils. The results of the present study suggest that Lip-TQ may prove to be an effective therapeutic formulation in the treatment of the drug-sensitive or drug-resistant A. baumannii infection as well.

An overview of chitosan and its application in infectious diseases

Infectious diseases, such as the coronavirus disease-19, SARS virus, Ebola virus, and AIDS, threaten the health of human beings globally. New viruses, drug-resistant bacteria, and fungi continue to challenge the human efficacious drug bank. Researchers have developed a variety of new antiviral and antibacterial drugs in response to the infectious disease crisis. Meanwhile, the development of functional materials has also improved therapeutic outcomes. As a natural material, chitosan possesses good biocompatibility, bioactivity, and biosafety. It has been proven that the cooperation between chitosan and traditional medicine greatly improves the ability of anti-infection. This review summarized the application and design considerations of chitosan-composed systems for the treatment of infectious diseases, looking forward to providing the idea of infectious disease therapy.

Efficacy of Levofloxacin Loaded Nonionic Surfactant Vesicles (Niosomes) in a Model of Pseudomonas aeruginosa Infected Sprague Dawley Rats

This study examined the effectiveness of niosomes loaded with levofloxacin in treating Pseudomonas aeruginosa (American Type Culture Collection—ATCC 27853) infections in Sprague Dawley rats since these infections are becoming more common and resistant to treatment. Levofloxacin entrapped in niosomes was prepared using the thin-film hydration method and was assessed for in vitro release and stability. Three groups of six (6) animals were infected with a lethal dose of Pseudomonas aeruginosa via the intraperitoneal (Ip) route. At six (6) hours postinfection, the animals were treated with either drug-free niosomes (control), free levofloxacin (conventional), or levofloxacin trapped in niosomes (Ip) at a dose of 7.5 mg/kg/once daily. Blood was collected via tail snips on days 0, 1, 3, 5, 7, and 10 for complete blood counts and viable bacterial counts (CFU/μl). At day 10, the animals were sacrificed, and the kidney, liver, and spleen were harvested for bacterial counts. The niosomes showed a sustained drug release profile and were most stable at 4°C. All animals in the control group succumbed to the infection; one animal from the conventional group died, and all niosome treated animals survived at day 10. The mean lymphocyte count (×10⁹) was lower for the niosome (7.258 ± 1.773) versus conventional group (17.684 ± 10.008) (p < 0.03) at day ten (10). Neutrophil counts (×10⁹) were lower for the niosome (2.563 ± 1.609) versus conventional (6.2 ± 6.548) (p < 0.02) groups. Though CFUs in the bloodstream were comparable for both treatment groups, the niosome treated group showed a significant reduction of CFUs in the liver, kidney, and spleen versus the conventional group (1.33 ± 2.074) vs (5.8 ± 3.74) (p < 0.043), (1.5 ± 2.35) vs (9.6 ± 8.65) (p < 0.038) and (3.8 4.71) vs (25.6 14.66) (p < 0.007), respectively. These findings indicate that niosome is promising as a drug delivery system in treating systemic infections, but further work using niosomes with surface modification is recommended.

Inhaled Liposomal Antimicrobial Delivery in Lung Infections

The management of difficult-to-treat acute and chronic respiratory infections (infections in cystic fibrosis, non-cystic fibrosis bronchiectasis, immunocompromised and mechanically ventilated patients) and difficult-to-treat pathogens (including multidrug-resistant strains) has become a challenge in clinical practice. The arsenal of conventional antibiotic drugs can be limited by tissue penetration, toxicities, or increasing antibiotic resistance. Inhaled antimicrobials are an interesting therapeutic approach for optimizing the management of respiratory infections. Due to extensive developments in liposome technology, a number of inhaled liposome-based antibiotic and antifungal formulations are available for human use and many products are undergoing clinical trials. Liposomes are biocompatible, biodegradable, and nontoxic vesicles able to encapsulate and carry antimicrobials, enhancing the therapeutic index of various agents and retention at the desired target within the lung. Liposomes reduce drug toxicity and improve tolerability, leading to better compliance and to decreased respiratory side effects. The aim of this article was to provide an up-to-date overview of nebulized liposomal antimicrobials for lung infections (with a special focus on liposomal amikacin, tobramycin, ciprofloxacin, and amphotericin B for inhalation), discussing the feasibility and therapeutic potential of these new strategies of preventing and treating bacteria, mycobacterial and fungal infections.

Polymyxin B-Polysaccharide Polyion Nanocomplex with Improved Biocompatibility and Unaffected Antibacterial Activity for Acute Lung Infection Management

The decade-old antibiotic, polymyxin B (PMB), is regarded as the last line defense against gram-negative "superbug." However, the serious nephrotoxicity and neurotoxicity strongly obstruct further application of this highly effective antibiotic. Herein, a charge switchable polyion nanocomplex exhibiting pH-sensitive property is proposed to deliver PMB which is expected to improve the biosafety of PMB on the premise of retaining excellent antibacterial activity. The polyion nanocomplex is prepared through electrostatic interaction of positively charged PMB and negatively charged 2,3-dimethyl maleic anhydride (DA) grafted chitoligosaccharide (CS). The negative charge of CS-DA will convert to positive due to the hydrolysis of amide bonds in acidic infectious environment, leading to the disassembly of CS-DA/PMB nanocomplex and release of PMB. CS-DA/PMB nanocomplex does not show significant toxicity to mammalian cells while retaining excellent bactericidal capability equivalent to free PMB. The nephrotoxicity and neurotoxicity of CS-DA/PMB dramatically decrease compared to free PMB. Moreover, CS-DA/PMB nanocomplex exhibits superior bactericidal activity against Pseudomonas aeruginosa in an acute lung infection mouse model. The pH-sensitive polyion nanocomplexes may provide a new way to reduce the side effects of highly toxic antibiotics without reducing their intrinsic antibacterial activity, which is the key factor to achieve extensive in vivo clinical applications.

Coupling quaternary ammonium surfactants to the surface of liposomes improves both antibacterial efficacy and host cell biocompatibility

By functionalizing the surface of PEG-liposomes with linkers bearing quaternary ammonium compounds (QACs), we generated novel bacteria disruptors with anti-adhesive properties and reduced cytotoxicity compared to free QACs. Furthermore, QAC-functionalized liposomes are a promising platform for future drug encapsulation. The QAC (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide (MTAB) was attached to maleimide-functionalized liposomes (DSPE-PEG) via thiol linker. The MTAB-functionalized liposomes were physicochemically characterized and their biological activity, in terms of anti-adherence activity and biofilm prevention in Escherichia coli were assessed. The results showed that MTAB-functionalized liposomes inhibit bacterial adherence and biofilm formation while reducing MTAB toxicity.

The antibacterial properties of phenolic isomers, carvacrol and thymol

Most of the antibacterial activities of essential oils from the Lamiaceae herbaceous plant family thyme and oregano are attributed to their bioactive isomeric monoterpenoid constituents, carvacrol and thymol. Commercially available antibiotics of thymol or carvacrol have not yet been developed but health products have incorporated thymol into their formulations for their antimicrobial properties. Carvacrol and thymol are generally considered safe for consumption and they have been used in dental applications, approved as food flavorings and have been considered as antibacterial additives in food and feed. Many studies have demonstrated that carvacrol and thymol are potent antibacterial agents against both Gram-positive and Gram-negative bacteria. The most frequently reported mechanism of antibacterial action of both isomers involves the disruption of bacterial membrane leading to bacterial lysis and leakage of intracellular contents resulting in death. Other proposed mechanisms of antibacterial action include the inhibition of efflux pumps, prevention in the formation and disruption of preformed biofilms, inhibition of bacterial motility, and inhibition of membrane ATPases. In addition, both isomers have been found to act additively or synergistically with conventional antibiotics important in overcoming the problem of bacteria resistance in food and disease.

Nanomedicine for anticancer and antimicrobial treatment: an overview

Nanoparticle-based treatment has become a potential therapeutic approach. The nanosize of these particles provides them with unique physicochemical properties and enhances their interaction with the biological system. Nanomaterials have the potential to overcome some of the major issues in the clinical world which may include cancer treatment and may be utilised to resolve the major problem of drug resistance in infection control. These particles are being used to improve present therapeutics by virtue of their shape, size and diverse intrinsic as well as chemical properties. The authors have discussed the use of nanoparticles in cancer treatment, infections caused by multidrug-resistant microbial strains and biofilm inhibition along with the detailed description of the current status of nanomaterials in the field of medicine.

Antimicrobial activity of polymyxin-loaded solid lipid nanoparticles (PLX-SLN): Characterization of physicochemical properties and in vitro efficacy

Antimicrobial resistance is a current public health concern, limiting the available therapeutic options used for the treatment of common bacterial infections. The development of new drug entities via biotechnological processes is however expensive and time-consuming. Therefore, old antimicrobial agents have been recovered for clinical use. An example of these drugs is polymyxin, which is known for its serious adverse side effects, such as nephrotoxicity, neurotoxicity and promotion of skin pigmentation. To overcome these limitations, the use of biodegradable nanoparticles has been proposed to allow site-specific targeting, increasing the drug's bioavailability and decreasing its side effects. The aim of this work was the development of an optimized pharmaceutical formulation composed of solid lipid nanoparticles (SLN) loading polymyxin B sulphate (PLX) for the treatment of bacterial infections. The PLX-loaded SLN were produced by a double emulsion method (w/o/w), obtaining particles with a mean size of approximately 200nm, polydispersity of 0.3 and zeta potential of -30mV. The encapsulation efficiency reached values above 90% for all developed formulations. SLN remained stable for a period of 6months of storage at room temperature. The occlusive properties of the SLN was shown to be dependent on the type of lipid, while the antimicrobial properties of PLX-loaded SLN were effective against resistant strains of Pseudomonas aeruginosa. Results from the differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS) analyses confirmed the crystallinity of the inner SLN matrices, suggesting the capacity of these particles to modify the release profile of the loaded drug.

Nanotechnology solutions to restore antibiotic activity

This review focuses on the development of nanoparticle systems that enables to enhance and restore the antibiotic activity for drug-resistant organisms. New and more aggressive antibiotic resistant bacteria and parasites calls for the development of new therapeutic strategies to overcome the inefficiency of conventional antibiotics and bypass treatment limitations related to these pathologies. Nanostructured biomaterials, nanoparticles in particular, have unique physicochemical properties such as ultra-small and controllable size, large surface area to mass ratio, high reactivity, and functionalizable structure. These properties can be applied to facilitate the administration of antimicrobial drugs, thereby overcoming some of the limitations in traditional antimicrobial therapeutics. Here the current progress and challenges in synthesizing nanoparticle platforms for restoring activity of various antimicrobial drugs are reviewed with an emphasis on antibiotics. We also call attention to the need to unite the shared interest between nanoengineers and microbiologists in developing nanotechnology for the treatment of microbial diseases.

Novel formulations for antimicrobial peptides

Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy.