RESUMEN
Bacterial infections in the respiratory tract are considered as one of the major challenges to the public health worldwide. Pulmonary delivery is an attractive approach in the management of bacterial respiratory infections with a few inhaled antibiotics approved. However, with the rapid emergence of antibiotic-resistant bacteria, it is necessary to develop new/alternative inhaled antibacterial agents in the post-antibiotic era. A pipeline of novel biological antibacterial agents, including antimicrobial peptides, RNAi therapeutics, and bacteriophages, has emerged to combat bacterial infections with excellent performance. In this review, the causal effects of bacterial infections on the related pulmonary infectious diseases will be firstly introduced. This is followed by an overview on the development of emerging antibacterial therapeutics for managing lung bacterial infections through nebulization/inhalation of dried powders. The obstacles and underlying proposals regarding their clinical transformation are also discussed to seek insights for further development. Research on inhaled therapy of these emerging antibacterials are still in the infancy, but the promising progress warrants further attention.
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Infecciones Bacterianas , Infecciones del Sistema Respiratorio , Humanos , Infecciones Bacterianas/tratamiento farmacológico , Antibacterianos , Bacterias , Pulmón , Infecciones del Sistema Respiratorio/tratamiento farmacológicoRESUMEN
Facing the increasing threat of multi-drug antimicrobial resistance (AMR), humans strive to search for antibiotic drug candidates and antibacterial alternatives from all possible places, from soils in remote areas to deep in the sea. In this "gold rush for antibacterials," researchers turn to the natural enemy of bacterial cells, bacteriophage (phages), and find them a rich source of weapons for AMR bacteria. Endolysins (lysins), the enzymes phages use to break the bacterial cells from within, have been shown to be highly selective and efficient in killing their target bacteria from outside while maintaining a low occurrence of bacterial resistance. In this review, we start with the structures and mechanisms of action of lysins against Gram-positive (GM+) bacteria. The developmental history of lysins is also outlined. Then, we detail the latest preclinical and clinical research on their safety and efficacy against GM+ bacteria, focusing on the formulation strategies of these enzymes. Finally, the challenges and potential hurdles are discussed. Notwithstanding these limitations, the trends in development indicate that the first, approved lysin drugs will be available soon in the near future. Overall, this review presents a timely summary of the current progress on lysins as antibacterial enzymes for AMR GM+ bacteria, and provides a guidebook for biomaterial researchers who are dedicating themselves to the battle against bacterial infections.
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Infecciones Bacterianas , Bacteriófagos , Antibacterianos/farmacología , Bacterias , Infecciones Bacterianas/tratamiento farmacológico , Bacterias Grampositivas , HumanosRESUMEN
PURPOSE: Previously, a respirable powder (RP) formulation of pirfenidone (PFD) was developed for reducing phototoxic risk; however, PFD-RP demonstrated unacceptable in vitro inhalation performance. The present study aimed to develop a new RP system of PFD with favorable inhalation properties by spray-drying method. METHODS: Spray-dried PFD (SD/PFD) was prepared by spray-drying with L-leucine, and the physicochemical properties and efficacy in an antigen-sensitized airway inflammation model were assessed. A pharmacokinetic study was also conducted after intratracheal and oral administration of PFD formulations. RESULTS: Regarding powder characterization, SD/PFD had dimpled surface with the mean diameter of 1.793 µm. In next generation impactor analysis, SD/PFD demonstrated high in vitro inhalation performance without the need of carrier particles, and the fine particle fraction of SD/PFD was calculated to be 62.4%. Insufflated SD/PFD (0.3 mg-PFD/rat) attenuated antigen-evoked inflammatory events in the lung, including infiltration of inflammatory cells and myeloperoxidase activity. Systemic exposure level of PFD after insufflation of SD/PFD at the pharmacologically effective dose was 600-fold lower than that after oral administration of PFD at the phototoxic dose. CONCLUSION: SD/PFD would be suitable for inhalation, and the utilization of an RP system with SD/PFD would provide a safer medication compared with oral administration of PFD.
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Antiinflamatorios/administración & dosificación , Antiinflamatorios/farmacocinética , Desecación , Neumonía/prevención & control , Piridonas/administración & dosificación , Piridonas/farmacocinética , Tecnología Farmacéutica/métodos , Administración por Inhalación , Administración Oral , Aerosoles , Animales , Antiinflamatorios/química , Antiinflamatorios/toxicidad , Líquido del Lavado Bronquioalveolar/inmunología , Cromatografía Liquida , Modelos Animales de Enfermedad , Composición de Medicamentos , Masculino , Ovalbúmina , Tamaño de la Partícula , Peroxidasa/metabolismo , Neumonía/sangre , Neumonía/inducido químicamente , Neumonía/inmunología , Polvos , Piridonas/química , Piridonas/toxicidad , Ratas Sprague-Dawley , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
PURPOSE: To investigate the applicability of Bipolar Charge Analyzer (BOLAR), a new commercial instrument developed by Dekati Ltd., in simultaneously characterizing the bipolar electrostatic charge profile and measuring the size distribution of commercial metered dose inhalers (MDIs). METHODS: Intal Forte(®) (sodium cromoglycate), Tilade(®) (nedocromil sodium), Ventolin(®) (salbutamol sulphate), and QVAR(®) (beclomethasone dipropionate) were used as model MDIs in this study. Three individual actuations of each MDI were introduced into the BOLAR at an air flow rate of 60 l/min. Charge and mass profiles for each actuation were determined. RESULTS: The BOLAR was found to have better performance in collecting valid charge data (≥80%) than valid mass data (≥50%). In all tested products, both positively and negatively charged particles were found in five defined size fractions between zero and 11.6 µm, with the charge magnitude decreased with increasing particle size. The net charge profiles obtained from the BOLAR qualitatively agreed with the results reported previously. In all suspension type MDIs, negligible masses were detected in the smallest size fraction (<0.95 µm), for which the charge was most likely caused by the propellant and excipients. QVAR was the only solution MDI tested and the charge and mass profiles were significantly different from the suspension-type MDIs. Its mass profile was found to follow closely with the charge profile. CONCLUSIONS: Positively and negatively charged MDI particles of different size fractions and their corresponding charge-to-mass profiles were successfully characterized by the BOLAR.
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Aerosoles/química , Inhaladores de Dosis Medida , Albuterol/química , Antiasmáticos/química , Beclometasona/química , Broncodilatadores/química , Química Farmacéutica/instrumentación , Cromolin Sódico/química , Diseño de Equipo , Humanos , Nedocromil/química , Tamaño de la Partícula , Electricidad EstáticaRESUMEN
Inhaled pharmaceuticals are formulated and delivered differently according to the therapeutic indication. However, specific device-formulation coupling is often fickle, and new medications or indications also demand new strategies. The discontinuation of chlorofluorocarbon propellants has seen replacement of older metered dose inhalers with dry powder inhaler formulations. High-dose dry powder inhalers are increasingly seen as an alternative dosage form for nebulised medications. In other cases, new medications have completely bypassed conventional inhalers and been formulated for use with unique inhalers such as the Staccato® device. Among these different devices, integration of software and electronic assistance has become a shared trend. This review covers recent device and formulation advances that are forming the current landscape of inhaled therapeutics.
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Química Farmacéutica/métodos , Sistemas de Liberación de Medicamentos/instrumentación , Sistemas de Liberación de Medicamentos/métodos , Pulmón/metabolismo , Tecnología Farmacéutica/instrumentación , Tecnología Farmacéutica/métodos , Administración por Inhalación , Química Farmacéutica/instrumentación , Inhaladores de Polvo Seco/instrumentación , Inhaladores de Polvo Seco/métodos , HumanosRESUMEN
Host cell invasion with strong antibiotics evading is a major feature of respiratory Staphylococcus aureus infections with severe recurrence. Bacteriophage (phage) therapy and design of liposomal phage to target intracellular pathogens have been described recently. The practicality for pulmonary delivery of liposomal phage, and how formulation compositions affecting the aerosolization and intracellular bacterial killing remain unexplored. In the present study, three commonly used phospholipids (SPC, EPC, and HSPC) were selected to investigate their ability for phage K nebulization and intracellular therapy in the form of liposome-phage nanocomplexes. The three lipid nanocarriers showed protection on phage K upon mesh nebulization and the pulmonary deposition efficiency was influenced by the lipid used. Moreover, the intracellular bacterial killing was strongly depended on the lipid types, where EPC-phage exhibited the best killing performance with no relapsing. Phage K with the aid of EPC liposomes was also observed to manage the tissue infection in a 3D spheroid model more effectively than other groups. Altogether, this novel EPC liposome-phage nanocomplex can be a promising formulation approach that enables inhalable phage to manage respiratory infections caused by bacteria strongly associated with human epithelial cells.
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Técnicas de Cocultivo , Células Epiteliales , Liposomas , Staphylococcus aureus , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/virología , Humanos , Células Epiteliales/virología , Fosfolípidos/química , Bacteriófagos , Infecciones Estafilocócicas , Administración por Inhalación , Nanopartículas , Nebulizadores y VaporizadoresRESUMEN
Natural products with antibacterial activity are highly desired globally to combat against multidrug-resistant (MDR) bacteria. Antibacterial peptide (ABP), especially cyclic ABP (CABP), is one of the abundant classes. Most of them were isolated from microbes, demonstrating excellent bactericidal effects. With the improved proteolytic stability, CABPs are normally considered to have better druggability than linear peptides. However, most clinically-used CABP-based antibiotics, such as colistin, also face the challenges of drug resistance soon after they reached the market, urgently requiring the development of next-generation succedaneums. We present here a detail review on the novel naturally-occurring CABPs discovered in the past decade and some of them are under clinical trials, exhibiting anticipated application potential. According to their chemical structures, they were broadly classified into five groups, including (i) lactam/lactone-based CABPs, (ii) cyclic lipopeptides, (iii) glycopeptides, (iv) cyclic sulfur-rich peptides and (v) multiple-modified CABPs. Their chemical structures, antibacterial spectrums and proposed mechanisms are discussed. Moreover, engineered analogs of these novel CABPs are also summarized to preliminarily analyze their structure-activity relationship. This review aims to provide a global perspective on research and development of novel CABPs to highlight the effectiveness of derivatives design in identifying promising antibacterial agents. Further research efforts in this area are believed to play important roles in fighting against the multidrug-resistance crisis.
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Antibacterianos , Péptidos Cíclicos , Péptidos Cíclicos/química , Péptidos Cíclicos/farmacología , Antibacterianos/farmacología , Antibacterianos/química , Relación Estructura-Actividad , Humanos , Péptidos Antimicrobianos/química , Péptidos Antimicrobianos/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Productos Biológicos/química , Productos Biológicos/farmacologíaRESUMEN
Methicillin-resistant Staphylococcus aureus (MRSA) has become a leading causative pathogen of nosocomial pneumonia with an alarming in-hospital mortality rate of 30%. Last resort antibiotic, vancomycin, has been increasingly used to treat MRSA infections, but the rapid emergence of vancomycin-resistant strains urges the development of alternative treatment strategies against MRSA-associated pneumonia. The bacteriolytic enzyme, lysostaphin, targeting the cell wall peptidoglycan of S. aureus, has been considered as a promising alternative for MRSA infections. Its proteinaceous nature is likely benefit from direct delivery to the lungs, but the challenges for successful pulmonary delivery of lysostaphin lying on a suitable inhalation device and a formulation with sufficient storage stability. In this study, the applicability of a vibrating mesh nebulizer (Aerogen Solo®) and a soft mist inhaler (Respimat®) was investigated. Both devices were capable of aerosolizing lysostaphin solution into inhalable droplets and caused minimum antibacterial activity loss. In addition, lysostaphin stabilized with phosphate-buffered saline and 0.1% Tween 80 was proved to have acceptable stability for at least 12 months when stored at 4 °C. These promising data encourage further clinical development of lysostaphin for management of MRSA-associated lung infections.
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Antibacterianos , Estabilidad de Medicamentos , Lisostafina , Staphylococcus aureus Resistente a Meticilina , Lisostafina/administración & dosificación , Lisostafina/química , Administración por Inhalación , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Antibacterianos/administración & dosificación , Antibacterianos/química , Antibacterianos/farmacología , Nebulizadores y Vaporizadores , Almacenaje de Medicamentos , Humanos , Pulmón/microbiología , Pulmón/efectos de los fármacosRESUMEN
Respiratory Staphylococcus aureus infection represents a common complication in lung cancer patients, which is characterized with progressively and recurrently intratumor invasion. Although bacteriophages are widely reported as an effective bioweapon for managing bacterial infections, its applicability in handling infectious complications during cancer chemotherapy remains unknown. In this work, we hypothesized cancer chemotherapeutics would influence the efficacy of bacteriophages. To verify this end, interactions between four anticancer drugs (Gemcitabine, Doxorubicin, Cisplatin, and Irinotecan) with phage K were investigated, where Cisplatin directly reduced phage titers while Gemcitabine and Doxorubicin partially inhibited its propagation. The antibacterial efficacy of drug-phage K combinations was tested in a S. aureus infected cancer cell model. Doxorubicin enhanced the antibacterial capacity of phage K, destroying 22-folds of cell-associated bacteria than that of phage K alone use. Also, S. aureus migration was remarkably reduced by Doxorubicin. Overall, our data suggested that Doxorubicin had synergistic effects with phage K in combating S. aureus intracellular infection and migration. This work may broaden the options of indication for phage clinical transformation and also provide reference for the adjunctive application of chemo drugs in intracellular infection management.
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Bacteriófagos , Neoplasias Pulmonares , Terapia de Fagos , Infecciones Estafilocócicas , Humanos , Staphylococcus aureus , Cisplatino , Doxorrubicina , AntibacterianosRESUMEN
The co-existence of various pathogenic bacteria on the surface of pork products exacerbates difficulties in food safety control. Developing broad-spectrum and stable antibacterial agents that are not antibiotics is an unmet need. To address this issue, all l-arginine residues of a reported peptide (IIRR)4-NH2 (zp80) were substituted with the corresponding D enantiomers. This novel peptide (IIrr)4-NH2 (zp80r) was expected to maintain favourable bioactivity against ESKAPE strains and have enhanced proteolytic stability compared with zp80. In a series of experiments, zp80r maintained favourable bioactivities against starvation-induced persisters. Electron microscopy and fluorescent dye assays were used to verify the antibacterial mechanism of zp80r. Importantly, zp80r reduced bacterial colonies in chilled fresh pork contaminated with multiple bacterial species. This newly designed peptide is a potential antibacterial candidate to combat problematic foodborne pathogens during storage of pork.
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Carne de Cerdo , Carne Roja , Animales , Porcinos , Carne Roja/análisis , Antibacterianos/farmacología , Péptidos/farmacología , BacteriasRESUMEN
Fracture-related infection (FRI) is a devastating complication in orthopedic surgery. A recent study showed that FRI causes more severe infection and further delays healing in osteoporotic bone. Moreover, bacterial biofilm formed on implants cannot be eradicated by systemic antibiotics, warranting novel treatments. Here, we developed a DNase I and Vancomycin hydrogel delivery vehicle to eradicate Methicillin-resistant Staphylococcus aureus (MRSA) infection in vivo. Vancomycin was encapsulated in liposomes, and DNase I and Vancomycin/liposomal-Vancomycin was loaded on thermosensitive hydrogel. In vitro drug release test showed a burst release of DNase I (77.2%) within 72 h and sustained release of Vancomycin (82.6%) up to day 14. The in vivo efficacy was evaluated in a clinically relevant ovariectomy (OVX) induced osteoporotic metaphyseal fracture model with MRSA infection, and a total of 120 Sprague Dawley rats were used. In the OVX with infection group, biofilm development caused a drastic inflammatory response, trabecular bone destruction, and non-union. In the DNase I and Vancomycin co-delivery hydrogel group (OVX-Inf-DVG), bacteria on bone and implant were eradicated. X-ray and micro-CT showed preservation of trabecular bone and bone union. HE staining showed the absence of inflammatory necrosis, and fracture healing was restored. The local elevation of TNF-α and IL-6 and increased number of osteoclasts were prevented in the OVX-Inf-DVG group. Our findings suggest that dual release of DNase I and Vancomycin initially followed by Vancomycin only later up to 14 days effectively eliminates MRSA infection, prevents biofilm development and provides a sterile environment to promote fracture healing in osteoporotic bone with FRI. STATEMENT OF SIGNIFICANCE: The biofilm on implants are difficult to eradicate, causing recurrent infection and non-union in fracture-related infection (FRI). Here we developed a hydrogel therapy with high in vivo efficacy to eliminate MRSA biofilm infection in a clinically-relevant FRI model in osteoporotic bone. By loading DNase I and vancomycin/liposomal-vancomycin on thermosensitive poly-(DL-lactic acidco-glycolic acid) (PLGA)-polyethylene glycol (PEG)-PLGA hydrogel, a dual release of DNase I and Vancomycin was achieved whilst preserving enzyme activity. In this model, the progressive development of infection caused a drastic inflammatory response, osteoclastogenesis, trabecular bone destruction, and non-union of fracture. These pathological changes were successfully prevented by the dual delivery of DNase I and vancomycin. Our findings provide a promising strategy for FRI in osteoporotic bone.
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Staphylococcus aureus Resistente a Meticilina , Osteoporosis , Fracturas Osteoporóticas , Infecciones Estafilocócicas , Ratas , Animales , Femenino , Vancomicina/farmacología , Liposomas , Curación de Fractura , Hidrogeles/farmacología , Ratas Sprague-Dawley , Antibacterianos/farmacología , Materiales Biocompatibles/farmacología , Osteoporosis/complicaciones , Osteoporosis/tratamiento farmacológico , Infecciones Estafilocócicas/tratamiento farmacológicoRESUMEN
The multi-inlet vortex mixer (MIVM) has emerged as a novel bottom-up technology for solid nanoparticle preparation. However, its performance in liposome preparation remains unknown. Here, two key process parameters (aqueous/organic flow rate ratio (FRR) and total flow rate (TFR)) of MIVM were investigated for liposome preparation. For this study, two model drugs (lysozyme and erythromycin) were chosen for liposome encapsulation as the representative hydrophilic and hydrophobic drugs, respectively. In addition, two modified MIVMs, one with herringbone-patterned straight inlets and one with zigzag inlets, were designed to further improve the mixing efficiency, aiming to achieve better drug encapsulation. Data showed that FRR played an important role in liposome size control, and a size of <200 nm was achieved by FRR higher than 3:1. Moreover, increasing TFR (from 1 to 100 mL/min) could further decrease the size at a given FRR. However, similar regularities in controlling the encapsulation efficiency (EE%) were only noted in erythromycin-loaded liposomes. Modified MIVMs improved the EE% of lysozyme-loaded liposomes by 2~3 times at TFR = 40 mL/min and FRR = 3:1, which was consistent with computational fluid dynamics simulations. In summary, the good performance of MIVM in the control of particle size and EE% makes it a promising tool for liposome preparation, especially for hydrophobic drug loading, at flexible production scales.
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AIMS: With the ageing population, fragility fractures have become one of the most common conditions. The objective of this study was to investigate whether microbiological outcomes and fracture-healing in osteoporotic bone is worse than normal bone with fracture-related infection (FRI). METHODS: A total of 120 six-month-old Sprague-Dawley (SD) rats were randomized to six groups: Sham, sham + infection (Sham-Inf), sham with infection + antibiotics (Sham-Inf-A), ovariectomized (OVX), OVX + infection (OVX-Inf), and OVX + infection + antibiotics (OVX-Inf-A). Open femoral diaphysis fractures with Kirschner wire fixation were performed. Staphylococcus aureus at 4 × 104 colony-forming units (CFU)/ml was inoculated. Rats were euthanized at four and eight weeks post-surgery. Radiography, micro-CT, haematoxylin-eosin, mechanical testing, immunohistochemistry (IHC), gram staining, agar plating, crystal violet staining, and scanning electron microscopy were performed. RESULTS: Agar plating analysis revealed a higher bacterial load in bone (p = 0.002), and gram staining showed higher cortical bone colonization (p = 0.039) in OVX-Inf compared to Sham-Inf. OVX-Inf showed significantly increased callus area (p = 0.013), but decreased high-density bone volume (p = 0.023) compared to Sham-Inf. IHC staining showed a significantly increased expression of TNF-α in OVX-Inf compared to OVX (p = 0.049). Significantly reduced bacterial load on bone (p = 0.001), enhanced ultimate load (p = 0.001), and energy to failure were observed in Sham-Inf-A compared to Sham-Inf (p = 0.028), but not in OVX-Inf-A compared to OVX-Inf. CONCLUSION: In osteoporotic bone with FRI, infection was more severe with more bone lysis and higher bacterial load, and fracture-healing was further delayed. Systemic antibiotics significantly reduced bacterial load and enhanced callus quality and strength in normal bone with FRI, but not in osteoporotic bone. Cite this article: Bone Joint Res 2022;11(2):49-60.
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Dry powder inhaler (DPI) is a device used to deliver a drug in dry powder form to the lungs. A wide range of DPI products is currently available, with the choice of DPI device largely depending on the dose, dosing frequency and powder properties of formulations. Computational fluid dynamics (CFD), together with various particle motion modelling tools, such as discrete particle methods (DPM) and discrete element methods (DEM), have been increasingly used to optimise DPI design by revealing the details of flow patterns, particle trajectories, de-agglomerations and depositions within the device and the delivery paths. This review article focuses on the development of the modelling methodologies of flow and particle behaviours in DPI devices and their applications to device design in several emerging fields. Various modelling methods, including the most recent multi-scale approaches, are covered and the latest simulation studies of different devices are summarised and critically assessed. The potential and effectiveness of the modelling tools in optimising designs of emerging DPI devices are specifically discussed, such as those with the features of high-dose, pediatric patient compatibility and independency of patients' inhalation manoeuvres. Lastly, we summarise the challenges that remain to be addressed in DPI-related fluid and particle modelling and provide our thoughts on future research direction in this field.
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Bacteriophage endolysins (lysins, or murein hydrolases) are enzymes that bacteriophages utilize to degrade the cell wall peptidoglycans (PG) and subsequently disintegrate bacterial cells from within. Due to their muralytic activity, lysins are considered as potential candidates to battle against antibiotic resistance. However, most lysins in their native form lack the capability of trespassing the outer membrane (OM) of Gram-negative (G-ve) bacteria. To turn the bacteriophage enzymes into antibacterial weapons against G-ve bacteria, endowing these enzymes the capability of accessing the PG substrate underneath the OM is critical. Here we show that fusing a membrane-permeabilizing peptide CeA at the C-terminus of a muralytic enzyme LysAB2 renders a two-step mechanism of bacterial killing and increases the activity of LysAB2 against the multidrug resistant Acinetobacter baumannii by up to 100â¯000-folds. The engineered LysAB2, termed LysAB2-KWK here, also shows remarkable activity against A. baumannii at the stationary phase and a prominent capability to disrupt biofilm formation. In addition, the enzyme shows a broad antibacterial spectrum against G-ve bacteria, a decent tolerance to serum, and a prolonged storage life. LysAB2-KWK rescues the larva of the greater wax moth Galleria mellonella from A. baumannii infection through systemic administration. Altogether, our work equips a globular lysin with OM permeabilization activity to enable effective killing of G-ve bacteria, reveals the critical role of the C-terminus of a globular lysin in the antibacterial activity, and points toward a viable route to engineer globular lysins as antibacterial enzymes for potential clinical use against multidrug resistant G-ve bacteria.
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Acinetobacter baumannii , Antiinfecciosos , Bacteriófagos , Antibacterianos/farmacología , Farmacorresistencia Bacteriana MúltipleRESUMEN
Protein and peptide drugs orally suffer from extremely low bioavailability principally for the complicated gastrointestinal environment along with the difficulty of passing through the mucus layer and the underlying epithelium. In our work, we fabricated mesoporous silica nanoparticles with modification groups (MSN-NH2@COOH/CPP5) that effectively penetrated the mucus layer and passed through the intestinal epithelium by mimicking the virus surface. Naked nanoparticles were prepared with inner pores of 6 nm diameter to allow efficient insulin loading and coated with the cationic cell-penetrating KLPVM peptide and the anionic glutaric anhydride to yield hydrophilic MSN-NH2@COOH/CPP5 with a ζ-potential of -0.49 mV. The apparent permeability coefficient of virus-mimicking nanoparticles was 14.61 × 10-5 cm/s. The virus-mimicking nanoparticles showed dramatically lower binding to mucin and faster penetration of the mucus layer than positively charged nanoparticles (MSN@NH2) with a ζ-potential of +35.00 mV. The KLPVM peptide enhanced the uptake of MSN-NH2@COOH/CPP5 by coculturing Caco-2 and E12 cells as an intestinal epithelium model. MSN-NH2@COOH/CPP5 enhanced apical-to-basal transcytosis for being internalized primarily through caveolae-mediated endocytosis. Indeed, for MSN-NH2@COOH/CPP5, the transepithelial transport of the Caco-2 cell monolayer was 2.4-fold higher than MSN@NH2 and 2.0-fold higher than MSN-NH2@COOH. In vitro, loading insulin into nanoparticles maintained the bioactivity of the protein under simulated intestinal conditions. Insulin loaded into MSN-NH2@COOH/CPP5 reduced the diabetic rats' blood glucose level by nearly 50%. The bioavailability of insulin encapsulated in the MSN-NH2@COOH/CPP5 nanoparticles was 2.1-fold more than insulin when administered directly into the jejunum. Nanoparticles with modifications indicated no significant toxicity in in vitro or in vivo preliminary studies. The obstacles of the mucus layer and intestinal epithelium may be effectively conquered by these virus-mimicking nanoparticles for oral delivery of protein and peptide drugs.
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Materiales Biomiméticos/química , Insulina/metabolismo , Mucosa Intestinal/metabolismo , Moco/metabolismo , Nanopartículas/química , Dióxido de Silicio/química , Virus , Administración Oral , Secuencia de Aminoácidos , Animales , Células CACO-2 , Portadores de Fármacos/química , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Insulina/administración & dosificación , Insulina/química , Absorción Intestinal , Oligopéptidos/química , Porosidad , RatasRESUMEN
With the advancement of technology, drug delivery systems and molecules with more complex architecture are developed. As a result, the drug absorption and disposition processes after administration of these drug delivery systems and engineered molecules become exceedingly complex. As the pharmacokinetic and pharmacodynamic (PK-PD) modeling allows for the separation of the drug-, carrier- and pharmacological system-specific parameters, it has been widely used to improve understanding of the in vivo behavior of these complex delivery systems and help their development. In this review, we summarized the basic PK-PD modeling theory in drug delivery and demonstrated how it had been applied to help the development of new delivery systems and modified large molecules. The linkage between PK and PD was highlighted. In particular, we exemplified the application of PK-PD modeling in the development of extended-release formulations, liposomal drugs, modified proteins, and antibody-drug conjugates. Furthermore, the model-based simulation using primary PD models for direct and indirect PD responses was conducted to explain the assertion of hypothetical minimal effective concentration or threshold in the exposure-response relationship of many drugs and its misconception. The limitations and challenges of the mechanism-based PK-PD model were also discussed.
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Bacteriophage-encoded endolysins (lysins) have emerged as a novel class of antibacterial agents to combat the surging antibiotic resistance. Lysins have specific structures and mechanisms to exert antibacterial effect against both Gram-positive (G+ve) and Gram-negative (G-ve) bacteria. However, its use against G-ve bacteria is limited because the outer membrane (OM) of G-ve bacteria hinders the permeation of exogenously applied lysins. Besides identifying lysins with intrinsic OM permeability, several other approaches including combining lysins with outer membrane permeabilizers (OMPs), protein engineering and formulating with nanocarriers have been proposed to enhance the permeability and activity of lysins. In the present review, we summarize strategies that have been developed to enable lysins to target G-ve bacteria in the past decade. While lysins demonstrates clear potential in managing bacterial infections caused by the drug-resistant G-ve bacteria, there are still challenges hindering their translation into clinical settings, including safety issues with OMP use, low efficiency against stationary phase bacteria and problems in stability. The applicability of protein engineering and formulation sciences to improve enzyme stability, and combination therapy with other classes of antibacterial agents to maximize the therapeutic potential have also been reviewed.
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Infecciones Bacterianas , Bacteriófagos , Antibacterianos/farmacología , Endopeptidasas , Bacterias Gramnegativas , HumanosRESUMEN
Carbapenem-resistant Klebsiella pneumoniae (CRKP) pose a significant threat to global public health. In present research, a total of 80 CRKP strains belonging to ST11 were collected with 70% (56 of 80 isolates) expressing a K47 capsular type. Thus, it is significant to prevent and control infections caused by these bacteria. Capsule depolymerases could degrade bacterial surface polysaccharides to reduce their virulence and expose bacteria to host immune attack. Previous studies have demonstrated the potential of phage-encoded depolymerases as antivirulent agents in treating CRKP infections in vitro and in vivo. Here, two capsule depolymerases (Dpo42 and Dpo43) derived from phage IME205 were expressed and characterized. Although both depolymerases act on strains with a capsular serotype K47, they are active against different subsets of strains, indicating subtle differences in capsule composition that exist within this serotype. The host range of phage IME205 matched to the sum of specificity range of Dpo42 and Dpo43. These two enzymes maintained stable activity in a relatively broad range of pH levels (pH 5.0-8.0 for Dpo42 and pH 4.0-8.0 for Dpo43) and temperatures (20-70°C). Besides, both Dpo42 and Dpo43 could make host bacteria fully susceptible to the killing effect of serum complement and display no hemolytic activity to erythrocytes. In summary, capsule depolymerases are promising antivirulent agents to combat CRKP infections.