Florfenicol core-shell composite nanogels as oral administration for efficient treatment of bacterial enteritis

To reduce the bitterness of florfenicol, avoid its degradation by gastric acid, and enhance its antibacterial activity against Escherichia coli by targeting and slowly releasing drugs at the site of intestinal infection, with pectin as an anion carrier and chitosan oligosaccharides (COS) as a cationic carrier, florfenicol-loaded COS@pectin core nanogels were self-assembled by electrostatic interaction and then encapsulated in sodium carboxymethylcellulose (CMCNa) shell nanogels through the complexation of CMCNa and Ca2+ to prepare florfenicol core-shell composite nanogels in this study. The florfenicol core-shell composite nanogels were investigated for their formula choice, physicochemical characterization, pH-responsive performances, antibacterial activity, therapeutic efficacy, and in vitro and in vivo biosafety studies. The results indicated that the optimized formula was 0.6 g florfenicol, 0.79 g CMCNa, 0.30 g CaCl2, 0.05 g COS, and 0.10 g pectin, respectively. In addition, the mean particle diameter, polydispersity index, zeta potential, loading capacity, and encapsulation efficiency were 124.0 ± 7.2 nm, -22.9 ± 2.5 mV, 0.42 ± 0.03, 43.4 % ± 3.1 %, and 80.5 % ± 3.4 %, respectively. The appearance, lyophilized mass, resolvability, scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and fourier transform infrared (FTIR) showed that the florfenicol core-shell composite nanogels were successfully prepared. Florfenicol core-shell composite nanogels had satisfactory stability, rheology, and pH-responsiveness, which were conducive to avoid degradation by gastric acid and achieve targeted and slow release at intestinal infection sites. More importantly, florfenicol core-shell composite nanogels had excellent antibacterial activity against Escherichia coli, a satisfactory therapeutic effect, and good palatability. In vitro and in vivo biosafety studies suggested the great promise of florfenicol core-shell composite nanogels. Therefore, the prepared florfenicol core-shell composite nanogels may be helpful for the treatment of bacterial enteritis as a biocompatible oral administration.

Development of a monoclonal antibody-based time-resolved fluorescence immunochromatographic assay strip for sensitively detecting florfenicol residues in milk and eggs: Theoretical chemical insights into unexpected high specificity

Florfenicol (FF), with its broad-spectrum antibacterial activity, is frequently abused in the livestock and poultry industries and has aroused the growing public concern. Owing to structural similarities and varying maximum residue limits between florfenicol and other chloramphenicol (CAP)-type antibiotics, including thiamphenicol (TAP) and chloramphenicol (CAP), there is an urgent need for a rapid and effective immunoassay method to distinguish them, in order to minimize the risk of false positives. Fortunately, a highly specific monoclonal antibody (mAb), named as SF11, has been developed using hybridoma technology. Molecular simulations have revealed that the mAb SF11's specificity in recognizing florfenicol stems from the π-π stacking interaction between florfenicol and the mAb SF11 binding pocket. Using this highly specific mAb, a sensitive time-resolved fluorescence immunochromatographic assay (TRFICA) strip for rapid florfenicol detection has been developed. Under optimal conditions, this TRFICA demonstrated good analytical performance for the detection of florfenicol in milk and eggs samples, with the half-maximal inhibition concentration (IC50) values of 1.89 and 2.86 ng mL-1, the limit of detection (LOD) of 0.23 and 0.48 ng mL-1, the cut-off values of 62.50 and 31.25 ng mL-1, and the testing time of approximately thirteen minutes. Spiked recoveries in the milk and eggs samples ranged from 104.7 % to 112.3 % and 95.3 % to 116.4 %, respectively, with no obvious cross-reactions with the other analogues observed. The TRFICA results correlated well with those of high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) for real samples, indicating that the developed TRFICA method was sensitive, accurate and adapted for the rapid determination of florfenicol in milk and egg samples.

Formulation, pharmacokinetics, and antibacterial activity of florfenicol-loaded niosome

The growing interest in employing nano-sized pharmaceutical formulations in veterinary medicine has prompted the exploration of the novel nanocarriers' ability to augment the therapeutic outcome. In this study, we harnessed niosomes, spherical nanocarriers formed through non-ionic surfactant self-assembly, to enhance the therapeutic efficacy of the broad-spectrum antibiotic florfenicol. Pre-formulation studies were conducted to identify the optimal parameters for preparing florfenicol-loaded niosomes (FLNs). These studies revealed that the formulation that consisted of Span 60, cholesterol, and dihexadecyl phosphate (DDP) at a molar ratio of 1:1:0.1 exhibited the highest entrapment efficiency (%EE) and uniform size distribution. In vitro antibacterial testing demonstrated the niosomal capacity to significantly reduce florfenicol minimum inhibitory concentration (MIC) against E. coli and S. aureus. Pharmacokinetic profiles of free florfenicol and FLN were assessed following oral administration of 30 mg florfenicol/kg body weight to healthy or E. coli-infected chickens. FLN exhibited a substantially higher maximum plasma concentration (Cmax) of florfenicol compared to free florfenicol. Furthermore, FLN showed significantly higher area under the curve (AUC0-t) than free florfenicol as revealed from the relative bioavailability studies. Lethal dose (LD) 50 values for both free florfenicol and FLN exceeded 5 g/kg of body weight, indicating high safety profile. Assessment of mortality protection in mice against lethal E. coli infections showed the significantly higher capability of FLN to improve the survival rate (75%) than free florfenicol (25%). Collectively, these findings demonstrate the niosomal ability to improve the oral bioavailability as well as the antibacterial activity of the incorporated veterinary antibiotic florfenicol.

Florfenicol sustained-release granules: an in vitro-in vivo correlation study in pigs

The objective of this study was to synthesize and characterize pharmaceutical characteristics of florfenicol sustained-release granules (FSRGs) in vitro and in vivo. FSRGs were synthesized using monostearate, polyethylene glycol 4000 and starch. In vitro dissolution profiles were studied using the rotating basket method in pH 1.2 HCl solution and pH 4.3 acetate buffer. Twenty-four male healthy Landrace×Yorkshire pigs were equally divided into three groups and administered a 20 mg/kg i.v bolus of florfenicol solution and dosed orally with FSRGs in the fasting and fed states. The Higuchi model was the best fit for the drug release profile in pH 1.2 and pH 4.3 media, and the mechanism of drug dissolution was governed by both diffusion and dissolution. We established a level A in vitro - in vivo correlation for FSRGs and the in vivo profile of the FSRGs can be estimated by the in vitro drug release.

Improving intestinal absorption and antibacterial effect of florfenicol via nanocrystallisation technology

To study the effects of nanocrystallisation technology on the intestinal absorption properties and antibacterial activity of florfenicol (FF). The florfenicol nanocrystals (FF-NC) were prepared by wet grinding and spray drying. Additionally, changes in particle size, charge, morphology, and dissolution of FF-NC in the long-term stability were monitored by laser particle sizer, TEM, SEM, paddle method, and the structure of FF-NC powder was characterised by nuclear magnetic resonance (NMR) test. The antibacterial activity, intestinal absorption and intestinal histocompatibility of FF-NC were investigated by the stiletto, mini broth dilution susceptibility test, in situ single-pass intestinal perfusion (SPIP) and haematoxylin-eosin (H-E) staining. After 12 months of storage, the particle size and zeta potential of FF-NC were 280.43 ± 8.21 nm and -19.64 ± 3.45 mV, and the electron microscopy results showed that FF-NC were nearly circular with no adhesion between particles. In addition, the drug loading, encapsulation efficiency, and dissolution of FF-NC did not change significantly during storage. The inhibition zone of FF-NC against Escherichia coli and Staphylococcus aureus was 21.37 ± 1.70 mm and 25.17 ± 2.47 mm, respectively. Compared with the FF, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of FF-NC are reduced, and the absorption rate constant (K_a) and efficient permeability coefficient (P_eff) of FF-NC in the three intestinal segments were increased by 1.28, 0.25, and 9.10 times and 0.59, 0.17, and 6.0 times, respectively. The results of tissue sections showed that FF-NC had little damage to the small intestinal. Nanocrystallisation technology is an effective method to increase the intestinal absorption and antibacterial activity of FF.

Nanoparticles for treatment of bovine Staphylococcus aureus mastitis

Staphylococcus aureus (S. aureus) is one of the most important zoonotic bacterial pathogens, infecting human beings and a wide range of animals, in particular, dairy cattle. Globally. S. aureus causing bovine mastitis is one of the biggest problems and an economic burden facing the dairy industry with a strong negative impact on animal welfare, productivity, and food safety. Furthermore, its smart pathogenesis, including facultative intracellular parasitism, increasingly serious antimicrobial resistance, and biofilm formation, make it challenging to be treated by conventional therapy. Therefore, the development of nanoparticles, especially liposomes, polymeric nanoparticles, solid lipid nanoparticles, nanogels, and inorganic nanoparticles, are gaining traction and excellent tools for overcoming the therapeutic difficulty accompanied by S. aureus mastitis. Therefore, in this review, the current progress and challenges of nanoparticles in enhancing the S. aureus mastitis therapy are focused stepwise. Firstly, the S. aureus treatment difficulties by the antimicrobial drugs are analyzed. Secondly, the advantages of nanoparticles in the treatment of S. aureus mastitis, including improving the penetration and accumulation of their payload drugs intracellular, decreasing the antimicrobial resistance, and preventing the biofilm formation, are also summarized. Thirdly, the progression of different types from the nanoparticles for controlling the S. aureus mastitis are provided. Finally, the difficulties that need to be solved, and future prospects of nanoparticles for S. aureus mastitis treatment are highlighted. This review will provide the readers with enough information about the challenges of the nanosystem to help them to design and fabricate more efficient nanoformulations against S. aureus infections.

Application of some nanoparticles in the field of veterinary medicine

Nanotechnology is a fast-growing technology that plays an important great impact on various fields of therapeutic applications. It is capable for solving several problems related to animal health and production. There are different nano-systems such as liposomes, metallic nanoparticles, polymeric micelles, polymeric nanospheres, functionalized fullerenes, carbon nanotubes, dendrimers, polymer-coated nanocrystals and nanoshells. In this review, we mentioned different methods for the preparation and characterization of nanoparticles. This review is concerned mainly on nanoparticle systems for antibiotic delivery which suffer from poor bioavailability and many side effects. Nanoparticles are characterized by many features include their minimal size, colossal surface zone to mass extent. The development of antimicrobials in nanoparticle systems is considered an excellent alternative delivery system for antimicrobials for the treatment of microbial diseases by increasing therapeutic effect and overcoming the side effects. In this paper, we reviewed some antimicrobial nanoparticle preparations and we focused on florfenicol and neomycin nanoparticle preparations as well as chitosan and silver nanoparticles preparations to prepare, characterize and compare their different pharmacological effects.

Brain targeted delivery of anticancer drugs: prospective approach using solid lipid nanoparticles

A brain tumour is amongst most devastating and challenging condition to overcome with suitable treatment as the drug has to cross the blood-brain barrier (BBB) with several physiological barriers like opsonisation by the reticuloendothelial system. Presently various techniques such as surgical, chemotherapeutic agents, and radiotherapy techniques have performed to extend the lifespan of patients diagnosed with glioblastoma, which did not maximise the overall survival of patients with a tumour. Nanotechnology is relied upon to diminish the requirement for intrusive methods for conveyance of therapeutics to the central nervous system. Colloidal nanocarriers sizing range 1-1000 nm have been utilised to cross BBB delivers the drug at cell levels with enhanced bioavailability and reduced toxicity. However, solid lipid nanoparticles (SLNs) are considered a highly flexible carrier for more successful remedially in brain tumour. The treatment of a brain tumour via SLNs is gaining greater potency due to its inimitable size and lipidic nature. This review focuses and represents the current strategies of SLNs in the brain tumour treatment with appropriate techniques adopted are highlighted. Based on this review, the authors concluded that SLNs embrace exclusive promising lipidic nanocarrier that could be utilised to target a brain tumour effectively.

Development and Characterization of Florfenicol-Loaded BSA Nanoparticles as Controlled Release Carrier

Florfenicol (FLO) is a broad-spectrum fluorinated antibiotic used for the treatment of bacterial diseases such as bovine respiratory disease (BRD) in cattle. FLO is a poorly soluble drug in aqueous solution, and its encapsulation in various nanovehicles has been reported to be less than 30%. In this context, the use of bovine serum albumin (BSA) as a nanocarrier for FLO is an interesting approach. BSA is a biocompatible, biodegradable, nontoxic, and nonimmunogenic natural protein, allowing the vehiculization of hydrophilic and hydrophobic drugs with a well-tolerated administration. The present work focuses on the fabrication and characterization of florfenicol-loaded BSA (FLO-BSA NPs), incorporation efficiency, and in vitro release pattern. FLO-BSA NPs nanoparticles were successfully obtained by a simple, low-cost and in a few steps method. The physicochemical properties of the obtained nanoparticles such as size (~ 120 nm), polydispersity index (0.04), and zeta potential (approximately - 40 mV) suggest a high colloidal stability and suitable characteristics for drug delivery. The drug loading reveals a high incorporation of florfenicol in the nanoparticles, in which 33.6 molecules of FLO are encapsulated per each molecule of BSA. The in vitro release profile exhibits an initial stage characterized by the burst effect and then a prolonged release of FLO from the albumin matrix, which is compatible with the Higuchi model and which follows a Fickian diffusion. The results together suggest a suitable tool for future investigations in drug delivery field in order to use this nanomaterial in food, pharmaceutical, and veterinary industry.

Safety and effectiveness of sodium colistimethate-loaded nanostructured lipid carriers (SCM-NLC) against P. aeruginosa: in vitro and in vivo studies following pulmonary and intramuscular administration

The usefulness of nanotechnology to increase the bioavailability of drugs and decrease their toxicity may be a tool to deal with multiresistant P. aeruginosa (Mr-Pa) respiratory infections. We describe the preparation and the in vivo efficacy and safety of sodium colistimethate-loaded nanostructured lipid carriers (SCM-NLC) by the pulmonary and intramuscular routes. Nanoparticles showed 1-2 mg/L minimum inhibitory concentration against eight extensively drug-resistant P. aeruginosa strains. In vivo, SCM-NLC displayed significantly lower CFU/g lung than the saline and similar to that of the free SCM, even the dose in SCM-NLC group was lower than free SCM. There was no tissue damage related to the treatments. Biodistribution assessments showed a mild systemic absorption after nebulization and a notorious absorption after IM route. Altogether, it could be concluded that SCM-NLC were effective against P. aeruginosa in vivo, not toxic and distribute efficiently to the lung and liver after pulmonary or intramuscular administrations.

Environmental mixtures of nanomaterials and chemicals: The Trojan-horse phenomenon and its relevance for ecotoxicity

The usage of engineered nanomaterials (NM) offers many novel products and applications with advanced features, but at the same time raises concerns with regard to potential adverse biological effects. Upon release and emission, NM may interact with chemicals in the environment, potentially leading to a co-exposure of organisms and the occurrence of mixture effects. A prominent idea is that NM may act as carriers of chemicals, facilitating and enhancing the entry of substances into cells or organisms, subsequently leading to an increased toxicity. In the literature, the term 'Trojan-horse effect' describes this hypothesis. The relevance of this mechanism for organisms is, however, unclear as yet. Here, a review has been performed to provide a more systematic picture on existing evidence. It includes 151 experimental studies investigating the exposure of various NM and chemical mixtures in ecotoxicological in vitro and in vivo model systems. The papers retrieved comprised studies investigating (i) uptake, (ii) toxicity and (iii) investigations considering both, changes in substance uptake and toxicity upon joint exposure of a chemical with an NM. A closer inspection of the studies demonstrated that the existing evidence for interference of NM-chemical mixture exposure with uptake and toxicity points into different directions compared to the original Trojan-horse hypothesis. We could discriminate at least 7 different categories to capture the evidence ranging from no changes in uptake and toxicity to an increase in uptake and toxicity upon mixture exposure. Concluding recommendations for the consideration of relevant processes are given, including a proposal for a nomenclature to describe NM-chemical mixture interactions in consistent terms.