PLGA nano- and microparticles for the controlled release of florfenicol: Experimental and theoretical study

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.

Delivery of florfenicol in veterinary medicine through a PLGA-based nanodelivery system: improving its performance and overcoming some of its limitations

As is the case with other veterinary antibiotics, florfenicol (FFC) faces certain limitations, such as low solubility in water, or the fact that it is reported to interfere with the immune response after some immunoprofilactic actions in livestock. Aiming to improve its efficacy and overall performance, FFC was loaded into a polymeric nanobased delivery system by succesfully using the emulsion-evaporation technique. The poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with FFC were characterized in terms of size (101 ± 0.52 nm), zeta potential (26.80 ± 1.30 mV) and poly-dispersity index (0.061 ± 0.019). The achieved loading was 2.24 μg FFC/mg of NPs, with an entrapment efficiency of 7.9%. The antimicrobial effect, the anti-biofilm formation and the cytotoxicity properties of the NPs were evaluated. The results indicated a MIC decreased by ~97.13% for S. aureus, 99.33% for E.coli and 64.1% for P. aeruginosa when compared to free FFC. The minimum inhibitory concentration (MIC) obtained indicated the potential for using a significantly lower dose of florfenicol. The delivery system produced biofilm inhibition while showing no cytotoxic effects when tested on porcine primary fibroblasts and horse mesenchymal stem cells. These findings suggest that florfenicol can be improved and formulations optimized for use in veterinary medicine through its incorporation into a nanobased delivery system designed to release in a controlled manner over time.

Old Antibiotics Can Learn New Ways: A Systematic Review of Florfenicol Use in Veterinary Medicine and Future Perspectives Using Nanotechnology

Florfenicol is a broad-spectrum bacteriostatic antibiotic used exclusively in veterinary medicine in order to treat the pathology of farm and aquatic animals. It is a synthetic fluorinated analog of thiamphenicol and chloramphenicol that functions by inhibiting ribosomal activity, which disrupts bacterial protein synthesis and has shown over time a strong activity against Gram-positive and negative bacterial groups. Florfenicol was also reported to have anti-inflammatory activity through a marked reduction in immune cell proliferation and cytokine production. The need for improvement came from (1) the inappropriate use (to an important extent) of this antimicrobial, which led to serious concerns about florfenicol-related resistance genes, and (2) the fact that this antibiotic has a low water solubility making it difficult to formulate an aqueous solution in organic solvents, and applicable for different routes of administration. This review aims to synthesize the various applications of florfenicol in veterinary medicine, explore the potential use of nanotechnology to improve its effectiveness and analyze the advantages and limitations of such approaches. The review is based on data from scientific articles and systematic reviews identified in several databases.

Electrospray Deposition of Polyvinylidene Fluoride (PVDF) Microparticles: Impact of Solvents and Flow Rate

Polymeric microparticles have been shown to have great impacts in the area of drug delivery, biosensing, and tissue engineering. Electrospray technology, which provides a simple yet effective technique in the creation of microparticles, was utilized in this work. In addition, altering the electrospray experimental parameters such as applied voltage, flow rate, collector distance, solvents, and the polymer-solvent mixtures can result in differences in the size and morphology of the produced microparticles. The effects of the flow rate at (0.15, 0.3, 0.45, 0.6, 0.8, and 1 mL/h) and N, N-Dimethylformamide (DMF)/acetone solvent ratios (20:80, 40:60, 60:40, 80:20, 100:0 v/v) in the production of polyvinylidene fluoride (PVDF) microparticles were studied. Scanning electron microscopy (SEM) was used to observe changes in the morphology of the microparticles, and this revealed that a higher acetone to DMF ratio produces deformed particles, while flow rates at (0.3 and 0.45 mL/h) and a more optimized DMF to acetone solvent ratio (60:40 v/v) produced uniform spherical particles. We discovered from the Raman spectroscopy results that the electrosprayed PVDF microparticles had an increase in piezoelectric β phase compared to the PVDF pellet used in making the microparticles, which in its original form is α phase dominant and non-piezoelectric.

Characterization of the Shells in Layer-By-Layer Nanofunctionalized Particles: A Computational Study

Drug delivery carriers are considered an encouraging approach for the localized treatment of disease with minimum effect on the surrounding tissue. Particularly, layer-by-layer releasing particles have gained increasing interest for their ability to develop multifunctional systems able to control the release of one or more therapeutical drugs and biomolecules. Although experimental methods can offer the opportunity to establish cause and effect relationships, the data collection can be excessively expensive or/and time-consuming. For a better understanding of the impact of different design conditions on the drug-kinetics and release profile, properly designed mathematical models can be greatly beneficial. In this work, we develop a continuum-scale mathematical model to evaluate the transport and release of a drug from a microparticle based on an inner core covered by a polymeric shell. The present mathematical model includes the dissolution and diffusion of the drug and accounts for a mechanism that takes into consideration the drug biomolecules entrapped into the polymeric shell. We test a sensitivity analysis to evaluate the influence of changing the model conditions on the total system behavior. To prove the effectiveness of this proposed model, we consider the specific application of antibacterial treatment and calibrate the model against the data of the release profile for an antibiotic drug, metronidazole. The results of the numerical simulation show that ∼85% of the drug is released in 230 h, and its release is characterized by two regimes where the drug dissolves, diffuses, and travels the external shell layer at a shorter time, while the drug is released from the shell to the surrounding medium at a longer time. Within the sensitivity analysis, the outer layer diffusivity is more significant than the value of diffusivity in the core, and the increase of the dissolution parameters causes an initial burst release of the drug. Finally, changing the shape of the particle to an ellipse produces an increased percentage of drugs released with an unchanged release time.

Recent advances in the formulation of PLGA microparticles for controlled drug delivery

Polymeric microparticles (MPs) are recognized as very popular carriers to increase the bioavailability and bio-distribution of both lipophilic and hydrophilic drugs. Among different kinds of polymers, poly-(lactic-co-glycolic acid) (PLGA) is one of the most accepted materials for this purpose, because of its biodegradability (due to the presence of ester linkages that are degraded by hydrolysis in aqueous environments) and safety (PLGA is a Food and Drug Administration (FDA)-approved compound). Moreover, its biodegradability depends on the number of glycolide units present in the structure, indeed, lower glycol content results in an increased degradation time and conversely a higher monomer unit number results in a decreased time. Due to this feature, it is possible to design and fabricate MPs with a programmable and time-controlled drug release. Many approaches and procedures can be used to prepare MPs. The chosen fabrication methodology influences size, stability, entrapment efficiency, and MPs release kinetics. For example, lipophilic drugs as chemotherapeutic agents (doxorubicin), anti-inflammatory non-steroidal (indomethacin), and nutraceuticals (curcumin) were successfully encapsulated in MPs prepared by single emulsion technique, while water-soluble compounds, such as aptamer, peptides and proteins, involved the use of double emulsion systems to provide a hydrophilic compartment and prevent molecular degradation. The purpose of this review is to provide an overview about the preparation and characterization of drug-loaded PLGA MPs obtained by single, double emulsion and microfluidic techniques, and their current applications in the pharmaceutical industry.Graphic abstract.

In situ Formed Implants, Based on PLGA and Eudragit Blends, for Novel Florfenicol Controlled Release Formulations

Drug controlled release technologies (DCRTs) represent an opportunity for designing new therapies. Main objectives are dose number optimization and secondary effects reduction to improve the level of patient/client acceptance. The present work studies DCRTs based in blended polymeric implants for single dose and long-term therapies of florfenicol (FF), a broad spectrum antibiotic. Polymers used were PLGA and Eudragit E100/S100 types. Eudragit/PLGA and FF/PLGA ratios were the main studied factors in terms of encapsulation efficiencies (EEs) and drug release profiles. In addition, morphological and physicochemical characterization were carried out. EEs were of 50-100% depending on formulation composition, and the FF releasing rate was increased or diminished when E100 or S100 were added, respectively. PLGA hydrolytic cleavage products possibly affect Eudragit solubility and matrix stability. Different mathematical models were used for better understanding and simulating release processes. Implants maintained the antimicrobial activity against Pseudomonas aeruginosa up to 12 days on agar plates. The developed DCRTs represents a suitable alternative for florfenicol long-term therapies.

Trimethoprim-Loaded Microspheres Prepared from Low-Molecular-Weight PLGA as a Potential Drug Delivery System for the Treatment of Urinary Tract Infections

Commonly, therapy of urinary tract infections suffers from increasing resistance to antibiotics and the ability of uropathogenic Escherichia coli (UPEC) to invade bladder cells and cause recurring infections. As an alternative strategy for instillation into the bladder, trimethoprim-loaded microparticles with poly(d,l-lactic-co-glycolic acid) (PLGA) as a matrix were prepared. To reduce particle loss by washout, their surface was grafted with bioadhesive wheat germ agglutinin, providing biomimicry akin to UPEC. Since PLGA 503H has shown a slow drug release profile, the low-molecular-weight PLGA 2300 was studied. Whereas the drug loading of PLGA 503H particles amounted to 2.8%, the drug content of PLGA 2300 particles was twice as high. Although the drug release pattern started with an initial burst of 30% after 24 h for both PLGA types, half of the trimethoprim content was released after 4 days from PLGA 503H microparticles as opposed to 2 days in the case of PLGA 2300. Higher drug loading and accelerated release render PLGA 2300 a viable alternative to PLGA 503H.

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.