1. bookVolume 73 (2022): Issue 4 (December 2022)
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1848-6312
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26 Mar 2007
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Evaluation of bacterial uptake, antibacterial efficacy against Escherichia coli, and cytotoxic effects of moxifloxacin-loaded solid lipid nanoparticles

Published Online: 07 Jan 2023
Volume & Issue: Volume 73 (2022) - Issue 4 (December 2022)
Page range: 260 - 269
Received: 01 Jul 2022
Accepted: 01 Nov 2022
Journal Details
License
Format
Journal
eISSN
1848-6312
First Published
26 Mar 2007
Publication timeframe
4 times per year
Languages
English

Resistance to antibiotics has become a serious healthcare issue as it erodes the efficiency of many currently used antibiotics (14). According to the World Health Organization (WHO), antimicrobial resistance is one of the most important dangers for people’s health in the world and may become the cause of 10 million deaths every year by 2050 (5). New antimicrobial strategies are therefore needed to address this issue. In the fight against antibiotic resistance, new studies are focused on discovering and developing alternative agents like synthetic active ingredients (6), plant metabolites (7), antimicrobial peptides (8), virulence inhibitors (9), phages (10), and nanosized drug delivery technologies (11, 12). These include nanoparticles, which are carrier systems with a size of 10–1,000 nm in diameter, usually of natural or synthetic and biodegradable or non-biodegradable materials (13). In these systems, a drug can be dissolved, trapped, and/or encapsulated (14, 15) to achieve higher efficacy through higher uptake at lower risk of adverse effects (16).

Among them, lipid nanoparticles (LNPs) have gained popularity over the last few decades. Solid lipid nanoparticles (SLNs) consist of a solid lipid core stabilised by surfactants. Nanostructured lipid carriers (NLCs), are a step further from SLNs (16, 17), as they contain a mixture of solid and liquid lipids. Lipid particles have many advantages over standard drug formulations because of their adaptability, low toxicity, high bioavailability, possibility to deliver both hydrophilic and lipophilic drugs, and easy scaling up that enables large-scale production (1820).

Due to their lipophilic nature, SLNs and NLCs can also easily cross barriers like the bacterial cell membrane (21), and entrap hydrophobic drugs. Although some studies (22, 23) reported encapsulation of hydrophilic drugs as well, loading of a high amount of hydrophilic drugs in these carriers is more challenging and involves careful selection of solid or liquid lipids and suitable surfactants used in lipophilic and aqueous phases (24).

One such hydrophilic drug is moxifloxacin (MOX), a water-soluble fluoroquinolone derivative with broad-spectrum antibiotic activity. It inhibits the bacterial DNA gyrase and topoisomerase IV enzymes to disrupt DNA replication and repair and kill susceptible bacterial cells (25). It is used in the treatment of skin (26) and respiratory tract infections like chronic bronchitis, pneumonia, and acute bacterial sinusitis. It is especially effective against recurrent Escherichia coli (E. coli) infections (27, 28).

Loading an antibiotic into colloidal carriers like LNPs could counteract the efflux mechanism, through which resistance is developed, and increase intracellular retention of the drug (29). Wong et al. (30) encapsulated ciprofloxacin, which belongs to the same antibiotic family as MOX, in multilamellar liposome vesicles to improve its in vivo activity against Francisella tularensis and Brucella melitensis. However, as far as we know, MOX has not been studied in this context so far. The aim of our study was to find a way to enhance its uptake into bacterial cell using these lipid carrier systems, as they structurally resemble the bacterial membrane. We also wanted to see if lower antibiotic concentration could maintain the efficiency of a standard treatment dose of MOX. We also characterised the nanoparticles in terms of their size, distribution, zeta potential, encapsulation efficiency, and in vitro release. To determine the biocompatibility of the newly developed formulations, we also investigated the cytotoxic effects of LNPs in RAW 264.7 monocyte/ macrophage-like cells.

Materials and methods

Glyceryl dibehenate (CAS Nos. 6916-74-1, 77538-19-3, 3023364-8; brand name Compritol® 888 ATO), serving as solid lipid, was a gift from Gattefossé-SAS (Saint-Priest, France). Poloxamer 407, Tween (polysorbate) 80, triethanolamine (TEA), and fluorescein were bought from Sigma (Munich, Germany). MOX was a gift from Koçak Farma (Istanbul, Turkey). Docosahexanoic acid (DHA) (CAS No. 6217-54-5) and oleic acid (CAS No. 112-80-1), serving as liquid lipids, were kindly provided by Croda Inc. (New Jersey, NJ, USA). In addition, bacterial media , namely tryptic soy agar (TSA; agar 15 g/L, casein peptone 15 g/L, sodium chloride 5 g/L, soy peptone 5 g/L) and tryptic soy broth (TSB; casein peptone 17 g/L, dipotassium hydrogen phosphate 2.5 g/L, glucose 2.5 g/L, sodium chloride 5 g/L, soya peptone 3 g/L) used for growing the bacteria and Mueller Hinton agar (MHA; agar 17 g/L, beef infusion solids 2 g/L, casein hydrolysate 17.5 g/L, starch 1.5 g/L) and cation-adjusted Mueller Hinton broth (MHB; acid hydrolysate of casein 17.5 g/L, beef extract 3 g/L, starch 1.5 g/L) used for antibacterial activity tests were purchased from Merck Life Science (Darmstadt, Germany). All the other chemicals were of analytical grade.

Chemicals used for cytotoxicity testing were purchased from the following suppliers: Dulbecco’s Modified Eagle Medium (DMEM) and Dulbecco’s Phosphate-Buffered Saline (PBS) from Wisent Bioproducts (Quebec, Canada), trypsin-EDTA from Biological Industries (Beit-Haemek, Israel), foetal bovine serum (FBS) and penicillin-streptomycin from Capricorn Scientific (Ebsdorfergrund, Germany), and dimethyl sulphoxide (DMSO) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) from Sigma-Aldrich Chemicals (Munich, Germany).

E. coli ATCC 25922 were obtained from the American Type Culture Collection (ATCC).

The RAW 264.7 monocyte/macrophage-like cells were kindly provided by Yeditepe University Faculty of Pharmacy, Department of Pharmaceutical Toxicology, İstanbul, Turkey.

Preparation of lipid nanoparticles

SLNs and NLCs were prepared by ultrasonication (31) using components reported in Table 1. For SLNs we used only solid lipids in the lipid phase. Lipids were first melted and heated to 70 °C with Tween 80 or poloxamer 407 used as emulsifiers. Then we heated 10 mL of water containing 10 mg of MOX to 70 °C and added to the lipid phase. The mixture was sonicated with a probe sonicator (Sonopuls, Bandelin, Germany) at 50 % amplitude for 1 min and let to cool down to room temperature (25 °C) for 2 h to allow formation of particles. A similar method was used to obtain the NLCs, except that solid and liquid lipids were combined as the lipid phase (see Table 1 for details). Moreover, blank nanoparticles (without MOX) were prepared to compare the effects.

Composition of lipid nanoparticles

Formulation codeSolid lipid (glyceryl dibehenate)Liquid lipid (docosahexaenoic acid, DHA)Liquid lipid (oleic acid)Tween 80Poloxamer 407Triethanolamine (TEA)
SLN1150 mg--100 mg--
SLN2150 mg---100 mg-
NLC1110 mg40 mg10 mg-100 mg10 mg
NLC2110 mg40 mg--100 mg10 mg

NLC – nanostructured lipid carrier; SLN – solid lipid nanoparticle

To label the nanoparticles, fluorescein (5 mg) was added instead of MOX at the lipid phase step and mixed with magnetic stirrer for 30 s. The water phase and the remaining steps were applied as described above.

Determination of particle size, polydispersity index, and zeta potential

Nanoparticle size and polydispersity index (PDI) were measured with photon correlation spectroscopy (aka dynamic light scattering) and zeta potential with laser Doppler velocimetry (both using the Nicomp Nano Z3000 system, PSS, Inc., New York, NY, USA. Each sample was measured in triplicate (32).

Encapsulation efficiency (EE)

To calculate loaded MOX we used an indirect method by measuring MOX content in supernatants. Samples were centrifuged (IEC Centra MP4R, Rockville, USA) at 9000 g for 20 min and MOX detected with a high performance liquid chromatograph (HPLC, Agilent 1260 Infinity, Agilent Technologies Inc., Waldbronn, Germany) using a C18 column (150 mm × 4.6 mm i.d., 5 μm; ACE, Reading, UK) at the wavelength of 302 nm. Column temperature was 30 °C. The mobile phase was a mix of methanol-distilled water-acetonitrile (60:45:5) (v/v/v). It was adjusted to pH 2.7 with o-phosphoric acid. The flow rate was 1 mL/min (33).

In vitro drug release studies

MOX release from the nanoparticles was determined with the dialysis bag method (34). One millilitre (1 mL) of each nanoparticle suspension was placed in a dialysis bag (12–14 kDa, Spectrum Labs, USA) and the bag immersed in 50 mL of PBS (pH 7.4) and held in a shaker (Nuve, Istanbul, Turkey) operating at 50 rpm at 37 °C. MOX release was determined in 1 mL of PBS taken out from the pool at 15 and 30 min, and 1, 2, 4, 6, 8, 12, and 24 h. After each reading the PBS buffer was replaced with the same volume of a fresh one. The amount of released MOX was measured with the Agilent HPLC mentioned above.

TEM analysis

To characterise the morphology of MOX-loaded SLNs and NLCs, the particles were observed under a FEI Tecnai G2 Spirit BioTwin (Thermo Fisher, Waltham, MA, USA) transmission electron microscope (TEM) operating at 40 kV and 80,000× magnification. Samples were mounted on copper grids with a mesh size of 200 (75 microns), stained with 2 % uranyl acetate for 2 min, and then the excess removed with filter paper. The remainder was dried in a Petri dish for 2 h before microscopy.

Stability tests

Vials with formulations were kept in a dark fridge at +4 °C for one month and their particle size, polydispersity index, and zeta potential rechecked as described above.

Bacteria

E. coli ATCC 25922 were cultivated in tryptic soy agar and tryptic soy broth at 35±1 °C, and the study was carried out with 24-hour fresh bacterial cultures.

Bacterial uptake of nanoparticles

To determine the bacterial uptake of SLNs and NLCs we used fluorescent microscopy and flow cytometry. Briefly, 0.1 mL of E. coli suspension at log phase was added to SLNs and NLCs and incubated at 37 °C for 2 h. After incubation, the bacterial pellet and culture supernatant were separated by centrifugation at 4137 g. The pellet was washed with sterile distilled water three times to discard free NLCs or SLNs and then resuspended in 1 mL of sterile distilled water. The fluorescent intensity of E. coli cells was observed with a CYTOFlex cytometer (Beckman Coulter, Suzhou, China). Blue fluorescence was collected through a 525/40 BP fluorescent channel with a 488 nm blocking filter. For each sample around ten thousand cells were analysed. Data were measured and histograms created and interpreted using the CytExpert 2.4 Software (Beckman Coulter, Indianapolis, IN, USA). In addition, to detect the position of MOX-loaded NLCs and SLNs in bacteria, the cells were observed under a DM IL inverted fluorescent microscope at 40× magnification and images taken (Leica, Munich, Germany).

Antibacterial activity

Antibacterial activity against E. coli was tested with the broth microdilution method for minimal inhibition concentration (MIC) and with the disc diffusion test for the inhibition zone according to the European Committee on Antimicrobial Susceptibility Testing standards (35). For the disc diffusion test we used 4.0±0.5 mm deep Mueller-Hinton agar plates (25 mL in a 90 mm circular Petri dish). Bacterial suspensions were prepared from fresh E. coli cultures in sterile saline (0.9 % NaCl) to the density of a 0.5 McFarland measured with a DEN-1B densitometer (Biosan SIA, Riga, Latvia). A sterile cotton swab was dipped into bacterial suspensions and spread on the agar surface in three directions. Discs with MOX-loaded SLNs and NLCs were then placed on the surface of inoculated agar plates and incubated at 35±1 °C for 18±2 h. After incubation, inhibition diameters around the discs were measured and compared to standard MOX as control.

For the broth microdilution (MIC) test 100 μL of cation-adjusted Mueller-Hinton broth added to all U-bottom microplate wells. We added 100 μL of MOX-loaded nanoparticle solution to the first well and diluted it further across 12 wells. Then the bacterial suspension (in saline, 0.9 % NaCl) with the density of the 0.5 McFarland (1x108 CFU/mL) was 1:100 diluted and added to all wells to obtain the final bacterial concentration of 5x105 CFU/mL. The microplates were then incubated at 35±1 °C for 18±2 h, and MIC determined as the lowest concentration of MOX-loaded SLN and NLC solutions that visibly inhibited the growth of E. coli.

Preparation of RAW 264.7 cell cultures

RAW 264.7 cells were seeded in 25 cm2 flasks filled with 7 mL of DMEM supplemented with 10 % FBS, and 1 % penicillin-streptomycin and then grown in an incubator (Sanyo, Osaka, Japan) at 37 °C in an atmosphere supplemented with 5 % CO2 for 24 h.

Cytotoxicity assay

Cytotoxicity was determined with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay as described earlier by Bacanli et al. (36). Cells were detached with a cell scraper and a total of 105 cells/well seeded in 96-well tissue-culture plates. The cells were incubated in full medium with various concentrations (0.010, 0.025, 0.05, and 0.1 μg/mL) of MOX alone, MOX-free SLNs, MOX-loaded SLNs, MOX-free NLCs, and MOX-loaded NLCs at 37 °C in an atmosphere supplemented with 5 % CO2 for 24, 48, and 72 h. For negative control we used a medium containing 10 % FBS and 1 % penicillin-streptomycin. After exposure, the medium was aspirated, cells washed with PBS, 10 μL of MTT (5 mg/ mL of stock solution with PBS) added to 100 μL of cell suspension per well, and cells incubated for another 3 h. The MTT dye was then carefully removed and 100 μL of DMSO added to each well. The absorbance of each well was measured with a microplate reader (Epoch, BioTek Instruments, Winooski, VT, USA) at 570 nm.

Statistical analysis

For statistical analysis we used the SPSS for Windows v. 20.0 software (IBM, New York, NY USA). All data are expressed as means ± standard deviations of measurements in three biological replicates. As the distribution was normal, differences between the groups were compared using Student’s t test. Statistical significance was set to p<0.05.

Results and discussion
Lipid nanoparticle properties

The composition of lipid nanoparticles is given in Table 1. Visual inspection did not reveal any separation between the oil and water phase in the MOX-loaded SLNs and NLCs, that is, emulsification was successful.

We aimed for small particles for better uptake by bacteria. SLN1, which contains Tween 80 as emulsifier, had significantly lower particle size and PDI compared to SLN2, which contains poloxamer 407 (p<0.05, Table 2). These differences in particle size and PDI are likely owed to the lower molecular weight of Tween 80 than that of poloxamer 407 (37), as suggested by similar studies (38, 39). PDI values of SLNs were below 0.3 characteristic of a monodisperse system (40). SLN1 had lower encapsulation efficiency than SLN2, which may be related to its lower particle size. Zeta potentials were significantly different (p<0.05), possibly due to different emulsifiers used in the SLNs.

Lipid nanoparticle properties

LNPParticle size (nm)Polydispersity indexZeta potential (mV)Encapsulation efficiency (%)
SLN1181.6±1.270.25±0.02-14.6±0.3268.61±0.20
SLN2201.8±1.650.29±0.02-17.5±0.1474.53±0.34
NLC1176.8±1.900.57±0.23-11.6±0.6177.82±0.21
NLC2132.4±1.620.51±0.53-6.3±0.3877.17±0.21

Results are represented as means ± standard deviations

NLC1 had bigger particles and distribution than NLC2. As known, particle size and distribution can be modified with sonication, which breaks coarse emulsion droplets to form a nano-emulsion, so it is one of important parameters to bear in mind while preparing lipid nanoparticles (41). If sonication is less effective, nanoparticles containing more liquid lipids, like NLC1, tend to form bigger particles, as liquid lipids increase the viscosity of coarse formulations.

Zeta potential of formulations may differ as particles contain different liquid phases. For instance, oleic acid, which was used in NLC2 as liquid phase, could shift the zeta potential from -6.3±0.38 to -11.6±0.61. However, there was no significant difference in encapsulation efficiency between NLCs (Table 2).

Table 3 shows that there were no significant changes in particle size, polydispersity index, and zeta potential measured in the formulations after one month, save for the drop in zeta potential in the SLN1 formulation. However, it is clear that particles tend to aggregate during storage, which leads to a gain in size and polydispersity index and loss in zeta potential.

Stability of lipid nanoparticles stored for one month at +4 °C

Particle size (nm)Polydispersity indexZeta potential (mV)
Type of LNPsBaseline valueAfter one month storageBaseline valueAfter one month storageBaseline valueAfter one month storage
SLN1181.6±1.27186.1±2.890.25±0.020.36±0.25-14.6±0.32-10.0±0.51*
SLN2201.8±1.65200.5±3.560.29±0.020.39±0.12-17.5±0.14-11.5±0.45*
NLC1176.8±1.90180.3±1.640.57±0.230.60±0.46-11.6±0.61-8.30±0.78
NLC2132.4±1.62135.2±3.980.51±0.530.65±0.22-6.3±0.38-5.62±0.96

Results are represent as means ± standard deviations. * significant difference from baseline (p<0.05)

TEM images and photon correlation spectroscopy of LNPs show spherical particles of similar size (Figure 1).

Figure 1

TEM images of SLN1 (a), SLN2 (b), NLC1 (c), and NLC2 (d)

Drug release

Figure 2 shows MOX release from nanoparticles. The release of standard (not nanoparticle-loaded) MOX was high in the first two hours, after which it kept dropping by the end of hour 4, at which point 95 % of MOX was released, and no more drug was until hour 24. LNPs slowed down its release thanks to its even dispersion in the lipid matrix and diffusion from it, as previously proposed by other authors (42, 43).

Figure 2

MOX release from nanoparticles

Bacterial uptake of nanoparticles

Figure 3 shows flow cytometry findings of E. coli cells. There is no fluorescence signal in control cells (Figure 3a), which were incubated with unlabelled nanoparticles, whereas the rest shows a strong signal (Figure 3b-f). Bacterial uptake of SLN1 and SLN2 (57.29 % and 50.74 %, respectively) was significantly more efficient than that of fluorescein solution alone (21.47 %) or either NLC (39.26 % for NLC1 and 32.79 % for NLC2) (p<0.05).

Figure 3

Flow cytometry results (a: blank NPS; b: fluorescein solution; c: SLN1; d: SLN2; e: NLC1; f: NLC2)

Judging by higher uptake of lipid nanoparticles than the fluorescein solution alone, drug encapsulation in nanoparticles should enhances drug absorption owing to the small size, prolonged release, and hydrophobic nature of lipid nanoparticles, which is similar to the Gram-negative bacterial cell wall (44). Apparently, smaller size of SLN1 is also the reason for higher bacterial uptake than that of SLN2, which is in line with previous reports (45).

These findings are confirmed by fluorescence microscopy (Figure 4), as only a small number of bacterial cells absorbed fluorescein solution alone (Figure 4a), whereas lipid nanoparticles show better absorption (Figure 4b-e) and therefore confirm that they can better enter bacteria than the free drug, as suggested in a related study (14).

Figure 4

Photomicrographs show bacterial uptake of formulations (a: fluorescein solution; b: SLN1; c: SLN2; d: NLC1; e: NLC2)(40× magnification)

Antibacterial activity

Table 4 shows the antibacterial activity of nanoparticles in terms of inhibition zone (diameter) and MIC. Only the SLN1 formulation was significantly more effective against E. coli (MIC 0.020 μg/mL, 34 mm) than MOX delivered as a standard solution (p<0.05). The NLC1 formulation showed better inhibition diameter (36 mm) than standard MOX but not MIC. In fact, SLN2 and both NLC formulations showed the same MIC as the corresponding standard MOX.

Antibacterial activity of MOX-loaded SLNs and NLCs

FormulationsInhibition diameter (mm)Minimal inhibition concentration (μg/mL)
Standard MOX solution for SLNs * (0.68 mg)33±0.070.041
SLN134±0.10***0.020
SLN232±0.110.041
Standard MOX solution for NLCs** (0.78 mg)35±0.080.023
NLC136±0.120.023
NLC235±0.050.023

The concentration was equal to the amount of MOX loaded into SLNs.

The concentration was equal to the amount of MOX loaded into NLCs.

significant difference p<0.05

Cytotoxic effects of MOX, MOX-free, and MOX-loaded LNPs in RAW 264.7 cells

RAW 264.7 cell viability (%)
24 h48 h72 h
0.010 µg/mL0.025 µg/mL0.05 µg/mL0.1 µg/mL0.010 µg/mL0.025 µg/mL0.05 µg/mL0.1 µg/mL0.010 µg/mL0.025 µg/mL0.05 µg/mL0.1 µg/mL
MOX88.65±0.0969.05±0.3556.48±0.0143.90±0.0389.42±0.0273.98±0.3359.43±0.0240.01±0.1086.62±0.2383.49±0.0854.58±0.0231.93±0.11
SLN1+MOX81.56±0.2675.43±0.2975.92±0.2374.55±0.2394.62±0.0281.95±0.1171.44±0.0358.43±0.0692.13±0.0891.46±0.3489.06±0.2873.70±0.22
SLN195.30±0.0868.91±0.1262.78±0.2557.75±0.0195.75±0.2991.22±0.0585.44±0.0664.09±0.0387.12±0.2782.65±0.0973.35±0.1169.72±0.17
SLN2+MOX93.14±0.0880.42±0.1966.66±0.4662.10±0.2188.73±0.0677.09±0.1263.16±0.1256.05±0.0492.13±0.0891.46±0.3489.06±0.2873.71±0.22
SLN290.98±0.3086.81±0.1264.91±0.0960.60±0.3196.51±0.2294.42±0.1280.82±0.0868.49±0.2296.02±0.3387.31±0.2769.95±0.0955.88±0.06
NLC1+MOX80.46±0.0981.65±0.1885.84±0.2681.47±0.0988.72±0.0972.27±0.0462.23±0.0251.10±0.1585.24±0.0976.56±0.3073.78±0.0956.03±0.32
NLC189.19±0.1378.73±0.1770.83±0.3353.27±0.0492.75±0.1382.93±0.0463.82±0.0954.44±0.0589.70±0.0980.44±0.0863.51±0.3554.76±0.20
NLC2+MOX78.43±0.3165.99±0.0556.58±0.2950.72±0.0476.23±0.2759.40±0.0353.59±0.0653.05±0.0894.10±0.2779.09±0.0373.90±0.0651.68±0.17
NLC285.54±0.0760.58±0.1056.67±0.2650.07±0.1683.62±0.0662.94±0.1254.81±0.0552.27±0.0491.99±0.4282.25±0.1274.99±0.0554.11±0.09

Results were given as means ± standard deviations

We know that E. coli with its thinner peptidoglycan layer and an outer lipopolysaccharide membrane has a limited permeability to drugs (46). Nanostructure with controlled drug release weakens its membrane resistance and increases drug uptake over time. In this sense, our findings are consistent with the ceftriaxone study by Kumar et al. (47).

We believe that the higher antibacterial activity of MOX loaded into SLN1 is related to the smaller size of SLN1 and distinct lipid and surfactant features, as earlier studies suggest that lipid nanoparticles with Tween 80 can generate higher antibacterial activity against E. coli (42). Furthermore, SLN1 can carry MOX directly to the target within the bacterium and also act as efflux pump inhibitor, that is, inhibit drug clearance from the cell (14, 48).

Nanoparticle cytotoxicity

None of the nanoparticles, whether loaded with MOX or not, lowered RAW 264.7 cell viability below 50 % after 24, 48, and 72 h of exposure to all studied concentrations. The highest concentration of standard MOX (not loaded into nanoparticles), however did lower cell viability below 50 %. Our findings therefore suggest that lipid nanoparticles in addition to having low cytotoxicity improve lower the cytotoxicity of MOX and lower its biocompatibility.

Similar observations of nanocarriers lowering MOX cytotoxicity were reported by several studies (4951).

Conclusion

By combining emulsifiers and lipids we successfully prepared stable SLNs and NLCs with high encapsulation efficiency for MOX. These newly designed lipid carriers offered better delivery of the drug into E. coli ATCC 25922 compared to the standard MOX formulation, and showed acceptable cytotoxicity and even protection from cytotoxic effects of MOX on RAW 264.7 cells. This finding, however, calls for further investigation and verification in other cell models.

Our findings show that MOX-loaded nanoparticles hold promise as potent chemotherapeutic drugs against E. coli. The most promising formulation is SLN1, as it has shown the best results with bacterial uptake and comparable antibacterial activity to MOX at much lower concentration.

Figure 1

TEM images of SLN1 (a), SLN2 (b), NLC1 (c), and NLC2 (d)
TEM images of SLN1 (a), SLN2 (b), NLC1 (c), and NLC2 (d)

Figure 2

MOX release from nanoparticles
MOX release from nanoparticles

Figure 3

Flow cytometry results (a: blank NPS; b: fluorescein solution; c: SLN1; d: SLN2; e: NLC1; f: NLC2)
Flow cytometry results (a: blank NPS; b: fluorescein solution; c: SLN1; d: SLN2; e: NLC1; f: NLC2)

Figure 4

Photomicrographs show bacterial uptake of formulations (a: fluorescein solution; b: SLN1; c: SLN2; d: NLC1; e: NLC2)(40× magnification)
Photomicrographs show bacterial uptake of formulations (a: fluorescein solution; b: SLN1; c: SLN2; d: NLC1; e: NLC2)(40× magnification)

Cytotoxic effects of MOX, MOX-free, and MOX-loaded LNPs in RAW 264.7 cells

RAW 264.7 cell viability (%)
24 h 48 h 72 h
0.010 µg/mL 0.025 µg/mL 0.05 µg/mL 0.1 µg/mL 0.010 µg/mL 0.025 µg/mL 0.05 µg/mL 0.1 µg/mL 0.010 µg/mL 0.025 µg/mL 0.05 µg/mL 0.1 µg/mL
MOX 88.65±0.09 69.05±0.35 56.48±0.01 43.90±0.03 89.42±0.02 73.98±0.33 59.43±0.02 40.01±0.10 86.62±0.23 83.49±0.08 54.58±0.02 31.93±0.11
SLN1+MOX 81.56±0.26 75.43±0.29 75.92±0.23 74.55±0.23 94.62±0.02 81.95±0.11 71.44±0.03 58.43±0.06 92.13±0.08 91.46±0.34 89.06±0.28 73.70±0.22
SLN1 95.30±0.08 68.91±0.12 62.78±0.25 57.75±0.01 95.75±0.29 91.22±0.05 85.44±0.06 64.09±0.03 87.12±0.27 82.65±0.09 73.35±0.11 69.72±0.17
SLN2+MOX 93.14±0.08 80.42±0.19 66.66±0.46 62.10±0.21 88.73±0.06 77.09±0.12 63.16±0.12 56.05±0.04 92.13±0.08 91.46±0.34 89.06±0.28 73.71±0.22
SLN2 90.98±0.30 86.81±0.12 64.91±0.09 60.60±0.31 96.51±0.22 94.42±0.12 80.82±0.08 68.49±0.22 96.02±0.33 87.31±0.27 69.95±0.09 55.88±0.06
NLC1+MOX 80.46±0.09 81.65±0.18 85.84±0.26 81.47±0.09 88.72±0.09 72.27±0.04 62.23±0.02 51.10±0.15 85.24±0.09 76.56±0.30 73.78±0.09 56.03±0.32
NLC1 89.19±0.13 78.73±0.17 70.83±0.33 53.27±0.04 92.75±0.13 82.93±0.04 63.82±0.09 54.44±0.05 89.70±0.09 80.44±0.08 63.51±0.35 54.76±0.20
NLC2+MOX 78.43±0.31 65.99±0.05 56.58±0.29 50.72±0.04 76.23±0.27 59.40±0.03 53.59±0.06 53.05±0.08 94.10±0.27 79.09±0.03 73.90±0.06 51.68±0.17
NLC2 85.54±0.07 60.58±0.10 56.67±0.26 50.07±0.16 83.62±0.06 62.94±0.12 54.81±0.05 52.27±0.04 91.99±0.42 82.25±0.12 74.99±0.05 54.11±0.09

Lipid nanoparticle properties

LNP Particle size (nm) Polydispersity index Zeta potential (mV) Encapsulation efficiency (%)
SLN1 181.6±1.27 0.25±0.02 -14.6±0.32 68.61±0.20
SLN2 201.8±1.65 0.29±0.02 -17.5±0.14 74.53±0.34
NLC1 176.8±1.90 0.57±0.23 -11.6±0.61 77.82±0.21
NLC2 132.4±1.62 0.51±0.53 -6.3±0.38 77.17±0.21

Stability of lipid nanoparticles stored for one month at +4 °C

Particle size (nm) Polydispersity index Zeta potential (mV)
Type of LNPs Baseline value After one month storage Baseline value After one month storage Baseline value After one month storage
SLN1 181.6±1.27 186.1±2.89 0.25±0.02 0.36±0.25 -14.6±0.32 -10.0±0.51*
SLN2 201.8±1.65 200.5±3.56 0.29±0.02 0.39±0.12 -17.5±0.14 -11.5±0.45*
NLC1 176.8±1.90 180.3±1.64 0.57±0.23 0.60±0.46 -11.6±0.61 -8.30±0.78
NLC2 132.4±1.62 135.2±3.98 0.51±0.53 0.65±0.22 -6.3±0.38 -5.62±0.96

Composition of lipid nanoparticles

Formulation code Solid lipid (glyceryl dibehenate) Liquid lipid (docosahexaenoic acid, DHA) Liquid lipid (oleic acid) Tween 80 Poloxamer 407 Triethanolamine (TEA)
SLN1 150 mg - - 100 mg - -
SLN2 150 mg - - - 100 mg -
NLC1 110 mg 40 mg 10 mg - 100 mg 10 mg
NLC2 110 mg 40 mg - - 100 mg 10 mg

Antibacterial activity of MOX-loaded SLNs and NLCs

Formulations Inhibition diameter (mm) Minimal inhibition concentration (μg/mL)
Standard MOX solution for SLNs * (0.68 mg) 33±0.07 0.041
SLN1 34±0.10*** 0.020
SLN2 32±0.11 0.041
Standard MOX solution for NLCs** (0.78 mg) 35±0.08 0.023
NLC1 36±0.12 0.023
NLC2 35±0.05 0.023

Martinez JL, Baquero F. Mutation frequencies and antibiotic resistance. Antimicrob Agents Chemother 2000;44:1771–7. doi: 10.1128/ AAC.44.7.1771-1777.2000 Martinez JL Baquero F Mutation frequencies and antibiotic resistance Antimicrob Agents Chemother 2000441771 7 10.1128/ AAC.44.7.1771-1777.2000Open DOISearch in Google Scholar

Boto L, Martinez JL. Ecological and temporal constraints in the evolution of bacterial genomes. Genes (Basel) 2011;2:804–28. doi: 10.3390/genes2040804 Boto L Martinez JL Ecological and temporal constraints in the evolution of bacterial genomes Genes (Basel) 20112804 28 10.3390/genes2040804392759724710293Open DOISearch in Google Scholar

Mackenzie JS, Jeggo M. The one health approach - why is it so important? Trop Med Infect Dis 2019;4(2):88. doi: 10.3390/ tropicalmed4020088 Mackenzie JS Jeggo M The one health approach - why is it so important? Trop Med Infect Dis 20194288 10.3390/ tropicalmed4020088Open DOISearch in Google Scholar

Martinez JL. General principles of antibiotic resistance in bacteria. Drug Discov Today Technol 2014;11:33–9. doi: 10.1016/j. ddtec.2014.02.001 Martinez JL General principles of antibiotic resistance in bacteria Drug Discov Today Technol 20141133 9 10.1016/j. ddtec.2014.02.001Open DOISearch in Google Scholar

World Health Organization (WHO). Antibiotic Resistance [displayed 15 March 2022]. Available at https://www.who.int/news-room/fact-sheets/detail/antibiotic-resistance World Health Organization (WHO) Antibiotic Resistance [displayed 15 March 2022]. Available at https://www.who.int/news-room/fact-sheets/detail/antibiotic-resistanceSearch in Google Scholar

Yeh YC, Huang TH, Yang SC, Chen CC, Fang JY. Nano-based drug delivery or targeting to eradicate bacteria for infection mitigation: a review of recent advances. Front Chem 2020;8:286. doi: 10.3389/ fchem.2020.00286 Yeh YC Huang TH Yang SC Chen CC Fang JY Nano-based drug delivery or targeting to eradicate bacteria for infection mitigation: a review of recent advances Front Chem 20208286 10.3389/ fchem.2020.00286Open DOISearch in Google Scholar

Sofowora A, Ogunbodede E, Onayade A. The role and place of medicinal plants in the strategies for disease prevention. Afr J Tradit Complement Altern Med 2013;10:210–29. doi: 10.4314/ajtcam.v10i5.2 Sofowora A Ogunbodede E Onayade A The role and place of medicinal plants in the strategies for disease prevention Afr J Tradit Complement Altern Med 201310210 29 10.4314/ajtcam.v10i5.2384740924311829Open DOISearch in Google Scholar

Chen CH, Lu TK. Development and challenges of antimicrobial peptides for therapeutic applications. Antibiotics (Basel) 2020;9(1):24. doi: 10.3390/antibiotics9010024 Chen CH Lu TK Development and challenges of antimicrobial peptides for therapeutic applications Antibiotics (Basel) 20209124 10.3390/antibiotics9010024716829531941022Open DOISearch in Google Scholar

Jiang Q, Chen J, Yang C, Yin Y, Yao K. Quorum sensing: a prospective therapeutic target for bacterial diseases. Biomed Res Int 2019;2019:2015978. doi: 10.1155/2019/2015978 Jiang Q Chen J Yang C Yin Y Yao K Quorum sensing: a prospective therapeutic target for bacterial diseases Biomed Res Int 201920192015978 10.1155/2019/2015978647557131080810Open DOISearch in Google Scholar

Lin DM, Koskella B, Lin HC. Phage therapy: an alternative to antibiotics in the age of multi-drug resistance. World J Gastrointest Pharmacol Ther 2017;8:162–73. doi: 10.4292/wjgpt.v8.i3.162 Lin DM Koskella B Lin HC Phage therapy: an alternative to antibiotics in the age of multi-drug resistance World J Gastrointest Pharmacol Ther 20178162 73 10.4292/wjgpt.v8.i3.162554737428828194Open DOISearch in Google Scholar

Gebreyohannes G, Nyerere A, Bii C, Sbhatu DB. Challenges of intervention, treatment, and antibiotic resistance of biofilm-forming microorganisms. Heliyon 2019;5(8):e02192. doi: 10.1016/j. heliyon.2019.e02192 Gebreyohannes G Nyerere A Bii C Sbhatu DB Challenges of intervention, treatment, and antibiotic resistance of biofilm-forming microorganisms Heliyon 201958e02192 10.1016/j. heliyon.2019.e02192Open DOISearch in Google Scholar

Arana L, Gallego L, Alkorta I. Incorporation of antibiotics into solid lipid nanoparticles: a promising approach to reduce antibiotic resistance emergence. Nanomaterials (Basel) 2021;11(5):1251. doi: 10.3390/nano11051251 Arana L Gallego L Alkorta I Incorporation of antibiotics into solid lipid nanoparticles: a promising approach to reduce antibiotic resistance emergence Nanomaterials (Basel) 20211151251 10.3390/nano11051251815191334068834Open DOISearch in Google Scholar

Duan Y, Dhar A, Patel C, Khimani M, Neogi S, Sharma P, Kumar NS, Vekariya RL. A brief review on solid lipid nanoparticles: part and parcel of contemporary drug delivery systems. RSC Adv 2020;10:26777–91. doi: 10.1039/D0RA03491F Duan Y Dhar A Patel C Khimani M Neogi S Sharma P Kumar NS Vekariya RL A brief review on solid lipid nanoparticles: part and parcel of contemporary drug delivery systems RSC Adv 20201026777 91 10.1039/D0RA03491FOpen DOISearch in Google Scholar

Marslin G, Revina AM, Khandelwal VK, Balakumar K, Sheeba CJ, Franklin G. PEGylated ofloxacin nanoparticles render strong antibacterial activity against many clinically important human pathogens. Colloids Surf B Biointerfaces 2015;132:62–70. 10.1016/j.colsurfb.2015.04.050 Marslin G Revina AM Khandelwal VK Balakumar K Sheeba CJ Franklin G PEGylated ofloxacin nanoparticles render strong antibacterial activity against many clinically important human pathogens Colloids Surf B Biointerfaces 201513262 70 10.1016/j.colsurfb.2015.04.05026005932Open DOISearch in Google Scholar

Sheeba CJ, Marslin G, Revina AM, Franklin G. Signaling pathways influencing tumor microenvironment and their exploitation for targeted drug delivery. Nanotechnol Rev 2014;3:123–51. doi: 10.1515/ ntrev-2013-0032 Sheeba CJ Marslin G Revina AM Franklin G Signaling pathways influencing tumor microenvironment and their exploitation for targeted drug delivery Nanotechnol Rev 20143123 51 10.1515/ ntrev-2013-0032Open DOISearch in Google Scholar

Naseri N, Valizadeh H, Zakeri-Milani P. Solid lipid nanoparticles and nanostructured lipid carriers: structure, preparation and application. Adv Pharm Bull 2015;5:305–13. doi: 10.15171/apb.2015.043 Naseri N Valizadeh H Zakeri-Milani P Solid lipid nanoparticles and nanostructured lipid carriers: structure, preparation and application Adv Pharm Bull 20155305 13 10.15171/apb.2015.043461689326504751Open DOISearch in Google Scholar

Škalko-Basnet N, Vanić Ž. Lipid-based nanopharmaceuticals in antimicrobial therapy. In: Boukherroub R, Szunerits S, Drider D, editors. Functionalized nanomaterials for the management of microbial infection. London: Elsevier; 2017. p. 111–52. Škalko-Basnet N Vanić Ž Lipid-based nanopharmaceuticals in antimicrobial therapy. In Boukherroub R Szunerits S Drider D editors Functionalized nanomaterials for the management of microbial infection London Elsevier 2017 p. 111 5210.1016/B978-0-323-41625-2.00005-3Search in Google Scholar

Severino P, De Hollanda LM, Santini A, Reis LV, Souto SB, Souto EB, Silva MA. Advances in nanobiomaterials for oncology nanomedicine. In: Grumezescu AM, editor. Nanobiomaterials in cancer therapy: Applications of nanobiomaterials. Vol. 7. Chapter 4. New York (NY): William Andrew Publishing; 2016. p. 91–115. Severino P De Hollanda LM Santini A Reis LV Souto SB Souto EB Silva MA Advances in nanobiomaterials for oncology nanomedicine. In Grumezescu AM editor Nanobiomaterials in cancer therapy: Applications of nanobiomaterials. Vol. 7. Chapter 4 New York (NY) William Andrew Publishing; 2016 p. 91 11510.1016/B978-0-323-42863-7.00004-9Search in Google Scholar

Madkhali OA. Perspectives and prospective on solid lipid nanoparticles as drug delivery systems. Molecules 2022;27(5):1543. doi: 10.3390/ molecules27051543 Madkhali OA Perspectives and prospective on solid lipid nanoparticles as drug delivery systems Molecules 20222751543 10.3390/ molecules27051543Open DOISearch in Google Scholar

Esim O, Hascicek C. Lipid-coated nanosized drug delivery systems for an effective cancer therapy. Curr Drug Deliv 2021;18:147–61. doi: 10.2174/1567201817666200512104441 Esim O Hascicek C Lipid-coated nanosized drug delivery systems for an effective cancer therapy Curr Drug Deliv 202118147 61 10.2174/156720181766620051210444132394833Open DOISearch in Google Scholar

Elmowafy M, Al-Sanea MM. Nanostructured lipid carriers (NLCs) as drug delivery platform: advances in formulation and delivery strategies. Saudi Pharm J 2021;29:999–1012. doi: 10.1016/j.jsps.2021.07.015 Elmowafy M Al-Sanea MM Nanostructured lipid carriers (NLCs) as drug delivery platform: advances in formulation and delivery strategies Saudi Pharm J 202129999 1012 10.1016/j.jsps.2021.07.015846350834588846Open DOISearch in Google Scholar

Misra S, Chopra K, Sinha VR, Medhi B. Galantamine-loaded solid-lipid nanoparticles for enhanced brain delivery: preparation, characterization, in vitro and in vivo evaluations. Drug Deliv 2016;23:1434–43. doi: 10.3109/10717544.2015.1089956 Misra S Chopra K Sinha VR Medhi B Galantamine-loaded solid-lipid nanoparticles for enhanced brain delivery: preparation, characterization, in vitro and in vivo evaluations Drug Deliv 2016231434 43 10.3109/10717544.2015.108995626405825Open DOISearch in Google Scholar

Yasir M, Sara UVS. Solid lipid nanoparticles for nose to brain delivery of haloperidol: in vitro drug release and pharmacokinetics evaluation. Acta Pharm Sin B 2014;4:454–63. doi: 10.1016/j.apsb.2014.10.005 Yasir M Sara UVS Solid lipid nanoparticles for nose to brain delivery of haloperidol: in vitro drug release and pharmacokinetics evaluation Acta Pharm Sin B 20144454 63 10.1016/j.apsb.2014.10.005462910826579417Open DOISearch in Google Scholar

Uner M. Preparation, characterization and physico-chemical properties of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC): their benefits as colloidal drug carrier systems. Pharmazie 2006;61:375–86. PMID: 16724531 Uner M Preparation, characterization and physico-chemical properties of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC): their benefits as colloidal drug carrier systems Pharmazie 200661375 86 PMID: 16724531Search in Google Scholar

The National Center for Biotechnology Information (NCBI). PubChem Compound Summary for CID 152946, Moxifloxacin [displayed 15 March 2022]. Available at https://pubchem.ncbi.nlm.nih.gov/compound/Moxifloxacin The National Center for Biotechnology Information (NCBI) PubChem Compound Summary for CID 152946, Moxifloxacin [displayed 15 March 2022]. Available at https://pubchem.ncbi.nlm.nih.gov/compound/MoxifloxacinSearch in Google Scholar

Guay DR. Moxifloxacin in the treatment of skin and skin structure infections. Ther Clin Risk Manag 2006;2:417–34. doi: 10.2147/ tcrm.2006.2.4.417 Guay DR Moxifloxacin in the treatment of skin and skin structure infections Ther Clin Risk Manag 20062417 34 10.2147/ tcrm.2006.2.4.417Open DOISearch in Google Scholar

Scholar E. Levofloxacin. In: Enna SJ, Bylund DB, editors. xPharm: The Comprehensive Pharmacology Reference. New York (NY): Elsevier; 2007. p. 1–6. Scholar E Levofloxacin In Enna SJ Bylund DB editors xPharm: The Comprehensive Pharmacology Reference New York (NY) Elsevier 2007 p. 1 610.1016/B978-008055232-3.63486-5Search in Google Scholar

Wu D, Ding Y, Yao K, Gao W, Wang Y. Antimicrobial resistance analysis of clinical Escherichia coli isolates in neonatal ward. Front Pediatr 2021;9:670470. doi: 10.3389/fped.2021.670470 Wu D Ding Y Yao K Gao W Wang Y Antimicrobial resistance analysis of clinical Escherichia coli isolates in neonatal ward Front Pediatr 20219670470 10.3389/fped.2021.670470818501634113589Open DOISearch in Google Scholar

Pinto-Alphandary H, Andremont A, Couvreur P. Targeted delivery of antibiotics using liposomes and nanoparticles: research and applications. Int J Antimicrob Agents 2000;13:155–68. doi: 10.1016/ s0924-8579(99)00121-1 Pinto-Alphandary H Andremont A Couvreur P Targeted delivery of antibiotics using liposomes and nanoparticles: research and applications Int J Antimicrob Agents 200013155 68 10.1016/ s0924-8579(99)00121-1Open DOISearch in Google Scholar

Wong JP, Cherwonogrodzky JW, Di Ninno VL, De la Cruz R, Saravolac EG. Liposome-encapsulates ciprofloxacin for the prevention and treatment of infectious diseases caused by intracellular pathogens. In: Shek PN, editor. Liposomes in biomedical applications. Amsterdam: Harwood Academic Publishers; 1995. p. 105–20. Wong JP Cherwonogrodzky JW Di Ninno VL De la Cruz R Saravolac EG Liposome-encapsulates ciprofloxacin for the prevention and treatment of infectious diseases caused by intracellular pathogens. In Shek PN editor Liposomes in biomedical applications Amsterdam Harwood Academic Publishers; 1995 p. 105 20Search in Google Scholar

Mussi SV, Sawant R, Perche F, Oliveira MC, Azevedo RB, Ferreira LA, Torchilin VP. Novel nanostructured lipid carrier co-loaded with doxorubicin and docosahexaenoic acid demonstrates enhanced in vitro activity and overcomes drug resistance in MCF-7/Adr cells. Pharm Res 2014;31:1882–92. doi: 10.1007/s11095-013-1290-2 Mussi SV Sawant R Perche F Oliveira MC Azevedo RB Ferreira LA Torchilin VP Novel nanostructured lipid carrier co-loaded with doxorubicin and docosahexaenoic acid demonstrates enhanced in vitro activity and overcomes drug resistance in MCF-7/Adr cells Pharm Res 2014311882 92 10.1007/s11095-013-1290-224522814Open DOISearch in Google Scholar

Topal GR, Kiymaci ME, Özkan Y. Preparation and in vitro characterization of vancomycin loaded PLGA nanoparticles for the treatment of Enterococcus faecalis infections. J Fac Pharm Ankara 2022;46:350–63. doi: 10.33483/jfpau.1073081 Topal GR Kiymaci ME Özkan Y Preparation and in vitro characterization of vancomycin loaded PLGA nanoparticles for the treatment of Enterococcus faecalis infections J Fac Pharm Ankara 202246350 63 10.33483/jfpau.1073081Open DOISearch in Google Scholar

Yurtdaş Kırımlıoğlu G, Özer S, Büyükköroğlu G, Yazan Y. Formulation and in vitro evaluation of moxifloxacin hydrochloride-loaded polymeric nanoparticles for ocular application. Lat Am J Pharm 2018;37:1850–62. Yurtdaş Kırımlıoğlu G Özer S Büyükköroğlu G Yazan Y Formulation and in vitro evaluation of moxifloxacin hydrochloride-loaded polymeric nanoparticles for ocular application. Lat Am J Pharm 2018371850 62Search in Google Scholar

Savaser A, Esim O, Kurbanoglu S, Ozkan SA, Özkan Y. Current perspectives on drug release studies from polymeric nanoparticles. In: Grumezescu AM, editors. Organic materials as smart nanocarriers for drug delivery. New York (NY): William Andrew Publishing; 2018. p. 101–45. Savaser A Esim O Kurbanoglu S Ozkan SA Özkan Y Current perspectives on drug release studies from polymeric nanoparticles. In Grumezescu AM editors Organic materials as smart nanocarriers for drug delivery. New York (NY) William Andrew Publishing; 2018 p. 101 4510.1016/B978-0-12-813663-8.00003-8Search in Google Scholar

The European Committee on Antimicrobial Susceptibility Testing (EUCAST). Breakpoint tables for interpretation of MICs and zone diameters version 12.0, valid from 2022-01-01 [displayed 15 March 2022]. Available at https://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/Breakpoint_tables/v_12.0_Breakpoint_Tables.pdf The European Committee on Antimicrobial Susceptibility Testing (EUCAST) Breakpoint tables for interpretation of MICs and zone diameters version 12.0, valid from 2022-01-01 [displayed 15 March 2022]. Available at https://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/Breakpoint_tables/v_12.0_Breakpoint_Tables.pdfSearch in Google Scholar

Bacanli M, Esim MO, Erdogan H, Sarper M, Erdem O, Özkan Y. Evaluation of cytotoxic and genotoxic effects of paclitaxel-loaded PLGA nanoparticles in neuroblastoma cells. Food Chem Toxicol 2021;154:112323. doi: 10.1016/j.fct.2021.112323 Bacanli M Esim MO Erdogan H Sarper M Erdem O Özkan Y Evaluation of cytotoxic and genotoxic effects of paclitaxel-loaded PLGA nanoparticles in neuroblastoma cells Food Chem Toxicol 2021154112323 10.1016/j.fct.2021.11232334111492Open DOISearch in Google Scholar

Sarwar A, Katas H, Zin NM. Antibacterial effects of chitosan– tripolyphosphate nanoparticles: impact of particle size molecular weight. J Nanoparticle Res 2014;16:2517. doi: 10.1007/s11051-014-2517-9 Sarwar A Katas H Zin NM Antibacterial effects of chitosan– tripolyphosphate nanoparticles: impact of particle size molecular weight J Nanoparticle Res 2014162517 10.1007/s11051-014-2517-9Open DOISearch in Google Scholar

Martins S, Tho I, Reimold I, Fricker G, Souto E, Ferreira D, Brandl M. Brain delivery of camptothecin by means of solid lipid nanoparticles: formulation design, in vitro and in vivo studies. Int J Pharm 2012;439:49–62. doi: 10.1016/j.ijpharm.2012.09.054 Martins S Tho I Reimold I Fricker G Souto E Ferreira D Brandl M Brain delivery of camptothecin by means of solid lipid nanoparticles: formulation design, in vitro and in vivo studies Int J Pharm 201243949 62 10.1016/j.ijpharm.2012.09.05423046667Open DOISearch in Google Scholar

Schöler N, Olbrich C, Tabatt K, Müller RH, Hahn H, Liesenfeld O. Surfactant, but not the size of solid lipid nanoparticles (SLN) influences viability and cytokine production of macrophages. Int J Pharm 2001;221:57–67. doi: 10.1016/s0378-5173(01)00660-3 Schöler N Olbrich C Tabatt K Müller RH Hahn H Liesenfeld O Surfactant, but not the size of solid lipid nanoparticles (SLN) influences viability and cytokine production of macrophages Int J Pharm 200122157 67 10.1016/s0378-5173(01)00660-311397567Open DOISearch in Google Scholar

Lages EB, Fernandes RS, Silva JO, de Souza AM, Cassali GD, de Barros ALB, Miranda Ferreira LA. Co-delivery of doxorubicin, docosahexaenoic acid, and alpha-tocopherol succinate by nanostructured lipid carriers has a synergistic effect to enhance antitumor activity and reduce toxicity. Biomed Pharmacother 2020;132:110876. doi: 10.1016/j.biopha.2020.110876 Lages EB Fernandes RS Silva JO de Souza AM Cassali GD de Barros ALB Miranda Ferreira LA Co-delivery of doxorubicin, docosahexaenoic acid, and alpha-tocopherol succinate by nanostructured lipid carriers has a synergistic effect to enhance antitumor activity and reduce toxicity Biomed Pharmacother 2020132110876 10.1016/j.biopha.2020.11087633113428Open DOISearch in Google Scholar

Das S, Ng WK, Kanaujia P, Kim S, Tan RB. Formulation design, preparation and physicochemical characterizations of solid lipid nanoparticles containing a hydrophobic drug: effects of process variables. Colloids Surf B Biointerfaces 2011;88:483–9. doi: 10.1016/j. colsurfb.2011.07.036 Das S Ng WK Kanaujia P Kim S Tan RB Formulation design, preparation and physicochemical characterizations of solid lipid nanoparticles containing a hydrophobic drug: effects of process variables Colloids Surf B Biointerfaces 201188483 9 10.1016/j. colsurfb.2011.07.036Open DOISearch in Google Scholar

Amasya G, Bakar-Ates F, Wintgens V, Amiel C. Layer by layer assembly of core-corona structured solid lipid nanoparticles with beta-cyclodextrin polymers. Int J Pharm 2021;592:119994. doi: 10.1016/j. ijpharm.2020.119994 Amasya G Bakar-Ates F Wintgens V Amiel C Layer by layer assembly of core-corona structured solid lipid nanoparticles with beta-cyclodextrin polymers Int J Pharm 2021592119994 10.1016/j. ijpharm.2020.119994Open DOISearch in Google Scholar

Singh S, Dobhal AK, Jain A, Pandit JK, Chakraborty S. Formulation and evaluation of solid lipid nanoparticles of a water soluble drug: Zidovudine. Chem Pharm Bull (Tokyo) 2010;58:650–5. doi: 10.1248/ cpb.58.650 Singh S Dobhal AK Jain A Pandit JK Chakraborty S Formulation and evaluation of solid lipid nanoparticles of a water soluble drug: Zidovudine Chem Pharm Bull (Tokyo) 201058650 5 10.1248/ cpb.58.650Open DOISearch in Google Scholar

Al-Qushawi A, Rassouli A, Atyabi F, Peighambari SM, Esfandyari-Manesh M, Shams GR, Yazdani A. Preparation and characterization of three tilmicosin-loaded lipid nanoparticles: physicochemical properties and in-vitro antibacterial activities. Iran J Pharm Res 2016;15:663–76. PMCID:PMC5316245 Al-Qushawi A Rassouli A Atyabi F Peighambari SM Esfandyari-Manesh M Shams GR Yazdani A Preparation and characterization of three tilmicosin-loaded lipid nanoparticles: physicochemical properties and in-vitro antibacterial activities Iran J Pharm Res 201615663 76 PMCID:PMC5316245Search in Google Scholar

Müller RH, Radtke M, Wissing SA. Nanostructured lipid matrices for improved microencapsulation of drugs. Int J Pharm 2002;242:121–8. doi: 10.1016/s0378-5173(02)00180-1 Müller RH Radtke M Wissing SA Nanostructured lipid matrices for improved microencapsulation of drugs Int J Pharm 2002242121 8 10.1016/s0378-5173(02)00180-112176234Open DOISearch in Google Scholar

Ebrahimi S, Farhadian N, Karimi M, Ebrahimi M. Enhanced bactericidal effect of ceftriaxone drug encapsulated in nanostructured lipid carrier against gram-negative Escherichia coli bacteria: drug formulation, optimization, and cell culture study. Antimicrob Resist Infect Control 2020;9(1):28. doi: 10.1186/s13756-020-0690-4 Ebrahimi S Farhadian N Karimi M Ebrahimi M Enhanced bactericidal effect of ceftriaxone drug encapsulated in nanostructured lipid carrier against gram-negative Escherichia coli bacteria: drug formulation, optimization, and cell culture study Antimicrob Resist Infect Control 20209128 10.1186/s13756-020-0690-4701152532041660Open DOISearch in Google Scholar

Kumar S, Bhanjana G, Kumar A, Taneja K, Dilbaghi N, Kim KH. Synthesis and optimization of ceftriaxone-loaded solid lipid nanocarriers. Chem Phys Lipids 2016;200:126–32. doi: 10.1016/j. chemphyslip.2016.09.002 Kumar S Bhanjana G Kumar A Taneja K Dilbaghi N Kim KH Synthesis and optimization of ceftriaxone-loaded solid lipid nanocarriers Chem Phys Lipids 2016200126 32 10.1016/j. chemphyslip.2016.09.002Open DOISearch in Google Scholar

Esim O, Sarper M, Ozkan CK, Oren S, Baykal B, Savaser A, Ozkan Y. Effect simultaneous delivery with P-glycoprotein inhibitor and nanoparticle administration of doxorubicin on cellular uptake and in vitro anticancer activity. Saudi Pharm J 2020;28:465–72. doi: 10.1016/j. jsps.2020.02.008 Esim O Sarper M Ozkan CK Oren S Baykal B Savaser A Ozkan Y Effect simultaneous delivery with P-glycoprotein inhibitor and nanoparticle administration of doxorubicin on cellular uptake and in vitro anticancer activity Saudi Pharm J 202028465 72 10.1016/j. jsps.2020.02.008Open DOISearch in Google Scholar

Akbar N, Gul J, Siddiqui R, Shah MR, Khan NA. Moxifloxacin and sulfamethoxazole-based nanocarriers exhibit potent antibacterial activities. Antibiotics (Basel) 2021;10(8):964. doi: 10.3390/ antibiotics10080964 Akbar N Gul J Siddiqui R Shah MR Khan NA Moxifloxacin and sulfamethoxazole-based nanocarriers exhibit potent antibacterial activities Antibiotics (Basel) 2021108964 10.3390/ antibiotics10080964Open DOISearch in Google Scholar

Kisich KO, Gelperina S, Higgins MP, Wilson S, Shipulo E, Oganesyan E, Heifets L. Encapsulation of moxifloxacin within poly(butyl cyanoacrylate) nanoparticles enhances efficacy against intracellular Mycobacterium tuberculosis. Int J Pharm 2007;345:154–62. doi: 10.1016/j. ijpharm.2007.05.062 Kisich KO Gelperina S Higgins MP Wilson S Shipulo E Oganesyan E Heifets L Encapsulation of moxifloxacin within poly(butyl cyanoacrylate) nanoparticles enhances efficacy against intracellular Mycobacterium tuberculosis Int J Pharm 2007345154 62 10.1016/j. ijpharm.2007.05.062Open DOISearch in Google Scholar

Tshweu LL, Shemis MA, Abdelghany A, Gouda A, Pilcher LA, Sibuyi NR, Meyer M, Dube A, Balogun MO. Synthesis, physicochemical characterization, toxicity and efficacy of a PEG conjugate and a hybrid PEG conjugate nanoparticle formulation of the antibiotic moxifloxacin. RSC Adv 2020;10:19770–80. doi: 10.1039/C9RA10872F Tshweu LL Shemis MA Abdelghany A Gouda A Pilcher LA Sibuyi NR Meyer M Dube A Balogun MO Synthesis, physicochemical characterization, toxicity and efficacy of a PEG conjugate and a hybrid PEG conjugate nanoparticle formulation of the antibiotic moxifloxacin RSC Adv 20201019770 80 10.1039/C9RA10872FOpen DOISearch in Google Scholar

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