Improved drug loading and antibacterial activity of minocycline-loaded PLGA nanoparticles prepared by solid/oil/water ion pairing method

Local delivery of minocycline-loaded PEG-PLA nanoparticles for the enhanced treatment of periodontitis in dogs

Background

Rapid local drug clearance of antimicrobials is a major drawback for the treatment of chronic periodontitis. In the study reported here, minocycline-loaded poly(ethylene glycol)-poly(lactic acid) nanoparticles were prepared and administered locally for long drug retention and enhanced treatment of periodontitis in dogs.

Methods

Biodegradable poly(ethylene glycol)-poly(lactic acid) was synthesized to prepare nanoparticles using an emulsion/solvent evaporation technique. The particle size and zeta potential of the minocycline-loaded nanoparticles (MIN-NPs) were determined by dynamic light scattering and the morphology of the nanoparticles was observed by transmission electron microscopy. The in vitro release of minocycline from MIN-NPs and in vivo pharmacokinetics of minocycline in gingival crevice fluid, after local administration of MIN-NPs in the periodontal pockets of beagle dogs with periodontitis, were investigated. The anti-periodontitis effects of MIN-NPs on periodontitis-bearing dogs were finally evaluated.

Results

Transmission electron microscopy examination and dynamic light scattering results revealed that the MIN-NPs had a round shape, with a mean diameter around 100 nm. The in vitro release of minocycline from MIN-NPs showed a remarkably sustained releasing characteristic. After local administration of the MIN-NPs, minocycline concentration in gingival crevice fluid decreased slowly and retained an effective drug concentration for a longer time (12 days) than Periocline^®. Anti-periodontitis effects demonstrated that MIN-NPs could significantly decrease symptoms of periodontitis compared with Periocline and minocycline solution. These findings suggest that MIN-NPs might have great potential in the treatment of periodontitis.

New perspectives on antiacne plant drugs: contribution to modern therapeutics

Acne is a common but serious skin disease, which affects approximately 80% adolescents and young adults in 11-30 age group. 42.5% of men and 50.9% of women continue to suffer from this disease into their twenties. Bacterial resistance is now at the alarming stage due to the irrational use of antibiotics. Hence, search for new lead molecule/bioactive and rational delivery of the existing drug (for better therapeutic effect) to the site of action is the need of the hour. Plants and plant-derived products have been an integral part of health care system since time immemorial. Therefore, plants that are currently used for the treatment of acne and those with a high potential are summarized in the present review. Most active plant extracts, namely, P. granatum, M. alba, A. anomala, and M. aquifolium exhibit minimum inhibitory concentration (MIC) in the range of 4-50 µg/mL against P. acnes, while aromatic oils of C. obovoides, C. natsudaidai, C. japonica, and C. nardus possess MICs 0.005-0.6 μL/mL and phytomolecules such as rhodomyrtone, pulsaquinone, hydropulsaquinone, honokiol, magnolol, xanthohumol lupulones, chebulagic acid and rhinacanthin-C show MIC in the range of 0.5-12.5 μg/mL. Novel drug delivery strategies of important plant leads in the treatment of acne have also been discussed.

A novel approach for antibody nanocarriers development through hydrophobic ion-pairing complexation

IgG-Fab fragment, a model antibody protein was hydrophobically modified by a novel approach of ion-pairing complexation. Three different sulphated ion-pairing agents were utilised including sodium dodecyl sulphate, taurocholic acid and dextran sulphate (DS). The formations of hydrophobic ion-pairing (HIP) complexes were dependant on pH and molar ratio of ion-pairing agent to Fab. Aqueous solubilities of HIP complexes were very low compared to Fab alone. In particular, when dextran sulphate was added as ion-pairing agent, formed Fab:DS HIP complexes were least soluble in water. Further, nanoparticles (NPs) loaded with drug and Fab:DS HIP complex were prepared and characterised with respect to encapsulation efficiency and size. We observed significant improvement in encapsulation efficiency for Fab:DS HIP complex-loaded nanoparticles. This study demonstrates a novel approach of formulating antibody-loaded nanoparticles which can also be employed for delivery of large antibodies.

BSA-PLGA-based core-shell nanoparticles as carrier system for water-soluble drugs

PURPOSE

Preparation, optimization and in vitro evaluation of core-shell nanoparticles comprising of a hydrophilic core of BSA surrounded by a hydrophobic shell of PLGA for loading water-soluble drugs.

METHODS

A double emulsion method was optimized for preparation of BSA-PLGA based core-shell nanoparticles. Proof of concept for core-shell type structure was established by visual techniques like confocal microscopy and TEM. Characterization was done for particle size, encapsulation efficiency, drug loading and in vitro drug release. Cellular uptake was assessed using confocal microscopy, bio-TEM and HPLC assay, and cytotoxic activity was tested by MTT assay in MG-63 osteosarcoma cells.

RESULTS

The optimized core-shell nanoparticles showed a particle size of 243 nm (PDI-0.13) and encapsulation efficiency of 40.5% with a drug loading of 8.5% w/w. In vitro drug release studies showed a sustained release for 12 h. Cellular uptake studies indicated a rapid and efficient uptake within 2 h. TEM studies indicated that the core-shell nanoparticles were localized in cytoplasm region of the cells. Gemcitabine loaded core-shell nanoparticles showed enhanced cytotoxicity against MG-63 cells as compared to marketed formulation of gemcitabine (GEMCITE®).

CONCLUSION

These results indicate that core-shell nanoparticles can be a good carrier system for delivering hydrophilic drugs like gemcitabine successfully to the cells with enhanced efficacy.

Encapsulation of exemestane in polycaprolactone nanoparticles: optimization, characterization, and release kinetics

This study was aimed at developing a polymeric drug delivery system for a steroidal aromatase inhibitor, exemestane (exe) intended for sustained targeted delivery of drug through intravenous route. Carboxylated polycaprolactone (cPCL) was synthesized by ring opening polymerization of caprolactone. Exe-loaded cPCL nanoparticles (NPs) were prepared by interfacial deposition of preformed polymer and characterized. A 3-factor, 3-level Box–Behnken design was used to derive a second-order polynomial equation and construct contour and response plots for maximized response of percentage drug entrapment (PDE) with constraints on particle size (PS). The independent variables selected were ratio of exe/cPCL, amount of cPCL, and volume of organic phase. Polymerization of caprolactone to cPCL was confirmed by Fourier transform infrared (FTIR) and gel permeation chromatography. The prepared NPs were evaluated for differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and in vitro release studies. Optimum formulation based on desirability (1.0) exhibited PDE of 83.96 % and PS of 180.5 nm. Check point analysis confirmed the role of the derived polynomial equation and contour plots in predicting the responses. Zeta potential of optimized formulation was −33.8 ± 2.1 mV. DSC studies confirmed the absence of any interaction between drug and polymer. TEM image showed non-aggregated and spherical shaped NPs. Drug release from NPs showed sustained release and followed Korsmeyer–Peppas model, indicating Fickian drug release. Thus, preparation of exe-loaded cPCL NPs with high PDE and desired PS suitable for providing passive targeting could be statistically optimized using Box–Behnken design.

Enhanced antibacterial activity of roxithromycin loaded pegylated poly lactide-co-glycolide nanoparticles

Background and the purpose of the study

The purpose of this study was to prepare pegylated poly lactide-co-glycolide (PEG-PLGA) nanoparticles (NPs) loaded with roxithromycin (RXN) with appropriate physicochemical properties and antibacterial activity. Roxithromycin, a semi-synthetic derivative of erythromycin, is more stable than erythromycin under acidic conditions and exhibits improved clinical effects.

Methods

RXN was loaded in pegylated PLGA NPs in different drug;polymer ratios by solvent evaporation technique and characterized for their size and size distribution, surface charge, surface morphology, drug loading, in vitro drug release profile, and in vitro antibacterial effects on S. aureus, B. subtilis, and S. epidermidis.

Results and conclusion

NPs were spherical with a relatively mono-dispersed size distribution. The particle size of nanoparticles ranged from 150 to 200 nm. NPs with entrapment efficiency of up to 80.0±6.5% and drug loading of up to 13.0±1.0% were prepared. In vitro release study showed an early burst release of about 50.03±0.99% at 6.5 h and then a slow and steady release of RXN was observed after the burst release. In vitro antibacterial effects determined that the minimal inhibitory concentration (MIC) of RXN loaded PEG-PLGA NPs were 9 times lower on S. aureus, 4.5 times lower on B. subtilis, and 4.5 times lower on S. epidermidis compared to RXN solution. In conclusion it was shown that polymeric NPs enhanced the antibacterial efficacy of RXN substantially.

Fabrication and in vitro release behavior of a novel antibacterial coating containing halogenated furanone-loaded poly(L-lactic acid) nanoparticles on microarc-oxidized titanium

Background

Dental implants have become increasingly common for the management of missing teeth. However, peri-implant infection remains a problem, is usually difficult to treat, and may lead eventually to dental implant failure. The aim of this study was to fabricate a novel antibacterial coating containing a halogenated furanone compound, ie, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone (BBF)-loaded poly(L-lactic acid) (PLLA) nanoparticles on microarc-oxidized titanium and to evaluate its release behavior in vitro.

Methods

BBF-loaded PLLA nanoparticles were prepared using the emulsion solvent-evaporation method, and the antibacterial coating was fabricated by cross-linking BBF-loaded PLLA nanoparticles with gelatin on microarc-oxidized titanium.

Results

The BBF-loaded PLLA nanoparticles had a small particle size (408 ± 14 nm), a low polydispersity index (0.140 ± 0.008), a high encapsulation efficiency (72.44% ± 1.27%), and a fine spherical shape with a smooth surface. The morphology of the fabricated antibacterial coating showed that the BBF-loaded PLLA nanoparticles were well distributed in the pores of the microarc oxidation coating, and were cross-linked with each other and the wall pores by gelatin. The release study indicated that the antibacterial coating could achieve sustained release of BBF for 60 days, with a slight initial burst release during the first 4 hours.

Conclusion

The novel antibacterial coating fabricated in this study is a potentially promising method for prevention of early peri-implant infection.

Gentamicin-loaded nanoparticles show improved antimicrobial effects towards Pseudomonas aeruginosa infection

Gentamicin is an aminoglycoside antibiotic commonly used for treating Pseudomonas infections, but its use is limited by a relatively short half-life. In this investigation, developed a controlled-release gentamicin formulation using poly(lactide-co-glycolide) (PLGA) nanoparticles. We demonstrate that entrapment of the hydrophilic drug into a hydrophobic PLGA polymer can be improved by increasing the pH of the formulation, reducing the hydrophilicity of the drug and thus enhancing entrapment, achieving levels of up to 22.4 μg/mg PLGA. Under standard incubation conditions, these particles exhibited controlled release of gentamicin for up to 16 days. These particles were tested against both planktonic and biofilm cultures of P. aeruginosa PA01 in vitro, as well as in a 96-hour peritoneal murine infection model. In this model, the particles elicited significantly improved antimicrobial effects as determined by lower plasma and peritoneal lavage colony-forming units and corresponding reductions of the surrogate inflammatory indicators interleukin-6 and myeloperoxidase compared to free drug administration by 96 hours. These data highlight that the controlled release of gentamicin may be applicable for treating Pseudomonas infections.