Factorial design, physicochemical characterisation and activity of ciprofloxacin-PLGA nanoparticles

Oral inhalation of dacomitinib nanocarriers as a therapeutic strategy for non-small cell lung cancer

Background: Development of an inhalable nanoformulation of dacomitinib (DMB) encapsulated in poly-(lactic-co-glycolic acid) nanoparticles (NPs) to improve solubility, facilitate direct lung delivery and overcome the systemic adverse effects.Methods: DMB-loaded poly-(lactic-co-glycolic acid) NPs were prepared using solvent evaporation and characterized for particle size, polydispersity index and zeta-potential. The NPs were evaluated for in vitro drug release, aerosolization performance and in vitro efficacy studies.Results: The NPs showed excellent particle characteristics and displayed a cumulative release of ∼40% in 5 days. The NPs demonstrated a mass median aerodynamic diameter of ∼3 μm and fine particle fraction of ∼80%. Further, in vitro cell culture studies showed improved cytotoxic potential of DMB-loaded NPs compared with free drug.Conclusion: The study underscores the potential of DMB-loaded NPs as a viable approach for non-small cell lung cancer treatment.

Holistic Study Design Following Quality by Design Approach for Fabrication of Hybrid Polymeric Nanoparticulate Based Dry Powders as Carriers for Ciprofloxacin

Resistance to antibiotics such as Ciprofloxacin (CIP) is becoming a critical issue and needs to be addressed globally. CIP is widely used because of manifold uses; however, the long-term therapy poses serious health risks including FDA black box warnings such as tendinitis and peripheral neuropathy. Therefore, nanotechnology-based products can be an effective measure to improve therapeutic outcomes by maintaining the dose at the target site while reducing the dose-dependent toxicity. Biodegradable and biocompatible polymers, Chitosan (CS) and Hyaluronic acid (HA) were used in this work due to their diverse biological characteristics. A simple yet economical ionic gelation method was employed to synthesize nanoparticles with a plexus-like network; nanoplexes, followed by spray-drying to obtain the dry powders to improve stability. Quality by Design (QbD) approach was utilized during the study for robustness and standardization followed by Design of Experiment (DoE) for optimization in a holistic way. The mean particle size of the optimized powder sample was found to be 301.1 nm with a percentage encapsulation efficiency (% EE) of 78.8%. In-vitro dissolution studies corroborated the controlled release of CIP over 48 h. Also, mathematical kinetic modeling was applied to obtain thorough insight into the mechanism of drug release. Moreover, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were presented to be lower in the case of prepared dry powder as compared to CIP, stating that nanotechnology can improve antimicrobial activity.

Synthesis of Glycopolymer Micelles for Antibiotic Delivery

In this work, we designed biodegradable glycopolymers consisting of a carbohydrate conjugated to a biodegradable polymer, poly(lactic acid) (PLA), through a poly(ethylene glycol) (PEG) linker. The glycopolymers were synthesized by coupling alkyne end-functionalized PEG-PLA with azide-derivatized mannose, trehalose, or maltoheptaose via the click reaction. The coupling yield was in the range of 40-50% and was independent of the size of the carbohydrate. The resulting glycopolymers were able to form micelles with the hydrophobic PLA in the core and the carbohydrates on the surface, as confirmed by binding with the lectin Concanavalin A. The glycomicelles were ~30 nm in diameter with low size dispersity. The glycomicelles were able to encapsulate both non-polar (rifampicin) and polar (ciprofloxacin) antibiotics. Rifampicin-encapsulated micelles were much smaller (27-32 nm) compared to the ciprofloxacin-encapsulated micelles (~417 nm). Moreover, more rifampicin was loaded into the glycomicelles (66-80 μg/mg, 7-8%) than ciprofloxacin (1.2-2.5 μg/mg, 0.1-0.2%). Despite the low loading, the antibiotic-encapsulated glycomicelles were at least as active or 2-4 times more active than the free antibiotics. For glycopolymers without the PEG linker, the antibiotics encapsulated in micelles were 2-6 times worse than the free antibiotics.

Recent advancements and perspective of ciprofloxacin-based antimicrobial polymers

In recent years, microbial pathogens, which are major sources of infections, have become a widespread concern across the world. The number of deaths caused by infectious diseases is continually rising, according to World Health Organization records. Antimicrobial resistance, particularly resistance to several drugs, is steadily growing in percentages of organisms. Ciprofloxacin is a second-generation fluoroquinolone with significant antimicrobial activity and pharmacokinetic characteristics. According to studies, many bacteria are resistant to the antibiotic ciprofloxacin. In this article, we look into polymers as ciprofloxacin macromolecular carriers with a wide range of antibacterial activity. We also discuss the latter form of coupling, in which ciprofloxacin and polymers are covalently bonded. This article also discusses the use of antimicrobial polymers in combination with ciprofloxacin in a various sectors. The current review article provides an overview of publications in the last five years on polymer loaded or modified with ciprofloxacin having applications in numerous sectors.

Development and Optimization of Ciprofloxacin HCl-Loaded Chitosan Nanoparticles Using Box–Behnken Experimental Design

Various chitosan (CS)-based nanoparticles (CS-NPs) of ciprofloxacin hydrochloride (CHCl) have been investigated for therapeutic delivery and to enhance antimicrobial efficacy. However, the Box–Behnken design (BBD)-supported statistical optimization of NPs of CHCl has not been performed in the literature. As a result, the goal of this study was to look into the key interactions and quadratic impacts of formulation variables on the performance of CHCl-CS-NPs in a systematic way. To optimize CHCl-loaded CS-NPs generated by the ionic gelation process, the response surface methodology (RSM) was used. The BBD was used with three factors on three levels and three replicas at the central point. Tripolyphosphate, CS concentrations, and ultrasonication energy were chosen as independent variables after preliminary screening. Particle size (PS), polydispersity index (PDI), zeta potential (ZP), encapsulation efficiency (EE), and in vitro release were the dependent factors (responses). Prepared NPs were found in the PS range of 198–304 nm with a ZP of 27–42 mV. EE and drug release were in the range of 23–45% and 36–61%, respectively. All of the responses were optimized at the same time using a desirability function based on Design Expert® modeling and a desirability factor of 95%. The minimum inhibitory concentration (MIC) of the improved formula against two bacterial strains, Pseudomonas aeruginosa and Staphylococcus aureus, was determined. The MIC of the optimized NPs was found to be decreased 4-fold compared with pure CHCl. The predicted and observed values for the optimized formulation were nearly identical. The BBD aided in a better understanding of the intrinsic relationship between formulation variables and responses, as well as the optimization of CHCl-loaded CS-NPs in a time- and labor-efficient manner.

Design and evaluation of hyaluronic acid-coated PLGA nanoparticles of raloxifene hydrochloride for treatment of breast cancer

CONTEXT

In the present study, hyaluronic acid (HA)-coated raloxifene-loaded poly(l-lactic-co-glycolic acid) (PLGA) nanoparticles have been developed to improve the anticancer potential and reduce side effects associated with the drug.

AIM AND OBJECTIVES

The investigation was aimed to formulate and optimize raloxifene hydrochloride (RALH)-loaded PLGA nanoparticles with surface modification using HA as a targeting moiety. To perform physicochemical characterization, in vitro cytotoxicity study (using MCF-7), in vitro drug release study and in vivo pharmacodynamic study of optimized formulation.

METHODOLOGY

Raloxifene hydrochloride-loaded PLGA nanoparticles were prepared by nanoprecipitation technique, followed by surface modification with HA. Formulation was optimized by using 23 factorial design and characterized by physicochemical, in vitro drug release, in vitro cytotoxicity studies, and in vivo pharmacokinetics.

RESULTS AND DISCUSSION

The particle size, PDI, zeta potential, entrapment efficiency, and loading capacity of spherically shaped RALH-loaded nanoparticles were 207.3 ± 4.2 d.nm, 0.218 ± 0.127, -.127 mV, 43.75 ± 1.2%, and 7.55 ± 1.14%, respectively. The in vitro drug release showed sustained release and followed Korsmeyer-Peppas model with non-Fickian release pattern. The in vitro cytotoxicity study of drug-loaded NPs by MTT assay on MCF-7 breast carcinoma cell showed anti-cancer activity after 48 h of treatment.

CONCLUSION

The results of the present investigation suggested that RALH-loaded HA-modified PLGA nanoparticles showed sustained drug release with anticancer activity and can be a promising approach for treatment of breast cancer.

Preparation, Physicochemical Assessment and the Antimicrobial Action of Hydroxyapatite-Gelatin/Curcumin Nanofibrous Composites as a Dental Biomaterial

In this study, we prepared and evaluated hydroxyapatite-gelatin/curcumin nanofibrous composites and determined their antimicrobial effects against Escherichia coli, Staphylococcus aureus, and Streptococcus mutans. Hydroxyapatite-gelatin/curcumin nanofibrous composites were prepared by the electrospinning method. The prepared nanocomposites were then subjected to physicochemical studies by the light scattering method for their particle size, Fourier transmission infrared spectroscopy (FTIR) to identify their functional groups, X-ray diffraction (XRD) to study their crystallinity, and scanning electron microscopy (SEM) to study their morphology. For the microbial evaluation of nanocomposites, the disk diffusion method was used against Streptococcus mutans, Staphylococcus aureus, and Escherichia coli. The results showed that the nanofibers were uniform in shape without any bead (structural defects). The release pattern of curcumin from the nanocomposite was a two-stage release, 60% of which was released in the first two days and the rest being slowly released until the 14th day. The results of the microbial evaluations showed that the nanocomposites had significant antimicrobial effects against all bacteria (p = 0.0086). It seems that these nanocomposites can be used in dental tissue engineering or as other dental materials. Also, according to the appropriate microbial results, these plant antimicrobials can be used instead of chemical antimicrobials, or along with them, to reduce bacterial resistance.

Statistical and Machine Learning-Driven Optimization of Mechanical Properties in Designing Durable HDPE Nanobiocomposites

The selection of nanofillers and compatibilizing agents, and their size and concentration, are always considered to be crucial in the design of durable nanobiocomposites with maximized mechanical properties (i.e., fracture strength (FS), yield strength (YS), Young’s modulus (YM), etc). Therefore, the statistical optimization of the key design factors has become extremely important to minimize the experimental runs and the cost involved. In this study, both statistical (i.e., analysis of variance (ANOVA) and response surface methodology (RSM)) and machine learning techniques (i.e., artificial intelligence-based techniques (i.e., artificial neural network (ANN) and genetic algorithm (GA)) were used to optimize the concentrations of nanofillers and compatibilizing agents of the injection-molded HDPE nanocomposites. Initially, through ANOVA, the concentrations of TiO₂ and cellulose nanocrystals (CNCs) and their combinations were found to be the major factors in improving the durability of the HDPE nanocomposites. Further, the data were modeled and predicted using RSM, ANN, and their combination with a genetic algorithm (i.e., RSM-GA and ANN-GA). Later, to minimize the risk of local optimization, an ANN-GA hybrid technique was implemented in this study to optimize multiple responses, to develop the nonlinear relationship between the factors (i.e., the concentration of TiO₂ and CNCs) and responses (i.e., FS, YS, and YM), with minimum error and with regression values above 95%.

Removal of methylene blue dye using nano zerovalent iron, nanoclay and iron impregnated nanoclay - a comparative study

There has been an increasing challenge from the emission of methylene blue (MB) dye-containing wastewater and its management methods in industry. The sorption process is one conventionally used method. In this study, nanoclay, nano zero valent iron (nZVI), and iron impregnated nanoclay were prepared and studied for the removal of MB dye in batch mode. The effects of operating parameters like pH, dye concentration, sorbent dosage, and contact time were investigated and optimized. The nZVI, nanoclay, and iron impregnated nanoclay sorbents showed zeta potentials of -32.1, -53.4, and -40.7 mV, respectively. All the nano adsorbents were crystalline. The nanoclay was characterized by an average surface area, pore volume and pore diameter of 43.49 m2 g-1, 0.104 cm3 g-1 and 2.806 nm, respectively. nZVI showed a surface area of 47.125 m2 g-1, pore volume of 0.119 cm3 g-1, and pore diameter of 3.291 nm. And iron impregnated nanoclay showed a surface area of 73.110 m2 g-1 with a pore volume of 15 cm3 g-1 and a pore diameter size of 3.83 nm. A Langmuir EXT nitrogen gas adsorption isotherm (R 2 ∼ 0.99) was the best fit. The thermodynamics parameters, such as ΔG° (-12.64 to -0.63 kJ mol-1), ΔH° (+0.1 to +62.15 kJ mol-1) and ΔS° (+0.10 to +0.22 kJ mol-1), confirmed that a spontaneous and endothermic adsorption process took place at a high rate of disorder. Iron impregnated nanoclay showed higher negative Gibbs free energy (-12.64 kJ mol-1), higher enthalpy change (+62.5 kJ mol-1) and entropy (+0.22 kJ mol-1) and gave a better MB removal performance. In addition, the lower negative heat of enthalpy for all adsorptions proved the dominance of physisorption. The methylene blue adsorption isotherm on nZVI and nanoclay showed the best fit with the Freundlich isotherm model with correlation coefficients (R 2) ∼0.98 and 0.99, respectively. Whereas the Langmuir adsorption isotherm was the best fit for iron impregnated nanoclay (R 2 ∼ 0.98). The adsorption activities of nZVI, nanoclay and iron impregnated nanoclay were fitted to a pseudo-second-order kinetic model with correlation coefficients (R 2) of 0.999, 0.997 and 0.983, respectively. The optimal pH 7.0 (RE: 99.1 ± 0.73%), initial MB concentration 40 ppm (RE: 99.9 ± 0.03%), contact time 120 min (RE: 99.9 ± 0.9%), and adsorbent dose 80 (99.9 ± 0.03%) were obtained for iron impregnated nanoclay. The optimal operational parameters of nanoclay and nZVI, respectively, were pH 11.0 and 13.0, initial MB concentration 20 and 20 ppm, adsorbent dose 100 and 140 mg, and contact time 120 and 140 min. In general, iron impregnated nanoclay has shown promising cationic dye adsorbance for industrial applications; but a recyclability test is suggested before scale-up.

A Tri-Stimuli Responsive (Maghemite/PLGA)/Chitosan Nanostructure with Promising Applications in Lung Cancer

A (core/shell)/shell nanostructure (production performance ≈ 50%, mean diameter ≈ 330 nm) was built using maghemite, PLGA, and chitosan. An extensive characterization proved the complete inclusion of the maghemite nuclei into the PLGA matrix (by nanoprecipitation solvent evaporation) and the disposition of the chitosan shell onto the nanocomposite (by coacervation). Short-term stability and the adequate magnetism of the nanocomposites were demonstrated by size and electrokinetic determinations, and by defining the first magnetization curve and the responsiveness of the colloid to a permanent magnet, respectively. Safety of the nanoparticles was postulated when considering the results from blood compatibility studies, and toxicity assays against human colonic CCD-18 fibroblasts and colon carcinoma T-84 cells. Cisplatin incorporation to the PLGA matrix generated appropriate loading values (≈15%), and a dual pH- and heat (hyperthermia)-responsive drug release behaviour (≈4.7-fold faster release at pH 5.0 and 45 °C compared to pH 7.4 and 37 °C). The half maximal inhibitory concentration of the cisplatin-loaded nanoparticles against human lung adenocarcinoma A-549 cells was ≈1.6-fold less than that of the free chemotherapeutic. Such a biocompatible and tri-stimuli responsive (maghemite/PLGA)/chitosan nanostructure may found a promising use for the effective treatment of lung cancer.

Enhanced Dermal Delivery of Flurbiprofen Nanosuspension Based Gel: Development and Ex Vivo Permeation, Pharmacokinetic Evaluations

PURPOSE

The objective of this study was to optimize the Flurbiprofen (FB) nanosuspension (NS) based gel and to investigate the in vitro release, ex vivo permeation, the plasma concentration-time profile and pharmacokinetic parameters.

METHODS

FB-NSs were developed using the wet milling process with the Design of Experiment (DoE) approach. The optimum FB-NS was characterized on the basis of SEM, DSC, XRPD, solubility and permeation studies. The dermal gel was prepared by incorporating FB-NS into HPMC gel. Then the in-vitro release, ex vivo permeation studies were performed, and pharmacokinetic studies were evaluated on rats.

RESULTS

The particle size, polydispersity index and zeta potential values of optimum NS were determined as 237.7 ± 6.8 nm, 0.133 ± 0.030 and - 30.4 ± 0.7 mV, respectively. By means of the surfactant content and nanosized particles of the nanosuspension, the solubility of FB was increased about 7-fold. The percentage permeated amount of FB from FB-NS gel (8.40%) was also found to be higher than the physical mixture (5.25%) and coarse suspension (reference) (2.08%) gels. The pharmacokinetic studies showed that the C_max of FB-NS gel was 2.5 times higher than the reference gel, while AUC_0-24 was 2.96 times higher.

CONCLUSION

FB-NSs were successfully prepared with a wet milling method and optimized with the DoE approach. The optimized FB nanosuspension gel provided better permeation and pharmacokinetic performance compared to FB coarse suspension gel.

Fate of Biodegradable Engineered Nanoparticles Used in Veterinary Medicine as Delivery Systems from a One Health Perspective

The field of veterinary medicine needs new solutions to address the current challenges of antibiotic resistance and the need for increased animal production. In response, a multitude of delivery systems have been developed in the last 20 years in the form of engineered nanoparticles (ENPs), a subclass of which are polymeric, biodegradable ENPs, that are biocompatible and biodegradable (pbENPs). These platforms have been developed to deliver cargo, such as antibiotics, vaccines, and hormones, and in general, have been shown to be beneficial in many regards, particularly when comparing the efficacy of the delivered drugs to that of the conventional drug applications. However, the fate of pbENPs developed for veterinary applications is poorly understood. pbENPs undergo biotransformation as they are transferred from one ecosystem to another, and these transformations greatly affect their impact on health and the environment. This review addresses nanoparticle fate and impact on animals, the environment, and humans from a One Health perspective.

Preparation of PLGA-chitosan based nanocarriers for enhancing antibacterial effect of ciprofloxacin in root canal infection

The aim of this study is to prepare and evaluate the antibacterial and antibiofilm activity of ciprofloxacin (CIP) loaded PLGA nanoparticles (F2) and CIP-PLGA nanoparticles coated with chitosan (F3) versus ciprofloxacin solution (Fl) as a control on Enterococcus faecalis. F2 was prepared using double emulsion evaporation technique then coated with chitosan (F3). The prepared F2 and F3 were evaluated for size, surface charge, encapsulation efficiency, morphology and in vitro release. F1, F2, F3, and Chitosan (CS) were assessed in vitro using agar diffusion technique and biofilm inhibition assay. Finally, biofilm inhibition on teeth using Colony Forming Unit (CFU) was implemented with different concentrations of the three formulae. The results revealed that F2 is 202.9 nm with a negative charge -0.0254 mv, while F3 is 339.6 nm with a positive charge +28.5 mv. The encapsulation efficiency of F2, and F3 was 64% and 78% respectively. The amount released was 92.62% and 78.3% for F2 and F3, respectively, after 72 h, while F1 showed 100% released in the first hour. CS, F1, F2, and F3, showed antibacterial effect with inhibition zone of 12 mm, 22 mm, 20 mm, and 32 mm respectively. Biofilm inhibition of F1, F2, and F3 were 60%, 74%, and 91.8%, respectively. F3 colony count was less than F2, and F1 in all concentrations. It can be concluded that F3 had proven to exhibit potential antibacterial and antibiofilm activity in a controlled release pattern consequently, they can be used as an intra-canal medication.

Monosized Polymeric Microspheres Designed for Passive Lung Targeting: Biodistribution and Pharmacokinetics after Intravenous Administration

Local as well as systemic therapy is often used to treat bacterial lung infections. Delivery of antibiotics to the vascular side of infected lung tissue using lung-targeting microspheres (MS) is a good alternative to conventional administration routes, allowing for localized high levels of antibiotics. This delivery route can also complement inhaled antibiotic therapy, especially in the case of compromised lung function. We prepared and characterized monodisperse poly(lactic-co-glycolic acid) (PLGA) MS loaded with levofloxacin using a flow-focusing glass microfluidic chip. In vitro characterization showed that the encapsulated LVX displayed a biphasic controlled release during 5 days and preserved its antibacterial activity. The MS degradation was investigated in vitro by cross-sectioning the MS using a focused ion beam scanning electron microscope and in vivo by histological examination of lung tissue from mice intravenously administered with the MS. The MS showed changes in the surface morphology and internal matrix, whereas the degradation in vivo was 3 times faster than that in vitro. No effect on the viability of endothelial and lung epithelial cells or hemolytic activity was observed. To evaluate the pharmacokinetics and biodistribution of the MS, complete quantitative imaging of the ¹¹¹indium-labeled PLGA MS was performed in vivo with single-photon emission computed tomography imaging over 10 days. The PLGA MS distributed homogeneously in the lung capillaries. Overall, intravenous administration of 12 μm PLGA MS is suitable for passive lung targeting and pulmonary therapy.

The effect of critical process parameters of the high pressure homogenization technique on the critical quality attributes of flurbiprofen nanosuspensions

Flurbiprofen (FB) is an effective nonsteroidal anti-inflammatory and BCS class II drug and its poor solubility plays a critical role in limiting its bioavailability. Nanosuspensions can be defined as nanosized colloidal dispersions of drug particles stabilized with stabilizers. The solubility of poor soluble drugs can be increased thanks to their small size and large surface area. The aim of this study is to optimize FB nanosuspensions. The formulations were stabilized with Plantacare 2000^® as a surfactant using a combination of High Speed Homogenization (HSH) and High Pressure Homogenization techniques (HPH). We also investigated the effects of the critical process parameters (CPPs) of these techniques (homogenization speed & time for HSH and homogenization pressure & cycle for HPH) on three critical quality attributes of nanosuspensions, being the particle size (PS), polydispersity index (PDI) and zeta potential (ZP). After the optimization of HSH, the macrosuspension was transferred to a high pressure homogenizer. After producing FB nanosuspensions by the HPH technique, seven processes which comprise different homogenization pressures, or combinations and different cycles, were applied. Due to the combination of HSH and HPH techniques and the optimization of CPPs, an optimum formulation for a dermal application was found using a 3³ full factorial design with these process parameters, and characterization studies were also performed.

Dexibuprofen Biodegradable Nanoparticles: One Step Closer towards a Better Ocular Interaction Study

Ocular inflammation is one of the most prevalent diseases in ophthalmology, which can affect various parts of the eye or the surrounding tissues. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, are commonly used to treat ocular inflammation in the form of eye-drops. However, their bioavailability in ocular tissues is very low (less than 5%). Therefore, drug delivery systems such as biodegradable polymeric PLGA nanoparticles constitute a suitable alternative to topical eye administration, as they can improve ocular bioavailability and simultaneously reduce drug induced side effects. Moreover, their prolonged drug release can enhance patient treatment adherence as they require fewer administrations. Therefore, several formulations of PLGA based nanoparticles encapsulating dexibuprofen (active enantiomer of Ibuprofen) were prepared using the solvent displacement method employing different surfactants. The formulations have been characterized and their interactions with a customized lipid corneal membrane model were studied. Ex vivo permeation through ocular tissues and in vivo anti-inflammatory efficacy have also been studied.

PLGA nanoparticle preparations by emulsification and nanoprecipitation techniques: effects of formulation parameters

This study presents the influence of the primary formulation parameters on the formation of poly-dl-lactic-co-glycolic nanoparticles by the emulsification-solvent evaporation, and the nanoprecipitation techniques. In the emulsification-solvent evaporation technique, the polymer and tensoactive concentrations, the organic solvent fraction, and the sonication amplitude effects were analyzed. Similarly, in the nanoprecipitation technique the polymer and tensoactive concentrations, the organic solvent fraction and the injection speed were varied. Additionally, the agitation speed during solvent evaporation, the centrifugation speeds and the use of cryoprotectants in the freeze-drying process were analyzed. Nanoparticles were characterized by dynamic light scattering, laser Doppler electrophoresis, and scanning electron microscopy, and the results were evaluated by statistical analysis. Nanoparticle physicochemical characteristics can be adjusted by varying the formulation parameters to obtain specific sizes and stable nanoparticles. Also, by adjusting these parameters, the nanoparticle preparation processes have the potential to be tuned to yield nanoparticles with specific characteristics while maintaining reproducible results.

Ciprofloxacin-Modified Degradable Hybrid Polyurethane-Polylactide Porous Scaffolds Developed for Potential Use as an Antibacterial Scaffold for Regeneration of Skin

The aim of the performed study was to fabricate an antibacterial and degradable scaffold that may be used in the field of skin regeneration. To reach the degradation criterion for the biocompatible polyurethane (PUR), obtained by using amorphous α,ω-dihydroxy(ethylene-butylene adipate) macrodiol (PEBA), was used and processed with so-called "fast-degradable" polymer polylactide (PLA) (5 or 10 wt %). To meet the antibacterial requirement obtained, hybrid PUR-PLA scaffolds (HPPS) were modified with ciprofloxacin (Cipro) (2 or 5 wt %) and the fluoroquinolone antibiotic inhibiting growth of bacteria, such as Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, which are the main causes of wound infections. Performed studies showed that Cipro-modified HPPS, obtained by using 5% of PLA, possess suitable mechanical characteristics, morphology, degradation rates, and demanded antimicrobial properties to be further developed as potential scaffolds for skin tissue engineering.

Novel drug delivery methods for the treatment of keratitis: moving away from surgical intervention

Introduction: Corneal ulceration is one of the leading causes of blindness especially in low- and mid-income countries (LMICs). Surgical treatment of microbial keratitis is associated with multiple challenges that include non-availability of donor corneal tissues, lack of trained corneal surgeons, and poor compliance to follow up care. As a result, the surgery fails in 70-90% cases. Therefore, improving outcome of medical treatment and thereby avoiding the need for the surgery is an unmet need in the care of corneal ulcer cases.Areas covered: In this review article, the authors have tried to compile information on the novel drug-delivery systems that have potential to enhance success of medical management. We have discussed the following systems: cyclodextrins, gel formulations, colloidal system, nanoformulations, drug-eluting contact lens, microneedle patch, and ocular inserts.Expert opinion: The goals of corneal ulcer treatment are as follows: rapid eradication of causative microorganisms, control of damage from induced inflammation and microbial toxins, and facilitation of repair. The ocular surface anatomy poses several challenges for drug delivery using standard topical therapy. The novel drug-delivery systems mentioned above aim to enhanced tear solubility; superior stability; improved bio-availability; reduced toxicity; besides facilitating targeted drug delivery and convenience of administration.

Preparation, characterisation and in vitro antibacterial property of ciprofloxacin-loaded nanostructured lipid carrier for treatment of Bacillus subtilis infection

Context: In this study, controlled ciprofloxacin (CIPRO) nanostrustructured lipid carriers of Precirol^® ATO 5/Transcutol^® HP (batch A) and tallow fat/Transcutol^® HP (batch B) was carreid out. Objective: The aim was to improve solubility and bioavailability of CIPRO. Objective: Study of controlled ciprofloxacin (CIPRO) nanostructured lipid carriers of Precirol^® ATO 5/Transcutol^® HP (batch A) and tallow fat/Transcutol^® HP (batch B). Methods: CIPRO concentrations C_1-5 (0.0, 0.2, 0.5, 0.8, and 1.0% w/w) as AC_1-5 and BC_1-5 were prepared by hot homogenisation and characterised by zetasizer, differential scanning calorimetry, Fourier transform infra-red spectroscopy, in vitro drug release and growth inhibitory zone diameter (IZD) on agar-seeded Bacillus subtilis. Results: AC₅ achieved polydispersed particles of ∼605 nm, 92% encapsulation efficiency (EE) and -28 mV similar to BC₅ (∼789 nm, 91% EE, and -31 mV). Crystallinity indices (AC₅ and BC₅) were low at 3 and 5%, respectively. CIPRO release in AC₅ was ∼98% in SGF (pH 1.2) and BC₅ similarly ∼98% in SIF (pH 6.8). Conclusions: AC₅ had superior growth inhibition of B. subtilis at lower concentration (1.2 µg/mL) than BC₅ and CIPRO controls; hence could serve as possible sustained delivery system of CIPRO.

Antibacterial Activity of Vancomycin Encapsulated in Poly(DL-lactide-co-glycolide) Nanoparticles Using Electrospraying

Vancomycin is often used to treat infections caused by β-lactam-resistant bacteria. However, methicillin-resistant strains of Staphylococcus aureus (MRSA) acquired resistance to vancomycin, rendering it less effective in the treatment of serious infections. In the search for novel antibiotics, alternative delivery mechanisms have also been explored. In this study, we report on the encapsulation of vancomycin in PLGA [poly(DL-lactide-co-glycolide)] nanoparticles by electrospraying. The nanoparticles were on average 247 nm in size with small bead formations on the surface. Clusters of various sizes were visible under the SEM (scanning electron microscope). Vancomycin encapsulated in PLGA (VNP) was more effective in inhibiting the growth of S. aureus Xen 31 (MRSA) and S. aureus Xen 36 than un-encapsulated vancomycin. Encapsulated vancomycin had a minimum inhibitory concentration (MIC) of 1 μg/mL against MRSA compared to 5 μg/mL of free vancomycin. At least 70% (w/w) of the vancomycin was encapsulated. Thirty percent of the vancomycin was released within the first 144 h, followed by slow release over 10 days. Vancomycin encapsulated in PLGA nanoparticles may be used to treat serious infections.

Tenofovir disoproxil fumarate loaded PLGA nanoparticles for enhanced oral absorption: Effect of experimental variables and in vitro, ex vivo and in vivo evaluation

In this study, PLGA based nanoparticles of tenofovir disoproxil fumarate (TDF) were designed for enhancing its oral absorption. To develop PLGA based TDF nanoparticles with the goal of minimum particle size and maximum entrapment efficiency statistical optimization techniques (factorial design and response surface methodology) were employed. The optimized nanoparticles were characterized for size, shape, charge and physical state. Further, the stability, cytotoxicity and metabolic protective effect of the nanoparticles were evaluated. Single dose pharmacokinetic study in rats was conducted to evaluate the oral absorption of the designed nanoparticles. Ex vivo everted gut sac studies were performed to evaluate the role of active uptake mechanisms in the absorption of the designed nanoparticles. The results showed that the statistical models employed could determine the interaction effects of the critical factors which were used in the optimization of the nanoparticles. The optimized nanoparticles with a particle size of 218±3.85nm and an entrapment efficiency of 57.3±1.6%. The nanoparticles were able to increase the AUC of tenofovir by 5.8 fold. It was observed that active uptake mechanisms predominantly via clathrin-mediated uptake played a key role in increasing the oral absorption of TDF.

Improved release of triamcinolone acetonide from medicated soft contact lenses loaded with drug nanosuspensions

Drug nanosuspensions (NSs) show a significant potential to improve loading and release properties of the poorly water soluble drug triamcinolone acetonide (TA) from poly(hydroxyethyl methacrylate) (pHEMA) soft contact lenses. In this work, TA NSs were developed by a controlled precipitation method using a fractional factorial Plackett-Burmann design. Poloxamer 407 (PL) and polyvinyl alcohol (PVA) as stabilizing agents were selected. NSs were characterized in terms of their drug content, particle size and morphology. Results indicate that all studied factors, except homogenization speed and sonication, have significant influence on the drug incorporation yield into NSs. Drug nanoparticles showed an interesting size that may be suitable for their incorporation into topical ocular drug delivery systems, as hydrogels. pHEMA hydrogels and daily-wear Hilafilcon B commercial contact lenses (SCLs) were employed to study TA loading capacity and drug release properties using NSs as loading system. Hydrogels have been synthesised by copolymerization of 2-hydroxyethyl methacrylate (HEMA) with methacrylic acid (MA) in accordance with a previous work (García-Millán et al., 2015). Both synthesised hydrogels and SCLs were characterized in terms of their mechanical and physical properties and TA loading and release properties. Selected TA NS was further characterized by studying its physical-chemical stability during the loading process. Results show that the use of TA NSs as loading medium significantly increases drug loading capacity and release of soft contact lenses in comparison with drug saturated solution. Synthesised pHEMA hydrogels and SCLs lenses have good properties as ophthalmic drug delivery systems, but SCLs load higher quantities of drug and release TA in shorter time periods than synthesised pHEMA hydrogel.

Biodegradable nitric oxide precursor-loaded micro- and nanoparticles for the treatment of Staphylococcus aureus biofilms

Bacteria in biofilms are more difficult to eradicate than planktonic bacteria and result in treatment challenges for many chronic infectious diseases. Nitric oxide (NO) is an endogenous molecule that offers potential as an alternative to conventional antibiotics; however its sustained topical delivery to biofilms is not readily achieved. With this in mind, we report the development of biodegradable poly(lactide-co-glycolide) (PLGA) based microparticles (MP) and nanoparticles (NP) for encapsulation of the NO precursor isosorbide mononitrate (ISMN) and the controlled delivery to Staphylococcus aureus (S. aureus) biofilms. Firstly, water-in-oil-in-water (w/o/w) emulsification/solvent evaporation methods for PLGA NP and MP syntheses were experimentally optimised with respect to particle size and ISMN loading/encapsulation efficiency. The influence of various experiment parameters, such as the volume of inner aqueous phase, concentration of surfactants, mixing time on the particle size, drug loading and encapsulation efficiency were investigated systematically. Both PLGA MP and NP formulations enabled sustained ISMN release in physiological media over 3 to 5 days. PLGA MP with diameters of ∼3 μm and ISMN loading of 2.2% (w/w) were identified as the optimum delivery system and demonstrated significant antibacterial activity in S. aureus biofilms. This behaviour is considered to be due to targeted biofilm delivery through a combination of effective penetration and sustained release of ISMN.

Respirable controlled release polymeric colloid (RCRPC) of bosentan for the management of pulmonary hypertension: in vitro aerosolization, histological examination and in vivo pulmonary absorption

Bosentan is an endothelin receptor antagonist (ERA) prescribed for patients with pulmonary arterial hypertension (PAH). The oral delivery of bosentan possesses several drawbacks such as low bioavailability (about 50%), short duration of action, frequent administration, hepatotoxicity and systemic hypotension. The pulmonary administration would circumvent the pre-systemic metabolism thus improving the bioavailability and avoids the systemic adverse effects of oral bosentan. However, the short duration of action and the frequent administration are the major drawbacks of inhalation therapy. Thus, the aim of this work is to explore the potential of respirable controlled release polymeric colloid (RCRPC) for effective, safe and sustained pulmonary delivery of bosentan. Central composite design was adopted to study the influence of formulation and process variables on nanoparticles properties. The particle size, polydispersity index (PDI), entrapment efficiency (EE) and in vitro bosentan released were selected as dependent variables. The optimized RCRPC showed particle size of 420 nm, PDI of 0.39, EE of 60.5% and sustained release pattern where only 31.0% was released after 16 h. The in vitro nebulization of RCRPC indicated that PLGA nanoparticles could be incorporated into respirable nebulized droplets better than drug solution. Pharmacokinetics and histopathological examination were determined after intratracheal administration of the developed RCRPC to male albino rats compared to the oral bosentan suspension. Results revealed the great improvement of bioavailability (12.71 folds) and sustained vasodilation effect on the pulmonary blood vessels (more than 12 h). Bosentan-loaded RCRPC administered via the pulmonary route may therefore constitute an advance in the management of PAH.

A novel nanoparticles impregnated ocular insert for enhanced bioavailability to posterior segment of eye: In vitro, in vivo and stability studies

The present investigation was carried out to demonstrate with the help of in vitro and in vivo studies that nanoparticles impregnated ocular inserts effectively delivers significant concentration of drug to the posterior segment of eye after topical administration for treatment of glaucoma. Drug loaded Nanoparticles and their ocular insert have been reported to reduce side effects of orally administered Acetazolamide. Eudragit NPs were prepared by the solvent diffusion nanoprecipitation technique. The prepared NPs were evaluated for various parameters such as particle size, zeta potential, % entrapment efficiency, % drug loading, DSC, FTIR, TEM and stability studies. Ocular inserts of NPs were prepared by solvent casting method. The prepared ocular inserts were evaluated for thickness, content uniformity, folding endurance, disintegration time, morphology and stability study. The NPs and ocular inserts were evaluated for in-vitro drug diffusion study, ex-vivo trans-corneal permeability study, in-vivo ocular tolerability and intra ocular pressure (IOP) reduction study. The optimized batch was stable for a period of 3months in lyophilized form. The optimized formulations had size range of 367nm±8nm, zeta potential around +7mV±1.3mV and 51.61%±3.84% entrapment efficiency with 19%±1.40% drug loading. The ex-vivo trans-corneal study showed higher cumulative corneal permeation, flux across corneal tissue (2.460±0.028μg/ml) and apparent corneal permeability (3.926×10^-6cm²/s & 3.863×10^-6cm²/s) from drug loaded Eudragit NPs and Ocular inserts as compared to drug solution (0.671±0.020μg/ml & 3.166×10^-6cm²/s). In-vivo study showed the Eudragit NPs and ocular insert produced significant (P<0.001) lowering in intra ocular pressure compared with the solution of free drug after 3h of topical ocular administration. Plain Eudragit NPs caused no inflammation and/or discomfort in rabbit eyes and neither affected the intra ocular pressure establishing their safety and non irritancy.

Counter-ion complexes for enhanced drug loading in nanocarriers: Proof-of-concept and beyond

Enhanced drug loading is an important prerequisite of nanomedicines, to reach administration dose while reducing the amount of excipient. Considering biocompatible and biodegradable polymers such as PLGA, pH dependent solubility characteristics along with limited organic solvent solubility of the drug hampers nanoparticle (NP) preparation. To improve loading of such molecules, a method based on using counter ions for complex formation is proposed. Formed complex alters the intrinsic solubility of active substance via electrostatic interaction without chemical modification. A proof-of-concept study was conducted with sodium dodecyl sulfate as counter-ion to fluoroquinolone antibiotic ciprofloxacin. Complex formation resulted in suppressed pH dependent solubility over pH 1.2-9.0 and an additional -80 fold increase in organic solubility was achieved. In consequence, NPs prepared by microjet reactor technology have shown enhanced drug loading efficiencies (-78%) and drug loading of 14%. Moreover, the counter-ion concept was also demonstrated with another class of antibiotics, water soluble aminoglycosides gentamycin and tobramycin. In addition, the counter ion was substituted by degradable excipients such as phosphatidic acid derivatives. Successful implementation has proven the counter-ion concept to be a platform concept that can be successfully implemented for a variety of active substances and counter-ions to enhance drug loading in nanocarriers.

Efficacy of Poly-Lactic-Co-Glycolic Acid Micro- and Nanoparticles of Ciprofloxacin Against Bacterial Biofilms

Bacterial biofilms are associated with a number of recurring infectious diseases and are a major cause for antibiotic resistance. Despite the broad use of polymeric microparticles and nanoparticles in biomedical research, it is not clear which particle size is more effective against biofilms. The purpose of this study was to evaluate the efficacy of sustained release poly-lactic-co-glycolic acid (PLGA) micro- and nanoparticles containing ciprofloxacin against biofilms of Staphylococcus aureus and Pseudomonas aeruginosa. The PLGA particles were prepared by the double emulsion solvent evaporation method. The resulting microparticles (12 μm) and nanoparticles (300 nm) contained drug loads of 7.3% and 4.5% (wt/wt) ciprofloxacin, respectively. Drug release was complete within 1 week following comparable release profiles for both particle sizes. Micro- and nanoparticles demonstrated a similar in vitro antibiofilm performance against mature P aeruginosa and S aureus with marked differences between the 2 strains. The sustained release of ciprofloxacin from micro- and nanoparticles over 6 days was equally effective as the continuous treatment with ciprofloxacin solution over the same period resulting in the eradication of culturable S aureus suggesting that reformulation of ciprofloxacin as sustained release PLGA micro- and nanoparticles might be valuable formulation approaches for the treatment of biofilms.

Antibacterial Activity of Ciprofloxacin-Encapsulated Cockle Shells Calcium Carbonate (Aragonite) Nanoparticles and Its Biocompatability in Macrophage J774A.1

The use of nanoparticle delivery systems to enhance intracellular penetration of antibiotics and their retention time is becoming popular. The challenge, however, is that the interaction of nanoparticles with biological systems at the cellular level must be established prior to biomedical applications. Ciprofloxacin-cockle shells-derived calcium carbonate (aragonite) nanoparticles (C-CSCCAN) were developed and characterized. Antibacterial activity was determined using a modified disc diffusion protocol on Salmonella Typhimurium (S. Typhimurium). Biocompatibilittes with macrophage were evaluated using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-Bromo-2'-deoxyuridine (BrdU) assays. Transcriptional regulation of interleukin 1 beta (IL-1β) was determined using reverse transcriptase-polymerase chain reaction (RT-PCR). C-CSCCAN were spherical in shape, with particle sizes ranging from 11.93 to 22.12 nm. Encapsulation efficiency (EE) and loading content (LC) were 99.5% and 5.9%, respectively, with negative ζ potential. X-ray diffraction patterns revealed strong crystallizations and purity in the formulations. The mean diameter of inhibition zone was 18.6 ± 0.5 mm, which was better than ciprofloxacin alone (11.7 ± 0.9 mm). Study of biocompatability established the cytocompatability of the delivery system without upregulation of IL-1β. The results indicated that ciprofloxacin-nanoparticles enhanced the antibacterial efficacy of the antibiotic, and could act as a suitable delivery system against intracellular infections.