Lung-targeted delivery system of curcumin loaded gelatin microspheres

Conception of pH-sensitive calcium alginate/poly vinyl alcohol hydrogel beads for controlled oral curcumin delivery systems. Antibacterial and antioxidant properties

Curcumin, a bioactive compound derived from the rhizome of Curcuma longa, has gained widespread attention for its potential therapeutic properties, including anti-inflammatory, antioxidant and anticancer effects. However, its poor aqueous solubility, instability and limited bioavailability have hindered its clinical applications. New beads formulations based on sodium alginate biopolymer (SA) and poly vinyl alcohol (PVA) were successfully prepared and evaluated as a potential drug vehicle for extended release of curcumin (Cur). Pristine and curcumin loaded calcium alginate/poly vinyl alcohol beads (CA/PVA and CA/PVA/Cur) at different compositions of SA and PVA were prepared by an ionotropic gelation method of SA followed by two freeze-thawing (FT) cycles for further crosslinking of PVA. Characterization techniques, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV-Visible spectroscopy, thermogravimetric analysis (TGA) and x-ray diffraction (XRD) were used to confirm the successful microencapsulation of curcumin within the CA/PVA microcapsules. Furthermore, the swelling of pristine beads, pH-sensitive properties and in vitro release studies of curcumin loaded beads were investigated at 37 °C in simulated gastric fluid (SGF), simulated intestinal fluid (SIF) and simulated colonic fluid (SCF). The effect of the polymer blend ratio, the encapsulation efficiency (EE %) of curcumin, the loading capacity (LC μg/mg), the sphericity factor (SF), the antioxidant activity of the elaborated beads and their antimicrobial properties against bacteria and fungi were just as much evaluated. The obtained results indicate that the swelling and the behavior of the developed beads were influenced by the pH of the test medium and the PVA content. The introduction of PVA into the SA matrix greatly enhanced the physicochemical properties, the encapsulation efficiency and the loading capacity of the elaborated microparticles. Results also suggested that the antioxidant activity of the loaded beads (CA/PVA/Cur) showed a higher DPPH radical scavenging activity while the bacterial and fungal strains proved sensitive to the different formulations used in the assay. Moreover, the important drug encapsulation efficiency and the sustainable drug release of these materials make them promising for the development of new drug carrier systems for colon targeting.

Preparation of Ergosterol-Loaded Nanostructured Lipid Carriers for Enhancing Oral Bioavailability and Antidiabetic Nephropathy Effects

In our previously studies, we confirmed that ergosterol could ameliorate diabetic nephropathy by suppressing the proliferation of mesangial cells and the accumulation of extracellular matrix (ECM). However, the therapeutic application of ergosterol may be confined due to poor aqueous solubility and low oral bioavailability. We aim to prepare ergosterol-loaded nanostructured lipid carriers (ERG-NLCs) to enhance the solubility and oral bioavailability of ergosterol. ERG-NLCs were prepared using glyceryl monostearate and decanoyl/octanoyl-glycerides by hot emulsification-ultrasonication method and characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) analysis, entrapment efficiency (EE), and drug loading (DL) capacity studies. The prepared ERG-NLCs were spherical, with particle size of 81.39 nm and negative zeta potential of 30.77 mV. Ergosterol was successfully encapsulated in NLCs with a high EE of 92.95% and a DL capacity of 6.51%. In pharmacokinetic study, C_max and AUC_0-∞ of ergosterol in ERG-NLCs were obviously enhanced, and the relative oral bioavailability of ERG-NLCs was 277.56% higher than that of raw ergosterol. Moreover, the in vitro pharmacodynamic study indicated that ERG-NLCs inhibited high-glucose-stimulated mesangial cells over proliferation and ECM accumulation more effectively compared to raw ergosterol. In conclusion, the validated ERG-NLCs showed that NLCs mediated delivery could be used as potential vehicle to enhance solubility, oral bioavailability and therapeutic efficacy of ergosterol.

Gelatin-stabilized composites of silver nanoparticles and curcumin: characterization, antibacterial and antioxidant study

This is a preliminary study of a material comprising gelatin (Gel), silver nanoparticles (AgNPs) and curcumin (Cur) aimed for wound-healing treatment. Gelatin was used to stabilize AgNPs and encapsulate curcumin to form a therapeutic composite (GelCurAg) for their strong bactericidal and antioxidant properties. GelCurAg formulations with different gelatin concentrations were characterized to attain information about their physiochemical properties and the loading efficiency of therapeutic agents. In vitro assessment of GelCurAg focused on antibacterial, antioxidant and cytotoxic aspects. The results suggested that Gel1CurAg (synthesized from 1% gelatin solution) could be utilized as potential therapeutic agents in treating infectious wound owing to its bactericidal and antioxidant effects and low toxicity for clinical uses.

Preparation and evaluation of tilmicosin microspheres and lung-targeting studies in rabbits

Tilmicosin (TMS) is a macrolide used extensively for pulmonary infections in clinical veterinary medicine. However, TMS has frequent administration and short elimination half-life. Therefore, tilmicosin-gelatine microspheres (TMS-GMS) were prepared by an emulsion-chemical cross-linking technique as a sustained-release formulation to extend drug half-life. The particle size distribution, in-vitro sustained-release properties, stability, and physical characteristics, as well as pharmacokinetic (PK) characteristics, were evaluated in rabbits. TMS-GMS were spherical in shape and had a mean diameter of 11.34±1.20μm; 95.65% of the microspheres varied in size from 5.0 to 25.0μm. Light and thermal stability tests indicated no significant changes in all observed indices. Importantly, compared to crude TMS, slower release of TMS from TMS-GMS was noted in drug release studies (in vitro). Pharmacokinetic (PK) characteristics were examined in the lung, liver, heart, kidney and muscle tissue of rabbits following IM injection of TMS-GMS or TMS-injection at a dose of 10mg/kg. The elimination half-life of TMS-GMS (59.21±0.21h) was longer than that of TMS-injection (38.56±0.13h) in the lung. The ratio of peak concentration (C_e) of TMS-GMS to TMS-injection was 2.19 (>1) in the lung, demonstrating the selectivity of TMS-GMS to target the lung compared to that of other tissues (C_e<1). Interestingly, the uptake value of TMS from TMS-GMS was 8.48 times higher in the lung than that for the TMS-injection, and was slightly higher than in the liver (1.85), heart (1.72), kidney (2.44) and muscle (2.79) tissues. TMS-GMS is a sustained-release formulation of TMS with potential to be used in veterinary clinical applications; possible benefits include lung-targeting and prolonged elimination half-life.

Nanomedicines guided nanoimaging probes and nanotherapeutics for early detection of lung cancer and abolishing pulmonary metastasis: Critical appraisal of newer developments and challenges to clinical transition

Lung cancer (LC) is the second most prevalent type of cancer and primary cause of mortality among both men and women, worldwide. The most commonly employed diagnostic modalities for LC include chest X-ray (CXR), magnetic-resonance-imaging (MRI), computed tomography (CT-scan), and fused-positron-emitting-tomography-CT (PET-CT). Owing to several limitations associated with the use of conventional diagnostic tools such as radiation burden to the patient, misleading diagnosis ("missed lung cancer"), false staging and low sensitivity and resolution, contemporary diagnostic regimen needed to be employed for screening of LC. In recent decades, nanotechnology-guided interventions have been transpired as emerging nanoimaging probes for detection of LC at advanced stages, while producing signal amplification, better resolution for surface and deep tissue imaging, and enhanced translocation and biodistribution of imaging probes within the cancerous tissues. Besides enormous potential of nanoimaging probes, nanotechnology-based advancements have also been evidenced for superior efficacy for treatment of LC and abolishing pulmonary metastasis (PM). The success of nanotherapeutics is due to their ability to maximise translocation and biodistribution of anti-neoplastic agents into the tumor tissues, improve pharmacokinetic profiles of anti-metastatic agents, optimise target-specific drug delivery, and control release kinetics of encapsulated moieties in target tissues. This review aims to overview and critically discuss the superiority of nanoimaging probes and nanotherapeutics over conventional regimen for early detection of LC and abolishing PM. Current challenges to clinical transition of nanoimaging probes and therapeutic viability of nanotherapeutics for treatment for LC and PM have also been pondered.

A novel phenolic propanediamine moiety-based lung-targeting therapy for asthma

Asthma is one of the most prevalent chronic inflammatory diseases of lung. Current asthma therapy using inhaled corticosteroid often results in undesired treatment outcome due to poor compliance and drugs’ lack of tissue specificity. N,N,N’-trimethyl-N’-(2-hydroxyl-3-methyl-5-¹²³Iiodobenzyl)-1,3-propanediamine (HIPD), a phenolic propanediamine derivative, has been used as an imaging agent for localized pulmonary diseases. Inspired by this, N,N,N’-trimethyl-N’-(4-hydroxyl-benzyl)-1,3-propanediamine (TPD), a new HIPD analog, was proposed as a lung-targeting ligand and covalently conjugated to an anti-inflammatory compound Rhein for asthma therapy. Cellular uptake efficiency of TPD-Rhein by A549 cells was significantly enhanced compared with Rhein. The enhanced cellular uptake was mainly mediated by organic cation transporters (OCTs) in an active manner, showing concentration- and energy-dependent. After systemic administration in rats, TPD-Rhein specifically distributed to lungs, displaying the highest C_max and AUC_0−t values of all tested tissues and resulting in a 13-fold increase in C_max and a 103-fold increase in AUC_0−t for lung compared with Rhein. Also, TPD-Rhein remarkably decreased serum histamine levels, serum IL-5 levels as well as bronchoalveolar lavage fluid IL-5 levels in lungs of asthmatic rats challenged by ovalbumin (OVA). Accordingly, histological examinations demonstrated that TPD-Rhein attenuated lung inflammation in rats, with no apparent toxicity against major organs. Together, phenolic propanediamine-based lung-targeting approach represents an efficient and safe strategy for asthma therapy.

Catan-ionic hybrid lipidic nano-carriers for enhanced bioavailability and anti-tumor efficacy of chemodrugs

To date there has not been any report on catan-ionic hybrid lipidic nano-carriers, let alone a report on applying them to deliver insoluble anti-tumor drugs. Catan-ionic hybrid lipidic nano-carriers containing curcumin (CUR-C-HLN) inherit the merits of catan-ionic systems, hybrid lipidic systems and nano-structured carriers (the second-generation substitute of solid lipidic nano-systems). Catan-ionic surfactants increased microvesicle stabilization by producing unordered isometric clusters, enhanced absorptive amount as an inhibitor of enzyme and protein, improved tumor accumulation by cellular endocytosis and membranous fusion; hybrid lipids helped to obtain high drug content and low leakage by forming a less-organized matrix arrangement. CUR-C-HLN favorably changed absorptive and pharmacokinetic properties after oral and/or intravenous administrations; improved cell growth inhibition, apoptotic inducing and anti-invasion effects; enhanced antitumor efficiency and reduced cancerous growth. Catan-ionic hybrid lipidic nano-carriers provide an alternative good choice for effective delivery of anticancerous chemodrugs.

Effective use of nanocarriers as drug delivery systems for the treatment of selected tumors

Nanotechnology has recently gained increased attention for its capability to effectively diagnose and treat various tumors. Nanocarriers have been used to circumvent the problems associated with conventional antitumor drug delivery systems, including their nonspecificity, severe side effects, burst release and damaging the normal cells. Nanocarriers improve the bioavailability and therapeutic efficiency of antitumor drugs, while providing preferential accumulation at the target site. A number of nanocarriers have been developed; however, only a few of them are clinically approved for the delivery of antitumor drugs for their intended actions at the targeted sites. The present review is divided into three main parts: first part presents introduction of various nanocarriers and their relevance in the delivery of anticancer drugs, second part encompasses targeting mechanisms and surface functionalization on nanocarriers and third part covers the description of selected tumors, including breast, lungs, colorectal and pancreatic tumors, and applications of relative nanocarriers in these tumors. This review increases the understanding of tumor treatment with the promising use of nanotechnology.

Preparation and evaluation of cefquinome-loaded gelatin microspheres and the pharmacokinetics in pigs

Cefquinome (CEF) is widely used for veterinary clinical applications because of its broad spectrum and high efficiency. However, frequent administrations are required due to its short elimination half-life. In this study, cefquinome sulfate gelatin microspheres (CEF-GMS) were prepared as a sustained-release formulation using emulsion chemical cross-linking technique. Physical properties, stability, sustained-release property in vitro, and pharmacokinetics in pigs were assessed. The morphology of CEF-GMS showed a good sphericity with porous structure on the surface, and the mean diameter was 8.80 ± 0.78 μm, with 90.60 ± 3.98% of the total in the range of 5-20 μm. There were no significant changes of all estimated indexes in the stability tests. In vitro drug release study showed that the release of CEF from CEF-GMS was much slower than that from crude CEF in a release medium. Pharmacokinetic characteristics were evaluated following intramuscular administration of CEF-GMS or Cefquinome sulfate injection (CEF-Inj) in pigs at a dosage of 4 mg CEF/kg body weight. The plasma drug concentration-time data of CEF-GMS and CEF-Inj were both best fitted by two-compartment models with first-order absorption, and the elimination half-life of CEF-GMS was almost 10 times that of CEF-Inj. Overall, CEF-GMS might be used as a sustained-release formulation of CEF for veterinary clinical applications.

Preparation of lung-targeting, emodin-loaded polylactic acid microspheres and their properties

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) has been identified to have the potential to improve lung fibrosis and lung cancer. To avoid the liver and kidney toxicities and the fast metabolism of emodin, emodin-loaded polylactic acid microspheres (ED-PLA-MS) were prepared and their characteristics were studied. ED-PLA-MS were prepared by the organic phase dispersion-solvent diffusion method. By applying an orthogonal design, our results indicated that the optimal formulation was 12 mg/mL PLA, 0.5% gelatin, and an organic phase:glycerol ratio of 1:20. Using the optimal experimental conditions, the drug loading and encapsulation efficiencies were (19.0±1.8)% and (62.2±2.6)%, respectively. The average particle size was 9.7±0.7 μm. In vitro studies indicated that the ED-PLA-MS demonstrated a well-sustained release efficacy. The microspheres delivered emodin, primarily to the lungs of mice, upon intravenous injection. It was also detected by microscopy that partial lung inflammation was observed in lung tissues and no pathological changes were found in other tissues of the ED-PLA-MS-treated animals. These results suggested that ED-PLA-MS are of potential value in treating lung diseases in animals.

Formulation of curcumin delivery with functionalized single-walled carbon nanotubes: characteristics and anticancer effects in vitro

CONTEXT

Single-walled carbon nanotubes (SWCNTs), an important class of artificial nanomaterials with unique physicochemical properties, were used as novel carriers of curcumin.

OBJECTIVE

Formulation and evaluation of curcumin-loaded SWCNTs systems for utilizing the curcumin's anticancer potential by circumventing conventional limitations of extremely low aqueous solubility and instability under physiological conditions, and combining SWCNTs photothermal therapy enabled by the strong optical absorbance of SWCNTs in the 0.8-1.4 μm resulting in excessive local heating.

METHODS

After functionalized SWCNTs were confirmed, they were conjugated with curcumin (SWCNT-Cur). Subsequently, the formulation was analyzed for size, zeta-potential and morphology. And the solubility, stability and release of curcumin were assessed using spectrofluorometer, and the solid state of the curcumin was determined using X-ray diffraction and UV spectroscopy. Furthermore, in PC-3 cells, photothermal response was further determined by irradiating laser after the antitumor effect of SWCNT-Cur was evaluated.

RESULTS AND DISCUSSION

SWCNTs were functionalized, and subsequent SWCNT-Cur conjugates were found to possess an average size of 170.4 nm, a zeta potential of -12.5 mV and to significantly enhance the solubility and stability of curcumin, overcoming the barriers to adequate curcumin delivery. Moreover, curcumin in SWCNT-Cur was in an amorphous form and could be rapidly released. In PC-3 cells, improved inhibition efficacy was achieved by SWCNT-Cur compared with native curcumin. Meanwhile, the SWCNTs in SWCNT-Cur served not only as scaffolds but also as thermal ablation agents, further inhibiting PC-3 cell growth.

CONCLUSION

SWCNT-Cur assemblies may provide a promising delivery system for curcumin for use in cancer therapy.

In vivo investigation of ceftiofur-loaded gelatin and PLGA microspheres in beagle dogs

Drug delivery systems based on polymer microspheres have received considerable attention. Ceftiofur sodium and ceftiofur hydrochloride is widely used for the treatment of bacterial diseases in animals but the delivery in vivo has not been reported. In this paper, we report the synthesis of microspheres from gelatin and PLGA, two kinds of typical natural and artificial materials, for loading ceftiofur and the in vivo investigation of the pharmacokinetics in beagle dogs. By controlling the synthesis parameters, gelatin and PLGA microspheres with diameter between 5 and 35 microns were obtained. Assay procedures based on high performance liquid chromatography were evaluated and confirmed. The dogs were randomly divided into three groups, i.e., control group, gelatin group, and PLGA group and administrated via intravenous injection. Plasma concentrations of ceftiofur over time were measured and analyzed. Results indicate that the main kinetic parameters do not show significant difference for the gelatin group and control group, but the area under the curve, plasma half-life, apparent volume of distribution, and clearance ratio of PLGA group show significant difference from the gelatin group and the control group. The PLGA microspheres show a low area under the curve but long time release.