Thermosensitive TMPO-oxidized lignocellulose/cationic agarose hydrogel loaded with deferasirox nanoparticles for photothermal therapy in melanoma

Deferasirox (DFX) is an iron-chelating agent effective in treating various kinds of cancers, which inhibits iron metabolism in cancer cells. The recent study aimed to prepare an injectable thermosensitive hydrogel based on lignocellulose and agarose containing deferasirox-loaded polypyrrole nanoparticles for local drug delivery in a combined chemo-photothermal therapy by laser light irradiation. Polypyrrole nanoparticles containing DFX were made by the emulsification method and optimized. Thermosensitive hydrogels were prepared by quaternary ammonium substituted agarose and TMPO-oxidized lignocellulose at different ratios, and the optimal hydrogel was selected based on gelation time, gelation temperature, and injectability. DFX- loaded polypyrrole nanoparticles were then added to the hydrogel, and the drug release, rheology test, injectability, degradation, and swelling percent, as well as cytotoxicity, and photothermal properties, were studied on B16F10, human melanoma cells. The hydrogel with 2 % anionic lignocellulose and 0.5 % cationic agarose showed the shortest gelation time and the highest mechanical strength. It transferred from a liquid state at 4 °C into a semisolid form at 37 °C with a gelation time of 10.3 min. The nanoparticles loaded in hydrogel showed dose-dependent cytotoxicity. The cytotoxic dose of the drug was reduced by laser light irradiation.

Development of Chlorantraniliprole and Lambda Cyhalothrin Double-Loaded Nano-Microcapsules for Synergistical Pest Control

Nanotechnology could greatly improve global agricultural food production. Chlorantraniliprole and lambda cyhalothrin double-loaded nano-microcapsules were fabricated to enhance the control of pests by pesticides and improve the pesticide utilization efficiency. The nano-microcapsules were synthesized using a method involving the solid in oil in water encapsulation technique and solvent evaporation. The nano-microcapsules slowly and simultaneously released lambda cyhalothrin and chlorantraniliprole. The cumulative lambda cyhalothrin and chlorantraniliprole release rates at 40 h were 80% and 70%, respectively. Indoor Spodoptera frugiperda control tests indicated that the double-loaded nano-microcapsules were more toxic than lambda cyhalothrin water-dispersible granules, chlorantraniliprole water-dispersible granules, and a mixture of lambda cyhalothrin water-dispersible granules and chlorantraniliprole water-dispersible granules, indicating that the pesticides in the nano-microcapsules synergistically controlled Spodoptera frugiperda. The results indicated that pesticide nano-microcapsules with synergistic effects can be developed that can improve the effective pesticide utilization efficiency and pesticide bioavailability. This is a new idea for achieving environmentally intelligent pesticide delivery.

Chemically-Induced Cross-Linking of Peptidic Fibrils for Scaffolding Polymeric Particles and Macrophages

EAK16-II (EAK) is a self-assembling peptide (SAP) that forms β-sheets and β-fibrils through ionic-complementary interactions at physiological ionic strengths. The soft materials can be injected in vivo, creating depots of drugs and cells for rendering pharmacological and biological actions. The scope of the applications of EAK is sought to extend to tissues through which the flow of extracellular fluid tends to be limited. In such anatomical locales the rate and extent of the fibrilization are limited insofar as drug delivery and cellular scaffolding would be impeded. A method is generated utilizing a carbodiimide cross-linker by which EAK fibrils are pre-assembled yet remain injectable soft materials. It is hypothesized that the resulting de novo covalent linkages enhance the stacking of the β-sheet bilayers, thereby increasing the lengths of the fibrils and the extent of their cross-linking, as evidenced in Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy, scanning electron microscopy, and atomic force microscopy analyses. The cross-linked EAK (clEAK) retains polymeric microspheres with an average diameter of 1 µm. Macrophages admixed with clEAK remain viable and do not produce the inflammatory mediator interleukin-1β. These results indicate that clEAK should be investigated further as a platform for delivering particles and cells in vivo.

Formulation and Characterisation of a Combination Captopril and Hydrochlorothiazide Microparticulate Dosage Form

Cardiovascular diseases such as hypertension and cardiac failure in South African children and adolescents are effectively managed long term, using a combination treatment of captopril and hydrochlorothiazide. The majority of commercially available pharmaceutical products are designed for adult patients and require extemporaneous manipulation, prior to administration to paediatric patients. There is a need to develop an age appropriate microparticulate dosing technology that is easy to swallow, dose and alter doses whilst overcoming the pharmacokinetic challenges of short half-life and biphasic pharmacokinetic disposition exhibited by hydrochlorothiazide and captopril. An emulsion solvent evaporation approach using different combinations of polymers was used to manufacture captopril and hydrochlorothiazide microparticles. Design of experiments was used to develop and analyse experimental data, and identifyoptimum formulation and process conditions for the preparation of the microparticles. Characterisation studies to establish encapsulation efficiency, in vitro release, shape, size and morphology of the microparticles were undertaken. The microparticles produced were in the micrometre size range, with an encapsulation efficiency >75% for both hydrochlorothiazide and captopril. The microparticulate technology is able to offer potential resolution to the half-life mediated dosing frequency of captopril as sustained release of the molecule was observed over a 12-h period. The release of hydrochlorothiazide of >80% suggests an improvement in solubility limited dissolution.

Characterization and in vitro antitumor activity of polymeric nanoparticles loaded with Uncaria tomentosa extract

Uncaria tomentosa (UT) extracts have been shown to have promising anti-tumor activity. We hypothesized that its incorporation into nanostructured systems could improve the anticancer properties. Here, poly-e-caprolactone (PCL) and poly-d,l-lactide-co-glycolide (PLGA) were employed to generate nanoparticles loaded with UT extract in a single emulsion solvent evaporation method. The nanoparticles were characterized by particle size, zeta potential, morphology and entrapment efficiency along with stability and release profiles. The nanoparticles presented entrapment efficiencies above 60% and a mean diameter below 300nm. UT-PCL nanoparticles presented higher entrapment efficiency and mean particle size as well as a slow release rate. The UT-PLGA nanoparticles showed higher drug loading. Two prostate cancer cell-lines, LNCaP and DU145 that were derived from metastatic sites, served as model systems to assess cytotoxicity and anti-cancer activity. In vitro, both formulations reduced the viability of DU145 and LNCaP cells. Yet, the UT-PLGA nanoparticles showed higher cytotoxicity towards DU145 cells while the UTPCL against LNCaP cells. The results confirm that the incorporation of UT into nanoparticles could enhance its anti-cancer activities that can offer a viable alternative for the treatment of prostrate canner and highlights the potential of nanostructured systems to provide a promising methodology to enhance the activity of natural extracts.

Bio Pharmaceutics Classification System (BCS) Class IV Drug Nanoparticles: Quantum Leap to Improve Their Therapeutic Index

Purpose: Biopharmaceutics classification system (BCS) class IV compounds, exhibits least oral bioavailability, low solubility and intestinal permeability among all pharmaceutical classes of drugs. Thus, these drugs need more compatible and efficient delivery system. Since, their solubility in various medium, remains a limitation so, polymeric nano coacervates based drug loading with modified approach for them may prove to be a solution ahead. Therefore, in present study Chitosan is opted for encapsulating the BCS class IV drug (Hydrochlorothiazide) to attain better stability, enhanced permeability and lower toxicity.

Methods: For this study, Hydrochlorothiazide (HCTZ) was opted for formulating chitosan based nano-coacervate system.

Results: Optimized HCTZ nanocoacervates exhibited the average particle size of 91.39 ± 0.75 nm with Poly-dispersity index score of 0.159 ± 0.01, indicating homogeneity of colloidal solution. Zeta potential and encapsulation efficiency of HCTZ nanocoacervates were recorded as -18.9 ± 0.8 mV and 76.69 ± 0.82 % respectively. Further, from TEM and SEM evaluation the average particle size for the same were found in conformity (35-50 nm), with almost spherical morphology. Also, the EDX (Electron Dispersive X-ray) spectrometry and FT – IR analysis of optimized formulation indicated the balanced chemical composition and interaction between the polymeric molecules. The HCTZ nano coacervates showed the linear diffusion profile through the dialysis membrane.

Conclusion: We can conclude from the present study that the optimized HCTZ nano coacervates may prove to be a suitable potential option for effective delivery of BCS class IV drugs.

Synthesis, characterization and antibacterial activity of juglone encapsulated PLGA nanoparticles

AIMS

The aim of the study was to examine the effect of different process parameters which including; initial juglone amount, initial poly(d,l-lactide co-glycolide) amount, polyvinyl alcohol volume and polyvinyl alcohol concentration on encapsulation of juglone to poly(d,l-lactide co-glycolide) nanoparticles.

METHODS AND RESULTS

The synthesized nanoparticle formulations were analyzed for reaction yield, encapsulation efficiency, particle size, polydispersity, zeta potential and juglone release. In conjunction with the highest encapsulation rate, the highest amount of juglone release was obtained for F4 formulation, which has 281·8 nm particle size, 0·217 polydispersity index, and -19·55 mV zeta potential. After the detailed physicochemical characterization of this formulation, the four different kinetic models were used and it was found that juglone release mechanism controlled by Fickian diffusion method. According to antimicrobial activity results, minimal inhibitory concentration (MIC) values of both F4 and free juglone is higher for Gram negative bacteria than Gram positive bacteria. Inhibition zone diameters in the quantitative methods are found 15 and 16 mm for Staphylococcus aureus, 9 and 7 mm for Bacillus cereus, respectively, for F4 and free juglone. Moreover, the MIC values for qualitative methods were found 31·5 μg ml^-1 for two bacteria strains.

CONCLUSIONS

It was found that the antibacterial activity of the juglone nanoparticles was higher and longer than the free juglone. Additionally, a similar antimicrobial effect with a lower juglone amount (obtained from controlled release study) indicates that nanoparticle formulation is more effective.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of nanoparticle formulations of juglone in biological systems and applications could be more beneficial than its free form due to its toxicity.

Preparation of Hydrochlorothiazide Nanoparticles for Solubility Enhancement

Nanoparticles can be considered as a useful tool for improving properties of poorly soluble active ingredients. Hydrochlorothiazide (Class IV of the Biopharmaceutical Classification System) was chosen as a model compound. Antisolvent precipitation-solvent evaporation and emulsion solvent evaporation methods were used for preparation of 18 samples containing hydrochlorothiazide nanoparticles. Water solutions of surfactants sodium dodecyl sulfate, Tween 80 and carboxymethyl dextran were used in mass concentrations of 1%, 3% and 5%. Acetone and dichloromethane were used as solvents of the model compound. The particle size of the prepared samples was measured by dynamic light scattering. The selected sample of hydrochlorothiazide nanoparticles stabilized with carboxymethyl dextran sodium salt with particle size 2.6 nm was characterized additionally by Fourier transform mid-infrared spectroscopy and scanning electron microscopy. It was found that the solubility of this sample was 6.5-fold higher than that of bulk hydrochlorothiazide.