Mechanism and determinants of nanoparticle penetration through human skin

The ability of nanoparticles to penetrate the stratum corneum was the focus of several studies. Yet, there are controversial issues available for particle penetration due to different experimental setups. Meanwhile, there is little known about the mechanism and determinants of their penetration. In this paper the penetration of four model gold nanoparticles of diameter 6 and 15 nm, differing in surface polarity and the nature of the vehicle, through human skin was studied using multiphoton microscopy. This is in an attempt to profoundly investigate the parameters governing particle penetration through human skin. Our results imply that nanoparticles at this size range permeate the stratum corneum in a similar manner to drug molecules, mainly through the intercellular pathways. However, due to their particulate nature, permeation is also dependent on the complex microstructure of the stratum corneum with its tortuous aqueous and lipidic channels, as shown from our experiments performed using skin of different grades of barrier integrity. The vehicle (toluene-versus-water) had a minimal effect on skin penetration of gold nanoparticles. Other considerations in setting up a penetration experiment for nanoparticles were also studied. The results obtained are important for designing a new transdermal carrier and for a basic understanding of skin–nanoparticle interaction

In vitro oslobađanje hidrofilnih i hidrofobnih ljekovitih tvari iz liposomskih disperzija i gelova

A method for determining the rate of hydrophilic and hydrophobic drug entities release from different types of liposomal dispersions and gels using a dialysis method is described. Dibucaine base and 5-fluorouracil were used as model drugs for a hydrophobic and hydrophilic drug, respectively. A dialysis technique was employed. Release rates were affected by the rate of rotation of the paddles of the tablet dissolution tester, temperature, and volume of release medium. The method was used to evaluate the in vitro drug release from hydrophilic and hydrophobic drug entities from liposomal dispersions and gels. The in vitro release study of dibucaine base showed no burst effect, while the in vitro release study of 5-fluorouracil showed a clear burst effect with an initial fast release phase followed by a sustained release phase.Opisana je metoda za određivanje brzine oslobađanja hidrofilnih i hidrofobnih ljekovitih tvari iz različitih vrsta liposomskih disperzija i gelova koristeći dijalizu. Dibukain baza i 5-fluorouracil upotrebljeni su kao modeli hidrofobnog, odnosno hidrofilnog lijeka. Na brzinu oslobađanja utjecala je brzina rotacije lopatica u aparatu u koje je pokus izvođen, temperatura i volumem medija za oslobađanje. Metoda je upotrebljena in vitro praćenje oslobađanja ljekovite tvari iz liposomskih disperzija i gelova. In vitro oslobađanje dibukain baze ne pokazuje učinak naglog oslobađanja, a 5-fluorouracila pokazuje, s brzim inicijalnim oslobađanjem iza kojeg slijedi usporeno oslobađanje

In vitro oslobađanje hidrofilnih i hidrofobnih ljekovitih tvari iz liposomskih disperzija i gelova

A method for determining the rate of hydrophilic and hydrophobic drug entities release from different types of liposomal dispersions and gels using a dialysis method is described. Dibucaine base and 5-fluorouracil were used as model drugs for a hydrophobic and hydrophilic drug, respectively. A dialysis technique was employed. Release rates were affected by the rate of rotation of the paddles of the tablet dissolution tester, temperature, and volume of release medium. The method was used to evaluate the in vitro drug release from hydrophilic and hydrophobic drug entities from liposomal dispersions and gels. The in vitro release study of dibucaine base showed no burst effect, while the in vitro release study of 5-fluorouracil showed a clear burst effect with an initial fast release phase followed by a sustained release phase.Opisana je metoda za određivanje brzine oslobađanja hidrofilnih i hidrofobnih ljekovitih tvari iz različitih vrsta liposomskih disperzija i gelova koristeći dijalizu. Dibukain baza i 5-fluorouracil upotrebljeni su kao modeli hidrofobnog, odnosno hidrofilnog lijeka. Na brzinu oslobađanja utjecala je brzina rotacije lopatica u aparatu u koje je pokus izvođen, temperatura i volumem medija za oslobađanje. Metoda je upotrebljena in vitro praćenje oslobađanja ljekovite tvari iz liposomskih disperzija i gelova. In vitro oslobađanje dibukain baze ne pokazuje učinak naglog oslobađanja, a 5-fluorouracila pokazuje, s brzim inicijalnim oslobađanjem iza kojeg slijedi usporeno oslobađanje

Prodigiosin-Functionalized Probiotic Ghosts as a Bioinspired Combination Against Colorectal Cancer Cells

Lactobacillus acidophilus ghosts (LAGs) with the unique safety of a probiotic, inherent tropism for colon cells, and multiple bioactivities offer promise as drug carriers for colon targeting. Our objective was to evaluate LAGs functionalized with prodigiosin (PG), apoptotic secondary bacterial metabolite, as a bioinspired formulation against colorectal cancer (CRC). LAGs were prepared by a chemical method and highly purified by density gradient centrifugation. LAGs were characterized by microscopic and staining techniques as relatively small-sized uniform vesicles (≈1.6 µm), nearly devoid of cytoplasmic and genetic materials and having a negatively charged intact envelope. PG was highly bound to LAGs envelope, generating a physiologically stable bioactive entity (PG-LAGs), as verified by multiple microscopic techniques and lack of PG release under physiological conditions. PG-LAGs were active against HCT116 CRC cells at both the cellular and molecular levels. Cell viability data highlighted the cytotoxicity of PG and LAGs and LAGs-induced enhancement of PG selectivity for HCT116 cells, anticipating dose reduction for PG and LAGs. Molecularly, expression of the apoptotic caspase 3 and P53 biomarkers in HCT116 intracellular proteins was significantly upregulated while that of the anti-apoptotic Bcl-2 (B-cell lymphoma 2) was downregulated by PG-LAGs relative to PG and 5-fluorouracil. PG-LAGs provide a novel bacteria-based combination for anticancer biomedicine

Bioinspired 3D-printed scaffold embedding DDAB-nano ZnO/nanofibrous microspheres for regenerative diabetic wound healing

There is a constant demand for novel materials/biomedical devices to accelerate the healing of hard-to-heal wounds. Herein, an innovative 3D-printed bioinspired construct was developed as an antibacterial/regenerative scaffold for diabetic wound healing. Hyaluronic/chitosan (HA/CS) ink was used to fabricate a bilayer scaffold comprising a dense plain hydrogel layer topping an antibacterial/regenerative nanofibrous layer obtained by incorporating the hydrogel with polylactic acid nanofibrous microspheres (MS). These were embedded with nano ZnO (ZNP) or didecyldimethylammonium bromide (DDAB)-treated ZNP (D-ZNP) to generate the antibacterial/healing nano/micro hybrid biomaterials, Z-MS@scaffold and DZ-MS@scaffold. Plain and composite scaffolds incorporating blank MS (blank MS@scaffold) or MS-free ZNP@scaffold and D-ZNP@scaffold were used for comparison. 3D printed bilayer constructs with customizable porosity were obtained as verified by SEM. The DZ-MS@scaffold exhibited the largest total pore area as well as the highest water-uptake capacity and in vitro antibacterial activity. Treatment of Staphylococcus aureus-infected full thickness diabetic wounds in rats indicated superiority of DZ-MS@scaffold as evidenced by multiple assessments. The scaffold afforded 95% wound-closure, infection suppression, effective regulation of healing-associated biomarkers as well as regeneration of skin structure in 14 d. On the other hand, healing of non-diabetic acute wounds was effectively accelerated by the simpler less porous Z-MS@scaffold. Information is provided for the first-time on the 3D printing of nanofibrous scaffolds using non-electrospun injectable bioactive nano/micro particulate constructs, an innovative ZNP-functionalized 3D-printed formulation and the distinct bioactivity of D-ZNP as a powerful antibacterial/wound healing promotor. In addition, findings underscored the crucial role of nanofibrous-MS carrier in enhancing the physicochemical, antibacterial, and wound regenerative properties of DDAB-nano ZnO. In conclusion, innovative 3D-printed DZ-MS@scaffold merging the MS-boosted multiple functionalities of ZNP and DDAB, the structural characteristics of nanofibrous MS in addition to those of the 3D-printed bilayer scaffold, provide a versatile bioactive material platform for diabetic wound healing and other biomedical applications

Nano zinc oxide-functionalized nanofibrous microspheres: A bioactive hybrid platform with antimicrobial, regenerative and hemostatic activities

Bioactive hybrid constructs are at the cutting edge of innovative biomaterials. PLA nanofibrous microspheres (NF-MS) were functionalized with zinc oxide nanoparticles (nZnO) and DDAB-modified nZnO (D-nZnO) for developing inorganic/nano-microparticulate hybrid constructs (nZnO@NF-MS and D-nZnO@NF-MS) merging antibacterial, regenerative, and haemostatic functionalities. The hybrids appeared as three-dimensional NF-MS frameworks made-up entirely of interconnecting nanofibers embedding nZnO or D-nZnO. Both systems achieved faster release of Zn2+ than their respective nanoparticles and D-nZnO@NF-MS exhibited significantly greater surface wettability than nZnO@NF-MS. Regarding bioactivity, D-nZnO@NF-MS displayed a significantly greater and fast-killing effect against Staphylococcus aureus. Both nZnO@NF-MS and D-nZnO@NF-MS showed controllable concentration-dependent cytotoxicity to human gingival fibroblasts (HGF) compared with pristine NF-MS. They were also more effective than pristine NF-MS in promoting migration of human gingival fibroblasts (HGF) in the in vitro wound healing assay. Although D-nZnO@NF-MS showed greater in vitro hemostatic activity than nZnO@NF-MS (blood-clotting index 22.82 ± 0.65% vs.54.67 ± 2.32%), both structures exhibited instant hemostasis (0 s) with no blood loss (0 mg) in the rat-tail cutting technique. By merging the multiple therapeutic bioactivities of D-nZnO and the 3D-structural properties of NF-MS, the innovative D-nZnO@NF-MS hybrid construct provides a versatile bioactive material platform for different biomedical applications

Miltefosine Lipid Nanocapsules for Single Dose Oral Treatment of Schistosomiasis Mansoni: A Preclinical Study.

Miltefosine (MFS) is an alkylphosphocholine used for the local treatment of cutaneous metastases of breast cancer and oral therapy of visceral leishmaniasis. Recently, the drug was reported in in vitro and preclinical studies to exert significant activity against different developmental stages of schistosomiasis mansoni, a widespread chronic neglected tropical disease (NTD). This justified MFS repurposing as a potential antischistosomal drug. However, five consecutive daily 20 mg/kg doses were needed for the treatment of schistosomiasis mansoni in mice. The present study aims at enhancing MFS efficacy to allow for a single 20mg/kg oral dose therapy using a nanotechnological approach based on lipid nanocapsules (LNCs) as oral nanovectors. MFS was incorporated in LNCs both as membrane-active structural alkylphospholipid component and active antischistosomal agent. MFS-LNC formulations showed high entrapment efficiency (EE%), good colloidal properties, sustained release pattern and physical stability. Further, LNCs generally decreased MFS-induced erythrocyte hemolytic activity used as surrogate indicator of membrane activity. While MFS-free LNCs exerted no antischistosomal effect, statistically significant enhancement was observed with all MFS-LNC formulations. A maximum effect was achieved with MFS-LNCs incorporating CTAB as positive charge imparting agent or oleic acid as membrane permeabilizer. Reduction of worm load, ameliorated liver pathology and extensive damage of the worm tegument provided evidence for formulation-related efficacy enhancement. Non-compartmental analysis of pharmacokinetic data obtained in rats indicated independence of antischistosomal activity on systemic drug exposure, suggesting possible gut uptake of the stable LNCs and targeting of the fluke tegument which was verified by SEM. The study findings put forward MFS-LNCs as unique oral nanovectors combining the bioactivity of MFS and biopharmaceutical advantages of LNCs, allowing targeting via the oral route. From a clinical point of view, data suggest MFS-LNCs as a potential single dose oral nanomedicine for enhanced therapy of schistosomiasis mansoni and possibly other diseases

Effect of microneedle treatment on the skin permeation of a nanoencapsulated dye

OBJECTIVES: The aim of the study was to investigate the effect of microneedle (MN) treatment on the transdermal delivery of a model drug (rhodamine B, Rh B) encapsulated in polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) focusing on the MN characteristics and application variables. METHODS: Gantrez® MNs were fabricated using laser-engineered silicone micro-mould templates. PLGA NPs were prepared using a modified emulsion–diffusion–evaporation method and characterized in vitro. Permeation of encapsulated Rh B through MN treated full thickness porcine skin was performed using Franz diffusion cells using appropriate controls. KEY FINDINGS: In vitro skin permeation of the nanoencapsulated Rh B (6.19 ± 0.77 μg/cm(2)/ h) was significantly higher (P<0.05) compared to the free solution (1.66 ± 0.53 μg/cm(2)/ h). Mechanistic insights were supportive of preferential and rapid deposition of NPs in the MN-created microconduits, resulting in accelerated dye permeation. Variables such as MN array configuration and application mode were shown to affect transdermal delivery of the nanoencapsulated dye. CONCLUSIONS: This dual MN/NPs mediated approach offers potential for both the dermal and transdermal delivery of therapeutic agents with poor passive diffusion

Vancomycin-functionalized Eudragit-based nanofibers: Tunable drug release and wound healing efficacy

There is an unmet demand for local vancomycin (VAN) delivery scaffolds with site retention and tunable release properties for cutaneous and surgical wounds. Nanofibers as drug delivery/cell regeneration promoting scaffolds offer great promise in this respect. High loading of the polar VAN into polymeric structures with tunable release properties can be achieved by simultaneous chemical bonding and polymer blending. Electrospinnable vancomycin-functionalized Eudragit E100 with a relatively high drug content and antibacterial activity (E-VAN) was investigated for the development of antimicrobial nanofibers with modifiable hydrophilicity, degradability, mechanical and release properties by blending with selected Eudragit polymers. A platform of fast dissolving nanofibers of value in immediate release applications and nanofibers with a wide spectrum of biphasic release profiles with either fast or sustained drug release at low, high and physiological pH for at least 7 days was generated. A selected nanofiber formulation with a relatively small size, adequate hydrophilicity, structural stability, and biphasic release profile at pH 7.4 showed high antibacterial activity against Staphylococcus aureus and healing efficacy of Staphylococcus aureus-inoculated full thickness excision wounds in a rat model. The E-VAN-based Eudragit nanofibers developed offer potential as versatile antimicrobial delivery/cell regeneration scaffolds for local applications under diverse pH conditions