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Polyurethanes (PUs) constitute an essential class of stimuli-responsive and biodegradable material, which has significantly contributed to the advancement of polymers utilization in the biomedical field. The bio-erodible PUs construct an active corridor for facilitating drug into tumor cells, which has significantly impacted the progression of nano-micellar delivery systems. The self-assembledcolloidal PUs pose distinctive features such as enhancing the solubility of hydrophobic chemotherapeutics, rapid cellular uptake, triggered erosion and drug release, bio-stimulus sensitivity, improvement in the targeting and proficiency ofbioactive. Cationic PUs can easily be condensed with genetic material to form polyplexes and have shown excellent transfection efficiency for potential gene therapy against various cancers. Their modifiable chemistry offers a tool to impart the desired multifunctionality such as biocompatibility, sensitivity to pH, redox, temperature, enzyme, etc. and ligand conjugation for active targeting. These diverse exceptional properties make them excellent nano-carrier for a variety of bioactive, including chemotherapeutic drugs, DNA, RNA, and diagnostic moieties to the target tissue or cells. The PUs based nano-devices have certainly uncovered the path to achieve ideal systems for controlled personalized therapy. The literature discussed in this review shed light on the research innovations carried out in the last ten years for the development of multifunctional PUs for triggered delivery of bioactive to treat various cancers., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In past years, nanostructured lipid carriers (NLCs) have emerged as novel topical antioxidant delivery systems because of combined positive features of liposomes and polymeric nanoparticles. Here, we seek to unlock the possibility of idebenone (IDB; an antioxidant)-loaded NLCs (IDB-NLCs) cellular interactions such as, viability and uptake, and its photoprotective effects against Ultraviolet-B (UVB)-mediated oxidative stress in immortal human keratinocyte cell line (HaCaT). The two-step preformulation strategy followed by three-level, three-variable, L9 (3(3)) Taguchi robust orthogonal design employed was important in improving IDB-NLCs key physicochemical aspects such as, entrapment efficiency, drug release (sustained), occlusion, skin deposition and physical stability. UV crosslinker, confocal microscopy and flow cytometry techniques were used to (1) mediate oxidative stress in HaCaT cells, (2) study a qualitative cellular uptake, (3) measure intracellular reactive oxygen species (ROS), and mitochondrial membrane potential, respectively. NLCs markedly improved biocompatibility of IDB under normal as well as stress conditions. Quantitative and qualitative cell uptake studies demonstrated a significant uptake of IDB-NLCs (3-fold increase) and nile red-labeled IDB-NLCs (NR-IDB-NLCs) at 2 h, respectively, hence exerted improved photoprotective effects., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Many biotherapeutic applications of gold nanoparticles make use of conjugated or adsorbed protein moieties. Physical parameters of association such as particle size, morphology, surface chemistry and temperature influences the protein-nanoparticle association and thereby their interaction with the biological environment. In present study, effect of size of chitosan reduced gold nanoparticles (CsAuNPs) and association temperature on structure and function of tetanus toxoid (TT) vaccine has been investigated. CsAuNPs were synthesized in the sizes of 20±3, 40±5 and 80±7 nm followed by loading of TT. Binding process of CsAuNPs with TT was investigated at their predetermined micro molar concentrations. Upon binding of TT onto CsAuNPs, particle surface was characterized using X-ray photoelectron spectroscopy. CD spectroscopic evaluation of TT bound 20 nm CsAuNPs led to 75% reduction in secondary structure of TT and thereby compromised immune function. Binding of TT with 40 and 80 nm sized CsAuNPs did not cause significant modifications in secondary structure or function of TT. Thermodynamic studies using temperature dependent fluorescence spectroscopy revealed an increase in association constants with the temperature. Based on thermodynamic data three phases in CsAuNPs and TT association process were traced. Samples from these distinct phases were also investigated for immunological recognition. Ex-vivo interaction of TT-CsAuNPs with TT positive and negative sera followed by relative change in particle size and zeta potential was studied. The findings here suggests prominent role of particle size and association temperature on adsorbed TT structure and function. Such studies may help in engineering functional nanotherapeutics., (Copyright © 2014 Elsevier B.V. All rights reserved.)

In the present work comparative evaluation of acetate and pH gradient techniques for effective drug loading in liposomes has been investigated. The acetazolamide (ACZ) loaded liposomes prepared by two methods were analyzed by vesicle size analysis, zeta potential, percent encapsulation efficiency, in vitro drug release studies and intraocular pressure lowering activity. ICH guidelines were followed for determining stability of the prepared liposomes. The superiority of acetate gradient method for active loading of acetazolamide has been established. The prepared acetate gradient positive liposomes showed extended hypotensive effect when compared to other liposomal formulations. Thus ACZ loaded liposomes prepared by acetate gradient technique may serve as promising ocular delivery system in the treatment of glaucoma. The current work emphasizes the fact that the techniques used for active drug loading into liposomes strongly influence the pharmaceutical performance of the final formulation., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Long-term exposure of the skin to UV light causes degenerative effects, which can be minimized by using antioxidant formulations. The major challenge in this regard is that a significant amount of antioxidant should reach at the site for effective photoprotection. However, barrier properties of the skin limit their use. In the present study, Vitamin E acetate was encapsulated into liposome for improving its topical delivery. However preparation of liposomes is very difficult due to number of formulation variables involved therein. In the present work systematic statistical study for the formulation of liposomes for topical delivery of Vitamin E using the factorial design approach was undertaken. Amount of phospholipid (PL) and cholesterol (CH) were taken at three different levels and liposomes were prepared using ethanol injection method. Liposomes were characterized for encapsulation efficiency, vesicle size, zeta potential, and drug deposition in the rat skin. Gels containing liposomal dispersion (batch with higher skin deposition of VE) were prepared in Carbopol 980 NF and were characterized for gel strength, viscosity and drug deposition in the rat skin. Stability of liposome dispersion and gel formulation was studied at 30 degrees C/65% RH for 3 months. Results of regression analysis revealed that vesicle size and drug deposition in the rat skin were dependent on the lipid concentration and lipid:drug ratio. Drug deposition in rat skin had an inverse relationship with respect to PL and CH concentration. Prepared liposomal dispersion (50 mg PL:6 mg CH) showed seven-fold increase in drug deposition compared to control (plain drug dispersion). Gel formulation demonstrated six-fold and four-fold increase in drug deposition compared to control gel and marketed cream, respectively. Liposome dispersion and gel formulation were found to be stable for 3 months. Factorial design was found to be well suited to identify the key variables affecting drug deposition. Improved drug deposition from liposomal preparations demonstrates its potential for dermal delivery.