Current Drug Delivery - Volume 16, Issue 2, 2019

Background: Owing to their great promise in the spinal surgeries, bone graft substitutes have been widely investigated for their safety and clinical potential. By the current advances in the spinal surgery, an understanding of the precise biological mechanism of each bone graft substitute is mandatory for upholding the induction of solid spinal fusion. Objective: The aim of the present review is to critically discuss various surgical implications and level of evidence of most commonly employed bone graft substitutes for spinal fusion. Method: Data was collected via electronic search using “PubMed”, “SciFinder”, “ScienceDirect”, “Google Scholar”, “Web of Science” and a library search for articles published in peer-reviewed journals, conferences, and e-books. Results: Despite having exceptional inherent osteogenic, osteoinductive, and osteoconductive features, clinical acceptability of autografts (patient’s own bone) is limited due to several perioperative and postoperative complications i.e., donor-site morbidities and limited graft supply. Alternatively, allografts (bone harvested from cadaver) have shown great promise in achieving acceptable bone fusion rate while alleviating the donor-site morbidities associated with implantation of autografts. As an adjuvant to allograft, demineralized bone matrix (DBM) has shown remarkable efficacy of bone fusion, when employed as graft extender or graft enhancer. Recent advances in recombinant technologies have made it possible to implant growth and differentiation factors (bone morphogenetic proteins) for spinal fusion. Conclusion: Selection of a particular bone grafting biotherapy can be rationalized based on the level of spine fusion, clinical experience and preference of orthopaedic surgeon, and prevalence of donor-site morbidities.

Background: Gemcitabine (GEM) is found effective in the treatment of many solid tumors. However, its use is restricted due to its small circulation half-life, fast metabolism and low capacity for selective tumor uptake. Folate receptors (FRs) have been recognized as cellular surface markers, which can be used for cancer targeting. PEGylated liposomes decorated with folic acid have been investigated for several anticancer agents not only to extend plasma half-life but also for tumor targeting via folic acid receptors which overexpressed on tumor cell surface. Objective: Therefore, the objective of the present study was to prepare GEM-loaded folic acid tagged liposomes to improve the pharmacokinetics and tumor distribution of GEM. Methods: The blank folate-targeted liposomes composed of HSPC/DSPE-mPEG2000/DSPE-mPEG-Folic acid were prepared first by thin film hydration technique. GEM was then loaded into liposomes by remote loading technique. The optimized liposomal formulations were evaluated in vitro for GEM release using dialysis technique, HeLa cell uptake using FACS technique, and cytotoxicity using MTT dye reduction assay. The comparative in vivo pharmacokinetic and biodistribution characteristics of radiolabeled (99mTc-labeled) plain GEM solution, and all liposomal formulations (conventional:CLs; stealth: SLs; folate targeted: FTLs) were evaluated in mice model. Results: GEM-loaded FTLs showed sustained release profile, efficient uptake by HeLa cells and greater cytotoxicity. Further, FTLs displayed significantly improved pharmacokinetics, and biodistribution profile of loaded GEM. Conclusion: In conclusion, the developed GEM-loaded folic acid receptor-targeted liposomal formulation could be a promising and potential alternative formulation for further development.

Background: The present work was designed to explore the efficacy of neuroactive drug (risperidone) loaded chitosan lipid nanoparticle (RIS-CH-LNPs) to enhance the bioactivity in schizophrenia via the nasal route. Methods: The three-factor and three-level formulation by design approach was used for optimization and their effects were observed on (Y1) size in nm, (Y2) % drug loading, and (Y3) % drug release. The optimized formulation RIS-CH-LNPopt was further evaluated for its surface morphology, ex-vivo permeation study, in-vivo behavior study, and stability study. The developed RIS-CH-LNPs showed nanometric size range with high drug loading and prolonged drug release. Results: The optimized formulation (RIS-CH-LNPopt) has shown the particle size (132.7 nm), drug loading (7.6 %), drug release (80.7 %) and further ex-vivo permeation study showed 2.32 fold enhancement over RIS-SUS(suspension). In-vivo behavior studies showed that RIS-CH-LNPopt is able to show significant greater bioefficacy as compared to RIS-SUS [intranasal (i.n), intravenous (i.v)]. The pharmacokinetic and brain/plasma ratio of developed chitosan nanoparticle was higher at all time-points as compared to RIS-SUS either given by intranasal or intravenous route that proves the direct nose to brain transport pathway of the drug via nasal administration. The developed chitosan nanoparticle increases nose to brain drug delivery as compared to the dispersion of equivalent dose. Conclusion: The findings of this study substantiate the existence of a direct nose-to-brain delivery route for RIS-CH-LNPs.

Background: Transdermal delivery is an alternative route for the administration of drugs. However, it requires the development of vehicles that allow the drugs to cross the layers of the skin and reach the systemic circulation. Objective: In this study, a new transdermal vehicle was evaluated using progesterone, estradiol, estradiol + estriol (Biest) and ketoprofen administered as model drugs. Methods: To evaluate the ex vivo permeation of the drugs, the Franz vertical diffusion cell with human skin was used. Results: After 24 h, the vehicle was able to deliver 18.32 μg/cm2 of progesterone and 92.07 μg/cm2 of ketoprofen through the skin to the receptor medium. The permeation percentages were 91%, 78.8%, 48.5%, 73.2%, and 63.6%, respectively, for estradiol, estradiol (Biest), estriol (Biest), progesterone and ketoprofen. For all drugs, sufficient amounts were delivered to achieve a systemic effect, and it was also possible to decrease the amount of emulsion applied. Conclusion: Thus, the vehicle demonstrated a high performance and the possibility of it being used for drugs that present difficulties in regards to administration by the transdermal route.

Background: Silybin (Sb) is the major flavolignan of the extract of Silybum marianum. It is used for the treatment of various acute and chronic liver toxicities, inflammation, fibrosis and oxidative stress. Many studies indicate that Sb is also active against different carcinomas and it has been very recently proposed to be beneficial in type 2 diabetes patients. However, Sb is a low water soluble and low permeable compound. Objective: In this study, Solid Lipid Nanoparticles (SLNs) were proposed to enhance the solubility and the intestinal absorption of Sb. Methods: SLNs were made of stearic acid and Brij 78 and subsequently coated with chitosan. Formulations were physically and chemically characterized. Stability studies were also assessed. Sb in vitro release was evaluated in different pH media. In vitro permeability test with artificial membranes and Caco-2 cells were performed. Cellular uptake and mucoadhesion studies were conducted. Results: Both nanoparticles were found to be stable. In vitro release indicated that SLNs may prevent burst release and gastric degradation of Sb. Higher extent of Sb permeation was observed for both nanoparticles in PAMPA and Caco-2 cell monolayer models. The results of the cellular uptake study suggested the involvement of active endocytic processes. Chitosan significantly improves mucoadhesion properties of nanoparticles. Conclusions: Together with the excellent stability, strong mucoadhesive property, and slow release, chitosan coated SLNs demonstrated promising potential to enhance absorption of hydrophobic Sb after oral administration.

Background: The current treatment of ocular neovascularization requires frequent intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents that cause severe side effects. Objective: The purpose of this study is to prepare and characterize a novel nanoscale delivery system of apatinib for ocular neovascularization. Methods: The optimized formulation showed a particle size of 135.04 nm, polydispersity index (PDI) of 0.28 ± 0.07, encapsulation efficiency (EE) of 65.92%, zeta potential (ZP) of -23.70 ± 8.69 mV, and pH of 6.49 ± 0.20. In vitro release was carried out to demonstrate a 3.13-fold increase in the sustainability of apatinib-loaded nanoparticles versus free apatinib solution. Result: Cell viability and VEGFA and VEGFR2 expression were analyzed in animal retinal pigment epithelial (ARPE-19) cells. Conclusion: The results confirmed the hypothesis that apatinib nanoparticles decreased toxicity (1.36 ± 0.74 fold) and efficient VEGF inhibition (3.51 ± 0.02 fold) via VEGFR2 mediation.

Background: Delivery of foreign cargoes into cells is of great value for bioengineering research and therapeutic applications. Objective: In this study, we proposed and established a carrier-free gene delivery platform utilizing staggered herringbone channel and silicon nanoneedle array, to achieve high-throughput in vitro gene transfection. Methods: With this microchip, fluidic micro vortices could be induced by the staggered-herringboneshaped grooves within the channel, which increased the contact frequency of the cells with the channel substrate. Transient disruptions on the cell membrane were well established by the nanoneedle array on the substrate. Result: Compared to the conventional nanoneedle-based delivery system, proposed microfluidic chip achieved flow-through treatment with high gene transfection efficiency (higher than 20%) and ideal cell viability (higher than 95%). Conclusion: It provides a continuous processing environment that can satisfy the transfection requirement of large amounts of biological molecules, showing high potential and promising prospect for both basic research and clinical application.

Objectives: Paclitaxel (Ptx) has been regarded as one of the most effective chemotherapeutic drugs for lung cancers. Increasing studies focused on the nano-delivery system of Ptx due to its poor solubility and hypersensitivity. The aim of the recent study was to investigate the antitumor effects of self-assembled Ptx nano-filaments for lung cancer cells. Methods: In the present study, we designed and synthesized novel Ptx-loaded nano-filaments through conjugation of Ptx and succinic acid (SA) (Ptx-SA, P-NFs). Non-small cell lung cancer (NSCLC) A549 and H460 cells were used for detecting the antitumor effects of P-NFs, including cytotoxicity, apoptosis, and migration. Western blotting was performed for analyzing mechanism. Results: P-NFs nano-filaments exerted superior antitumor effects against NSCLC cells compared with free Ptx using cytotoxicity tests. Furthermore, P-NFs nano-filaments were much more effective in inducing NSCLC cells apoptosis and inhibiting A549 cells migration than free Ptx. To elucidate the underlying mechanisms, the expression of apoptotic and endoplasmic reticulum (ER) stress proteins was detected. The results indicated that P-NFs nano-filaments enhanced the expression of bax/bcl-2, protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1α (IRE1α), phospho- c-Jun N-terminal kinase (p-JNK), and C/EPB homologous protein (CHOP), which suggested that the strong antitumor effect of P-NFs nano-filaments may be partially attributed to the activation ER stress. Conclusion: The current work demonstrated that P-NFs nano-filaments showed superior cytotoxicity of lung cancer cells, highlighting a novel profile of nano-filaments delivery systems as potential strategies for facilitating the therapeutic efficacy of Ptx in lung cancer treatment.