Gold nanoparticles for 99mTc-doxorubicin delivery: formulation, in vitro characterization, comparative studies in vivo stability and biodistribution

Tailored green synthesized silymarin-selenium nanoparticles: Topical nanocarrier of promising antileishmanial activity

Poor drug penetration, emerging drug resistance, and systemic toxicity are among the major obstacles challenging the current treatment of cutaneous leishmaniasis. Hence, developing advanced strategies for effective and targeted delivery of antileishmanial agents is crucial. Several drug delivery carriers have been developed till current date for dermal/transdermal delivery, especially those which are fabricated using eco-friendly synthesis approaches, since they protect the environment from the harmful effects of chemical waste disposal. This work describes the preparation of selenium nanoparticles loaded with silymarin via one-pot green reduction technique, for treatment of cutaneous leishmaniasis. The selected silymarin loaded selenium nanoparticles (SSNs4-0.1) displayed good loading efficiency of 58.22 ± 0.56 %, zeta potential of -30.63 ± 0.40 mV, hydrodynamic diameter of 245.77 ± 11.12 nm, and polydispersity index of 0.19 ± 0.01. It exhibited good physical stability, as well as high ex vivo deposition % in the epidermis (46.98 ± 1.51 %) and dermis (35.23 ± 1.72 %), which was further proven using confocal laser microscopy. It also exhibited significant cytocompatibility and noticeable cellular internalization of 90.02 ± 3.81 % in human fibroblasts, as well as high trypanothione reductase inhibitory effect (97.10 ± 0.30 %). Results of this study confirmed the successful green synthesis of silymarin-loaded selenium nanoparticles; delineating them as one of the promising antileishmanial topical delivery systems.

Brain targeting of zolmitriptan via transdermal terpesomes: statistical optimization and in vivo biodistribution study by 99mTc radiolabeling technique

Zolmitriptan (ZT) is a potent second generation triptan, commonly administered to alleviate migraine attacks. ZT suffers various limitations; massive hepatic first pass metabolism, P-gp efflux transporters susceptibility, and limited (≈40%) oral bioavailability. Transdermal route of administration could be explored to enhance its bioavailability. A 23.31 full factorial design was constructed to developed twenty-four ZT loaded terpesomes via thin film hydration technique. The influence of drug: phosphatidylcholine ratio, terpene type, terpene concentration and sodium deoxycholate concentration on the characterization of the developed ZT-loaded terpesomes was assessed. Particle size (PS), zeta potential (ZP), ZT entrapment efficiency (EE%), drug loading (DL%) and drug released percentages after 6 h (Q6h) were the selected dependent variables. Further morphological, crystallinity, and in-vivo histopathological studies were conducted for the optimum terpesomes (T6). 99mTc-ZT and 99mTc-ZT-T6 gel were radio-formulated for in-vivo biodistribution studies in mice following transdermal application of 99mTc-ZT-T6 gel, relative to 99mTc-ZT oral solution. T6 terpesomes [comprising ZT and phosphatidylcholine (1:15), cineole (1% w/v) and sodium deoxycholate (0.1% w/v)] were optimum with respect to spherical PS (290.2 nm), ZP (-48.9 mV), EE% (83%), DL% (3.9%) and Q6h (92.2%) with desirability value of 0.85. The safety of the developed T6 terpesomes was verified by the in-vivo histopathological studies. 99mTc-ZT-T6 gel showed maximum brain concentration (5 ± 0.1%ID/ g) with highest brain to blood ratio of 1.92 ± 0.1 at 4 h post transdermal application. Significant improvement of ZT brain relative bioavailability (529%) and high brain targeting efficiency (315%) were revealed with 99mTc-ZT-T6 gel, which confirmed successful ZT delivery to the brain. Terpesomes could be safe, successful systems capable of improving ZT bioavailability with high brain targeting efficiency.

Sonophoresis-assisted transdermal delivery of antimigraine-loaded nanolipomers: Radio-tracking, histopathological assessment and in-vivo biodistribution study

Migraine is a disabling neurovascular polygenic disorder affecting life quality with escorted socioeconomic encumbrances. Herein, we investigated the consolidated amalgamation of passive lipomer approach alongside active sonophoresis assisted transdermal delivery of zolmitriptan (ZT) using high frequency ultrasound pre-treatment protocol to mitigate migraine attacks. A modified nanoprecipitation technique was utilized to prepare zolmitriptan loaded lipomers (ZTL) adopting 23 factorial design. Three factors were scrutinized namely lipid type, ZT: lipid ratio and ZT: Gantrez® ratio. The prepared systems were characterized regarding particle size, zeta potential, polydispersity index, entrapment efficiency and in-vitro release studies. The best achieved ZTL system was evaluated for ZT- Gantrez® intermolecular interactions, drug crystallinity, morphology, ex-vivo permeation and histopathological examination. Finally, a comparative in-vivo biodistribution study through radiotracking technique using Technetium-99 m was adopted. L2 was the best-achieved ZTL system with respect to spherical particle size (390.7 nm), zeta-potential (-30.8 mV), PDI (0.2), entrapment efficiency (86.2%), controlled release profile, flux (147.13 μg/cm2/hr) and enhancement ratio (5.67). Histopathological studies proved the safety of L2 system upon application on skin. L2 revealed higher brain Cmax (12.21 %ID/g), prolonged brain MRT (8.67 hr), prolonged brain 0.23 hr), significantly high relative bioavailability (2929.36%) and similar brain Tmax (0.5 hr) compared to I.V. route with higher brain/blood ratio. Thus, sonophoresis assisted transdermal delivery of ZTL offers a propitious alterative to alleviate migraine symptoms.

Self-Assembling Lecithin-Based Mixed Polymeric Micelles for Nose to Brain Delivery of Clozapine: In-vivo Assessment of Drug Efficacy via Radiobiological Evaluation

Purpose

The research objective is to design intranasal brain targeted CLZ loaded lecithin based polymeric micelles (CLZ- LbPM) aiming to improve central systemic CLZ bioavailability.

Methods

In our study, intranasal CLZ loaded lecithin based polymeric micelles (CLZ- LbPM) were formulated using soya phosphatidyl choline (SPC) and sodium deoxycholate (SDC) with different CLZ:SPC:SDC ratios via thin film hydration technique aiming to enhance drug solubility, bioavailability and nose to brain targeting efficiency. Optimization of the prepared CLZ-LbPM using Design-Expert® software was achieved showing that M6 which composed of (CLZ:SPC: SDC) in respective ratios of 1:3:10 was selected as the optimized formula. The optimized formula was subjected to further evaluation tests as, Differential Scanning Calorimetry (DSC), TEM, in vitro release profile, ex vivo intranasal permeation and in vivo biodistribution.

Results

The optimized formula with the highest desirability exhibiting (0.845), small particle size (12.23±4.76 nm), Zeta potential of (-38 mV), percent entrapment efficiency of > 90% and percent drug loading of 6.47%. Ex vivo permeation test showed flux value of 27 μg/cm².h and the enhancement ratio was about 3 when compared to the drug suspension, without any histological alteration. The radioiodinated clozapine ([¹³¹I] iodo-CLZ) and radioiodinated optimized formula ([¹³¹I] iodo-CLZ-LbPM) were formulated in an excellent radioiodination yield more than 95%. In vivo biodistribution studies of [¹³¹I] iodo-CLZ-LbPM showed higher brain uptake (7.8%± 0.1%ID/g) for intranasal administration with rapid onset of action (at 0.25 h) than the intravenous formula. Its pharmacokinetic behavior showed relative bioavailability, direct transport percentage from nose to brain and drug targeting efficiency of 170.59%, 83.42% and 117% respectively.

Conclusion

The intranasal self-assembling lecithin based mixed polymeric micelles could be an encouraging way for CLZ brain targeting.

Review of the Delivery Kinetics of Thermosensitive Liposomes

Thermosensitive liposomes (TSL) are triggered nanoparticles that release the encapsulated drug in response to hyperthermia. Combined with localized hyperthermia, TSL enabled loco-regional drug delivery to tumors with reduced systemic toxicities. More recent TSL formulations are based on intravascular triggered release, where drug release occurs within the microvasculature. Thus, this delivery strategy does not require enhanced permeability and retention (EPR). Compared to traditional nanoparticle drug delivery systems based on EPR with passive or active tumor targeting (typically <5%ID/g tumor), TSL can achieve superior tumor drug uptake (>10%ID/g tumor). Numerous TSL formulations have been combined with various drugs and hyperthermia devices in preclinical and clinical studies over the last four decades. Here, we review how the properties of TSL dictate delivery and discuss the advantages of rapid drug release from TSL. We show the benefits of selecting a drug with rapid extraction by tissue, and with quick cellular uptake. Furthermore, the optimal characteristics of hyperthermia devices are reviewed, and impact of tumor biology and cancer cell characteristics are discussed. Thus, this review provides guidelines on how to improve drug delivery with TSL by optimizing the combination of TSL, drug, and hyperthermia method. Many of the concepts discussed are applicable to a variety of other triggered drug delivery systems.

IAEA Contribution to Nanosized Targeted Radiopharmaceuticals for Drug Delivery

The rapidly growing interest in the application of nanoscience in the future design of radiopharmaceuticals and the development of nanosized radiopharmaceuticals in the late 2000′s, resulted in the creation of a Coordinated Research Project (CRP) by the International Atomic Energy Agency (IAEA) in 2014. This CRP entitled ‘Nanosized delivery systems for radiopharmaceuticals’ involved a team of expert scientist from various member states. This team of scientists worked on a number of cutting-edge areas of nanoscience with a focus on developing well-defined, highly effective and site-specific delivery systems of radiopharmaceuticals. Specifically, focus areas of various teams of scientists comprised of the development of nanoparticles (NPs) based on metals, polymers, and gels, and their conjugation/encapsulation or decoration with various tumor avid ligands such as peptides, folates, and small molecule phytochemicals. The research and development efforts also comprised of developing optimum radiolabeling methods of various nano vectors using diagnostic and therapeutic radionuclides including Tc-99m, Ga-68, Lu-177 and Au-198. Concerted efforts of teams of scientists within this CRP has resulted in the development of various protocols and guidelines on delivery systems of nanoradiopharmaceuticals, training of numerous graduate students/post-doctoral fellows and publications in peer reviewed journals while establishing numerous productive scientific networks in various participating member states. Some of the innovative nanoconstructs were chosen for further preclinical applications—all aimed at ultimate clinical translation for treating human cancer patients. This review article summarizes outcomes of this major international scientific endeavor.