Radioiodinated doxorubicin as a new tumor imaging model: preparation, biological evaluation, docking and molecular dynamics

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.

Cod liver oil nano-structured lipid carriers (Cod-NLCs) as a promising platform for nose to brain delivery: Preparation, in vitro optimization, ex vivo cytotoxicity & in vivo biodistribution utilizing radioiodinated zopiclone

Nano-structured lipid carriers containing zopiclone were prepared as a targeted drug delivery system to convey zopiclone directly to brain via nasal route. Nano-structured lipid carriers were constructed adopting hot emulsification-ultrasonication method using palmitic acid in place of the solid lipid, cod liver oil as liquid lipid, and poloxamer 407 as a surfactant. A three-factor three-level central composite face-centered design was used to optimize the formulated nano-structured lipid carriers. The independent factors were lipid amount (X₁), surfactant amount (X₂), and sonication time (X₃). The examined responses were entrapment efficiency (EE,Y₁,%), particle size (PS,Y₂,nm), zeta potential(mV), polydispersity index(PDI,Y₃), in vitro release(Q8h,Y₄,%) and dissolution efficiency (DE,Y₅,%). The optimum formula showed high entrapment efficiency of 94.31% ± 2.44, in vitro drug release of 83.89% ± 1.77 with dissolution efficiency equals 88.63% ± 2.01, small particle size of 71.27 nm ± 13.57 and low polydispersity index 0.097 ± 0.15. In vivo biodistribution in mice was evaluated by a radiobiological technique using radioiodinated zopiclone([¹³¹I]iodo-ZP). Results revealed the superiority of the intranasal route to deliver zopiclone directly to brain faster and higher brain uptake (6.9 ± 1.02%ID/g at 5 min post-administration). The current study confirmed that intranasal administration of nano-structured lipid carriers had great potential as an effective tool for targeted brain zopiclone delivery for insomnia treatment.

New 5-Aryl-1,3,4-Thiadiazole-Based Anticancer Agents: Design, Synthesis, In Vitro Biological Evaluation and In Vivo Radioactive Tracing Studies

A new series of 5-(4-chlorophenyl)-1,3,4-thiadiazole-based compounds featuring pyridinium (3), substituted piperazines (4a-g), benzyl piperidine (4i), and aryl aminothiazoles (5a-e) heterocycles were synthesized. Evaluation of the cytotoxicity potential of the new compounds against MCF-7 and HepG2 cancer cell lines indicated that compounds 4e and 4i displayed the highest activity toward the tested cancer cells. A selectivity study demonstrated the high selective cytotoxicity of 4e and 4i towards cancerous cells over normal mammalian Vero cells. Cell cycle analysis revealed that treatment with either compound 4e or 4i induced cell cycle arrest at the S and G2/M phases in HepG2 and MCF-7 cells, respectively. Moreover, the significant increase in the Bax/Bcl-2 ratio and caspase 9 levels in HepG2 and MCF-7 cells treated with either 4e or 4i indicated that their cytotoxic effect is attributed to the ability to induce apoptotic cell death. Finally, an in vivo radioactive tracing study of compound 4i proved its targeting ability to sarcoma cells in a tumor-bearing mice model.

Radiolabeling, biological distribution, docking and ADME studies of 99mTc-Ros as a promising natural tumor tracer

Rosmarinic acid (Ros) is one of phenolic metabolites with powerful potency as an anticancer agent, with different mechanisms to diminish the cancer cells. This current study represents radiolabeling of Ros with 99mTc using SnCl2 in pH4 for 15 min at 60 °C, The yield up to 92.2%. Biological evaluation in normal and cancer mice revealed the localization of the tracer in tumor tissue. Furthermore, docking and ADME (Absorption, Distribution, Metabolism, and Excretion) studies were performed, The resulted data clarifies the use of Ros as a promissing natural tracer.

Extraction, purification and radioiodination of Khellin as cancer theranostic agent

Khellin was successfully extracted from Ammi visnaga fruits with a recovery percent of 96.15%. Next radio-iodination of Khellin was successfully achieved with a high yield. The biodistribution study of [¹³¹I]iodo-khellin in tumour bearing mice revealed that khellin preferentially localization at tumour tissue. Target prediction study for [¹³¹I]iodo-khellin revealed that PI3K and VEGFR are potential targets for iodo-khellin with good affinity. The results of this study potentiate [¹³¹I]iodo-khellin as a good theranostic agent for tumour imaging and therapy.

Discovery of New Coumarin-Based Lead with Potential Anticancer, CDK4 Inhibition and Selective Radiotheranostic Effect: Synthesis, 2D & 3D QSAR, Molecular Dynamics, In Vitro Cytotoxicity, Radioiodination, and Biodistribution Studies

Novel 6-bromo-coumarin-ethylidene-hydrazonyl-thiazolyl and 6-bromo-coumarin-thiazolyl-based derivatives were synthesized. A quantitative structure activity relationship (QSAR) model with high predictive power r² = 0.92, and RMSE = 0.44 predicted five compounds; 2b, 3b, 5a, 9a and 9i to have potential anticancer activities. Compound 2b achieved the best ΔG of –15.34 kcal/mol with an affinity of 40.05 pki. In a molecular dynamic study 2b showed an equilibrium at 0.8 Å after 3.5 ns, while flavopiridol did so at 0.5 Å after the same time (3.5 ns). 2b showed an IC₅₀ of 0.0136 µM, 0.015 µM, and 0.054 µM against MCF-7, A-549, and CHO-K1 cell lines, respectively. The CDK4 enzyme assay revealed the significant CDK4 inhibitory activity of compound 2b with IC₅₀ of 0.036 µM. The selectivity of the newly discovered lead compound 2b toward localization in tumor cells was confirmed by a radioiodination biological assay that was done via electrophilic substitution reaction utilizing the oxidative effect of chloramine-t. ¹³¹I-2b showed good in vitro stability up to 4 h. In solid tumor bearing mice, the values of tumor uptake reached a height of 5.97 ± 0.82%ID/g at 60 min p.i. ¹³¹I-2b can be considered as a selective radiotheranostic agent for solid tumors with promising anticancer activity.

Amelioration of Tumor Targeting and In Vivo Biodistribution of 99mTc-Methotrexate-Gold Nanoparticles (99mTc-Mex-AuNPs)

Gold nanoparticles (AuNPs) represent very attractive and promising drug delivery carriers due to their unique dimensions, adjustable surface functions, and controllable drug release. Therefore, AuNPs are used to overcome the limitations of conventional chemotherapy, for example methotrexate (Mex), one of the first-generation chemotherapy drugs for cancer treatment, whose usefulness has been restricted due to drug resistance and dose-dependent side effects. In the present study, the AuNPs drug delivery system was synthesized and loaded with technetium-99 m radiolabeled Methotrexate (^99mTc-Mex) to produce new potential nanoradiopharmaceutical for tumor targeting and further imaging. The Methotrexate loaded gold nanoparticles (Mex-AuNPs) successfully prepared in small spherical particle size (20.3 nm), polydispersity index PDI (< 0.5) and a zeta potential (-17.6 mV) with loading efficiency% (93 ± 1.2%) of methotrexate at 30 min as an optimum stirring time and showed strong absorption peak for Mex-AuNPs at λ_max, 525 nm. The in vitro release profile of Mex-AuNPs showed high release percent of methotrexate at pH 5; the Q_0.5 h and Q_8h were 21.2 ± 1.5% and 92.9 ± 3.4%, respectively. The in vitro cytotoxicity was investigated at different concentrations (0.024-50 μl/100 μl) of Mex-AuNPs (1 mg/ml) against MCF-7 (Michigan Cancer Foundation-7) breast cancer cells by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay technique. Mex-AuNPs showed higher anticancer activity with low inhibitory concentration (IC₅₀ = 0.098 μl/100 μl) that was three times lower than the inhibitory concentration (IC₅₀) of methotrexate (IC₅₀ = 0.3 μl/100 μl). ^99mTc-Mex complex prepared by direct reduction method at maximum radiochemical yield (RCY)% ̴ 98.3 ± 1.09 % was loaded in AuNPs to form ^99mTc-Mex-AuNPs with loading efficiency% (93 ± 1.2 %) at 30 min of stirring time. ^99mTc-Mex-AuNPs showed convenient in vitro stability in mice serum up to 24 h with RCY% > 90 %. The preclinical biodistribution studies of ^99mTc-Mex-AuNPs were performed in 3 experimental groups A (intravenous (I.V.) injected normal mice), B and C (I.V. and intratumor (I.T.) injected tumor bearing mice, respectively). The ^99mTc-Mex-AuNPs achieved highest tumor uptake (93 ± 0.39 %ID/g) and highest Target/NonTarget (T/NT) ratio (58.1 ± 0.91) with high Tumor/Blood (T/B) ratio (25.8 ± 0.11) at 10 min post I.T. injection and retained high tumor uptake (79 ± 0.65 %ID/g) up to 60 min post I.T. injection before escaping into blood stream. Consequently, ^99mTc-Mex-AuNPs can be considered as new potential nanoradiopharmaceutical in tumor diagnosis.

New quinoxaline compounds as DPP-4 inhibitors and hypoglycemics: design, synthesis, computational and bio-distribution studies

The current work represents the design and synthetic approaches of a new set of compounds 6–10 bearing the 1,4-dimethyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamide scaffold. The biological evaluation revealed that most of the new compounds were promising selective dipeptidyl peptidase-IV (DPP-4) inhibitors and in vivo hypoglycemic agents utilizing linagliptin as a standard drug. The acute toxicity examination confirmed the safety profile of all compounds. Molecular docking studies related the significant DPP-4 suppression activity of compounds 9a, 10a, 10f, 10g to their nice fitting in the active pocket of DPP-4. In addition, the molecular dynamic study exhibited the stability of both 10a and 10g within the active site of DPP-4. The QSAR study showed that the difference between the predicted activities is very close to the experimental suppression effect. Moreover, both compounds 10a and 10g obeyed Lipinski's rule, indicating their efficient oral bioavailability. Compound 10a was radiolabeled, forming the ¹³¹I-SQ compound 10a to study the pharmacokinetic profile of this set of compounds. The biodistribution pattern hit the target protein since the tracer accumulated mainly in the visceral organs where DPP-4 is secreted in a high-level, thus with consequent stimulation of insulin secretion, leading to the target hypoglycemic effect.

The current work represents the design and synthetic approaches of a new set of compounds 6–10 bearing the 1,4-dimethyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamide scaffold.

Stabilized oral nanostructured lipid carriers of Adefovir Dipivoxil as a potential liver targeting: Estimation of liver function panel and uptake following intravenous injection of radioiodinated indicator

PURPOSE

Adefovir dipivoxil (AD), a nucleoside reverse transcriptase inhibitor is effective against Hepatitis B virus. Its poor oral bioavailability leads to frequent administration causing severe adverse effects. Thereby the entrapment of AD within lipid nanoparticulate systems is a way of increasing AD oral bioavailability as a result of improving intestinal permeability with efficient liver-targeted delivery together with higher drug stability during storage.

METHODS

AD-loaded nanostructured lipid carriers (AD-NLCs) were prepared via solvent emulsification diffusion technique adopting 2⁴ full factorial design to study the effect of lipid percentage, presence of egg yolk lecithin, surfactant type and percentage on entrapment efficiency (E.E.%), particle size and percent in-vitro drug released after 8 h (Q8hrs).

RESULTS

Formula (F12) showed E.E.% of 90.5 ± 0.2%, vesicle size of 240.2 ± 2.5 nm and Q8hrs of 58.55 ± 9.4% was selected as the optimum formula with desirability value of 0.757 based on highest EE%, lowest P.S. and Q8hrs. Further evaluation of the optimized formula using radioiodinated rose bengal (RIRB) in thioacetamide induced liver damage in Swiss Albino mice revealed a higher liver uptake of 22 ± 0.01% ID/g (percent injected dose/g organ) and liver uptake/Blood (T/B) ratio of 2.22 ± 0.067 post 2 h of I.V injection of RIRB compared to 9 ± 0.01% ID/g and 0.64 ± 0.017 in untreated group, respectively.

CONCLUSION

NLCs could be successfully used as oral drug delivery carriers of the antiviral drug Adefovir Dipivoxil to the liver with higher stability and oral bioavailability. Graphical abstract.