Drug Concentration In Lymph Nodes Research Articles

An Integrated Spatial Dynamics-Pharmacokinetic Model Explaining Poor Penetration of Anti-retroviral Drugs in Lymph Nodes.

Although combined anti-retroviral therapy (cART) suppresses plasma HIV viremia below the limit of detection in a majority of HIV patients, evidence is emerging that the distribution of the anti-retroviral drugs is heterogeneous in tissue. Clinical studies measuring antiretroviral drug concentrations in lymph nodes (LNs) revealed lower concentrations compared to peripheral blood levels suggesting poor drug penetration properties. Our current study is an attempt to understand this poor anti-retroviral drug penetration inside lymph node lobules through integrating known pharmacokinetic and pharmacodynamic (PK/PD) parameters of the anti-retroviral drugs into a spatial model of reaction and transport dynamics within a solid lymph node lobule. Simulated drug penetration values were compared against experimental results whenever available or matched with data that is available for other drugs in a similar class. Our integrated spatial dynamics pharmacokinetic model reproduced the experimentally observed exclusion of antivirals from lymphoid sites. The strongest predictor of drug exclusion from the lymphoid lobule, independent of drug class, was lobule size; large lobules (high inflammation) exhibited high levels of drug exclusion. PK/PD characteristics associated with poor lymphoid penetration include high cellular uptake rates and low intracellular half-lives. To determine whether this exclusion might lead to ongoing replication, target CD4+ T cell, infected CD4+ T cell, free virus, and intracellular IC50 values of anti-retroviral drugs were incorporated into the model. Notably, for median estimates of PK/PD parameters and lobule diameters consistent with low to moderate inflammation, the model predicts no ongoing viral replication, despite substantial exclusion of the drugs from the lymphoid site. Monte-Carlo studies drawn from the prior distributions of the PK/PD parameters predicts increases in site-specific HIV replication in a small fraction of the patient population for lobule diameters greater than 0.2 mm; this fraction increases as the site diameter/ inflammation level increases. The model shows that cART consisting of two nRTIs and one PI is the most likely treatment combination to support formation of a sanctuary site, a finding that is consistent with clinical observations.

Nanodrug formulations to enhance HIV drug exposure in lymphoid tissues and cells: clinical significance and potential impact on treatment and eradication of HIV/AIDS.

Although oral combination antiretroviral therapy effectively clears plasma HIV, patients on oral drugs exhibit much lower drug concentrations in lymph nodes than blood. This drug insufficiency is linked to residual HIV in cells of lymph nodes. While nanoformulations improve drug solubility, safety and delivery, most HIV nanoformulations are intended to extend plasma levels. A stable nanodrug combination that transports, delivers and accumulates in lymph nodes is needed to clear HIV in lymphoid tissues. This review discusses limitations of current oral combination antiretroviral therapy and advances in anti-HIV nanoformulations. A 'systems approach' has been proposed to overcome these limitations. This concept has been used to develop nanoformulations for overcoming drug insufficiency, extending cell and tissue exposure and clearing virus for treating HIV/AIDS.

Systems Approach to targeted and long-acting HIV/AIDS therapy.

Medication adherence and insufficient drug levels are central to HIV/AIDS disease progression. Recently, Fletcher et al. confirmed that HIV patients on oral antiretroviral therapy had lower intracellular drug concentrations in lymph nodes than in blood. For instance, in the same patient, multiple lymph node drug concentrations were as much as 99% lower than in blood. This study built upon our previous finding that HIV patients taking oral indinavir had 3-fold lower mononuclear cell drug concentrations in lymph nodes than in blood. As a result, an association between insufficient lymph node drug concentrations in cells and persistent viral replication has now been validated. Lymph node cells, particularly CD4 T lymphocytes, host HIV infection and persistence; CD4 T cell depletion in blood correlates with AIDS progression. With established drug targets to overcome drug insufficiency in lymphoid cells and tissues, we have developed and employed a "Systems Approach" to engineer multi-drug-incorporated particles for HIV treatment. The goal is to improve lymphatic HIV drug exposure to eliminate HIV drug insufficiency and disease progression. We found that nano-particulate drugs that absorb, transit, and retain in the lymphatic system after subcutaneous dosing improve intracellular lymphatic drug exposure and overcome HIV lymphatic drug insufficiency. The composition, physical properties, and stability of the drug nanoparticles contribute to the prolonged and enhanced drug exposure in lymphoid cells and tissues. In addition to overcoming lymphatic drug insufficiency and potentially reversing HIV infection, targeted drug nanoparticle properties may extend drug concentrations and enable the development of long-acting HIV drug therapy for enhanced patient compliance.

Synthesis, characterization and targeting potential of zidovudine loaded sialic acid conjugated-mannosylated poly(propyleneimine) dendrimers

The present investigation was aimed at exploring dual targeting of anti-HIV drug, zidovudine (ZDV) via sialic acid conjugated-mannosylated poly(propyleneimine) (PPI) dendritic nano-constructs. Fourth generation PPI dendrimers, sialic acid conjugated PPI dendrimers (SPPI), mannose conjugated PPI dendrimers (MPPI) and dual ligand system i.e. sialic acid conjugated-mannosylated PPI dendrimers (SMPPI) were synthesized and characterized by FT-IR and 1H NMR spectroscopies and were further confirmed by size exclusion chromatography and differential scanning calorimetry. Various parameters like drug loading, pH dependent in vitro release, hemolytic toxicity, macrophage uptake and cytotoxicity concerning PPI, SPPI, MPPI and SMPPI dendrimers were evaluated. ZDV loaded SMPPI, SPPI and MPPI have shown reduced hemolytic toxicity, cytotoxicity and in vitro drug release at pH 7.4. Extremely significant (P<0.001) increase in cellular uptake of ZDV by macrophage cells was observed in case of SMPPI as compared to PPI and free drug. The in vivo blood level and tissue distribution studies in albino rats also demonstrated potential of dual targeted system towards sialoadhesin and carbohydrate receptors. The drug concentration in lymph nodes was increased to about 28 times in case of SMPPI (1335 ± 17.6 ng/g) as compared to free drug (48 ± 5.8 ng/g) at 6th hr. The results suggested that such dual ligand dendritic system (SMPPI) hold potential to enhance biocompatibility and site specific delivery of antiretroviral drug, ZDV.

Mitoxantrone-loaded BSA nanospheres and chitosan nanospheres for local injection against breast cancer and its lymph node metastases: II: Tissue distribution and pharmacodynamics

Bovine serum albumin (BSA) and chitosan (CS) nanospheres of mitoxantrone (MTO) were comparatively evaluated in terms of tissue distribution, acute toxicity and therapeutic efficiency against breast cancer and its lymph node metastases. After local injection in rats, MTO nanospheres showed a slower elimination rate and a much higher drug concentration in lymph nodes compared with MTO solution, and a lower drug concentration in other tissues. There was no observed acute toxicity to the main tissues of Kunming mice after local injection of MTO-BSA-NS. Mild toxicity to liver and lung was observed for MTO-CS-NS, but, for MTO solution, severe toxicity to liver and lung and much lower number of white blood cells were observed. Human MCF-7 breast cancer in nude mice and animal model of P388 lymph node metastases in Kunming mice were applied to investigate the therapeutic efficiency. The inhibition rate of the nanospheres against breast cancer was much higher than that of MTO solution, and lymph node metastases were efficiently inhibited by the nanospheres, especially MTO-BSA-NS.

Drug concentration in lymph nodes after preoperative administration of UFT (a blend of Tegafur and uracil) for non-small-cell lung cancer

Background. UFT a blend of uracil and Tegafur (1-[2-tetrahydrofuryl]-5 fluorouracil), molar ratio, 4 : 1 is an anti-tumor agent for oral administration that is presumed to maintain the concentration of 5-fluorouracil (5-FU) in tumor tissue. The concentration of 5-FU achieved with UFT in lymph node metastases has, however, not yet been examined; in this study we aimed to clarify the transfer of 5-FU to lymph node metastases in patients treated with UFT.