Sanyog Jain

The intracellular drug delivery and anti tumor activity of doxorubicin loaded poly(γ-benzyl L-glutamate)-b-hyaluronan polymersomes

We have investigated the intracellular delivery of doxorubicin (DOX) loaded poly(gamma-benzyl L-glutamate)-block-hyaluronan (PBLG-b-HYA) based polymersomes (PolyDOX) in high (MCF-7) and low (U87) CD44 expressing cancer cell models. DOX was successfully loaded into polymersomes using nanoprecipitation method and in vitro drug release pattern were achieved at pH 5.5 and 7.4 up to 10 days. Block copolymer vesicles without loaded DOX were non cytotoxic in both cells at concentration 150-650 microg/mL. Flow cytometry data suggested successful uptake of PolyDOX in cells and high accumulation was found in MCF-7 than U87 cells. Microscopy imagings revealed that in MCF-7 cells PolyDOX was more in cytoplasm and free DOX in nuclei, whereas in U87 cells free DOX was also found in the cytoplasm. Cytotoxicity of the drug was concentration and exposure time dependent. In addition, PolyDOX significantly enhanced reactive oxygen species (ROS) level in both cells. PolyDOX also suppressed growth of breast tumor on female Sprague-Dawley (SD) rats as compared to phosphate buffer saline pH 7.4 (PBS) control group. In addition reduced level of serum enzymes (LDH and CPK) by PolyDOX formulation indicated less cardiotoxicity of DOX after loading in polymersomes. Results suggest that intracellular delivery of PolyDOX was depended on the CD44 expression level in cells due to presence of hyaluronic acid on the surface of polymersomes, and could be used as a self-targeting drug delivery cargo in over-expressed CD44 glycoprotein cells of breast cancer.

Oral delivery of anticancer drugs: challenges and opportunities.

The present report focuses on the various aspects of oral delivery of anticancer drugs. The significance of oral delivery in cancer therapeutics has been highlighted which principally includes improvement in quality of life of patients and reduced health care costs. Subsequently, the challenges incurred in the oral delivery of anticancer agents have been especially emphasized. Sincere efforts have been made to compile the various physicochemical properties of anticancer drugs from either literature or predicted in silico via GastroPlus™. The later section of the paper reviews various emerging trends to tackle the challenges associated with oral delivery of anticancer drugs. These invariably include efflux transporter based-, functional excipient- and nanocarrier based-approaches. The role of drug nanocrystals and various others such as polymer based- and lipid based-nanocarriers in the bioavailability enhancement along with their clinical outcomes has also been discussed exhaustively. Furthermore, an insight on the various absorption mechanisms of these nanocarriers across the gastrointestinal tract has also been highlighted.

The effect of the oral administration of polymeric nanoparticles on the efficacy and toxicity of tamoxifen

The present investigation reports on the conditions for preparation of tamoxifen loaded PLGA nanoparticles (Tmx-NPs) for oral administration. Tmx-NPs with >85% entrapment efficiency and 165.58 ± 3.81 nm particle size were prepared and freeze dried. Freeze dried Tmx-NPs were found to be stable in various simulated GIT media (pH 1.2, pH 3.5, pH 6.8, SGF & SIF). No significant changes in characteristics of Tmx-NPs were observed after 3 months accelerated stability studies. The cell viability in C127I cells was found to be relatively lower in Tmx-NP treated cells as compared to free Tmx treated cells. CLSM imaging reveled that nanoparticles were efficiently localized into the nuclear region of C127I cells. Oral bioavailability of Tmx was increased by 3.84 and 11.19 times as compared to the free Tmx citrate and Tmx base respectively, when formulated in NPs. In vivo oral antitumor efficacy of Tmx-NPs was carried out in DMBA induced breast tumor model and tumor size was reduced up to 41.56% as compared to untreated groups which showed an increase in tumor size up to 158.66%. Finally, Tmx-NPs showed the marked reduction in hepatotoxicty when compared with free Tmx citrate as evidenced by histopathological examination of liver tissue as well as AST, ALT and MDA levels. Therefore Tmx-NPs could have the significant value for the oral chronic breast cancer therapy with reduced hepatotoxicity.

Solid lipid nanoparticles: an oral bioavailability enhancer vehicle

Introduction: The therapeutic efficacy of perorally administered drugs is often obscured by their poor oral bioavailability (BA) and low metabolic stability in the gastrointestinal tract (GIT). Solid lipid nanoparticles (SLNs) have emerged as potential BA enhancer vehicles for various Class II, III and IV drug molecules. Area covered: This review examines the recent advancements in SLN technology, with regards to oral drug delivery. The discussion critically examines the effect of various key constituents on SLN absorption and their applications in oral drug delivery. The relationship between the complexity of absorption (and various factors involved during absorption, including particle size), stability and the self-emulsifying ability of the lipids used has been explored. Expert opinion: The protective effect of SLNs, coupled with their sustained/controlled release properties, prevents drugs/macromolecules from premature degradation and improves their stability in the GIT. An extensive literature survey reveals that direct peroral administration of SLNs improves the BA of drugs by 2- to 25-fold. Overall, the ease of large-scale production, avoidance of organic solvents and improvement of oral BA make SLNs a potential BA enhancer vehicle for various Class II, III and IV drugs.

Liposomes modified with cyclic RGD peptide for tumor targeting.

Cyclic RGD peptide anchored sterically stabilized liposomes (RGD-SL) were investigated for selective and preferential presentation of carrier contents at angiogenic endothelial cells overexpressing αvβ3 integrins on and around tumor tissue and thus for assessing their targetabilty. Liposomes were prepared using distearoylphosphatidylcholine (DSPC), cholesterol and distearoylphosphatidylethanolamine–polyethyleneglycol–RGD peptide conjugate (DSPE–PEG–RGD) in a molar ratio 56:39:5. The control RAD peptide anchored sterically stabilized liposomes (RAD-SL) and liposome with 5 mol% PEG (SL) without peptide conjugate which had similar lipid composition were used for comparison. The average size of all liposome preparations prepared was approximately 105 nm and maximum drug entrapment was 10.2±1.1%. In vitro endothelial cell binding of liposomes exhibited 7-fold higher binding of RGD-SL to HUVEC in comparison to the SL and RAD-SL. Spontaneous lung metastasis and angiogenesis assays show that RGD peptide anchored liposomes are significantly (p<0.01) effective in the prevention of lung metastasis and angiogenesis compared to free 5-FU, SL and RAD-SL. In therapeutic experiments, 5-FU, SL, RGD-SL and RAD-SL were administered intravenously on day 4 at the dose of 10 mg 5-FU/kg body weight to B16F10 tumor bearing BALB/c mice resulting in effective regression of tumors compared with free 5-FU, SL and RAD-SL. Results indicate that cyclic RGD peptide anchored sterically stabilized liposomes bearing 5-FU are significantly (p<0.01) active against primary tumor and metastasis than the non-targeted sterically stabilized liposomes and free drug. Thus cyclic RGD peptide anchored sterically stabilized liposomes hold potential of targeted cancer chemotherapeutics.

RGD-anchored magnetic liposomes for monocytes/neutrophils-mediated brain targeting.

Negatively charged magnetic liposomes were prepared using soya lecithin (Soya PC), cholesterol and phosphatidyl serine (PS) for their preferential presentation to circulating blood phagocytes (monocytes and neutrophils). PS ratio was optimized in terms of drug and magnetite loading, in vitro magnetic responsiveness and ex vivo monocytes/neutrophils uptake. RGD peptide was covalently coupled to the negatively charged liposomes composed of PC, cholesterol, PS and phopsphatidyl ethanolamine (PE) via carbodiimide-mediated coupling. In vivo cellular sorting study under magnetic guard indicated an increase in relative count of neutrophils and monocytes. Results suggest that selective uptake of RGD-anchored magnetic liposomes by these cells imparts them magnetic property. High levels of a model drug diclofenac sodium was quantified in target organ brain. In case of negatively charged uncoated magnetic liposomes brain levels of the drug was 5.95-fold compared to free drug and 7.58-fold in comparison to non-magnetic formulation, while for RGD-coated magnetic liposomes this ratio was 9.1-fold compared to free drug solution, 6.62-fold compared to non-magnetic RGD-coated liposomes and 1.5-fold when compared to uncoated magnetic liposomes. Liver uptake was significantly bypassed (37.2% and 48.3% for uncoated and RGD-coated magnetic liposomes, respectively). This study suggested the potential of negatively charged and RGD-coated magnetic liposomes for monocytes/neutrophils-mediated active delivery of drugs to relatively inaccessible inflammatory sites, i.e. brain. The study opens a new perspective of active delivery of drugs for a possible treatment of cerebrovascular diseases.

Toxicity of Multiwalled Carbon Nanotubes with End Defects Critically Depends on Their Functionalization Density

Carboxylated carbon nanotubes stand as the most promising nanovectors for biomedical and pharmaceutical applications due to their ease of covalent conjugation with eclectic functional molecules including therapeutic drugs, proteins, and oligonucleotides. In the present study, we attempt to investigate how the toxicity of acid-oxidized multiwalled carbon nanotubes (MWCNTs) can be tweaked by altering their degree of functionalization and correlate the toxicity trend with their biodistribution profile. In line with that rationale, mice were exposed to 10 mg/kg of pristine (p) and acid-oxidized (f) MWCNTs with varying degrees of carboxylation through a single dose of intravenous injection. Thereafter, extensive toxicity studies were carried out to comprehend the short-term (7 day) and long-term (28 day) impact of p- and various f-MWCNT preparations on the physiology of healthy mice. Pristine MWCNTs with a high aspect ratio, surface hydrophobicity, and metallic impurities were found to induce significant hepatotoxicity and oxidative damage in mice, albeit the damage was recovered after 28 days of treatment. Conversely, acid-oxidized carboxylated CNTs with shorter lengths, hydrophilic surfaces, and high aqueous dispersibility proved to be less toxic and more biocompatible than their pristine counterparts. A thorough scrutiny of various biochemical parameters, inflammation indexes, and histopathological examination of liver indicated that toxicity of MWCNTs systematically decreased with the increased functionalization density. The degree of shortening and functionalization achieved by refluxing p-MWCNTs with strong mineral acids for 4 h were sufficient to render the CNTs completely hydrophilic and biocompatible, while inducing minimal hepatic accumulation and inflammation. Quantitative biodistribution studies in mice, intravenously injected with Tc-99m labeled MWCNTs, clearly designated that clearance of CNTs from reticuloendothelial system (RES) organs such as liver, spleen, and lungs was critically functionalization density dependent. Well-individualized MWCNTs with shorter lengths (<500 nm) and higher degrees of oxidation (surface carboxyl density >3 μmol/mg) were not retained in any of the RES organs and rapidly cleared out from the systematic circulation through renal excretion route without inducing any obvious nephrotoxicity. As both p- and f-MWCNT-treated groups were devoid of any obvious nephrotoxicity, CNTs with larger dimensions and lower degrees of functionalization, which fail to clear out from the body via renal excretion route, were thought to be excreted via biliary pathway in faeces.

Co-encapsulation of tamoxifen and quercetin in polymeric nanoparticles: implications on oral bioavailability, antitumor efficacy, and drug-induced toxicity.

The present investigation reports the preparation, optimization, and characterization of orally administrable PLGA-NPs co-encapsulated with tamoxifen (Tmx) and quercetin (QT). The developed formulation was found to have particle size 185.3 ± 1.20 nm, PDI 0.184 ± 0.004, entrapment efficiency 67.16 ± 1.24% Tmx, 68.60 ± 1.58% QT at a Tmx/QT ratio of 1:2 w/w. The stability of the freeze-dried formulation was established in simulated gastrointestinal fluids for 8 h and at accelerated stability condition for 3 months. DPPH free radical scavenging assay confirmed that the functional architecture of QT was retained in freeze-dried NPs. Higher cellular uptake, cytotoxicity, and nuclear co-localization of Tmx-QT-NPs in MCF-7 cells revealed higher efficiency of the formulation. At the same time, higher Caco-2 cell uptake revealed its potential for oral delivery, which was well corroborated with in vivo pharmacokinetics, which suggested ∼ 5-fold and ∼ 3-fold increase in oral bioavailability as compared to the free Tmx citrate and free QT, respectively. Concomitantly, significantly higher tumor suppression was observed in the case of the developed formulation in contrast to respective free drug(s) and their combination when tested against a DMBA-induced breast cancer model in female SD rats. Multiple oral administrations of Tmx-QT-NPs efficiently controlled the tumor angiogenesis as revealed by normalized levels of respective markers (MMP-2 and MMP-9). The safety profile of Tmx-QT-NPs was also established, and no measurable hepatotoxicity or oxidative stress was observed when measured as a function of respective biochemical markers in contrast to free drug(s) and their combinations. In a nutshell, the co-encapsulation strategy with PLGA-NPs could be a promising approach in improving oral delivery of Tmx and QT for cancer therapy.

Carbon nanotubes in cancer theragnosis

Carbon nanotubes as a unique and novel class of nanomaterials have shown considerable promise in cancer therapy and diagnosis amidst the myriad of nanocarriers. The presence of a large surface area enables the engineering of the surface of nanotubes, thus making them biocompatible, and large benefits can be harnessed from them. Together with their ability to encapsulate small molecules, stacking interactions and conjugation, nanotubes have improved the profile of anticancer agents. The propensity to absorb the body transparent NIR radiation also envisages photothermal and photoacoustic therapy using nanotubes. This article sheds light on the role of carbon nanotubes in cancer therapy and diagnosis based on recent findings.

Sustained Ocular Drug Delivery from a Temperature and pH Triggered Novel In Situ Gel System

Various ocular diseases like glaucoma, conjunctivitis, and dry eye syndrome require frequent drug administration. Poor ocular bioavailability of drugs (< 1%) from conventional eye drops is due mainly to the precorneal loss factors that include rapid tear turnover, nonproductive absorption, transient residence time in the cul-de-sac, and the relative impermeability of the drugs to corneal epithelial membrane. These problems may be overcome by the use of in situ gel-forming systems that are instilled as drops into the eye and undergo a sol-gel transition in the cul-de-sac. Our present work describes the formulation and evaluation of an ocular delivery system of timolol maleate based on the concept of both temperature and pH-triggered in situ gelation. Pluronic F-127 (a thermosensitive polymer) in combination with chitosan (pH-sensitive polymer also acts as permeation enhancer) was used as gelling agent. The developed formulation was characterized for various in vitro parameters e.g., clarity, gelation temperature and pH, isotonicity, sterility, rheological behavior, drug release profile, transcorneal permeation profile, and ocular irritation. Developed formulation was clear, isotonic solution, that converted into gel at temperatures above 35°C and pH 6.9–7.0. A significant higher drug transport across corneal membrane and increased ocular retention time was observed using the developed formulation. The developed system is a viable alternative to conventional eye drops for the treatment of glaucoma and various other ocular diseases.