Sandeep K. Singh

Development of docetaxel nanocapsules for improving in vitro cytotoxicity and cellular uptake in MCF-7 cells

Abstract The aim of this study was to fabricate docetaxel loaded nanocapsules (DTX-NCs) with a high payload using Layer-by-Layer (LbL) technique by successive coating with alternate layers of oppositely charged polyelectrolytes. Developed nanocapsules (NCs) were characterized in terms of morphology, particle size distribution, zeta potential (ζ-potential), entrapment efficiency and in vitro release. The morphological characteristics of the NCs were assessed using transmission electron microscopy (TEM) that revealed coating of polyelectrolytes around the surface of particles. The developed NCs successfully attained a submicron particle size while the ζ-potential of optimized NCs alternated between (+) 34.64 ± 1.5 mV to (−) 33.25 ± 2.1 mV with each coating step. The non-hemolytic potential of the NCs indicated the suitability of the developed formulation for intravenous administration. A comparative study indicated that the cytotoxicity of positively charged NCs (F4) was significant higher (p < 0.05) rather than negative charged NCs (F3), plain drug (DTX) and marketed preparation (Taxotere®) when evaluated in vitro on MCF-7 cells. Furthermore, cell uptake studies evidenced a higher uptake of positive NCs (≥1.2 fold) in comparison to negative NCs. In conclusion, formulated NCs are an ideal vehicle for passive targeting of drugs to tumor cells that may result in improved efficacy and reduced toxicity of encapsulated drug moiety.

Hyaluronic acid anchored paclitaxel nanocrystals improves chemotherapeutic efficacy and inhibits lung metastasis in tumor-bearing rat model

Paclitaxel (PTX) is a first line anti-tumor agent and is widely used in the treatment of breast cancer. However, there are several limitations associated with the drug which hamper its successful clinical application. To address these obstacles we envisaged developing a nanocrystal based formulation that can overcome its limitations and significantly improve its efficacy. In this work paclitaxel nanocrystals with particle size <250 nm were developed and subsequently coated with hyaluronic acid (HA) to impart both long circulating and tumor targeting properties. A systematic cell based in vitro evaluation of HA-PTX/NC on 2D monolayer and 3D spheroids demonstrates that hyaluronic acid coating was able to significantly improve the therapeutic efficacy compared to marketed formulation of PTX (Taxol™). It was observed that interaction of HA-PTX/NC with CD44 receptors played a significant role in enhancing the uptake and thereby efficacy of PTX against cancer cells. In vivo studies revealed that HA-PTX/NC significantly prolonged the blood circulation time of PTX with an increase of 8.4 fold of AUC0–∞ in comparison to Taxol™. Furthermore HA-PTX/NC were found to exhibit higher antitumor efficacy, reduced lung metastasis and reduced toxicity in LA-7 tumor bearing rat model than Taxol™. Findings suggested that anchoring hyaluronic acid on PTX nanocrystals can be a promising approach for anticancer therapy.

Phospholipid complexation of NMITLI118RT+: way to a prudent therapeutic approach for beneficial outcomes in ischemic stroke in rats

Abstract Withania somnifera Dunal (Solanaceae) known as Ashwagandha, a popular plant of Indian origin is known to possess tremedous medicinal potential, often used as anti-inflammatory, anti-platelet, antihypertensive, hypoglycemic, hypolipidemic and adaptogenic candidate. Some of its chemotypes developed by CSIR, India includes NMITLI-101, NMITLI-118, NMITLI-128. In this study the investigators have attempted development of a phytosomal complex of NMITLI118RT + (standardized ethanolic extract of a new chemotype of W. somnifera Dunal.), its pharmaceutical characterization and evaluation of its neuro-protective potential against experimenal stroke in rats in continuation with their previous work in this area. The phytosomal complex (NIMPLC) was prepared by following a cohesive optimization design and was characterized on the basis of solubility, dissolution profile, FT-IR, DSC-TGA analysis, zeta potential, physical stability, forced degradation and photolytic degradation. Results were suggestive of a pharmaceutically acceptable formulation. NIMPLC was taken up further for biological evaluation using the middle cerebral artery occlusion (MCAO) model in rats. It could be demonstrated that the beneficial effects of NMITLI118RT + could be augmented by NIMPLC in 1 h pre and 6 h post treatment as was evident from reduction in MDA levels, increment in GSH levels, reduction in neurological deficit (ND) scores and reduction in infarct size. The study could successfully demonstrate the beneficial effects of NIMPLC in brain function restoration following stroke.

Pharmacokinetics and bioavailability assessment of Miltefosine in rats using high performance liquid chromatography tandem mass spectrometry

Miltefosine (MFS) is the first effective oral drug for treatment of visceral, mucosal and cutaneous leishmaniasis. In this study, liquid chromatography coupled mass spectrometry (LC-MS/MS) method of MFS was validated in rat plasma and its practical utilization to pharmacokinetic studies in rats for the first time. A rapid, selective and sensitive LC-MS/MS method for MFS in rat plasma was linear over the calibration range of 1-500ng/mL. MFS and Phenacetin (internal standard) were separated on Phenomenex Luna 3μ HILIC 200A (150×4.6mm) column under isocratic condition using methanol: 0.1% formic acid in triple distilled water, 90:10 (v/v) mobile phase at a flow rate of 0.8mL/min. The total chromatographic run time was 4.0min. The intra- and inter-day assay accuracy was observed between 99.45-102.88% and 99.92-101.58%, respectively. The intra- and inter-day assay precision was observed between 2.68-5.54% and 2.35-5.94%, respectively. The validated assay was practically applied to determine the plasma concentrations after oral and intravenous administration of MFS to rats. After oral administration, MFS showed Cmax (3200.00±95.39ng/mL) was observed at 12.00h (tmax) and t1/2 was 102.36±16.65h. The absolute bioavailability of MFS was 60.33±2.32%.

Anomalous connection of superior vena cava to the left atrium masquerading as epilepsy: a case report with review of literature.

An 11-year-old girl who presented with recurrent epileptic fits was eventually found to have a superior vena cava draining into the left atrium. There was no atrial septal defect. The patient underwent a successful surgical correction.

Evaluation of oral pharmacokinetics, in vitro metabolism, blood partitioning and plasma protein binding of novel antidiabetic agent, S009-0629 in rats

S009‐0629 [methyl‐8‐(methylthio)‐2‐phenyl‐6‐p‐tolyl‐4,5‐dihydro‐2H‐benzo[e]indazole‐9‐carboxylate] is a novel antidiabetic agent with PTP1B inhibitory activity. In this study, we have investigated the in vitro metabolic stability, plasma protein binding, blood partitioning, and oral pharmacokinetic study of S009‐0629 in rats. The plasma protein binding, blood partitioning, and metabolic stability were determined by HPLC method. The oral pharmacokinetic study was analyzed by liquid chromatography coupled mass spectrometry (LC‐MS/MS) method. The plasma protein binding of S009‐0629 using modified charcoal adsorption method at 5 and 10 µg/mL was 80.58 ± 1.04% and 81.95 ± 1.15%, respectively. The KRBC/PL of S009‐0629 was independent of concentration and time. The in‐vitro half‐life of S009‐0629 at 5 and 10 µM using rat liver microsomes was determined as 273 ± 24.46 and 281.67 ± 26.53 min, respectively. After oral administration, S009‐0629 exhibited Cmax 55.51 ± 1.18 ng/mL was observed at 18 hr (tmax). S009‐0629 was found to have the large apparent volume of distribution (1,894.93 ± 363.67 L/kg). Oral in‐vivo t1/2 of S009‐0629 was found to be 41.23 ± 5.96 hr. A rapid and highly sensitive LC‐MS/MS method was validated for S009‐0629 in rat plasma. S009‐0629 has high plasma protein binding and low hepatic extraction. S009‐0629 has no affinity with human P‐gp and BCRP in ATPase assay. After oral dosing, S009‐0629 has slow absorption and elimination in rats.

Rutin phospholipid complexes confer neuro-protection in ischemic-stroke rats

Rutin, a natural flavonol glycoside is known to possess significant radical scavenging properties which might have beneficial effects in cerebral ischemia. However its oral administration and pharmaceutical use is limited due to its poor aqueous solubility and bioavailability. The current investigation aimed at development of rutin–phospholipid complexes (Ru–PLCs) and its characterization to provide neuro-protective effects in brain injury following stroke. Ru–PLCs were successfully fabricated and findings demonstrated improvement in bio-pharmaceutical properties on the basis of solubility, partition coefficient, dissolution profile, morphology, zeta potential, physical stability, FT-IR, DSC-TGA, forced degradation, photolytic degradation, ROS detection and oral pharmacokinetic studies. Ru–PLCs considerably improved functional outcomes in experimental stroke (MCAO model in rats) at a dose less than half of the effective dose of rutin. Effectiveness of treatment as evident from pharmaceutical properties as well as therapeutic activity was of the following order: Ru–EPLC > Ru–TPLC > rutin.

Determination of permeability, plasma protein binding, blood partitioning, pharmacokinetics and tissue distribution of Withanolide A in rats: A neuroprotective steroidal lactone

Preclinical Research & Development