Deepak Singodia

Investigations into an alternate approach to target mannose receptors on macrophages using 4-sulfated N-acetyl galactosamine more efficiently in comparison with mannose-decorated liposomes: an application in drug delivery

UNLABELLED In this study the potential of 2 different ligands, i.e., palmitoyl mannose (Man-Lip) and 4-SO(4)GalNAc (Sulf-Lip) to target resident macrophages was investigated after surface decoration of Amphotericin B (AmB) loaded liposomes. In the case of Sulf-Lip, the 4-SO(4)GalNAc was adsorbed through electrostatic interaction on cationic liposomes, which was confirmed by change in zeta potential from +48.2 ± 3.7 mV for Lip to +12.2 ± 1.3 mV for Sulf-Lip. The mean particle size of Sulf-Lip and Man-Lip was found to be 139.4 ± 7.4 nm and 147.4 ± 8.6 nm, respectively. Flow cytometric data reveal enhanced uptake of Sulf-Lip in both J774 and RAW cell lines in comparison with the uptake of Man-Lip. Intracellular localization studies indicate that the fluorescence intensity of Sulf-Lip was much higher in comparison with that of Man-Lip and Lip formulations. Sulf-Lip and Man-Lip showed significantly higher localization of AmB at all time points in comparison with Lip (P < 0.05) after intravenous (IV) administration. The studies provide evidence that 4-SO(4)GalNAc possesses a promising feature for targeting resident macrophages and its application in the conditions of leishmaniasis is in the offing. FROM THE CLINICAL EDITOR This in vivo study compares two different ligands to deliver Amphotericin B l(AmB) loaded liposomes to resident macrophages. Targeted approaches showed significantly higher localization of AmB at all time points in comparison to non-targeted liposomes, and future applications in leishmaniasis are already under preparation.

Emerging trend in nano-engineered polyelectrolyte-based surrogate carriers for delivery of bioactives.

Importance of the field: In recent decades a new colloidal drug delivery system based on layer-by-layer (LbL) technology has emerged, which offers promising means of delivering bioactive agents, specifically biological macromolecules including peptides and DNA. Nano-engineered capsules specifically fabricated from biocompatible and biodegradable polyelectrolytes (PEs) can provide a better option for encapsulation of cells thereby protecting cells from immunological molecules in the body, and their selective permeability can ensure the survival of encapsulated cells. Areas covered in this review: This review encompasses a strategic approach to fabricate nano-engineered microcapsules through meticulous selection of polyelectrolytes and core materials based on LbL technology. The content of the article provides evidence for its wide array of applications in medical therapeutics, as indicated by the quantity of research and patents in this area. Recent developments and approaches for tuning drug release, biocompatibility and cellular interaction are discussed thoroughly. What the reader will gain: This review aims to provide an overview on the development of LbL capsules with specific orientation towards drug and macromolecular delivery and its integration with other drug delivery systems, such as liposomes. Take home message: Selection of PEs for the fabrication of LbL microcapsules has a profound effect on stability, drug release, biocompatibility and encapsulation efficacy. The release can be easily modulated by varying different physicochemical as well as physiological conditions. Scale-up approaches for the fabrication of LbL microcapsules by means of automation must be considered to improve the possibility of application of LbL microcapsules on a large scale.

RGD modified albumin nanospheres for tumour vasculature targeting

Objectives  Cyclic arginine‐glycine‐aspartic acid (RGD) peptide‐anchored sterically stabilized albumin nanospheres (RGD‐SN) have been investigated for the selective and preferential presentation of carrier contents at angiogenic endothelial cells overexpressing avb3 integrins on and around tumour tissue. Their targetabilty was assessed.

Liposomes modified with YIGSR peptide for tumor targeting

YIGSR peptide anchored sterically stabilized liposomes (YIGSR-SL) were investigated for selective and preferential presentation of carrier contents at angiogenic endothelial cells overexpressing laminin receptors on and around tumor tissue and thus for assessing their targetabilty. In vitro endothelial cell binding of liposomes exhibited 7-fold higher binding of YIGSR-SL to HUVEC in comparison to the nontargeted sterically stabilized liposomes (SL). Spontaneous lung metastasis and angiogenesis assays show that YIGSR peptide anchored liposomes are significantly (P ≤ 0.01) effective in the prevention of lung metastasis and angiogenesis compared to free 5-fluorouracil (5-FU) and SL. YIGSR-SL was very effective in regression of tumors in BALB/c mice bearing B16F10 melanoma cells. Results indicate that YIGSR peptide anchored sterically stabilized liposomes bearing 5-FU are significantly (P ≤ 0.01) active against primary tumor and metastasis than the SL and free drug. Thus, YIGSR peptide anchored sterically stabilized liposomes hold potential of targeted cancer chemotherapeutics.

Investigations on feasibility of in situ development of amphotericin B liposomes for industrial applications.

Amphotericin B (AmB) liposome formulations are very successful in the treatment of fungal infections and leishmaniasis. But higher cost limits its widespread use among people in developing countries. Therefore, we have developed a modified ethanol-injection method for the preparation of AmB liposomes. Two liposomal formulations were developed with dimyristoyl phosphatidylcholine [F-1a] and soya phosphatidylcholine [F-2a], along with egg phosphatidyl glycerol and cholesterol. AmB was dissolved in acidified dimethyl acetamide and mixed with ethanolic lipid solution and rapidly injected in 5% dextrose to prepare liposomes. Liposomes were characterized on the basis of size (~100 nm), zeta (–43.3 ± 2.8 mV) and percent entrapment efficiency (>95%). The in vitro release study showed an insignificant difference (P ≥ 0.05) for 24-hour release between marketed AmB liposomes (AmBisome) and F-1a and F-2a. Proliposome concentrate, used for the preparation of in situ liposomes, was physically stable for more than 3 months at experimental conditions. Similarly, AmB showed no sign of degradation in reconstituted liposomes stored at 2–8°C for more than 3 months. IC50 value of Ambisome (0.18 µg/mL) was comparatively similar to F-1a (0.17 µg/mL) and F-2a (0.16 µg/mL) against intramacrophagic amastigotes. Under experimental conditions, a novel modified method for AmB liposomes is a great success and generates interest for development as a platform technology for many therapeutic drug products.

Polymeric nanospheres modified with YIGSR peptide for tumor targeting

YIGSR peptide anchored pegylated nanospheres (YIGSR-SN) loaded with 5-fluorouracil (5-FU) were investigated for selective and preferential presentation of carrier contents at angiogenic endothelial cells over-expressing laminin receptors on and around tumor tissue and thus for assessing their targetability. Pegylated nanosphere (SN) without peptide conjugate were used for comparison. The average size of all nanosphere preparations prepared was ∼108 nm and maximum drug entrapment was 68.5 ± 5.2%. In vitro endothelial cell binding of nanospheres exhibited 8-fold higher binding of YIGSR-SN to HUVEC in comparison to the SN. Spontaneous lung metastasis and angiogenesis assays show that YIGSR peptide anchored nanospheres are significantly (p ≤ 0.05) effective in the prevention of lung metastasis and angiogenesis compared to free 5-FU and SN. In therapeutic experiments, 5-FU, SN, and YIGSR-SN 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 in YIGSR-SN compared with free 5-FU and SN. Results indicate that YIGSR peptide anchored pegylated nanospheres bearing 5-FU are significantly (p ≤ 0.05) active against primary tumor and metastasis than the non-targeted pegylated nanospheres and free drug. Thus, YIGSR peptide anchored pegylated nanospheres hold potential of targeted cancer chemotherapeutics.

Ciprofloxacin surf-plexes in sub-micron emulsions: A novel approach to improve payload efficiency and antimicrobial efficacy

The aim of this study was to investigate antimicrobial efficacy and pharmacokinetic profile of ciprofloxacin (CFn) loaded oil-in-water (o/w) submicron emulsion (SE-CFn). This study emphasized on development of hydrophobic ion-pair complexes of CFn with sodium deoxycholate (SDC) [CFn-SDC], which was incorporated in the core of SE (SE-CFn-SDC). SE-CFn-SDC was characterized for globulet size (278±12 nm), zeta potential (-25.3±1 mV), viscosity (2.6±0.3 cP), transmission electron microscopy (TEM), drug entrapment and for in vitro release profile. The entrapment efficiency (EE) was significantly improved (≥80%; p≤0.05) on ion-pairing while it was merely 27.2±3.1% for free CFn. The cytotoxicity studies of formulations on J774 macrophage cells showed that more than 90±3% of cells were viable, even at high concentration (100 μg/ml). SE-CFn-SDC was further modified with cationic inducer chitosan (SE-CH-CFn-SDC), which showed almost twofold and fourfold enhancement in antimicrobial efficacy as compared to SE-CFn-SDC and SE-CFn, respectively when tested in vitro against E. coli, S. aureus, and P. aeruginosa. When tested in male Balb/c mice, the AUC(0-24h) of SE-CH-CFn-SDC (23.27±2.8 h μg/ml) was found to be 1.7-fold and 5-fold higher as compared to SE-CFn-SDC (13.17±0.88 h μg/ml) and CFn solution (4.70±0.77 h μg/ml), respectively. The study demonstrates that surfactant based ionic complex formation incorporated in surface modified submicron emulsion is a promising approach to improve payload efficiency of poorly water soluble drugs with improved antimicrobial efficacy and pharmacokinetic profile.

Vitamin B12 Grafted Layer-by-Layer Liposomes Bearing HBsAg Facilitate Oral Immunization: Effect of Modulated Biomechanical Properties

Adhesion forces of nanoparticulate materials toward biological membrane are crucial for designing a delivery system for therapeutic molecules and vaccines. The present study aims to investigate the impact of surface roughness of the nanoparticulate system in oral delivery of antigen and its targeting to toward intestinal antigen presenting cells. To evaluate this hypothesis, layer-by-layer coated liposomes (LBL-Lipo) were fabricated using sodium alginate and Vitamin B12 conjugated Chitosan (VitB12-Chi) as anionic and cationic polyelectrolyte, respectively. Change in surface roughness was observed on changes in pH from gastric to intestinal conditions attributed to increase and decrease in charge density on VitB12-Chi. Surface roughness was measured in terms of root-mean-square measured by topographical analysis using atomic force microscopy. LBL-Lipo were further characterized for their size, zeta potential, and release behavior to evaluate the potential for oral vaccine delivery. In vitro cell uptake in macrophage cells (J-744) shows about 2- and 3.1-fold increased uptake of rough LBL-Lipo over smooth LBL-Lipo at 37 °C (endocytosis) and 4 °C (endocytosis inhibition) indicating improved biological interaction. Further in vivo immunization study revealed that prototype formulations were able to produce 4.8- and 3.3-fold higher IgG and IgA levels in serum and feces, respectively, in comparison to smooth LBL-Lipo.