Impact of formulation parameters on self-assembled liposomes (LeciPlex® III): A detailed investigation

The present study investigated the feasibility of fabricating self-assembled liposomes, LeciPlex®, a phospholipid-based vesicular nanocarrier using cationic, anionic, and nonionic stabilizers. The phospholipid investigated was soy phosphatidylcholine and the nano-precipitation method based on solvent diffusion was applied as the fabrication technique of liposomes in this study. The effects of various formulation variables, such as lipid and stabilizer concentration, total solid concentration, and solvent type on the self-assembly of vesicles were studied for physical characterization including particle size analysis, differential scanning calorimetry, viscosity, optical transmittance, transmission electron microscopy, and small angle neutron scattering. All three LeciPlex® systems exhibited a direct relationship between particle size and phospholipid concentration. The two categoric variables, solvent, and stabilizer used to prepare LeciPlex® demonstrated a significant effect on particle size for all three LeciPlex® systems. Small angle neutron scattering, and optical transmittance confirmed the formation of micellar systems at a phospholipid: stabilizer ratio of 1:2 and vesicular systems at a ratio of 2:1 for the systems stabilized with anionic and nonionic surfactants. In contrast to this, the LeciPlex® formed with the cationic stabilizer Dioctadecyldimethylammonium bromide (DODAB), formed vesicles at both ratios. From these investigations, it was clear that the formulation space for LeciPlex® was diversified by the addition of cationic, anionic, and non-ionic stabilizers.

Antiproliferative and apoptotic potential of methotrexate lipid nanoparticle in murine breast cancer model

Aim: To evaluate the efficacy of novel methotrexate-loaded nanoparticles (MTX-NPs) in vitro and in vivo in the treatment of breast cancer. Materials & methods: MTX-NPs were tested for cellular uptake, cell viability, cell cycle, cellular wound migration and changes in tumor volume using characterized NPs. Results: The solid lipid NPs (SLNPs) showed strong cellular uptake, increased apoptosis, controlled cytotoxicity at lower IC50 of methotrexate and a sizable reduction in tumor burden. Conclusion: MTX-NP oral formulation can be a promising candidate in breast cancer treatment with improved cellular uptake and in vivo efficacy.

Investigation of pre-clinical pharmacokinetic parameters of atovaquone nanosuspension prepared using a pH-based precipitation method and its pharmacodynamic properties in a novel artemisinin combination

OBJECTIVES

Recently, a growing resistance to antimalarial drugs such as chloroquine, sulfadoxine-pyrimethamine, artemisinin derivatives and mefloquine has been observed. The pharmacokinetic limitation of the current therapy and multi-drug resistance has resulted in an urgent need to study the new antimalarial combinations with existing drugs. This study investigated the activity of a novel triple combination of atovaquone (nanosized)-proguanil-artesunate as an alternative artemisinin combination therapy. Atovaquone in this combination was formulated as a freeze-dried nanosuspension and its pharmacokinetic parameters were also evaluated.

METHODS

The suppressive and curative effect of atovaquone nanosuspension, proguanil, and artesunate were studied in a murine model. The in vivo pharmacokinetics of the newly developed atovaquone nanosuspension with particle size less than 200 nm was investigated.

RESULTS

Prophylactic efficacy of atovaquone nanosuspension alone at 1/80th the therapeutic dose was proven. In the curative test, atovaquone nanosuspension and proguanil at 1/10th the therapeutic dose was the minimum effective dose that resulted in complete cure of parasitaemia. As a triple combination, atovaquone nanosuspension in combination with proguanil at 1/80th the therapeutic dose of each and 1/5th the therapeutic dose of artesunate resulted in a complete cure. The in vivo pharmacokinetics of the nanosuspension showed a significant (three times) reduction in T_max value and the area under the curve of the nanosuspension was 1.9 times greater as compared with the plain suspension.

CONCLUSIONS

The potential of the synergistic combination of atovaquone nanosuspension-proguanil-artesunate in curing the multi-drug resistant malarial infection at reduced doses of all three drugs could be a solution to pill burden observed with the current therapy.

In vitro Evaluation of Novel Sustained Release Microspheres of Glipizide Prepared by the Emulsion Solvent Diffusion-Evaporation Method

The objective of the current investigation is to reduce dosing frequency and improve patient compliance by designing and systematically evaluating sustained release microspheres of Glipizide. An anti-diabetic drug, Glipizide, is delivered through the microparticulate system using ethyl cellulose as the controlled release polymer. Microspheres were developed by the emulsion solvent diffusion-evaporation technique by using the modified ethanol,-dichloromethane co-solvent system. The polymer mixture of ethyl cellulose and Eudragit^® S100 was used in different ratios (1:0, 1:1, 2:3, 1:4 and 0:1) to formulate batches F1 to F5. The resulting microspheres were evaluated for particle size, densities, flow properties, morphology, recovery yield, drug content, and in vitro drug release behavior. The formulated microspheres were discrete, spherical with relatively smooth surface, and with good flow properties. Among different formulations, the fabricated microspheres of batch F3 had shown the optimum percent drug encapsulation of microspheres and the sustained release of the Glipizide for about 12 h. Release pattern of Glipizide from microspheres of batch F3 followed Korsmeyers-peppas model and zero-order release kinetic model. The value of ‘n’ was found to be 0.960, which indicates that the drug release was followed by anomalous (non-fickian) diffusion. The data obtained thus suggest that a microparticulate system can be successfully designed for sustained delivery of Glipizide and to improve dosage form characteristics for easy formulation.

Advances in polymeric micelles for drug delivery and tumor targeting

A plethora of formulation techniques have been reported in the literature for targeting drugs to specific sites. Polymeric micelles (PMs) can be targeted to tumor sites by passive as well as active mechanisms. Some inherent properties of PMs, including size in the nanorange, stability in plasma, longevity in vivo, and pathological characteristics of tumor allow PMs to be targeted to the tumor site by a passive mechanism called the enhanced permeability and retention effect. PMs formed from an amphiphilic block copolymer are suitable for encapsulation of poorly water-soluble, hydrophobic anticancer drugs. Other characteristics of PMs such as separate functionality at the outer shell are useful for targeting the anticancer drug to tumor by active mechanisms. PMs can be conjugated with many ligands such as antibody fragments, epidermal growth factors, α(2)-glycoprotein, transferrin, and folate to target micelles to cancer cells. Application of heat or ultrasound are the alternative methods to enhance drug accumulation in tumoral cells. Targeting using micelles can also be directed toward tumor angiogenesis, which is a potentially promising target for anticancer drugs. PMs have been used for the delivery of many anticancer agents in preclinical and clinical studies. This review summarizes recently available information regarding targeting of anticancer drugs to the tumor site using PMs.