Thermoresponsive liquid crystalline formulation of Exemestane: Design and structural characterization

Lyotropic liquid crystalline phases: Drug delivery and biomedical applications

Liquid crystal (LC)-based nanoformulations may efficiently deliver drugs and therapeutics to targeted biological sites. Lyotropic liquid crystalline phases (LLCPs) have received much interest in recent years due to their unique structural characteristics of both isotropic liquids and crystalline solids. These LLCPs can be utilized as promising drug delivery systems to deliver drugs, proteins, peptides and vaccines because of their improved drug loading, stabilization, and controlled drug release. The effects of molecule shape, microsegregation, and chirality are very important in the formation of liquid crystalline phases (LCPs). Homogenization of self-assembled amphiphilic lipids, water and stabilizers produces LLCPs with different types of mesophases, bicontinuous cubic (cubosomes) and inverse hexagonal (hexosomes). Moreover, many studies have also shown higher bioadhesivity and biocompatibility of LCs due to their structural resemblance to biological membranes, thus making them more efficient for targeted drug delivery. In this review, an outline of the engineering aspects of LLCPs and polymer-based LLCPs is summarized. Moreover, it covers parenteral, oral, transdermal delivery and medical imaging of LC in targeting various tissues and is discussed with a scope to design more efficient next-generation novel nanosystems. In addition, a detailed overview of advanced liquid crystal-based drug delivery for vaccines and biomedical applications is reviewed.

A Novel Molecular Reservoir Based on Reverse Self-Assembled Liquid Crystals - A New Strategy for Prolonging the Duration in Action of Analgesics

PURPOSE

The aim of this study was to develop liquid crystal (LC) precursors to obtain novel long-acting analgesics for injection based on depot systems and compare the difference between the cubic and hexagonal precursors in delivering Diclofenac sodium (DS).

METHODS

Diclofenac sodium liquid crystal precursor injections were prepared and characterized, followed by in vitro release, pharmacodynamic, and pharmacokinetic studies.

RESULTS

The optimal formulations were prepared with a ratio of Phytantriol/ethanol/water as 76:19:5 for cubic LC precursors, and a ratio of Phytantriol/ethanol/water/Vitamine-E acetate as 72:18:5:5 for hexagonal, both loading various drug dosages (2.5%, 3.75% and 5%), respectively. Polarized light microscopy and small angle diffraction confirmed that the precursors were isotropic fluids and transformed into gels with Pn3m or HII framework in water. Rheological studies have shown that precursors belong to Newtonian fluids and gels to pseudoplastic fluids. The release showed that the DS in the commercial injection (DS-inj) was completely liberated within 6 h, whereas only 46.55% and 49.73% of the DS in 2.5% cubic precursors and 2.5% hexagonal precursors were freed, respectively. Pharmacodynamic studies have shown that cubic, hexagonal and DS-inj raised the pain threshold in mice by 169.4%, 157.3% and 113.79%, respectively. The mean retention times of DS in cubic and hexagonal were 3.16 and 2.67 times longer than DS-inj, respectively, according to pharmacokinetic results.

CONCLUSION

In conclusion, cubic and hexagonal are both promising analgesic sustained release formulations. In addition, based only on the current comparison, cubic seems to have a better long-acting effect.

QbD Assisted Development of Lipidic Nanocapsules for Antiestrogenic Activity of Exemestane in Breast Cancer

Some breast cancers are caused by hormonal imbalances, such as estrogen and progesterone.These hormones play a function in directing the growth of cancer cells. The hormone receptors in hormone receptor-positive breast cancer lead breast cells to proliferate out of control. Cancer therapy such as hormonal, targeted, radiation is still unsatisfactory because of these challenges viz. MDR (Multiple drug resistance), off-targeting, severe adverse effects. A novel aromatase inhibitor exemestane (Exe) exhibits promising therapy in breast cancer. This study aims to develop and optimize Exe-loaded lipid nanocapsules (LNCs) by using DSPC, PF68 and olive oil as lipid, surfactant and oil phase, respectively and to characterize the same. The prepared nanocapsules were investigated via in-vitro cell culture and in-vivo animal models. The LNCs exhibited cytotoxicity in MCF-7 cell lines and enhanced anti-cancer activity and reduced cardiotoxicity in DMBA-induced animal model when compared to the drug. Additionally, in-vivo pharmacokinetics revealed a 4.2-fold increased oral bioavailability when compared with Exe suspension. This study demonstrated that oral administration of Exe-loaded LNCs holds promise for the antiestrogenic activity of exemestane in breast cancer.