One-step self-assembled nanomicelles for improving the oral bioavailability of nimodipine

Self-Assembled Polymers for Gastrointestinal Tract Targeted Delivery through the Oral Route: An Update

Gastrointestinal tract (GIT) targeted drug delivery systems have gained growing attention as potential carriers for the treatment of different diseases, especially local colonic diseases. They have lower side effects as well as enhanced oral delivery efficiency because of various therapeutics that are vulnerable to acidic and enzymatic degradation in the upper GIT are protected. The novel and unique design of self-assembled nanostructures, such as micelles, hydrogels, and liposomes, which can both respond to external stimuli and be further modified, making them ideal for specific, targeted medical needs and localized drug delivery treatments through the oral route. Therefore, the aim of this review was to summarize and critically discuss the pharmaceutical significance and therapeutic feasibility of a wide range of natural and synthetic biomaterials for efficient drug targeting to GIT using the self-assembly method. Among various types of biomaterials, natural and synthetic polymer-based nanostructures have shown promising targeting potential due to their innate pH responsiveness, sustained and controlled release characteristics, and microbial degradation in the GIT that releases the encapsulated drug moieties.

Anti-inflammatory efficacy of Berberine Nanomicelle for improvement of cerebral ischemia: formulation, characterization and evaluation in bilateral common carotid artery occlusion rat model

BACKGROUND

Berberine (BBR) is a plant alkaloid that possesses anti-inflammatory and anti-oxidant effects with low oral bioavailability. In this study, micelle formulation of BBR was investigated to improve therapeutic efficacy and examined its effect on the secretion of inflammatory cytokines in cerebral ischemia in the animal model.

MATERIAL AND METHODS

Nano formulation was prepared by thin-film hydration method, and characterized by particle size, zeta potential, morphology, encapsulation efficacy, and drug release in Simulated Gastric Fluid (SGF) and Simulated Intestine Fluid (SIF). Then, Wistar rats were pretreated with the drug (100 mg/kg) and nano-drug (25, 50, 75, 100 mg/kg) for 14 days. Then, on the fourteenth day, stroke induction was accomplished by Bilateral Common Carotid Artery Occlusion (BCCAO); after that, Tumor Necrosis Factor - Alpha (TNF-α), Interleukin - 1 Beta (IL-1ß), and Malondialdehyde (MDA) levels were measured in the supernatant of the whole brain, then the anti-inflammatory effect of BBR formulations was examined.

RESULT AND DISCUSSION

Micelles were successfully formed with appropriate characteristics and smaller sizes than 20 nm. The Poly Dispersity Index (PDI), zeta potential, encapsulation efficacy of micelles was 0.227, - 22 mV, 81%, respectively. Also, the stability of nano micelles was higher in SGF as compared to SIF. Our outcomes of TNF-a, IL-1B, and MDA evaluation show a significant ameliorating effect of the Berberine (BBR) and BBR-loaded micelles in pretreated groups.

CONCLUSION

Our experimental data show that pretreated groups in different doses (nano BBR 100, 75, 50 mg/kg, and BBR 100 mg/kg) successfully showed decreased levels of the inflammatory factors in cerebral ischemia compared with the stroke group and pretreated group with nano BBR in the dose of 25 mg/kg. Nano BBR formulation with a lower dose can be a better candidate than conventional BBR formulation to reduce oxidative and inflammatory factors in cerebral ischemia. Therefore, BBR-loaded micelle formulation could be a promising protective agent on cerebral ischemia.

Golgi Apparatus-Targeted Chondroitin-Modified Nanomicelles Suppress Hepatic Stellate Cell Activation for the Management of Liver Fibrosis

Liver fibrosis is a serious liver disease associated with high morbidity and mortality. The activation of hepatic stellate cells (HSCs) and the overproduction of extracellular matrix proteins are key features during disease progression. In this work, chondroitin sulfate nanomicelles (CSmicelles) were developed as a delivery system targeting HSCs for the treatment of liver fibrosis. CS-deoxycholic acid conjugates (CS-DOCA) were synthesized via amide bond formation. Next, retinoic acid (RA) and doxorubicin (DOX) were encapsulated into CSmicells to afford a DOX+RA-CSmicelles codelivery system. CSmicelles were selectively taken up in activated HSCs and hepatoma (HepG2) cells other than in normal hepatocytes (LO2), the internalization of which was proven to be mediated by CD44 receptors. Interestingly, DOX+RA-CSmicelles preferentially accumulated in the Golgi apparatus, destroyed the Golgi structure, and ultimately downregulated collagen I production. Following tail-vein injection, DOX+RA-CSmicelles were delivered to the cirrhotic liver and showed synergistic antifibrosis effects in the CCl₄-induced fibrotic rat model. Further, immunofluorescence staining of dissected liver tissues revealed CD44-specific delivery of CS derivatives to activated HSCs. Together, our results demonstrate the great potential of CS based carrier systems for the targeted treatment of chronic liver diseases.

PEGylated Solanesol for Oral Delivery of Coenzyme Q10

Coenzyme Q₁₀ (CoQ₁₀) is widely used in preventive or curative treatment of cardiovascular diseases. However, CoQ₁₀ exhibits an extremely low solubility in aqueous medium as well as a poor oral bioavailability. Therefore, solanesyl poly(ethylene glycol) succinate (SPGS) and CoQ₁₀ were formulated as CoQ₁₀-SPGS micelles with a high content of CoQ₁₀ to improve the bioavailability of CoQ₁₀ in rat. Findings indicate that, in the CoQ₁₀-SPGS micelles, SPGS is self-assembled into stable nanosized micelles with a CoQ₁₀ loading capacity of more than 39%. The CoQ₁₀-SPGS micelles exhibit an enhanced photostability upon exposure to simulated sunlight. In vivo experiments demonstrate that, as compared to that of the coarse suspensions of CoQ₁₀, there was three-fold enhancement of oral bioavailability for CoQ₁₀-loaded SPGS micelles depending on varying molecular weight of SPGS. In the encapsulation of CoQ₁₀ by SPGS micelles, the self-assembled nanocarriers with strong muco-adhesive properties lead to increases in the solubility and oral absorption of lipophilic CoQ₁₀ nanoparticles.