Hexagonal liquid crystalline system containing Cinnamaldehyde for enhancement of skin permeation of Sinomenine hydrochloride

A liquid crystal in situ gel based on rotigotine for the treatment of Parkinson's disease

One of the most common neurodegenerative illnesses is Parkinson's disease (PD). Rotigotine (RTG) is a dopamine agonist that exerts anti-Parkinsonian effects through dopamine receptor agonism to improve motor symptoms and overall performance in PD patients. In this study, an in situ liquid crystal gel called rotigotine-gel (RTG-gel) was developed using soya phosphatidyl choline (SPC) and glycerol dioleate (GDO) to provide long-acting slow-release benefits of rotigotine while minimizing side effects. This study prepared the RTG-gel precursor solution using SPC, GDO, and ethanol (in the ratio of 54:36:10, w/w/w). The internal structures of the gel were confirmed by crossed-polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), and differential scanning calorimetry (DSC). The rheological properties of the RTG-gel precursor solution indicate a favorable combination of low viscosity and excellent flowability. The gel that produced during water absorption was also highly viscous and structurally stable, which helped to maintain the drug delayed release at the injection site. In vitro release assays showed that the in vitro release of RTG-gel followed Ritger-Peppas. The RTG-gel precursor solution was administered by subcutaneous injection, and the results of in vivo pharmacokinetic tests in SD rats showed that the plasma elimination half-life (t1/2) was 59.28 ± 16.08 h; the time to peak blood concentration (Tmax) was 12.00 ± 10.32 h, and the peak concentration (Cmax) was 29.9 ± 10.10 ng/mL. The blood concentration remained above 0.1 ng/mL for 20 days after administration and was still detectable after 31 days of administration, and the bioavailability of RTG can reach 72.59%. The results of in vitro solvent exchange tests showed that the RTG-gel precursor solution undergoes rapid exchange upon contact with PBS, and the diffusion of ethanol can reach 48.1% within 60 min and 80% within 8 h. The results of cytotoxicity test showed 89.27 ± 4.32% cell survival after administration of the drug using RTG-gel. The results of tissue extraction at the administration site showed that healing of the injection site without redness and hemorrhage could be observed after 14 days of injection. The results of tissue section of the administered site showed that the inflammatory cells decreased and granulation tissue appeared after 14 days of administration, and there was basically no inflammatory cell infiltration after 35 days of administration, and the inflammatory reaction was basically eliminated. It shows that RTG-gel has some irritation to the injection site, but it can be recovered by itself in the later stage, and it has good biocompatibility. In summary, RTG-gel might be a potential RTG extended-release formulation for treating PD.

A Compound Essential Oil Alters Stratum Corneum Structure, Potentially Promoting the Transdermal Permeation of Hydrophobic and Hydrophilic Ingredients

BACKGROUND

The stratum corneum (SC) is the main barrier of the skin, and cosmeceuticals are different from ordinary cosmetics in that they need to deliver active ingredients targeting specific skin problems through the SC into the deeper layers of the skin. Thus, we designed a compound essential oil (CEO) extracted from Salvia miltiorrhiza Bge and Cinnamomum cassia Presl, supplemented with borneol to deliver active ingredients through the SC.

METHODS

The CEO was prepared by flash extraction combined with the microwave method. Moreover, the main components of the CEO were determined using gas chromatography-mass spectrometry (GCMS). Visualization techniques, such as scanning electron microscopy (SEM), haematoxylin-eosin (HE) staining, and confocal laser scanning microscopy (CLSM), were used to study the permeationpromoting mechanism of the CEO on the skin. Furthermore, the permeation-promoting effects of the CEO on both hydrophobic and hydrophilic ingredients were tested via in vitro skin penetration experiments and in vivo microdialysis experiments.

RESULTS

The results indicated the ability of the CEO to alter the structure of the SC, leading to enhanced transdermal permeation of hydrophobic and hydrophilic ingredients. The 1.5% CEO group demonstrated the best permeation-promoting effect compared to the other CEO groups and blank groups (P<0.05). Furthermore, the CEO displayed an expedited permeability-promoting effect on hydrophobic ingredients compared to hydrophilic ingredients.

CONCLUSION

It is concluded that the prepared CEO can promote the transdermal permeation of hydrophobic and hydrophilic ingredients. This study will provide a reference for the application of the prepared CEO in the development of cosmeceuticals with natural efficacy.