The Effect of Prescription on the Framework of Lipid Matrix and In Vitro Properties

Transdermal administration of ibuprofen-loaded hexagonal liquid crystal gel for enhancement of drug concentration in the uterus: in vitro and in vivo evaluation

Primary dysmenorrhea is a common disease in women, and oral administration of Ibuprofen (IBU) is associated with first-pass effects and gastrointestinal irritation. Here, we developed ibuprofen-loaded hexagonal liquid crystal (IBU HLC) gel for transdermal administration. In this study, the structure of prepared IBU HLC was characterized using polarizing microscopey (PLM) and small angle X ray diffraction (SAXS). In vitro drug release behavior and percutaneous penetration were investigated, and drug transdermal behavior was observed by confocal laser scanning microscope (CLSM). Finally, the pharmacokinetic profile and tissue distribution were investigated after transdermal administration. The PLM and SAXS results showed that the inner structure of IBU HLC was hexagonal phase. Moreover, in vitro release, skin permeation and CLSM demonstrated that IBU HLC had an excellent sustained-release effect, and a good transdermal penetration effect accompanied by the combination of multiple percutaneous routes. Pharmacokinetic studies indicated that IBU entered the blood circulation through abdominal transdermal administration in small amounts, mainly entering the uterus, and had a certain targeting ability. In conclusion, the IBU HLC gel would be a promising sustained-release preparation for transdermal administration to relieve dysmenorrhea with a significant drug concentration in the uterus.

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

Sinomenine hydrochloride (SH) is usually applied to treat rheumatoid arthritis (RA) with severe side effect due to oral administration. Cinnamaldehyde (CA) as essential oil possesses anti-RA effect and can facilitate transdermal penetration. Hence, this study developed hexagonal liquid crystalline (HII) gels to deliver two components (SH and CA) across the skins. HII gels were prepared and characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS) and rheology. Moreover, in vitro drug release behavior and ex vivo skin permeation were investigated. Finally, Fourier transform infrared spectral analysis (FTIR) and confocal laser scanning microscopy (CLSM) were used to explore the skin penetration mechanism. PLM and SAXS showed that the inner structure of the gels was HII phase. The addition of lipophilic or hydrophilic molecule slowed down one another's release and the release model was dominated by Fickian diffusion (n< 0.43). Furthermore, in vitro permeation studies indicated that appropriate CA could improve the skin permeability of SH. FTIR and CLSM suggested that infiltration occurred due to disruption of the lipid bilayer structure and increased fluidity of the skin. In conclusion, HII gels and CA exhibited a penetration-promoting effect for transdermal applications in SH.

In Situ Liquid Crystal Gel as a Promising Strategy for Improving Ocular Administration of Dexamethasone: Preparation, Characterization, and Evaluation

The purpose of this study was to design an in situ liquid crystal gel (ISLG) as an ophthalmic drug delivery system for dexamethasone (DEX) to enhance its eye retention and ocular bioavailability. The in situ liquid crystal gels (ISLGs) were prepared using a phytantriol/PEG400/water (65:30:5, w/w) ternary system. Polarized light microscope (PLM), small-angle X-ray scattering (SAXS), and rheology analysis confirmed that the internal structure of the preparations was Pn3m cubic phase liquid crystal gels with pseudoplastic fluid properties. Meanwhile, in vitro release behavior of the preparations conforms to the Higuchi equation. Corneal penetration experiments showed that compared with DEX sodium phosphate eye drops, DEX-ISLGs(F2) produced a 5.45-fold increase in the P_app value, indicating a significant enhancement of corneal penetration. In addition, in vivo experiments have confirmed that the ISLGs have better biocompatibility and longer retention time in the cornea. Simultaneously, corneal hydration level, eye irritation experiments, and histological observations proved the safety of the preparations. Pharmacokinetic studies have shown that the ISLG could maintain the DEX concentration in aqueous humor for at least 12 h after administration, which significantly improves the bioavailability of the drug. Collectively, these results indicated that ISLG would be a potential drug carrier for the treatment of diabetic retinopathy (DR).

The Evaluations of Menthol and Propylene Glycol on the Transdermal Delivery System of Dual Drug-Loaded Lyotropic Liquid Crystalline Gels

This study aimed to evaluate the effects of two different structural alcohol permeation enhancers (menthol and propylene glycol) on the internal structure and in vitro properties of the dual drug-loaded lyotropic liquid crystalline (LLC) gels. The LLC gels were prepared and characterized by polarized light microscopy, small-angle X-ray scattering, differential scanning calorimetry, attenuated total reflectance-Fourier transform infrared spectrum, and rheology. Based on the results, the inner structure of the gels was Q_II mesophase and exhibited a pseudoplastic fluid behavior. The level of internal order in the LLC mesophase would be affected by introduced 2 wt% menthol (MEN) and propylene glycol (PG). The in vitro release experiment showed that the release behavior of sinomenine hydrochloride (SH) and cinnamaldehyde (CA) from the LLC system was dominated by Fickian diffusion (n < 0.43). MEN and PG had the opposite effects on the release of hydrophilic SH, while the MEN and PG both increased the release of lipophilic drug CA. Furthermore, in vitro permeation studies indicated that MEN and PG could both improve the skin permeability of SH and CA, and MEN displayed more pronounced enhancement. All the samples showed no skin irritation on the normal rat skin. Collectively, in our research, monoterpenoid MEN exhibited a better penetration-promoting effect than straight-chain fatty alcohol PG on the dual drug-loaded LLC system.