Percutaneous penetration of felbinac after application of transdermal patches: relationship with pharmacological effects in rats

Skin absorption of felbinac solid nanoparticles in gel formulation containing l-menthol and carboxypolymethylene

BACKGROUND

It is important to design an effective formulation to enhance the skin penetration, and nanotechnologies have been used in dermal and transdermal drug delivery. In this study, we prepared formulations (gels) containing l-menthol and felbinac (FEL) solid nanoparticles (FEL-NP gel) for topical application, and investigated the local and systemic absorption of the prepared FEL-NP gel.

METHODS

FEL solid nanoparticles were obtained by bead milling of FEL powder (microparticles), and a topical formulation (FEL-NP gel) consisting of 1.5% FEL solid nanoparticles), 2% carboxypolymethylene, 2% l-menthol, 0.5% methylcellulose, and 5% 2-hydroxypropyl-β-cyclodextrin (w/w %) were prepared.

RESULTS

The particle size of FEL nanoparticles was 20-200 nm. The released FEL concentration from FEL-NP gel was significantly higher than that from FEL gel without bead mill treatment (carboxypolymethylene gel in which FEL microparticles (MPs) instead of FEL nanoparticles were incorporated, FEL-MP gel), and FEL was released as nanoparticles from the gel. Moreover, both transdermal penetration and percutaneous absorption of FEL-NP gel were significantly increased compared with those of FEL-MP gel, and the area under the FEL concentration-time curve (AUC) of FEL-NP gels was 1.52- and 1.38-fold of commercially available FEL ointment and FEL-MP gel, respectively. In addition, after 24 h of treatment, the FEL content in rat skin treated with FEL-NP gels was 1.38- and 2.54-fold higher than that when treated with commercially available FEL ointment and FEL-MP gel, respectively. Moreover, the enhanced skin penetration of FEL-NP gels was significantly attenuated by inhibition of energy-dependent endocytosis, such as clathrin-mediated endocytosis.

CONCLUSIONS

We successfully prepared a topically applied carboxypolymethylene gel containing FEL nanoparticles. In addition, we observed that the endocytosis pathway was mainly related to the high skin penetration of FEL nanoparticles, and FEL-NP gel application resulted in high local tissue concentration and systemic absorption of FEL. These findings provide useful information for the design of topically applied nanoformulations against inflammation by providing local and systemic effects.

Evaluation of the Percutaneous Absorption of Drug Molecules in Zebrafish

In recent decades, zebrafish (Danio rerio) has become a widely used vertebrate animal model for studying development and human diseases. However, studies on skin medication using zebrafish are rare. Here, we developed a novel protocol for percutaneous absorption of molecules via the zebrafish tail skin, by applying a liquid solution directly, or using a filter paper imbibed with a chemical solution (coating). Human skin is capable of absorbing felbinac and loxoprofen sodium hydrate (LSH), but not glycyrrhetinic acid (GA) and terbinafine hydrochloride (TH). To evaluate the possibility and the quality of transdermal absorption in zebrafish, we transdermally administered these four drugs to zebrafish. Pharmacokinetics showed that felbinac was present in the blood of zebrafish subjected to all administration methods. Felbinac blood concentrations peaked at 2 h and disappeared 7 h after administration. GA was not detected following transdermal administrations, but was following exposure. LSH was not found in the circulatory system after transdermal administration, but TH was. A dose-response correlation was observed for felbinac blood concentration. These findings suggest that zebrafish are capable of absorbing drug molecules through their skin. However, the present data cannot demonstrate that zebrafish is a practical model to predict human skin absorption. Further systemic studies are needed to observe the correlations in percutaneous absorption between humans and zebrafish.

Pharmacokinetics, Safety, and Tolerability of Intravenous Felbinac Trometamol in Healthy Chinese Volunteers: A First-in-Human Single- and Multiple-Dose Escalation Phase I Study with a Randomized, Double-Blind, Placebo-Controlled Design

BACKGROUND

Felbinac trometamol, an anti-inflammatory and analgesic drug, has been used to treat immediate postoperative pain.

OBJECTIVE

The aim of this study was to evaluate the safety, tolerability, and pharmacokinetics of single or multiple intravenous infusions of felbinac trometamol in healthy Chinese volunteers.

METHODS

A total of 56 healthy subjects were enrolled in a single-ascending dose study (11.78-377.00 mg), meanwhile 36 subjects were enrolled in a multiple-ascending dose study (47.13-188.50 mg). Safety endpoints included treatment-emergent adverse events, vital signs, electrocardiograms, and laboratory parameters. Pharmacokinetic endpoints included exposure of subjects to felblinac and metabolites of the drug in plasma, urine, and feces.

RESULTS

Felblinac time to maximum plasma concentration was obtained at 0.5 h, corresponding to the end of the infusion. Maximum plasma concentration and area under the curve increased in a dose-dependent manner for felblinac and its metabolite, showing linear pharmacokinetic characteristics at single and multiple doses. After intravenous infusions of multiple doses three times (30 min each time) per day, the accumulation ratio of felblinac and its metabolite based on the area under the curve had a range of 1.34-1.45 and 1.60-1.87, respectively, across cohorts. After administration of the fourth dose, the plasma concentration of both felblinac and its metabolites was maintained at a steady state. Felbinac trometamol was well tolerated. Neither treatment-emergent adverse event frequency nor severity increased with increasing felbinac trometamol dose.

CONCLUSIONS

Felbinac trometamol was well tolerated in our study. Based on the dose range in this study, 94.25 mg is the recommended target dose for a phase II study.

CLINICAL TRIAL REGISTRATION

CTR20170496 and CTR20180896. The dates of registration are 2017-06-19 and 2018-07-02 ( https://www.chinadrugtrials.org.cn/ ).

Design and Evaluation of a Novel Felbinac Transdermal Patch: Combining Ion-Pair and Chemical Enhancer Strategy

The aim of this study was to design a novel felbinac (FEL) patch with significantly higher (P < 0.05) skin permeation amount than the commercial product SELTOUCH® using ion-pair and chemical enhancer strategy, overcoming the disadvantage of the large application area of SELTOUCH®. Six complexes of FEL with organic amines diethylamine (DEA), triethylamine (TEA), N-(2'-hydroxy-ethanol)-piperdine (HEPP), monoethanolamine (MEtA), diethanolamine (DEtA), and triethanolamine (TEtA) were prepared by ion-pair interaction, and their formation were confirmed by differential scanning calorimetry (DSC), powder X-ray diffraction (pXRD), infared spectroscopy (IR), and proton nuclear magnetic resonance spectroscopy ((1)H-NMR). Subsequently, the effect of ion-pair complexes and chemical enhancers were investigated through in vitro and in vivo experiments using rabbit abdominal skin. Results showed that FEL-TEA was the most potential candidate both in isopropyl palmitate (IPP) solution and transdermal patches. Combining use of 10% N-dodecylazepan-2-one (Azone), the optimized FEL-TEA patch achieved a flux of 18.29 ± 2.59 μg/cm(2)/h, which was twice the amount of the product SELTOUCH® (J = 9.18 ± 1.26 μg/cm(2)/h). Similarly, the area under the concentration curve from time 0 to time t (AUC0-t ) in FEL-TEA patch group (15.94 ± 3.58 h.μg/mL) was also twice as that in SELTOUCH® group (7.31 ± 1.16 h.μg/mL). Furthermore, the in vitro skin permeation results of FEL-TEA patch was found to have a good correlation with the in vivo absorption results in rabbit. These findings indicated that a combination of ion-pair and chemical enhancer strategy could be useful in developing a novel transdermal patch of FEL.

[Development of Selective LC Analysis Method for Biogenic and Related Compounds Based on a Fluorous Affinity Technique]

A separation-oriented derivatization method combined with LC has been developed for the selective analysis of biogenic and related compounds. In this method, we utilized a specific affinity between perfluoroalkyl-containing compounds, i.e., 'fluorous' compounds (fluorophilicity). Our strategy involves the derivatization of target analytes with perfluoroalkyl reagents, followed by selective retention of the derivatives with a perfluoroalkyl-modified stationary phase LC column. The perfluoroalkylated derivatives are strongly retained on the column owing to their fluorophilicity, whereas non-derivatized species, such as sample matrices, are hardly retained. Therefore, utilizing this derivatization method, target analytes can be determined selectively without interference from matrices. This method has been successfully applied to the LC analysis of some biogenic and related compounds in complex biological samples.

Dermal microdialysis technique to evaluate the trafficking of surface-modified lipid nanoparticles upon topical application

PURPOSE

To evaluate the skin pharmacokinetics and tissue distribution of cell penetrating peptides (CPP) modified nano-structured lipid carrier (NLC) using an in vivo dermal microdialysis (MD) technique.

METHODS

Celecoxib (Cxb) encapsulated NLCs (CXBN), CPP modified CXBN (CXBN-CPP) and Cxb-Solution (CXBS) formulations were prepared and tested for in vitro skin distribution. MD was used to assess pharmacokinetic parameters of Cxb after topical application of Cxb formulations. The effect of pre-treatment with Cxb formulations was evaluated for expression of prostaglandin-E2 (PGE(2)) and Interleukin-6 (IL-6) after exposure of xylene using MD. Allergic contact dermatitis (ACD) model was used to confirm in vivo therapeutic response of Cxb formulations.

RESULTS

The cumulative permeation of Cxb in MD dialysate after 24 h for CXBN-CPP was significantly higher (p < 0.001) than CXBN and CXBS. Further, pre-treatment with CXBN-CPP significantly inhibited PGE(2) and IL-6 expression compared to CXBS and CXBN (p < 0.001). In ACD model, CXBN-CPP showed significant reduction (p < 0.001) in ear thickness compared to controls.

CONCLUSIONS

Surface modification of NLC with CPPs can enhance the skin permeation of Cxb and MD can be used to investigate pharmacokinetics of Cxb nanoparticles in the skin.