Investigation of ß-caryophyllene as terpene penetration enhancer: Role of stratum corneum retention.

Terpenes are usually used as penetration enhancers (PE) for transdermal drug delivery (TDD) of various molecules. However, TDD of hydrophilic macromolecules is becoming an urgent challenge due to their potent activities. The aim of this study was to investigate the potential application of ß-caryophyllene (ß-CP), a sequiterpene, as PE for TDD of hydrophilic macromolecules for the first time. Commonly used PEs, namely azone and 1,8-cineole (1,8-CN), were applied as controls. Transepidermal water loss (TEWL) analysis revealed that the reduction of skin barrier function caused by ß-CP was reversible. Transdermal experiments showed that when skin was treated with ß-CP or azone, there was a significant permeation-enhancing effect on fluorescein isothiocyanate (FITC) and FITC-dextran with different molecular weight (MW) of 4k or 10k. CLSM analysis confirmed that ß-CP and azone can facilitate the penetration of FD-4k through epidermis and dermis. However, the cytotoxicity of azone against epidermal keratinocytes was significantly higher than ß-CP and 1,8-CN. Additionally, application of ß-CP and 1,8-CN didn't increase erythema index (EI) but the EI values of azone group increased significantly and irreversibly, indicating the high biocompatibility of the natural terpenes. ß-CP had better permeation-enhancing effect and higher stratum corneum (SC) retention than 1,8-CN due to its increased carbon chain length and lipophilicity, as further demonstrated by molecular dynamics (MD) simulation studies. Skin electrical resistance (SER) and attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) studies revealed a significant interfering effect of ß-CP on SC lipids. Taken together, ß-CP exhibited significant penetration enhancement of hydrophilic macromolecules due to its SC retention and SC lipid fluidization ability.

[Research model integrating "both medicinal and adjuvant properties" for essential oils from Chinese medicinal: based on characterization of medicinal properties].

Essential oils(EOs) from Chinese medicinals, which can be used as adjuvants and exert certain therapeutic effect, are directly used in Chinese medicine formulas. Conventional research strategy for EOs from Chinese medicinals is to compare the efficacy of the prescriptions before and after the addition of EOs, and the penetration-enhancing mechanisms of EOs remain unclear. In modern research on EOs from Chinese medicinals, the method for studying chemical penetration enhancers is often used, which fails to reflect the overall efficacy of EOs. This study clarified the property regularity of EOs from Chinese medicinals as transdermal penetration enhancers, and thereby proposed a research model which integrated the medicinal and adjuvant properties of EOs from Chinese medicinals via "component-delivery-effect" characterization route. The core concept is that constituents of EOs from Chinese medicinals and their delivery process play a key role in their external application. This research model is expected to serve as a reference for further research on EOs from Chinese medicinals for transdermal application.

[Comparative study of penetration-enhancing effect in vitro of cinnamon oil and cinnamaldehyde on ibuprofen].

To compare the penetration-enhancing effect of cinnamon oil and its main components (cinnamaldehyde) on ibuprofen and their self-percutaneous absorption behavior in vitro. Firstly, cinnamon oil was extracted by steam distillation, then the compositions were analyzed by gas chromatography mass spectrometry (GC-MS) and the cinnamaldehyde content in cinnamon oil was determined by high performance liquid chromatography (HPLC). With azone as positive control, ibuprofen as model drug, cinnamon oil and cinnamaldehyde as penetration enhancers (PE) were prepared and administered to the SD rat's abdominal skin. The penetration-enhancing effects of cinnamon oil and cinnamaldehyde and their own transdermal absorption properties were compared. The results showed that yield of cinnamon oil was (3.55±0.36)% (n=3), and the cinnamaldehyde content in cinnamon oil was (73.48±0.21)% (n=3). As compared with blank group, the enhancing rate (ER) of cinnamon oil, cinnamaldehyde, and azone was 3.56, 1.13, 2.47 respectively. The cumulative penetration rate of cinnamaldehyde in cinnamon oil and cinnamaldehyde monomer in 24 h was (63.30±0.98)%, (51.03±3.34)% (n=4) respectively. The penetration-enhancing effect of cinnamon oil was significantly better than that of cinnamaldehyde, indicating the existence of muti-component synergy. The penetration rate of cinnamaldehyde in cinnamon oil was higher than that of cinnamaldehyde monomer, suggesting that a "pull effect" may be present.

Cytotoxicity and penetration enhancement activity of essential oils from warming the interior medicinals with hot or warm property in terms of Traditional Chinese Medicine.

OBJECTIVE: To investigate on the cytotoxicity and penetration enhancement effect of essential oils (EOs) from warming the interior medicinals (WIM) from Traditional Chinese Medicine (TCM). METHODS: EOs were extracted from WIM of Bichengqie (Litseae Fructus), Dingxiang (Flos Syzygii Aromatici), Huajiao (Pericarpium Zanthoxyli Bungeani), and Xiaohuixiang (Fructus Foeniculi) with warm nature, and Ganjiang (Rhizoma Zingiberis), Gaoliangjiang (Rhizoma Alpiniae Officinari), Rougui (Cortex Cinnamomi Cassiae), and Wuzhuyu (Fructus Evodiae Rutaecarpae) with hot nature, respectively. Their chemical compositions were analyzed by gas chromatography-mass spectrometry (GC-MS). The cytotoxicity of the extracted eight EOs on HaCaT cells was measured and compared. Moreover, analyses of cell cycle and cell apoptosis were performed to investigate the cytotoxic mechanism. The transdermal penetration enhancement effects of the extracted eight EOs on ibuprofen were further compared by the modified Franz diffusion cell method. RESULTS: The most abundant constituents in the extracted eight EOs were determined to be monoterpenes, especially oxygen-containing monoterpenes. The HaCaT cell cytotoxicity of EOs from WIM with hot nature were significantly (P = 0.020) higher than that with warm nature. Both ginger oil and zanthoxylum oil significantly induced G0/G1 phase arrestment in HaCaT cell cycle. For ginger oil from WIM with hot nature and zanthoxylum oil from WIM with warm nature, the main mechanisms of the cytotoxicity were found to be the induction of cellular necrosis and the cellular apoptosis, respectively. Furthermore, most of the tested EOs showed remarkable penetration enhancement activity on ibuprofen. However, no statistical significance (P = 0.18) was found between penetration enhancement activity of EOs from WIM with warm nature and EOs from WIM with hot nature. CONCLUSION: With the enhanced penetration activity, the extracted EOs from the WIM demonstrated their significant effect of the cytotoxicity on the skin cells.

Development of phospholipid vesicle-based permeation assay models capable of evaluating percutaneous penetration enhancing effect.

OBJECTIVES: The phospholipid vesicle-based permeation assay (PVPA) model has recently been introduced as an in vitro model which can mimic stratum corneum (SC) barriers to estimate the skin permeability of drugs. The aim of this study was to evaluate whether the PVPA model was suitable for the evaluation of penetration enhancing effect of skin penetration enhancers (PE). METHODS: The PVPA model was optimized by changing the lipid composition of both small liposomes (SL), and large liposomes (LL). The barrier properties of the PVPA model were monitored by electrical resistance and permeability measurement of the fluorescent marker Rhodamine B (RB). Then the permeation studies of the five active compounds with different physicochemical properties, namely, ferulic acid, paeoniflorin, albiflorin, tetrahydrocolumbamine, and tetrahydropalmatine, were performed directly on PVPA model to evaluate the penetration enhancing effect of menthol. RESULTS AND DISCUSSIONS: The enhancement ratio (ER) ranking of the five active compounds observed using the optimized PVPA model was in accordance with what observed with Franz diffusion cell device using porcine ear skin. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) analysis of PVPA model and porcine ear skin after treatment with menthol has shown similar mechanism of menthol which perturbs the SC lipid arrangement and extracts the SC lipids. CONCLUSIONS: In summary, the optimized PVPA model was used for the first time for the evaluation of the permeation enhancing effect. The optimized PVPA model has shown potential to be applied in a more standardized, cheaper, and ethical way for the screening of PE.

Development of essential oils as skin permeation enhancers: penetration enhancement effect and mechanism of action.

CONTEXT: Essential oils (EOs) have shown the potential to reversibly overcome the stratum corneum (SC) barrier to enhance the skin permeation of drugs. OBJECTIVE: The effectiveness of turpentine, Angelica, chuanxiong, Cyperus, cinnamon, and clove oils were investigated for the capacity and mechanism to promote skin penetration of ibuprofen. MATERIALS AND METHODS: Skin permeation studies of ibuprofen across rat abdominal skin with the presence of 3% w/v EOs were carried out; samples were withdrawn from the receptor compartment at 8, 10, 22, 24, 26, 28, 32, 36, and 48 h and analyzed for ibuprofen content by the HPLC method. The mechanisms of penetration enhancement of EOs were further evaluated by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) analysis and determination of the properties of EOs. Moreover, the toxicities of EOs on skin cells were also measured. RESULTS: The enhancement ratio (ER) values of turpentine, Angelica, chuanxiong, Cyperus, cinnamon, clove oils and azone were determined to be 2.23, 1.83, 2.60, 2.49, 2.63 and 1.97, respectively. Revealed by ATR-FTIR analysis, a linear relationship (r = 0.9045) was found between the ER values and the total of the shift of peak position of SC lipids. Furthermore, the results of HaCaT skin cell toxicity evaluation revealed that the natural EOs possessed relatively lower skin irritation potential. CONCLUSION: Compared with azone, the investigated EOs possess significantly higher penetration enhancement effect and lower skin toxicity. EOs can promote the skin permeation of ibuprofen mainly by disturbing rather than extracting the SC lipids.

Delivery of fluorescent-labeled cyclodextrin by liposomes: role of transferrin modification and phosphatidylcholine composition.

Drug-in-CD-in-liposome (DCL) systems which encapsulate the drug/CD inclusion complexes into inner aqueous phase of liposomes have been applied as a novel strategy to improve efficacy of lipophilic antitumor drugs. The aim of this work was to assess the role of transferrin (Tf) modification and phosphatidylcholine (PC) composition on the properties of liposomes containing hydroxypropyl-ß-cyclodextrin (HP-ß-CD). Fluorescence dye, FITC, was conjugated with HP-ß-CD to facilitate the analysis. The resulting FITC-HP-ß-CD was further encapsulated into liposomes and then the liposomes were modified with Tf. The FITC-HP-ß-CD-loaded liposomes with different PC compositions were compared in terms of particle size, zeta potential, FITC content, FITC-HP-ß-CD leakage, phase transition temperature (Tm) and cellular uptake. The apparent partition coefficient values of different PCs were also determined. Compared to PEGylated liposomes, FITC-HP-ß-CD-loaded liposomes modified with Tf had been proved to significantly increase vesicle stability and specific cellular uptake. Moreover, PC composition affected the properties of liposomes. Soybean phosphatidylcholine (SPC) liposomes modified with Tf were found to be more easily internalized into tumor cells than 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and hydrogenated soybean phosphatidylcholine (HSPC) while Tf density on the liposomal surface was similar. And the lipophilicity of SPC was found to be much higher than DPPC and HSPC. Collectively, by the optimization of PC composition, the development of DCL modified with Tf might represent a potential strategy for the antitumor application of lipophilic drugs.

Potential of Essential Oils as Penetration Enhancers for Transdermal Administration of Ibuprofen to Treat Dysmenorrhoea.

The present study was conducted to evaluate and compare five essential oils (EOs) as penetration enhancers (PEs) to improve the transdermal drug delivery (TDD) of ibuprofen to treat dysmenorrhoea. The EOs were prepared using the steam distillation method and their chemical compositions were identified by GC-MS. The corresponding cytotoxicities were evaluated in epidermal keartinocyte HaCaT cell lines by an MTT assay. Furthermore, the percutaneous permeation studies were carried out to compare the permeation enhancement effect of EOs. Then the therapeutic efficacy of ibuprofen with EOs was evaluated using dysmenorrheal model mice. The data supports a decreasing trend of skin cell viability in which Clove oil >Angelica oil > Chuanxiong oil > Cyperus oil > Cinnamon oil >> Azone. Chuanxiong oil and Angelica oil had been proved to possess a significant permeation enhancement for TDD of ibuprofen. More importantly, the pain inhibitory intensity of ibuprofen hydrogel was demonstrated to be greater with Chuanxiong oil when compared to ibuprofen without EOs (p < 0.05). The contents of calcium ion and nitric oxide (NO) were also significantly changed after the addition of Chuanxiong oil (p < 0.05). In summary, we suggest that Chuanxiong oil should be viewed as the best PE for TDD of ibuprofen to treat dysmenorrhea.