Development, validation and application of a gas chromatography method for the determination of dillapiole from Piper aduncum essential oil in skin permeation samples.

The essential oil extracted from the leaves of Piper aduncum has antifungal, insecticidal and antibacterial activity. Studies with its main compound, dillapiole (DIL) revealed antibacterial and anti-inflammatory potential. Despite all this bioactivity, there is no updated report on the development and validation of analytical and bioanalytical methodology to quantify DIL in skin samples. A selective, precise, accurate and adequate method for the determination of DIL in solutions, porcine ear skin samples and receptor fluid was developed and validated by headspace extraction-gas chromatography with flame ionization detection (HS-GC-FID). HS-GC-FID was applied to determine DIL in Franz cell permeation and retention studies using porcine ear skin samples. In the HS-GC-FID method, matrix-related interferences were not observed at the peak of the DIL retention time. The results showed a high recovery (>97%) after the extraction procedure, allowing the quantification of DIL in complex matrices. In vitro permeation/retention for DIL showed cumulative amounts permeated in the order: receptor fluid (21.98 ± 1.19 µg/cm2 ) > epidermis (15.40 ± 1.20 µg/cm2 ) > dermis (9.52 ± 1.13 µg/cm2 ). HS-GC-FID was successfully validated and the results point to DIL transdermal permeation and to the potential to develop pharmaceutical formulations for skin delivery to treat inflammation or infections.

Piper aduncum Essential Oil Rich in Dillapiole: Development of Hydrogel-Thickened Nanoemulsion and Nanostructured Lipid Carrier Intended for Skin Delivery.

The essential oil extracted from the leaves of Piper aduncum, an aromatic plant from the Amazon region, is rich in dillapiole and presents anti-inflammatory activity. In this study, nanoemulsions (NE) and nanostructured lipid carriers (NLC), which are biocompatible nanostructured systems of a lipid nature, were prepared by high-pressure homogenization for the yet unexplored skin delivery of dillapiole. The addition of hydroxyethylcellulose produced hydrogel-thickened NE or NLC in view to improving the viscosity and skin adherence of the nanoformulations. Formulations were characterized with respect to dillapiole content, droplet size, polydispersity index, zeta potential, morphology, rheological behavior, bioadhesion, skin permeation profile, and in vitro irritancy (HET-CAM). The formulations developed presented spherical, homogeneous nanometric particle size (around 130 nm), narrow polydispersity index (<0.3), and negative zeta potential (around −40 mV). Dillapiole content was slightly lower in NLC compared to NE since the production process involves heating. The hydrogels containing nanocarriers showed pseudoplastic behavior with bioadhesive characteristics. The developed formulations exhibited a controlled release profile, dillapiole delivery up to the dermis, the layer of interest for anti-inflammatory potential, and low irritant potential in the chorioallantoic membrane (HET-CAM). Both hydrogels-thickened NE and NLC seemed to be promising formulations for skin delivery of Piper aduncum essential oil.

Correlation between the Skin Permeation Profile of the Synthetic Sesquiterpene Compounds, Beta-Caryophyllene and Caryophyllene Oxide, and the Antiedematogenic Activity by Topical Application of Nanoemulgels.

Sesquiterpene compounds are applied as permeation promoters in topical formulations. However, studies exploring their impact on nanostructured systems, changes in permeation profile, and consequently, its biological activity are restricted. This study aimed to investigate the correlation between the skin permeation of the major sesquiterpenes, beta-caryophyllene, and caryophyllene oxide from the oleoresin of Copaifera multijuga, after delivery into topical nanoemulgels, and the in vivo antiedematogenic activity. First, ten nanoemulgels were prepared and characterized, and their in vitro permeation profile and in vivo anti-inflammatory activity were evaluated. In equivalent concentrations, ß-caryophyllene permeation was greater from oleoresin nanoemulgels, resulting in greater in vivo antiedematogenic activity. However, an inverse relationship was observed for caryophyllene oxide, which showed its favored permeation and better in vivo anti-inflammatory effect carried as an isolated compound in the nanoemulgels. These results suggest that the presence of similar compounds may interfere with the permeation profile when comparing the profiles of the compounds alone or when presented in oleoresin. Furthermore, the correlation results between the permeation profile and in vivo antiedematogenic activity corroborate the establishment of beta-caryophyllene as an essential compound for this pharmacological activity of C. multijuga oleoresin.

Achyrocline satureioides (Lam.) DC (Asteraceae) Extract-Loaded Nanoemulsions as a Promising Topical Wound Healing Delivery System: In Vitro Assessments in Human Keratinocytes (HaCaT) and HET-CAM Irritant Potential.

Achyrocline satureioides (Lam.) DC Asteraceae extracts (ASEs) have been investigated for the treatment of various skin disorders. This study reports the effects of ASE-loaded nanoemulsions (NEASE) on the cellular viability, death by necrosis, and migration of immortalized human keratinocytes (HaCaT cell line), as well as the irritant potential through the hen's egg chorioallantoic membrane test (HET-CAM). NEASE exhibited a polydispersity index above 0.12, with a droplet size of 300 nm, ζ-potential of -40 mV, and content of flavonoids close to 1 mg/mL. No cytotoxicity of the ASE was observed on HaCaT by MTT assay (up to 10 µg/mL). A significant increase of HaCaT viability was observed to NEASE (up to 5 µg/mL of flavonoids), compared to treatment with the ASE. The necrosis death evaluation demonstrated that only NEASE did not lead to cell death at all the tested concentrations. The scratch assay demonstrated that NEASE was able to increase the cell migration at low flavonoid concentrations. Finally, the HET-CAM test proved the non-irritative potential of NEASE. Overall, the results indicate the potential of the proposed formulations for topical use in wound healing, in view of their promising effects on proliferation and migration in keratinocytes, combined with an indication of the absence of cytotoxicity and non-irritating potential.

3-O-Methylquercetin from Achyrocline satureioides-cytotoxic activity against A375-derived human melanoma cell lines and its incorporation into cyclodextrins-hydrogels for topical administration.

3-O-Methylquercetin (3OMQ), a natural 3-O-methylflavonoid, was isolated from Achyrocline satureioides and purified using the high-performance counter current chromatography (HPCCC) on a semi-preparative scale. High-purity 3OMQ (98%) was obtained with excellent recovery (81.8% (w/w)) and good yield (190 mg/100 g of plant). Isolated 3OMQ was evaluated against the A375 human amelanotic melanoma cancer cell line and A375-derived with different degrees of aggressiveness (A375-A7, A375-G10, and A375-PCDNA3). The results showed that 3OMQ reduced the cell viability of all strains, demonstrating time- and dose-dependent responses. 3OMQ was used to obtain hydrogels for the topical treatment of melanoma. Thus, 3OMQ was incorporated into hypromellose hydrogels with/without different cyclodextrins (CDs). The 3OMQ formulations showed permeation/retention in all skin layers, namely stratum corneum, epidermis, and dermis. A significant amount of 3OMQ was found in the replication site of the melanoma cells (epidermis and dermis). Altogether, these results demonstrate that 3OMQ can be isolated from Achyrocline satureioides by HPCCC on a semi-preparative scale and exhibit cytotoxic activity against melanoma cells. Its incorporation into an HPMC hydrogel containing HP-ß-CD yielded a formulation with excellent technological and biopharmaceutical characteristics for evaluating the topical management of melanoma.

Recent Patents on Permeation Enhancers for Drug Delivery Through Nails.

The human nail is a unique barrier with a keratinized constitution that favors protection and fine touch. However, many disorders can affect the nail, among them, are the onychomycosis and psoriasis. Systemic oral therapy has been applied to treat these diseases, even presenting disadvantages, including side effects, drug interactions, contraindications, toxicity, high cost and low patient compliance. A great option to succeed in dealing with the problems associated with oral therapy is the topical administration of drugs. However, nail composition, low diffusion through ungual route and reduced tissue bioavailability for topical treatments are limiting factors. These drawbacks can be overcome by promoting penetration through the nails by employing penetration enhancers. The review focuses on patents that highlight permeation enhancers applied to nail drug delivery for the treatment of onychomycosis and psoriasis. Literature and patent searches were conduced regarding the topic of interest. The substantial literature and patent search revealed that permeation enhancers, especially chemicals, are great strategies for promoting the ungual delivery of drugs. Nail topical therapy containing permeation enhancers is an attractive option for delivering localized treatments.

Optimization, validation and application of headspace solid-phase microextraction gas chromatography for the determination of 1-nitro-2-phenylethane and methyleugenol from Aniba canelilla (H.B.K.) Mez essential oil in skin permeation samples.

Aniba canelilla (H.B.K.) Mez is an aromatic plant from the Amazon region whose essential oil has 1-nitro-2-phenylethane (NP) and methyleugenol (ME) as major compounds. Despite of the scientifically proven antifungal and anti-inflammatory activities for these compounds, there is no report up to date about the topical permeation or quantification of NP and ME on skin samples. The aim of this study was the validation of an optimized bioanalytical method by solid-phase microextraction in headspace mode in gas chromatograph with flame ionization detector (HS-SPME-GC-FID) for the determination of NP and ME from the oil in different samples from permeation study, such as porcine ear skin (PES) layers (stratum corneum, epidermis and dermis) and receptor fluid (RF). For this propose polydimethylsiloxane fibers (100 µm) were used and HS-SPME extraction condition consisted of 53 °C, 21 min, and 5% w.v-1 NaCl addition. The wide range of the calibration curve (2.08-207.87 µg mL-1 for NP and 0.40-40.41 µg mL-1 for ME), the presence of matrix interferences and the intrinsic characteristics of HS-SPME required a data linearization using Log10. Thereby, data and the gained results presented homoscedasticity, normalization of residues and adequate linearity (r2 > 0.99) and accuracy for both compounds. In order to verify the applicability of the validated method, the HS-SPME-GC-FID procedure was performed to determine the amount of NP and ME permeated and retained in samples after Franz diffusion cell study from different dosages (20, 100 and 200 µL) of A. canelilla oil. Compounds permeation showed a progressive increase and penetration dependence based on the dosage applied. Furthermore, retention was in order receptor fluid >> dermis >> epidermis >> stratum corneum for both compounds, suggesting NP and ME could penetrate deep tissue, probably due to the partition coefficient, mass, size, and solubility of these compounds. In conclusion, the proposed method by HS-SPME-GC-FID to quantify 1-nitro-2-phenylethane and methyleugenol from Aniba canelilla essential oil was able to determine selectively, precisely and accurately these main compounds in skin permeation samples.

Anti-inflammatory Effect from a Hydrogel Containing Nanoemulsified Copaiba oil (Copaifera multijuga Hayne).

Copaiba oil is used as a popular medicine in the Amazonian forest region, especially due to its anti-inflammatory properties. In this paper, we describe the formulation of hydrogel containing copaiba oil nanoemulsions (with positive and negative charges), its skin permeation, and its anti-inflammatory activity in two in vivo models: mouse ear edema and rat paw edema. Three hydrogels were tested (Carbopol®, hydroxyethylcellulose and chitosan), but only Carbopol® and hydroxyethylcellulose hydrogels presented good stability and did not interfere with the nanoemulsions droplet size and polydispersity index. In skin permeation assay, both formulations, positively charged nanoemulsion (PCN) and negatively charged nanoemulsion (NCN), presented a high retention in epidermis (9.76 ± 2.65 µg/g and 7.91 ± 2.46 µg/cm2, respectively) followed by a smaller retention in the dermis (2.43 ± 0.91 and 1.95 ± 0.56 µg/cm2, respectively). They also presented permeation to the receptor fluid (0.67 ± 0.22 and 1.80 ± 0.85 µg/cm2, respectively). In addition, anti-inflammatory effect was observed to NCN and PCN with edema inhibitions of 69 and 67% in mouse ear edema and 32 and 72% in rat paw edema, respectively. Histological cuts showed the decrease of inflammatory factors, such as dermis and epidermis hyperplasia and inflammatory cells infiltration, confirming the anti-inflammatory effect from both copaiba oil nanoemulsions incorporated in hydrogel.