A monolithic drug-in-adhesive patch of methoxyflavones from Kaempferia parviflora: In vitro and in vivo evaluation

Design, Development, and Evaluation of Treprostinil Embedded Adhesive Transdermal Patch

Clinical application of treprostinil in pulmonary arterial hypertension is hampered by adverse effects caused by its high dosing frequency. The objective of this investigation was to Formulate an adhesive-type transdermal patch of treprostinil and evaluate it both in vitro and in vivo. A 3²-factorial design was utilized to optimize the selected independent variables (X₁: drug amount, X₂: enhancer concentration) on the response variables (Y₁: drug release, Y₂: transdermal flux). The optimized patch was evaluated for various pharmaceutical properties, skin irritation, and pharmacokinetics in rats. Optimization results signify considerable influence (p < 0.0001) of X₁ on both Y₁ and Y₂, as compared to X₂. The optimized patch possesses higher drug content (>95%), suitable surface morphology, and an absence of drug crystallization. FTIR analysis revealed compatibility of the drug with excipients, whereas DSC thermograms indicate that the drug exists as amorphous in the patch. The adhesive properties of the prepared patch confirm adequate adhesion and painless removal, while the skin irritation study confirms its safety. A steady drug release via Fickian diffusion and greater transdermal delivery (~23.26 µg/cm²/h) substantiate the potential of the optimized patch. Transdermal therapy resulted in higher treprostinil absorption (p < 0.0001) and relative bioavailability (237%) when compared to oral administration. Overall, the results indicate that the developed drug in the adhesive patch can effectively deliver treprostinil through the skin and could be a promising treatment option for pulmonary arterial hypertension.

Fabrication, Optimization, and Characterization of Antibacterial Electrospun Shellac Fibers Loaded with Kaempferia parviflora Extract

This study aimed to develop a Kaempferia parviflora (KP) extract based on electrospun shellac fibers capable of transporting methoxyflavones. This study used a Box-Behnken design to determine the optimal production parameters that influence the fiber diameter and bead-to-fiber ratio responses. The optimization step produced fibers with a small diameter (574 nm) and a lower bead-to-fiber ratio (0.48 beads per fiber) by combining 37.25% w/w shellac and 1.50% w/w KP extract with a solution feed rate of 0.8 mL/h and an electrical voltage of 18 kV. The KP extract was found to be dispersed throughout the electrospun shellac fibers during the characterization study. The results were highly correlated with the theoretical values, indicating that the regression models used to predict the response variables were adequate. A study of in vitro dissolution confirmed that KP extract-loaded electrospun shellac fibers could produce a sustained-release profile within 10 h. Additionally, KP-infused shellac fibers demonstrated antibacterial activity against Staphylococcus aureus. This KP loading method combined with shellac properties provided a new delivery system and could be used to explore novel biomedical materials.

Development and Characterisation of a Topical Methyl Salicylate Patch: Effect of Solvents on Adhesion and Skin Permeation

The advent of skin patch formulation design and technology has enabled the commercialisation of methyl salicylate (MS) as a topical patch. However, the most fundamental aspect of skin permeation is unknown at present. The study aims to investigate the effect of solvent choice on the skin permeation of MS in a neat solvent system and patch formulation with an emphasis on patch adhesion. MS in six selected solvents (propylene glycol (PG), Transcutol^®, isopropyl myristate, Labrasol^®, Plurol^® oleique CC 497 and Maisine^® CC) was characterised and in vitro permeation studies were also performed. An ATR-FTIR analysis on solvent-treated skin was conudcted. Patch formulation was prepared and characterised for adhesion, in vitro drug release and skin permeation studies. The highest MS permeation was found in neat PG over 24 h (~90 μg/cm²) due to its strong skin protein conformation effect. Transcutol^® and isopropyl myristate showed better skin deposition and formulation retention, respectively. Nevertheless, PG enhanced the patch adhesion despite having a lower cumulative amount of MS permeated (~80 μg/cm²) as compared with Transcutol^® and Maisine^® (~110-150 μg/cm²). These two solvents, however, demonstrated better skin deposition and formulation retention but a lower patch adhesion. The unpredictable influence of the solvent on patch adhesion highlights the importance of the trade-off between patch adhesion and skin permeation during formulation design.

Formulation Development and Pharmaceutical Evaluation of Lysiphyllum strychnifolium Topical Patches for Their Anti-inflammatory Potential

Topical drug delivery systems are interesting and popular dosage forms for formulation development. Thai herbs are used in alternative medicine to treat patients suffering from severe illnesses. They have significant economic and cultural value in Thailand. This work prepared Thai herbal topical patches of Lysiphyllum strychnifolium stem extracts using pectin and Eudragit^® NM 30D, and glycerin as a plasticizer. Astilbin was selected as a chemical marker in L. strychnifolium stem extracts. The L. strychnifolium stem extracts showed a statistically significant decrease in nitrate accumulation. The various properties of Thai herbal topical patches were not significantly different from blank patches. However, the trends of the properties depended on the amount of Eudragit^® NM 30D. All ingredients were homogeneously mixed in Thai herbal topical patches and showed a smooth and compact film. The astilbin content was found in a range of 52.72-63.36 μg/cm². The in vitro release of astilbin depended on the amount of Eudragit^® NM 30D. The kinetics of astilbin release were fitted to the Korsmeyer-Peppas model. The astilbin showed low permeation; thus, polyethylene glycol 400 was used as a permeation enhancer. Polyethylene glycol 400 could increase the permeation rates of astilbin and the cumulative amount of astilbin in pig skin. This would be suitable for preparing the Thai herbal topical patches and could be developed for pharmaceutical and herbal products.

Formulation and Pharmacokinetic Evaluation of a Drug-in-Adhesive Patch for Transdermal Delivery of Koumine

The aim of this study was to develop a suitable drug-in-adhesive patch for transdermal delivery of koumine. Acrylic polymer Duro-Tak® 87-4287, which contains hydroxyl groups, may significantly enhance the skin permeation of koumine from transdermal patches containing 0.93-3.72% koumine. Among permeation enhancers, 10% azone showed the greatest potential and increased the flux of koumine to 1.48-fold that of the control. Therefore, an optimized patch formulation containing 3.72% koumine and 10% azone in Duro-Tak® 87-4287 that offers good physical properties was selected for an in vivo pharmacokinetic study using rats. The maximal plasma drug concentration (C_max) of koumine after transdermal administration (4 mg/patch) was 25.80 ± 1.51 ng/mL, which was in the range of those after oral administration (3 mg/kg and 15 mg/kg). The time to the maximal concentration (T_max) and the half-life (t_1/2) of the drug with transdermal administration were 3.96 ± 0.46 h and 21.10 ± 1.36 h, respectively, which were longer than those with oral administration. Furthermore, the area under the concentration-time curve (AUC_0-72 h) of 898.20 ± 45.57 ng·h/mL for the transdermal patch was much higher than that for oral administration (15 mg/kg). In conclusion, the drug-in-adhesive patch containing koumine provides a steady plasma koumine level and sustained release in vivo and can be an effective means of transdermal delivery for koumine.

Waterborne poly(urethane-urea)s films as a sustained release system for ketoconazole

Ketoconazole (KTZ) was incorporated in waterborne poly(urethane-urea)s dispersions (WPUU), aiming at the production of films for drug sustained release. Dispersions based on poly(ethylene glycol-block-propylene glycol) (PEG-b-PPG) (four monomers with different contents of PEG hydrophilic segments), poly(propylene glycol), isophorone diisocyanate, dime-thylolpropionic acid and hydrazine were produced and characterized by apparent viscosity and average particle size (APS). Cast films-drug interaction was investigated by Fourier-Transform infrared spectrometry (FTIR). In vitro dissolution assays were performed in simulated gastrointestinal juices, followed by application of kinetic models. Stable pseudoplastic dispersions, with APS between 27 to 320 nm were obtained. FTIR from KTZ-loaded films indicated interactions between polymer and drug. In vitro release of KTZ was achieved above 80%, notably influenced by PEG-based segments content up to 2 h, followed by sustained release for 8 h. Higuchi’s and first-order equations described the drug kinetic profile, as diffusion of the drug and erosion of the swollen polymer, respectively.

Kaempferia parviflora and Its Methoxyflavones: Chemistry and Biological Activities

Kaempferia parviflora (KP), a health-promoting herb, has been traditionally used for treating a variety of diseases. Pharmacological studies have claimed the various benefits from KP and its main effective methoxyflavones, including cellular metabolism-regulating activity, anticancer activity, vascular relaxation and cardioprotective activity, sexual enhancing activity, neuroprotective activity, antiallergic, anti-inflammatory, and antioxidative activity, antiosteoarthritis activity, antimicroorganism activity, and transdermal permeable activity. These might be associated with increased mitochondrial functions and activated cGMP-NO signaling pathway. However, the underlying molecular mechanisms of KP and its methoxyflavones are still under investigation. The clinical applications of KP and its methoxyflavones may be limited due to their low bioavailability. But promising strategies are on the way. This review will comprehensively discuss the biological activities of KP and its methoxyflavones.

The physiochemical, mechanical, and adhesive properties of solvent-cast vitamin E/Soluplus® films

Soluplus® is an amphiphilic graft copolymer used in hot melt extrusion applications and electrospinning. Very little information is available on the use of Soluplus® as a film former and in the development of film-based formulations. The overall aim of this work was to study the mechanical and adhesive properties of Soluplus® films prepared by the solvent casting technique. More specifically, we discovered that vitamin E can serve as a plasticizer for the Soluplus® polymer and to significantly modulate its mechanical and adhesive properties. Vitamin E (0-75% w/w) and Soluplus® were dissolved in ethanol and cast on liners to produce transparent films. Cast films were tested for their physiochemical properties by IR, XRD, and MDSC, and for their adhesive and mechanical properties by texture analysis. Vitamin E was found to be miscible with Soluplus® and to reduce the crystallinity of the films. Vitamin E also decreased the films' tensile strength and Young's modulus while significantly increasing their percent elongation. The most notable effect was the observed increase in the adhesiveness (tackiness) and hydrophobicity of the films, which was evidenced by a significant increase in their water contact angle and a decrease in their swelling capacity and disintegration. These observations indicated that vitamin E/Soluplus® blends might be used for the preparation of highly pliable films, especially when made with 30-50% vitamin E, and in the development of a new type of pressure sensitive adhesive films when prepared with ≥65% vitamin E load.

Betahistine dihydrochloride transdermal delivery via optimized thermosensitive gels: percutaneous absorption evaluation using rat growth as a biomarker

The aim of this study was to develop and optimize a betahistine dihydrochloride (BH) thermoreversible bioadhesive gel intended for transdermal delivery. The gels were obtained via cold method. A full factorial design was employed to investigate the joint effect of Poloxamer 407 concentration (18 and 20%), adhesive polymer type (Polyvinyl pyrolidone, Hydroxypropyl methylcellulose, and Carbopol 934), and adhesive polymer concentration (0.5 and 1.5%) on gelling temperature, viscosity at 37 °C, and adhesion strength. Data collected were analyzed using multiple linear regression. A desirability index approach with relative importance weight was used to choose the most desirable formulation. F4 (20% Poloxamer+1.5% Carbopol) was selected for further characterization. F4 released 96.97% drug in 12 h across hairless rat skin. F4 gelation temperature and time were 36 ± 0.35 °C, and 6 ± 0.7 min, respectively. F4 adhesive force was 8835.68 dyne/cm². F4 was tested for its appetite suppressing effect in a rat model and it was evaluated histopathologically. Rats' chow intake and weight gain was significantly decreased with no signs of inflammation or lipolysis when the optimized BH gel formulation, F4, was compared with untreated animals and animals treated with BH free gel. The results suggest that BH is percutaneously absorbed from the gel base and that the BH gel is tolerable. The desirability index approach with relative importance weight of responses was effective in determination of the optimum formulation. BH is systemically effective and well-tolerated when applied topically in hydrogel-based systems. The Carbopol-Poloxamer gel is a promising modality for transdermal delivery of BH.

Dose- and time-dependent pharmacokinetics of apigenin trimethyl ether

Apigenin trimethyl ether (5,7,4'-trimethoxyflavone, ATE), one of the key polymethoxyflavones present in black ginger (rhizome of Kaempferia parviflora) possesses various health-promoting activities. To optimize its medicinal application, the pharmacokinetics of ATE was assessed in Sprague-Dawley rats with emphases to identify the impacts from dose and repeated dosing on its major pharmacokinetic parameters. Plasma ATE levels were monitored by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Upon single intravenous administration (2 mg/kg), plasma levels of ATE declined through an apparent first-order process while dose-escalation to 4 and 8 mg/kg led to its non-linear disposition, which could be described by the Michaelis-Menten model. Similarly, dose-dependent oral pharmacokinetics was confirmed and when the dose was escalated from 5 to 15 and 45 mg/kg, much longer mean residence time (MRT_0→last), higher dose-normalized maximal plasma concentration (C_max/Dose) and exposure (AUC/Dose) were observed at 15 and/or 45 mg/kg. One-week daily oral administration of ATE at 15 mg/kg caused its accelerated elimination and the plasma exposure (AUC) after intravenous (2 mg/kg) and oral administration (15 mg/kg) dropped ~40 and 60%, respectively. As ATE displayed both dose- and time-dependent pharmacokinetics, caution is needed in the medicinal applications of ATE and/or black ginger.

A novel transdermal nanoethosomal gel of betahistine dihydrochloride for weight gain control: in-vitro and in-vivo characterization

Background

Betahistine dihydrochloride (BDH) is a histamine analog used to control weight gain, with short elimination half-life and gastric irritation as side effects.

Objective

The aim of the current investigation is to formulate and optimize a topical BDH ethosomal gel for weight gain control.

Materials and methods

Box–Behnken design was applied to study the effect of independent variables: phosphatidylcholine (PC), propylene glycol (PG), and ethanol on vesicle size; entrapment efficiency; % drug release; and flux. The morphology and zeta potential of the optimized formulation were evaluated. The % drug release, flux, and pharmacodynamics of the optimized formulation gel were studied.

Results

The size and entrapment efficiency percent had a direct positive relationship with the concentration of PC and negative relationship with ethanol and PG. The % drug release and flux decreased with increasing PC and PG, while ethanol enhanced both responses. Regression modeling indicated a good correlation between dependent and independent variables, where F16 was chosen as the optimized formulation. F16 showed well-defined spherical vesicles and zeta potential of −24 mV, and % release from the gel exceeded 99.5% over 16 h with the flux of 0.28 mg/cm²/h. Food intake and weight gain of rats were significantly decreased after transdermal application of the BDH ethosomal gel when compared with control, placebo, and BDH gel. The histopathological findings proved the absence of inflammation and decrease in adipose tissue.

Conclusion

Results obtained showed a significant, sustained transdermal absorption of BDH ethosomal gel and, consequently, a decrease in food intake and weight gain.

Transdermal Adhesive Patches Loaded with Ketoprofen Evaluated by Dynamic Detection of Percutaneous Absorption

Topical delivery has many benefits toward NSAIDs administration, and the best-selling transdermal preparation in 2015 was the NSAID patch MOHRUS®. Herein, we report a ketoprofen adhesive patch (KAP) and evaluate the penetration and absorption compared to MOHRUS®. Microdialysis sampling technique was applied to determine drug penetration in the dermis and subcutaneous tissue. Simultaneously, blood samples were withdrawn over time to obtain the drug absorption in plasma. The ketoprofen concentrations in the dermis, subcutaneous tissue, and plasma were compared with the commercially available patch (MOHRUS®). Based on the detection, pharmacokinetic parameters including C_max, T_max, and AUC_0-8h were determined for both the formulations. No significant differences were found in the dermis, subcutaneous tissue, and plasma in rats according to the bioequivalence assessment. The KAP demonstrated multiple therapeutic advantages including the controlled drug release and the sustained drug concentration in the skin as well as in plasma. The pharmacokinetic study coupled with microdialysis sampling provided an effective strategy to evaluate transdermal delivery.

Quantification of apigenin trimethyl ether in rat plasma by liquid chromatography-tandem mass spectrometry: Application to a pre-clinical pharmacokinetic study

Apigenin trimethyl ether (5,7,4'-trimethoxyflavone, ATE) is a naturally occurring polymethoxyflavone with a wide range of health-promoting activities. In this study, a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of ATE in rat plasma. Protein precipitation was applied as plasma clean-up procedure; the electrospray ionization was operated in its positive ion mode while ATE and formononetin (internal standard) were measured by multiple reactions monitoring (ATE: m/z 313.1→298.1; formononetin: 269.2→213.3). This LC-MS/MS method displayed good selectivity, sensitivity (lower limit of quantification=2.5ng/ml), accuracy (both intra- and inter-day analytical recovery within 100±10%) and precision (both intra- and inter-day RSD <10%). The matrix effect was found to be insignificant. The pharmacokinetic profiles of ATE were subsequently examined in Sprague-Dawley rats after single oral administration (10mg/kg). When given in an aqueous suspension, ATE was slowly absorbed with quite low plasma exposure (AUC). Fasting further attenuated its oral absorption and led to ∼70% drops in average maximal plasma concentration (C_max) and AUC. When dosed in a solution formulated with 2-hydroxypropyl-β-cyclodextrin, the oral absorption of ATE was substantially improved with ∼500% increases in average C_max and AUC. Clearly, aqueous solubility has been identified as a barrier to the oral absorption of ATE. The information obtained from this study will facilitate further medicinal exploration on ATE.