Crotamiton-loaded tea tree oil containing phospholipid-based microemulsion hydrogel for scabies treatment: in vitro, in vivo evaluation, and dermatokinetic studies

Assessment of the in vitro acaricidal activity of Bravecto® (fluralaner) and a proposed orange oil-based formulation vehicle for the treatment of Sarcoptes scabiei

BACKGROUND

Sarcoptic mange is a serious animal welfare concern in bare-nosed wombats (Vombatus ursinus). Fluralaner (Bravecto®) is a novel acaricide that has recently been utilised for treating mange in wombats. The topical 'spot-on' formulation of fluralaner can limit treatment delivery options in situ, but dilution to a volume for 'pour-on' delivery is one practicable solution. This study investigated the in vitro acaricidal activity of Bravecto, a proposed essential oil-based diluent (Orange Power®), and two of its active constituents, limonene and citral, against Sarcoptes scabiei.

METHODS

Sarcoptes scabiei were sourced from experimentally infested pigs. In vitro assays were performed to determine the lethal concentration (LC50) and survival time of the mites when exposed to varying concentrations of the test solutions.

RESULTS

All compounds were highly effective at killing mites in vitro. The LC50 values of Bravecto, Orange Power, limonene and citral at 1 h were 14.61 mg/ml, 4.50%, 26.53% and 0.76%, respectively. The median survival times of mites exposed to undiluted Bravecto, Orange Power and their combination were 15, 5 and 10 min, respectively. A pilot survival assay of mites collected from a mange-affected wombat showed survival times of < 10 min when exposed to Bravecto and Orange Power and 20 min when exposed to moxidectin.

CONCLUSIONS

These results confirm the acaricidal properties of Bravecto, demonstrate acaricidal properties of Orange Power and support the potential suitability of Orange Power and its active constituents as a diluent for Bravecto. As well as killing mites via direct exposure, Orange Power could potentially enhance the topical delivery of Bravecto to wombats by increasing drug penetration in hyperkeratotic crusts. Further research evaluating the physiochemical properties and modes of action of Orange Power and its constituents as a formulation vehicle would be of value.

Biocompatible phospholipid-based nanovesicular drug delivery system of ketoprofen: Systematic development, optimization, and preclinical evaluation

The present work involved development of phospholipid-based permeation enhancing nanovesicles (PENVs) for topical delivery of ketoprofen. Screening of phospholipids and process parameters was performed. Central composite design was used for optimization of factors, that is, amount (%, w/w) of phospholipid and ethanol at three levels. The optimized nanovesicles (NVs) were loaded with different terpenes and then incorporated into a gel base. Optimized NVs exhibited 69% entrapment efficiency, 51% transmittance, 328 nm mean vesicle size, and polydispersity index of 0.25. In vitro release kinetics evaluation indicated best fitting as per Korsemeyer-Peppa's model and drug release via Fickian-diffusion mechanism. The optimized NVs loaded with mint terpene showed minimal degree of deformability and maximal elasticity as compared with the conventional NVs and liposomes. Rheology and texture analysis indicated pseudoplastic flow and smooth texture of the vesicle gel formulation. Ex vivo permeation studies across Wistar rat skin indicated low penetration (0.43-fold decrease) and high skin retention (4.26-fold increase) of ketoprofen from the optimized PENVs gel vis-à-vis the conventional gel. Skin irritancy study indicated lower scores for PENVs gel construing its biocompatible nature. Stability studies confirmed cold storage is best suitable for vesicle gel, and optimized PENVs were found to be suitable for topical delivery of ketoprofen.

Medical Applications of Hydrogels in Skin Infections: A Review

Skin infections are common diseases for which patients seek inpatient and outpatient medical care. Globally, an increasing number of people are affected by skin infections that could lead to physical and psychological damage. Skin infections always have a broad spectrum of clinical presentations that require physicians to make an aggressive and accurate diagnosis for prescribing the proper symptomatic antimicrobials. In most instances, the treatment for skin infections mainly includes oral or topical anti-infective drugs. However, some of the classical anti-infective drugs have limitations, such as poor water solubility, low bioavailability, and poor targeting efficiency, which can lead to poor efficacy, adverse effects, and drug resistance. Therefore, research priorities should focus on the development of more effective drug delivery systems with new materials. Hydrogels are a highly multifunctional class of medical materials with potential applications in dermatology. Several hydrogel dressings with anti-infective functions have been formulated and demonstrated to improve the efficacy and tolerance of oral or topical classical anti-infective drugs to a certain degree. In this study, the medical applications of hydrogels for the treatment of various skin infections are systematically reviewed to provide an important theoretical reference for future research studies on the treatment options for skin infections.

Preparation, Characterization, and Evaluation of Curcumin-Graphene Oxide Complex-Loaded Liposomes against Staphylococcus aureus in Topical Disease

This study describes the development and characterization of curcumin with graphene oxide complex (CUR + GO) loaded into liposomes for treating skin disease. The developed complex was characterized by X-ray diffraction and showed a broad halo pattern, confirming the amorphous nature of the resulting complex. Furthermore, scanning electron microscopy revealed the irregular porous morphology of the complex-highlighting loss of the crystallinity and the emergence of the amorphous phase. Additionally, the liposomes showed long-term stability at 2-8 °C and 25 ± 2 °C/60 ± 5%RH with nonsignificant variations in the particle size, polydispersity index, and zeta potential. Overall, optical and high-resolution transmission electron microscopy images of liposomes showed a consistent shape, and no aggregation with uniform particle size distribution was observed. Furthermore, the cumulative drug release in the first 6 h was 71.24 and 64.24% for CUR-loaded liposomes and CUR-GO-loaded liposomes, respectively. The lower value of drug release might be attributed to the complex development. The drug release model found the first order with non-Fickian diffusion process, which is often observed at higher n > 0.5. The antibacterial activity of the CUR with GO-loaded liposome (D2) offered higher anti-microbial activity over other formulations against the mentioned bacterial microorganism that causes skin diseases.

Hispolon-Loaded Liquid Crystalline Nanoparticles: Development, Stability, In Vitro Delivery Profile, and Assessment of Hepatoprotective Activity in Hepatocellular Carcinoma

The present work describes the development and characterization of liquid crystalline nanoparticles of hispolon (HP-LCNPs) for treating hepatocellular carcinoma. HP-LCNPs were prepared by a top-down method utilizing GMO as the lipid and Pluronic F-127 as the polymeric stabilizer. The prepared formulations (HP1-HP8) were tested for long-term stability, where HP5 showed good stability with a particle size of 172.5 ± 0.3 nm, a polydispersity index (PDI) of 0.38 ± 0.31 nm, a zeta potential of -10.12 mV ± 0.05, an entrapment efficiency of 86.81 ± 2.5%, and a drug loading capacity of 12.51 ± 1.12%. Optical photomicrography and transmission electron microscopy images demonstrated a consistent, low degree of aggregation and a spherical shape of LCNPs. The effect of temperature and pH on the optimized formulation (HP5) indicated good stability at 45 °C and at pH between 2 and 5. In vitro gastrointestinal stability indicated no significant change in the particle size, PDI, and entrapment efficiency of the drug. The drug release study exhibited a biphasic pattern in simulated gastric fluid (pH 1.2) for 2 h and simulated intestinal fluid (pH 7.4) for up to 24 h, while the best fitting of the profile was observed with the Higuchi model, indicating the Fickian diffusion mechanism. The in vivo pharmacokinetic study demonstrated nearly 4.8-fold higher bioavailability from HP5 (AUC: 1774.3 ± 0.41 μg* h/mL) than from the HP suspension (AUC: 369.11 ± 0.11 μg* h/mL). The anticancer activity evaluation revealed a significant improvement in antioxidant parameters and serum hepatic biomarkers (SGOT, SGPT, ALP, total bilirubin, and GGT) in the diethyl nitrosamine-treated group of rats with the optimized LCNP formulation (HP5) vis-à-vis HP suspension.

Insights from a Box-Behnken Optimization Study of Microemulsions with Salicylic Acid for Acne Therapy

The present study brings to attention a method to develop salicylic acid-based oil in water (O/W) microemulsions using a tensioactive system based on Tween 80, lecithin, and propylene glycol (PG), enriched with a vegetable oat oil phase and hyaluronic acid. The systems were physically characterized and the Quality by design approach was applied to optimize the attributes of microemulsions using Box-Behnken modeling, combined with response surface methodology. For this purpose, a 33 fractional factorial design was selected. The effect of independent variables namely X1: Tween 80/PG (%), X2: Lecithin (%), X3: Oil phase (%) was analyzed considering their impact upon the internal structure and evaluated parameters chosen as dependent factors: viscosity, mean droplet size, and work of adhesion. A high viscosity, a low droplet size, an adequate wettability-with a reduced mechanical work-and clarity were considered as desirable for the optimal systems. It was found that the optimal microemulsion which complied with the established conditions was based on: Tween 80/PG 40%, lecithin 0.3%, oat oil 2%, salicylic acid 0.5%, hyaluronic acid 1%, and water 56.2%. The response surface methodology was considered an appropriate tool to explain the impact of formulation factors on the physical properties of microemulsions, offering a complex pattern in the assessment of stability and quality attributes for the optimized formulation.