Formation of Antihyperlipidemic Nano-Ezetimibe from Volatile Microemulsion Template for Enhanced Dissolution Profile

Formation of alginate gel stabilized silica nanoparticles for encapsulation and topical delivery of minoxidil

Silica nanoparticles-embedded smart-gels are efficient drug carrier systems due to their structural flexibility, high porosity, and ease of formulation development. Herein, the extent of interaction of minoxidil (MXD), a potent vasodilator prodrug, with silica nanoparticles (SiNPs) and alginate (ALG) was investigated. The SiNPs were prepared by extracting silica from rice husk ash, and these SiNPs were further used to prepare MXD-loaded-SiNPs (MXD-SiNPs) by loading them with an appropriate amount of MXD. The as-prepared MXD-SiNPs were encapsulated in ALG polymer by freeze-gelation method and evaluated by various characterization techniques. The amorphous nature of the SiNPs was confirmed by XRD examination, while the nature of physical interaction and encapsulation of the drug in the SiNPs and ALG gel was examined by FTIR analysis. TEM analysis revealed that the MXD-SiNPs had a monodisperse collection of spherical nanoparticles, while the particle size (∼150 nm) of as-prepared formulation was determined from DLS studies. The drug entrapment efficiency was 86 % and the loading efficiency was 22 %. The as-developed MXD-SiNPs@ALG gel formulation exhibited sustained release over 12 h compared to pure MXD and MXD-SiNPs. These results suggest that the newly developed formulation has several advantageous properties that make it suitable for cutaneous administration of the drug.

Formulation of Microemulsion-Based Gels for Enhanced Topical Administration of Nonsteroidal Anti-Inflammatory Drugs

Nonsteroidal anti-inflammatory drugs are commonly administered orally to manage pain and inflammation, but they can have negative gastrointestinal side effects. Topical delivery is an alternative, and microemulsions (μEs) have been shown to be effective in facilitating, but they suffer from a liquid nature and low long-term retention on the skin. Hence, microemulsified gels (μEGs) have been developed, and in this study, we explored certain μEGs with diclofenac sodium (DF-Na) and naproxen sodium (NP-Na) with the hypothesis to ensure a slower and more sustained delivery of NSAIDs through the skin. The μEGs comprised castor oil (∼8%), water (∼12%), Tween-20 (∼72%), Span-20 (∼8%), poloxamer 407, and DF-Na or NP-Na. Optical microscopy was used to study the microstructures in the μEs and μEGs, and phase transitions from water-in-oil (w/o) to oil-in-water (o/w) with continuous networks were observed. Based on studies with dynamic light scattering and analyses of electron micrographs, it was observed that the μEs and μEGs loaded with DF-Na and NP-Na comprised monomodal nanodroplets. The average sizes of the droplets were (∼35 nm) and (∼60 nm) for the μEGs, without and with drugs. Fluorescence spectroscopy was used to ensure that the drugs were more likely to be present in the hydrophobic microenvironment of the formulations. Moreover, ex vivo permeation studies were conducted at pH values of 5.5 and 7.4 across rabbit skin. The release rates of DF-Na (>99 ± 1.5%, P < 0.07) and NP-Na (>89 ± 1.1%, P < 0.01) were slower for the μEGs within 8-10 h than for the μEs at the low pH, which is of relevance to the optimal pH of the skin. It was observed that μEGs with high viscosities are effective and may have potential for use in topical drug delivery applications.

Synergistic stabilization of a menthol Pickering emulsion by zein nanoparticles and starch nanocrystals: Preparation, structural characterization, and functional properties

A Pickering emulsion was synergistically stabilised with zein nanoparticles (ZNPs) and starch nanocrystals (SNCs) to prepare it for menthol loading. After response surface optimisation of the emulsion preparation conditions, a Pickering emulsion prepared with a ZNPs:SNCs ratio of 1:1, a particle concentration of 2 wt% and a water:oil ratio of 1:1 provided the highest menthol encapsulation rate of the emulsions tested (83%) with good storage stability within 30 days. We examined the bilayer interface structure of the emulsion by optical microscopy, scanning electron microscopy, and confocal laser scanning microscopy. The results of simulated digestion experiments showed that the release rate of free fatty acid was 75.06 ± 1.23%, which ensured bioavailability. At the same time, the emulsions facilitated the slow release of menthol. Bacteriostatic studies revealed that the Pickering emulsion had a protective effect on menthol, with the most significant inhibitory effects on Escherichia coli and Staphylococcus aureus under the same conditions. Overall, this study proposes a novel approach for the application and development of l-menthol by combining it with Pickering emulsion.

Targeted Strategy in Lipid-Lowering Therapy

Dyslipidemia is characterized by a diminished lipid profile, including increased level of total cholesterol and low-density lipoprotein cholesterol (LDL-c) and reduced level of high-density lipoprotein cholesterol (HDL-c). Lipid-lowering agents represent an efficient tool for the prevention or reduction of progression of atherosclerosis, coronary heart diseases and metabolic syndrome. Statins, ezetimibe, and recently proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are the most effective and used drugs in clinical lipid-lowering therapy. These drugs are mainly aimed to lower cholesterol levels by different mechanisms of actions. Statins, the agents of the first-line therapy-known as 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitors-suppress the liver cholesterol synthesis. Ezetimibe as the second-line therapy can decrease cholesterol by inhibiting cholesterol absorption. Finally, the PCSK9 inhibitors act as an inducer of LDL excretion. In spite of their beneficial lipid-lowering properties, many patients suffer from their serious side effects, route of administration, or unsatisfactory physicochemical characteristics. Clinical demand for dose reduction and the improvement of bioavailability as well as pharmacodynamic and pharmacokinetic profile has resulted in the development of a new targeted therapy that includes nanoparticle carriers, emulsions or vaccination often associated with another more subtle form of administration. Targeted therapy aims to exert a more potent drug profile with lipid-lowering properties either alone or in mutual combination to potentiate their beneficial effects. This review describes the most effective lipid-lowering drugs, their favorable and adverse effects, as well as targeted therapy and alternative treatments to help reduce or prevent atherosclerotic processes and cardiovascular events.

Preparation of Eprinomectin Nanoemulsions and Determination of Their Pharmacokinetics and Pharmacodynamics in Dairy Cows

This study aimed to develop an anthelmintic that leaves no residues and is safe and efficient for use in cows. We constructed classical pseudoternary phase diagrams using experimental animal data to optimize and characterize the eprinomectin nanoemulsion formulas. The emulsion samples prepared with ethyl acetate, polysorbate 80, and 1-propanediol as the main components were transparent and uniform when observed under a Hitachi transmission electron microscope (TEM) system. A Mastersizer 3000 laser particle size analyzer was used to determine the particle sizes of the prepared nanoemulsions. The nanoemulsions were homogeneously dispersed, with an average particle size of 12.61 nm and a polydispersity index of (PDI) 0.297. High-performance liquid chromatography confirmed no statistically significant changes in the samples after 24 months at 4 °C, 25 °C, and 37 °C; the samples exhibited long-term stability. The PK/PD studies confirmed that the injection of eprinomectin nanoemulsions at a dose of 0.2 mg/kg body weight was effective, with a withdrawal period of 0 days for dairy cows. The total extermination rate of the nanoemulsions against adult nematodes was 98.40±1.52%. The AUC_milk/plasma ratio was 0.67±0.03. The optimal dose was found to be 0.2 mg/kg body weight.

Microemulsified Gel Formulations for Topical Delivery of Clotrimazole: Structural and In Vitro Evaluation

Microemulsified gels (μEGs) with fascinating functions have become indispensable as topical drug delivery systems due to their structural flexibility, high stability, and facile manufacturing process. Topical administration is an attractive alternative to traditional methods because of advantages such as noninvasive administration, bypassing first-pass metabolism, and improving patient compliance. In this article, we report on the new formulations of microemulsion-based gels suitable for topical pharmaceutical applications using biocompatible and ecological ingredients. For this, two biocompatible μE formulations comprising clove oil/Brij-35/water/ethanol (formulation A) and clove oil/Brij-35/water/1-propanol (formulation B) were developed to encapsulate and improve the load of an antimycotic drug, Clotrimazole (CTZ), and further gelatinized to control the release of CTZ through skin barriers. By delimiting the pseudo-ternary phase diagram, optimum μE formulations with clove oil (∼15%) and Brij-35 (∼30%) were developed, keeping constant surfactant/co-surfactant ratio (1:1), to upheld 2.0 wt % CTZ. The as-developed formulations were further converted into smart gels by adding 2.0 wt % carboxymethyl cellulose (CMC) as a cross-linker to adhere to the controlled release of CTZ through complex skin barriers. Electron micrographs show a fine, monodispersed collection of CTZ-μE nanodroplets (∼60 nm), which did not coalesce even after gelation, forming spherical CTZ-μEG (∼90 nm). However, the maturity of CTZ nanodroplets observed by dynamic light scattering suggests the affinity of CTZ for the nonpolar microenvironment, which was further supported by the peak-to-peak correlation of Fourier transform infrared (FTIR) analysis and fluorescence measurement. In addition, HPLC analysis showed that the in vitro permeation release of CTZ-μEG from rabbit skin in the ethanolic phosphate buffer (pH = 7.4) was significantly increased by >98% within 6.0 h. This indicates the sustained release of CTZ in μEBG and the improvement in transdermal therapeutic efficacy of CTZ over its traditional topical formulations.