Development of Triamcinolone Acetonide-Loaded Microemulsion as a Prospective Ophthalmic Delivery System for Treatment of Uveitis: In Vitro and In Vivo Evaluation

Exploring the Impact of Polysaccharide-Based Nanoemulsions in Drug Delivery

Nanoemulsions are tiny mixtures of water and oil stabilized by surfactants, and they have become increasingly popular across various industries, including medicine. With droplet sizes in the nanometer scale, these mixtures are both compact and effective. This discussion explores the potential of polysaccharide-based nanotechnology as an innovative approach to drug delivery. Nanoemulsions offer several benefits, such as enhanced drug solubility and bioavailability, which are crucial for drugs that poorly dissolve in water. The incorporation of natural polysaccharides as emulsifiers in these nanoemulsions ensures their biocompatibility and safety within the body. Additionally, nanoemulsions can facilitate a sustained release of medications, allowing for gradual drug release over an extended period. This controlled release can be achieved through the careful selection and formulation of polysaccharides. This review addresses the methods for producing polysaccharide-based nanoemulsions and examines their physical and chemical properties. It highlights the influence of polysaccharide molecular weight and structure on the stability of nanoemulsions and the effectiveness of drug encapsulation. By understanding these factors, researchers can develop more efficient and safe drug delivery systems utilizing nanoemulsions. Additionally, the present article provides explicit and thorough information about the use of NPLS-based nano-carriers encapsulating a number of drugs designed to treat a variety of conditions, such as diabetes, cancer, HIV, malaria, cardiovascular and respiratory diseases, and skin diseases. For this reason, it is very important to review the most recent developments in polysaccharide-based nano-biocarriers in drug delivery and their application in the treatment of diseases. In this work, we concentrated on the preparation of polysaccharide-based nano-biocarriers, commonly used polysaccharides for the preparation of nano-biocarriers, and drugs loaded on polysaccharide-based nano-biocarriers to treat diseases. In the near future, polysaccharide-based nano-biocarriers will be used more and more frequently in drug delivery and disease treatment.

Tear-Driven Phase Transition Microemulsion for Ocular Delivery of Dexamethasone in the Effective Treatment of Uveitis

PURPOSE

The goal of this study was to develop dexamethasone-loaded tear-driven phase transition microemulsions (PTMEs) to effectively treat uveitis.

METHODS

PTMEs were prepared using the oil titration method. Physicochemical parameters, in vitro release, and ocular irritation studies were performed. The in vivo study, total cell count, and total protein content were estimated on the rabbit eye model.

RESULTS

The study revealed that developed PTMEs had nanoglobule sizes, acceptable physicochemical properties, and prolonged drug release. Ex-vivo and in-vivo studies concluded that higher permeability and improved anti-inflammatory properties were observed for PTMEs compared to marketed formulation.

CONCLUSION

The prepared PTMEs showed a sustained release pattern and enhanced therapeutic effectiveness, making them a promising alternative to conventional eye drops for treating uveitis.

Enhanced Anti-Inflammatory and Skin Barrier Repair Effects of Nanoemulsions Supplemented with Boesenbergia rotunda for Atopic Dermatitis

Betamethasone dipropionate (BD) is a potent anti-inflammatory drug for atopic dermatitis (AD); however, it leads to serious adverse effects during prolonged use. We aimed to improve the biochemical properties and lower the risk of toxicity by preparing nanoemulsions containing Boesenbergia rotunda rhizome hexane extract (Hex) and essential oils (EO). Physicochemical characterization and 3-month long-term stability testing were conducted. Gas chromatography-mass spectrometry analysis was used to compare the volatile composition after nanoemulsion formulation. Further, various assays related to AD management, including antioxidant potentials, anti-inflammatory activities through inhibition of 5-lipoxygenase and cyclooxygenase-2, and nitric oxide release suppression in lipopolysaccharides-induced RAW 264.7 macrophages, were investigated. In addition, antibacterial activity against Staphylococcus aureus and cytotoxicity to RAW 264.7 macrophages and HaCaT human keratinocyte cells were also evaluated. Monodispersed nanoemulsions (<20 nm) were successfully generated by an ultrasound-assisted method. BD was successfully encapsulated into B. rotunda-based nanoemulsions with more than 95% encapsulation efficiency (EE). The major phytochemicals present in EO and Hex remained after nanoemulsion formulation. The nanoemulsions were compatible with skin pH (5.2-5.8) and exhibited stability with respect to particle size, polydispersity index, transmittance, pH, and EE when stored for 3 months at -20 °C. The BD nanoemulsions loaded with B. rotunda exhibited antioxidant activities and significantly increased the 5-lipoxygenase inhibitory activity. Furthermore, the suppression of nitric oxide release was remarkably enhanced, whereas lower cytotoxicity was observed. The BD nanoemulsions improved the level of involucrin and filaggrin in HaCaT cells, implying their valuable property for skin barrier repair. The formulation of BD into nanoemulsions also enhanced S. aureus inhibition. Either B. rotunda nanoemulsions loaded with or without BD show promise for the topical treatment and prevention of AD.

Alopecia Management Potential of Rosemary-Based Nanoemulgel Loaded with Metformin: Approach Combining Active Essential Oil and Repurposed Drug

Introduction

Androgenetic alopecia (AGA) is a multifactorial and age-related dermatological disease that affects both males and females, usually at older ages. Traditional hair repair drugs exemplified by minoxidil have limitations such as skin irritation and hypertrichosis. Thus, attention has been shifted to the use of repurposing drugs. Metformin is an anti-diabetic drug, that can promote hair follicle regeneration via upregulation of the hair-inductive capability. Hence, the current study aims to fabricate a safe and effective nanoemulsion to improve metformin efficacy in targeting AGA.

Methods

Rosemary oil was selected as the oily phase due to its ability to increase blood flow and hair growth. Rosemary-based nanoemulsions were statistically optimized by Box-Behnken experimental design, loaded with metformin, and incorporated into a hydrogel to form a nanoemulgel. Metformin-loaded nanoemulsions were assessed for their diametric size, uniformity, zeta potential, and metformin characteristics within the formulated nanosystem. The nanoemulgel was then evaluated in terms of its pH, percentage drug content, and in-vitro release performance. In-vivo study assessed the nanoemulgel's ability to augment hair growth in rats.

Results

The experimental design displayed that using 50%w/w, 20%w/w, and 10%w/w of Cremophor®, Labrafil®, and deionized water, respectively, resulted in nanoemulsion formulation with the smallest globule size (125.01 ± 0.534 nm), unimodal size distribution (PDI=0.103), negative surface charge (-19.9 ± 2.01 mV) with a spherical morphological structure. Rosemary-based nanoemulgel displayed acceptable physicochemical characterizations namely; a neutral pH value of 6.7±0.15, high drug content (92.9± 2.3%), and controlled metformin in-vitro release. Besides, the formulated nanoemulgel significantly increased the number of hair follicles in the animal model compared with other controls and tested groups.

Conclusion

The designed nanoemulgel is a promising approach for treating androgenic alopecia.

Microemulsions strongly promoted the activity of α-bisabolol against different Leishmania species and its skin permeation

This study aimed to develop microemulsions (MEs) containing α-bisabolol for the topical treatment of cutaneous leishmaniasis (CL). Initially, pseudoternary phase diagrams were developed using α-bisabolol as the oil phase, Eumulgin® CO 40 as the surfactant, Polymol® HE as the co-surfactant, and distilled water as the aqueous phase. Two transparent liquid systems (TLS) containing 5% of α-bisabolol were selected and characterized (F5E25 and F5EP25). Next, skin permeation and retention assays were performed using Franz cells. The interaction of the formulation with the stratum corneum (SC) was evaluated using the FTIR technique. The cytotoxicity was evaluated in murine peritoneal macrophages. Finally, the antileishmanial activity of microemulsions was determined in promastigotes and amastigotes of L. amazonensis (strain MHOM/BR/77/LTB 0016). As a result, the selected formulations showed isotropy, nanometric size (below 25 nm), Newtonian behavior and pH ranging from 6.5 to 6.9. The MEs achieved a 2.5-fold increase in the flux and skin-permeated amount of α-bisabolol. ATR-FTIR results showed that microemulsions promoted fluidization and extraction of lipids and proteins of the stratum corneum, increasing the diffusion coefficient and partition coefficient of the drug in the skin. Additionally, F5E25 and F5EP25 showed higher activity against promastigotes (IC50 13.27 and 18.29, respectively) compared to unencapsulated α-bisabolol (IC50 53.8). Furthermore, F5E25 and F5EP25 also showed antileishmanial activity against intracellular amastigotes of L. amazonensis, with IC50 50 times lower than free α-bisabolol and high selectivity index (up to 15). Therefore, the systems obtained are favorable to topical administration, with significant antileishmanial activity against L. amazonensis promastigotes and amastigotes, being a promising system for future in vivo trials.

Nanosuspensions in ophthalmology: Overcoming challenges and enhancing drug delivery for eye diseases

This review article provides a comprehensive overview of the advancements in using nanosuspensions for controlled drug delivery in ophthalmology. It highlights the significance of ophthalmic drug delivery due to the prevalence of eye diseases and delves into various aspects of this field. The article explores molecular mechanisms, drugs used, and physiological factors affecting drug absorption. It also addresses challenges in treating both anterior and posterior eye segments and investigates the role of mucus in obstructing micro- and nanosuspensions. Nanosuspensions are presented as a promising approach to enhance drug solubility and absorption, covering formulation, stability, properties, and functionalization. The review discusses the pros and cons of using nanosuspensions for ocular drug delivery and covers their structure, preparation, characterization, and applications. Several graphical representations illustrate their role in treating various eye conditions. Specific drug categories like anti-inflammatory drugs, antihistamines, glucocorticoids, and more are discussed in detail, with relevant studies. The article also addresses current challenges and future directions, emphasizing the need for improved nanosuspension stability and exploring potential technologies. Nanosuspensions have shown substantial potential in advancing ophthalmic drug delivery by enhancing solubility and absorption. This article is a valuable resource for researchers, clinicians, and pharmaceutical professionals in this field, offering insights into recent developments, challenges, and future prospects in nanosuspension use for ocular drug delivery.

Lipid-based nanocarriers challenging the ocular biological barriers: Current paradigm and future perspectives

Eye is the most specialized and sensory body organ and treating eye diseases efficiently is necessary. Despite various attempts, the design of a consummate ophthalmic drug delivery system remains unsolved because of anatomical and physiological barriers that hinder drug transport into the desired ocular tissues. It is important to advance new platforms to manage ocular disorders, whether they exist in the anterior or posterior cavities. Nanotechnology has piqued the interest of formulation scientists because of its capability to augment ocular bioavailability, control drug release, and minimize inefficacious drug absorption, with special attention to lipid-based nanocarriers (LBNs) because of their cellular safety profiles. LBNs have greatly improved medication availability at the targeted ocular site in the required concentration while causing minimal adverse effects on the eye tissues. Nevertheless, the exact mechanisms by which lipid-based nanocarriers can bypass different ocular barriers are still unclear and have not been discussed. Thus, to bridge this gap, the current work aims to highlight the applications of LBNs in the ocular drug delivery exploring the different ocular barriers and the mechanisms viz. adhesion, fusion, endocytosis, and lipid exchange, through which these platforms can overcome the barrier characteristics challenges.

Nanotechnology-based ocular drug delivery systems: recent advances and future prospects

Ocular drug delivery has constantly challenged ophthalmologists and drug delivery scientists due to various anatomical and physiological barriers. Static and dynamic ocular barriers prevent the entry of exogenous substances and impede therapeutic agents' active absorption. This review elaborates on the anatomy of the eye and the associated constraints. Followed by an illustration of some common ocular diseases, including glaucoma and their current clinical therapies, emphasizing the significance of drug therapy in treating ocular diseases. Subsequently, advances in ocular drug delivery modalities, especially nanotechnology-based ocular drug delivery systems, are recommended, and some typical research is highlighted. Based on the related research, systematic and comprehensive characterizations of the nanocarriers are summarized, hoping to assist with future research. Besides, we summarize the nanotechnology-based ophthalmic drugs currently on the market or still in clinical trials and the recent patents of nanocarriers. Finally, inspired by current trends and therapeutic concepts, we provide an insight into the challenges faced by novel ocular drug delivery systems and further put forward directions for future research. We hope this review can provide inspiration and motivation for better design and development of novel ophthalmic formulations.

Preparation of a Sunitinib loaded microemulsion for ocular delivery and evaluation for the treatment of corneal neovascularization in vitro and in vivo

Background: Corneal neovascularization (CNV) is a pathological condition that can disrupt corneal transparency, thus harming visual acuity. However, there is no effective drug to treat CNV. Sunitinib (STB), a small-molecule multiple receptor tyrosine kinase inhibitor, was shown to have an effect on CNV. The purpose of this study was to develop an STB microemulsion (STB-ME) eye drop to inhibit CNV by topical application. Methods: We successfully prepared an STB-ME by the phase inversion emulsification method, and the physicochemical properties of STB-MEs were investigated. The short-term storage stability, cytotoxicity to human corneal epithelial cells, drug release, ocular irritation, ocular pharmacokinetics and the inhibitory effect on CNV were evaluated in vitro and in vivo. Results: The optimal formulation of STB-ME is composed of oleic acid, CRH 40, Transcutol P, water and sodium hyaluronate (SH). It is a uniform spherical particle with a mean droplet size of 18.74 ± 0.09 nm and a polydispersity index of 0.196 ± 0.004. In the in vitro drug release results, STB-ME showed sustained release and was best fitted by a Korsmeyer-Peppas model (R ² = 0.9960). The results of the ocular pharmacokinetics in rabbits showed that the formulation containing SH increased the bioavailability in the cornea (2.47-fold) and conjunctiva (2.14-fold). STB-ME (0.05% and 0.1%), administered topically, suppressed alkali burn-induced CNV in mice more effectively than saline, and high-dose (0.1%) STB-ME had similar efficacy to dexamethasone (0.025%). Conclusion: This study provides a promising formulation of STB-ME for the inhibition of CNV by topical administration, which has the excellent characteristics of effectiveness, sustained release and high ocular bioavailability.

Development of Triamcinolone Acetonide Nanocrystals for Ocular Administration

Triamcinolone acetonide (TA) is a powerful anti-inflammatory drug used in the treatment of inflammatory ocular disorders; however, its poor aqueous solubility and ocular anatomical barriers hinder optimal treatment. The aim of this work was to obtain triamcinolone acetonide nanocrystals (TA-NC) to improve ocular corticosteroid therapy. Self-dispersible TA-NC were prepared by the bead milling technique followed by spray-drying, exhaustively characterized and then evaluated in vivo in an ocular model of endotoxin-induced uveitis (EIU). Self-dispersible TA-NC presented an average particle size of 257 ± 30 nm, a narrow size distribution and a zeta potential of -25 ± 3 mV, which remained unchanged for 120 days under storage conditions at 25 °C. In addition, SEM studies of the TA-NC showed uniform and spherical morphology, and FTIR and XRDP analyses indicated no apparent chemical and crystallinity changes. The subconjunctival administration of TA-NC in albino male white rabbits showed no clinical signs of ocular damage. In vivo studies proved that treatment with self-dispersible TA-NC alleviated the inflammatory response in the anterior chamber and iris in EUI rabbit eyes. Dispersible TA-NC are a promising approach to obtaining a novel nanometric TA formulation for ocular disorders.

Development of a Luliconazole Nanoemulsion as a Prospective Ophthalmic Delivery System for the Treatment of Fungal Keratitis: In Vitro and In Vivo Evaluation

Luliconazole (LCZ), a novel imidazole drug, has broad-spectrum and potential antifungal effects, which makes it a possible cure for fungal keratitis; nevertheless, its medical use in ocular infections is hindered by its poor solubility. The purpose of this study was to design and optimize LCZ nanoemulsion (LCZ-NE) formulations using the central composite design-response surface methodology, and to investigate its potential in improving bioavailability following ocular topical administration. The LCZ-NE formulation was composed of Capryol 90, ethoxylated hydrogenated castor oil, Transcutol® P and water. The shape of LCZ-NE was spherical and uniform, with a droplet size of 18.43 ± 0.05 nm and a low polydispersity index (0.070 ± 0.008). The results of an in vitro release of LCZ study demonstrated that the LCZ-NE released more drug than an LCZ suspension (LCZ-Susp). Increases in the inhibition zone indicated that the in vitro antifungal activity of the LCZ-NE was significantly improved. An ocular irritation evaluation in rabbits showed that the LCZ-NE had a good tolerance in rabbit eyes. Ocular pharmacokinetics analysis revealed improved bioavailability in whole eye tissues that were treated with LCZ-NE, compared with those treated with LCZ-Susp. In conclusion, the optimized LCZ-NE formulation exhibited excellent physicochemical properties, good tolerance, enhanced antifungal activity and bioavailability in eyes. This formulation would be safe, and shows promise in effectively treating ocular fungal infections.

Customized cationic nanoemulsions loading triamcinolone acetonide for corneal neovascularization secondary to inflammatory processes

Customized cationic oil-in-water nanoemulsions (NEs) have been produced to improve the bioavailability of poorly water-soluble drugs, such as triamcinolone acetonide (TA). TA is a synthetic glucocorticoid with anti-inflammatory and antiangiogenic therapeutic properties and it is widely used as an effective treatment in ocular disorders. In this work, TA-NEs were characterized using two different custom-made cationic surfactants, showing a high positive surface charge favouring corneal penetration and a particle size below 300 nm. Both TA-NE formulations demonstrated to be stable at 4 °C during the first months of storage. Furthermore, TA-NEs were able to produce antiangiogenic effects in chicken membranes. The TA-NEs safety profile was evaluated using in vitro and in vivo ocular tolerance tests. Out of the two formulations, the one showing no irritant effects was screened in vivo demonstrating capacity to ameliorate ocular inflammation in New Zealand rabbits significantly, specially to reduce the risk of ocular inflammation processes, with antiangiogenic activity, and can therefore be exploited as a suitable formulation to avoid inflammatory reactions upon ocular surgical procedures, such as cataracts.

Facile synthesis of pH-responsive sodium alginate/carboxymethyl chitosan hydrogel beads promoted by hydrogen bond

In this work, a novel synthesis strategy of sodium alginate/carboxymethyl chitosan hydrogel beads promoted by hydrogen bond was described. The beads were prepared by dropping the blends of two polymers into the citric acid solution. Besides hydrogen bonding, electrostatic interactions were also involved in the formation of the hydrogel beads. The thermal stability experiments revealed that the more the content of carboxymethyl chitosan, the better the thermal stability of the beads. The beads exhibited excellent pH sensitivity, pH reversibility, and lactoferrin loading capacity. The swelling ratio of the bead and its protein releasing profile was pH-dependent, which could prevent premature protein release in the gastric environment. Also, the circular dichroism results demonstrated that lactoferrin could maintain its structure during the loading and releasing process. The obtained results revealed that the hydrogel beads prepared in this work could be used as a potential protein carrier for oral delivery.

Development and Characterization of Nanoemulsions for Ophthalmic Applications: Role of Cationic Surfactants

The eye is a very complex organ comprising several physiological and physical barriers that compromise drug absorption into deeper layers. Nanoemulsions are promising delivery systems to be used in ocular drug delivery due to their innumerous advantages, such as high retention time onto the site of application and the modified release profile of loaded drugs, thereby contributing to increasing the bioavailability of drugs for the treatment of eye diseases, in particular those affecting the posterior segment. In this review, we address the main factors that govern the development of a suitable nanoemulsion formulation for eye administration to increase the patient’s compliance to the treatment. Appropriate lipid composition and type of surfactants (with a special emphasis on cationic compounds) are discussed, together with manufacturing techniques and characterization methods that are instrumental for the development of appropriate ophthalmic nanoemulsions.

Efficacy and safety testing of dissolving microarray patches in Chinese subjects

OBJECTIVES

There is a lack of clinical research in the Chinese market concerning dissolving microarray (DMA) patches in cosmetic applications. In this study, the clinical efficacy and safety tests of DMA patch technology were performed on Chinese consumers.

METHODS

A 4-week clinical efficacy and safety evaluation was conducted on 30 Chinese female subjects with crow's feet and eye bags. DMA patches loaded with hyaluronic acid (HA-DMA) were applied under the eyes and corners of the eyes of the subjects three times a week over four consecutive weeks. Skin firmness and dermal layer strength were measured using ultrasound, and changes in skin wrinkles were detected using VISIA-CR and Primos Lite. Eye bag ratings were evaluated by professional dermatologists based on the 0-6 grades of eye bags in the "Skin Aging Atlas Volume 2: Asian Type."

RESULTS

HA-DMA patches produced good clinical improvements on both crow's feet and eye bags in the study participants. HA-DMA effectively increased skin firmness while reducing the number, area, and volume of crow's feet, along with reducing eye bag ratings. The reductions in all metrics were statistically significant with positive effects evident in as little as 1 week of treatment. There were no adverse effects related to the treatments observed during the test period.

CONCLUSIONS

In a clinical efficacy trial of 30 Chinese female subjects, HA-DMA showed excellent therapeutic benefits without adverse effects while reducing crow's feet and eye bags. HA-DMA is expected to be a safe, effective, and novel cosmetic for improving the appearance of aging skin.

Nanoemulsions as Ophthalmic Drug Delivery Systems

Nanoemulsions are liquid-in-liquid dispersion with a droplet size of about 100 nm. They have a transparent appearance, high rate of bioavailability, and increased shelf life. Nanoemulsions mainly consist of oil, water, surfactant, and cosurfactant and can be prepared by high- and low-energy methods. Diluted nanoemulsions are utilized for the delivery of ophthalmic drugs due to their capability to penetrate the deep layers of the ocular structure, provide a sustained release effect, and reduce the frequency of administration and side effects. These nanoemulsions are subjected to certain tests, such as safety, stability, pH profile, rheological studies, and so on. Cationic nanoemulsions are prepared for topical ophthalmic delivery of active ingredients from cationic agents to increase the drug residence time on the ocular surface, reducing their clearance from the ocular surface and improving drug bioavailability. This review article summarizes the main characteristics of nanoemulsions, ophthalmic nanoemulsions, and cationic nanoemulsions and their components, methods of preparation, and the evaluation parameters for ophthalmic nanoemulsions.