Proglycosomes: A novel nano-vesicle for ocular delivery of tacrolimus

Tofacitinib in dermatology: a potential opportunity for topical applicability through novel drug-delivery systems

Tofacitinib is a first-generation JAK inhibitor approved by the US FDA for treating rheumatoid arthritis. It exhibits a broad-spectrum inhibitory effect with abilities to block JAK-STAT signalling. The primary objective of this review is to obtain knowledge about cutting-edge methods for effectively treating a variety of skin problems by including tofacitinib into formulations that are based on nanocarriers. The review also highlights clinical trials and offers an update on published clinical patents. Nanocarriers provide superior performance compared to conventional treatments in terms of efficacy, stability, drug bioavailability, target selectivity and sustained drug release. Current review has the potential to make significant contributions to the ongoing discussion involving dermatological treatments and the prospective impact of nanotechnology on transforming healthcare within this field.

Tacrolimus-Loaded Cationic Nanoemulsion In-Situ Gel System: In-Vitro Characterization and Performance in a Dry-Eye Rabbit Model

Dry eye disease (DED) is a highly prevalent ocular surface disease that affects life quality and reduces productivity at work. The purpose of this study is to improve the efficacy of tacrolimus (FK506) in the treatment of DED using the special eye surface retention properties of cationic nanoemulsion (CNE) modified by thermosensitive in-situ gel (ISG) (CNE-ISG). The precorneal retention of CNE-ISG containing 0.05% FK506 (50 min) was longer than that of CNE containing 0.05% FK506 (25 min) and commercial suspension containing 0.1% FK506 (Talymus®) (10 min). Successfully modeled dry-eye rabbits were treated with 0.05% CNE-ISG (twice/day), 0.05% CNE and 0.1% suspension (Talymus®) (thrice/day). Schirmer's tear secretion test showed no significant difference between the CNE-ISG group and the healthy group after 5 days of treatment (p > 0.05). The results of a tear ferning test (TFT) showed that the tear-fern-like crystal branches in the CNE-ISG group returned to normal after 5 days of treatment. Histological analysis showed that the number of goblet cells in the CNE-ISG group significantly increased. HET-CAM stimulation test showed that the CNE-ISG group had no ocular irritation. The above results indicated that CNE-ISG might be a promising delivery system and as an effective dosage form was employed for FK506 in the treatment of DED.

Pegylated nanoceria: A versatile nanomaterial for noninvasive treatment of retinal diseases

Oxidative stress induced reactive oxygen species has been implicated as the primary molecular mechanism in the pathogenesis of debilitating retinal diseases such as diabetic retinopathy, neovascularization and age-related macular degeneration. Nanoceria (cerium oxide nanoparticles) has recently received much attention, because of its superior and regenerative radical scavenging properties. This review focuses on retinal applications of nanoceria and functionalized nanoceria. Studies in animal models showed that nanoceria possess antioxidant, anti-inflammatory, anti-angiogenic, anti-apoptotic properties and preserves retinal morphology and prevents loss of retinal functions. Nanoceria have been tested in animal models of age-related macular degeneration and neovascularization and their efficacy have been shown to persist for a long time, without any collateral effects. To date, several pharmaceutical formulations of nanoceria have been developed for their prospective clinical ophthalmic applications such as chitosan coated nanoceria, nanoceria loaded into hydrogels, nanoceria embedded in wafers and contact lens and organosilane or polyethylene glycol functionalized nanoceria. Based on their nano size range, ocular permeation could be achieved to allow topical administration of nanoceria. PEGylation of nanoceria represents the key strategy to support eye drop formulation with enhanced corneal permeation, without altering chemical physical properties. Based on their excellent antioxidant properties, nano-size, safety and tolerability, PEGylated nanoceria represent a new potential therapeutic for the treatment.

Recent trends and updates on ultradeformable and elastic vesicles in ocular drug delivery

Ocular drug delivery is enigmatic on account of various physiological precorneal barriers that ultimately hinder efficient drug penetration and corneal absorption. Ultradeformable vesicles embody non-ionic surfactants, edge activators and vesicular builders that provide enormous elasticity and deformability. The elastic vesicles can cross the ocular barriers owing to their peculiar squeezability and distorting ability and, thus, establish an infallible shot for ocular delivery. This review provides an overview of the recent advancements and updates of elastic vesicles as effective ocular drug delivery vehicles.

Mucin-targeting-aptamer functionalized liposomes for delivery of cyclosporin A for dry eye diseases

Traditional eye drops are convenient to use; however, their effectiveness is limited by their poor retention time and bioavailability in the eyes due to ocular barriers. Therefore, strategies to enhance ocular drug delivery are required. Herein, we constructed a mucin-1 aptamer-functionalized liposome and loaded it with cyclosporin A, a common ocular drug in eye drops used to treat dry eye diseases (DED). Drug encapsulation slightly reduced the liposome size without changing the surface potential of liposomes. Approximately 90% of the cholesterol-modified aptamers were inserted to the liposomes. We evaluated the cytotoxicity, anti-inflammatory effects, cell permeability regulation, and retention time of liposomes in human corneal epithelial cells under dry eye conditions. These results suggest that the aptamer-functionalized liposomes are more efficient as nanocarriers than non-functionalized liposomes and drug-free liposomes. They restore inflammation levels by 1-fold and remain in the cells for up to 24 h. An in vivo study was also performed in a rat DED model, which demonstrated the efficacy of aptamer-functionalized liposomes in restoring tear production and corneal integrity. The present study demonstrated the capability of aptamer-functionalized liposomes in the delivery of ocular drugs for the management of ocular diseases.

Preparation of a novel tacrolimus ion sensitive ocular in situ gel and in vivo evaluation of curative effect of immune conjunctivitis

BACKGROUND

The aim of this study was to formulate a novel TAC preparation into an in situ gel for ocular drug delivery, in order to prolong the residence time on mucosal surfaces and increase patient compliance.

METHODS

The optimal formulation was characterized by surface morphology, gelling capacity, viscosity, stability and in vitro release. In vivo studies were also conducted to evaluate the precorneal retention and pharmacodynamic results.

RESULTS

In this study, the TAC in situ gel can be prepared by a simple solvent stirring method, and the optimized formulation exhibited good stability within 3 months. During storage, the initial viscosity of the formula had little change. The results of viscosity measurement showed that TAC in situ gel was typical of pseudo plastic systems and exhibited a marked increase in viscosity stimulated with STF. In vitro and in vivo studies illustrated that TAC in situ gel administration facilitated the retention and sustained release of TAC.

CONCLUSIONS

TAC combined with in situ gelling agents demonstrates an efficient topical drug delivery platform.

Formulation and development of tacrolimus-gellan gum nanoformulation for treatment of dry eye disease

The present study aimed at the development and evaluation of tacrolimus gellan gum nanoparticles (TGNPs) for the effective management of dry eye disease (DED) following topical application. TGNPs were developed by ionotropic gelation between gellan gum and aluminum chloride. Developed TGNPs were nanosized (274.46 ± 8.90 nm) with high % encapsulation efficiency (74.2 ± 2.4%) and loading capacity (36.14 ± 1.7%). The nanosize and spherical morphology of TGNPs was confirmed by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) revealed no interaction between drug and GG. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) confirms the conversion of crystalline tacrolimus to amorphous post encapsulation in the nanoparticle. TGNPs showed prolonged drug release throughout 12 h and higher pre-corneal retention compared to tacrolimus solution. HET-CAM studies, histopathological evaluation, and Draize test confirmed the safety of the formulation for ocular use. Further, the pharmacodynamic studies using experimental DED in rabbits showed that TGNPs are effective in treating symptoms of DED. In conclusion, topical delivery of TGNPs could hold potential for efficient management of DED.

Ten Years of Knowledge of Nano-Carrier Based Drug Delivery Systems in Ophthalmology: Current Evidence, Challenges, and Future Prospective

The complex drug delivery barrier in the eye reduces the bioavailability of many drugs, resulting in poor therapeutic effects. It is necessary to investigate new drugs through appropriate delivery routes and vehicles. Nanotechnology has utilized various nano-carriers to develop potential ocular drug delivery techniques that interact with the ocular mucosa, prolong the retention time of drugs in the eye, and increase permeability. Additionally, nano-carriers such as liposomes, nanoparticles, nano-suspensions, nano-micelles, and nano-emulsions have grown in popularity as an effective theranostic application to combat different microbial superbugs. In this review, we summarize the nano-carrier based drug delivery system developments over the last decade, particularly review the biology, methodology, approaches, and clinical applications of nano-carrier based drug delivery system in the field of ocular therapeutics. Furthermore, this review addresses upcoming challenges, and provides an outlook on potential future trends of nano-carrier-based drug delivery approaches in ophthalmology, and hopes to eventually provide successful applications for treating ocular diseases.

Topical Tacrolimus Progylcosomes Nano-Vesicles As a Potential Therapy for Experimental Dry Eye Syndrome

The present work aimed to evaluate the efficacy of topical tacrolimus (0.01%) loaded propylene glycol (PG) modified nano-vesicles (Proglycosomes Nano-vesicles, PNVs) for the treatment of experimental dry eye syndrome (DES) in rabbits. DES was induced by topical application of atropine (1.0%) and benzalkonium chloride (0.1%) aqueous solution. PNVs treatment (PNV group) was compared with tacrolimus solution 0.01% (TAC group) and untreated group and healthy group were used as controls. PNV treated animals showed improved clinical performance with marked increase in tear production and tear break-up time (TBUT). Further, PNVs also subside ocular inflammation as evident from absence of matrix metalloprotenaise-9 and normal ocular surface temperature (32.3 ± 0.34 °C). Additionally, PNVs have positive effect on ocular and epithelial damage observed through low ocular surface staining score and improved globlet cell density. The PNV treatment was found to more effectively compared to TAC solution and most of the parameters were close to those of healthy animals. In conclusion, tacrolimus PNV formulation (0.01%) could be a potential therapy for treatment of dry eye syndrome.

Formulation development, optimization, and in vitro assessment of thermoresponsive ophthalmic pluronic F127-chitosan in situ tacrolimus gel

To overcome problems associated with topical delivery of tacrolimus (TCS), a thermoresponsive in situ gel system containing pluronic F127 (PL), and chitosan (CS) was developed, to enhance the precorneal retention, and to sustain the release of the drug. The PL-CS in situ gel was optimized using a 2-factor-3-level central composite experimental design by selecting the concentration of PL and CS as independent variables while gelation time, gelation temperature, and spreadability as dependent variables. The optimized formulation was developed using 22.5 g PL and 0.3 g CS, gels at 33.6 °C, in 22.93 s, and showed the spreadability of 6.2 cm. In vitro studies conducted for the optimized gel revealed the sustained release of TCS (81.73% in 4 h) and improved corneal permeation (74.13% in 4 h), compared with TCS solution. The mechanism of release of TCS followed the Higuchi model with Fickian diffusion transport. Further, histopathology and HET-CAM studies revealed that the developed gel was non-irritating and safe for ocular administration.

Topical tacrolimus nanocapsules eye drops for therapeutic effect enhancement in both anterior and posterior ocular inflammation models

Tacrolimus has shown efficacy in eye inflammatory diseases. However, due to the drug lability, its formulation into a stable ophthalmic product remains a challenge. Tacrolimus-loaded nanocapsules (NCs) were designed for ocular instillation. Further, the stability and effects of the formulation were analyzed under different experimental conditions. Physicochemical characterization of the NCs revealed suitable homogeneous size and high encapsulation efficiency. Moreover, the lyophilized formulation was stable at ICH long term and accelerated storage conditions, for at least 18 and 3 months, respectively. The tacrolimus NCs did not elicit any eye irritation in rabbits after single- and multiple-dose applications. Additionally, ex vivo penetration assays on isolated porcine cornea and pharmacokinetics analyses in various rabbit eye compartments demonstrated the superiority of the NCs in retention and permeation into the anterior chamber of the eye compared to the free drug dissolved in oil. Moreover, multiple dose ocular instillation of the NCs in rats allowed high tacrolimus levels in the eye with very low plasma concentrations. Finally, the developed delivery system achieved a significant decrease in four typical inflammatory markers in a murine model of keratitis, an anterior chamber inflammation. Furthermore, these NCs, applied as eye drops, displayed clinical and histological efficacy in the mainly posterior chamber inflammation model of murine, experimental auto-immune uveitis.

Amelioration of Endotoxin-Induced Uveitis in Rabbit by Topical Administration of Tacrolimus Proglycosome Nano-Vesicles

This work was aimed to improve the efficacy of tacrolimus in the treatment of endotoxin-induced uveitis (EIU) using propylene glycol modified lipid vesicles termed as proglycosome nano-vesicles (PNVs). PNVs were prepared by modified film hydration method. Experimental uveitis in rabbit eye was induced by an intravitreal injection of 20 μL of the endotoxin solution containing 100 ng of lipopolysaccharide endotoxin. In vivo efficacy of PNVs was determined by studying clinical symptoms of uveitis using slit lamp examination and by quantitatively measuring levels of tumor necrosis factor-alpha, interleukin-6, leukocytes and total proteins in aqueous humor, 24 h after intravitreal injection of endotoxin. Comparison was made with healthy, untreated and tacrolimus solution treated eyes. PNVs developed were nano-sized, deformable and showed sustained release of tacrolimus over period of 12 h. In vivo results indicated statistically significant difference between the effects of PNVs in the treatment of EIU compared to tacrolimus. PNV treatment not only subsides clinical symptoms of uveitis but also prevented breakdown of blood aqueous barrier. Tacrolimus loaded PNVs are potential new topical treatment for uveitis.

Nanotechnology for the Treatment of Allergic Conjunctival Diseases

Allergic conjunctivitis is one of the most common external eye diseases and the prevalence has been increasing. The mainstay of treatment is topical eye drops. However, low bioavailability, low ocular drug penetration, transient resident time on the ocular surface due to tear turnover, frequent topical applications and dependence on patient compliance, are the main drawbacks associated with topical administration. Nanotechnology-based medicine has emerged to circumvent these limitations, by encapsulating the drugs and preventing them from degradation and therefore providing sustained and controlled release. Using a nanotechnology-based approach to load the drug is particularly useful for the delivery of hydrophobic drugs such as immunomodulatory agents, which are commonly used in allergic conjunctival diseases. In this review, different nanotechnology-based drug delivery systems, including nanoemulsions, liposomes, nanomicelles, nanosuspension, polymeric and lipid nanoparticles, and their potential ophthalmic applications, as well as advantages and disadvantages, are discussed. We also summarize the results of present studies on the loading of immunomodulators or nonsteroidal anti-inflammatory drugs to nano-scaled drug delivery systems. For future potential clinical use, research should focus on the optimization of drug delivery designs that provide adequate and effective doses with safe and satisfactory pharmacokinetic and pharmaco-toxic profiles.

Polyoliposomes: novel polyol-modified lipidic nanovesicles for dermal and transdermal delivery of drugs

Various lipid nanovesicular systems have been developed with the aim to enhance the delivery of drugs via transdermal route. However, their clinical applications are often limited due to the barrier nature of skin and lack of flexibility. Herein, we have modified the conventional nanoliposomes (CLs) prepared by a thin-film hydration method by the addition of a polyol (glycerol) to form novel lipid nanovesicular structures termed 'POLYOLIPOSOMES' (PLs). They were further named as PL-B (before film formation) and PL-A (after film formation), depending on the stage of glycerol addition during production. Optimized CLs, PL-B and PL-A showed spherical nanovesicles and hydrodynamic diameter of 181.3 ± 4.11 nm, 114.2 ± 7.21 nm and 170.2 ± 6.51 nm, respectively. PLs showed significantly higher % entrapment efficiency and deformability index in comparison to CLs, indicating their higher flexibility. Furthermore, DSC and attenuated total relection (ATR)-Fourier transform infrared (FTIR) studies revealed the intercalation of glycerol into the lipid bilayer of PLs and interaction between nanovesicles and skin. Moreover, ex vivo and in vivo skin permeation studies confirmed the enhanced drug delivery of PLs via the transdermal route. Taken together, these results illustrate the potential of PLs as a novel lipid nanovesicular system for drug delivery via the transdermal route for both systematic (PL-B) as well as cutaneous diseases (PL-A).

Cationic nanoemulsions with prolonged retention time as promising carriers for ophthalmic delivery of tacrolimus

Tacrolimus, also known as FK506, is a first-line drug for the topical treatment of immune-mediated inflammatory anterior ocular diseases (IIAODs). However, due to its limited water solubility, hydrophobic nature and relatively high molecular weight, topical application of FK506 features poor bioavailability. Numbers of formulations have been attempted to enhance the erratic bioavailability of FK506 through various techniques. But until now, none of them could satisfy the clinical needs completely. Here, a novel formulation of FK506, FK506-loaded cationic nanoemulsions (FK506 CNE), was developed to prolong the precorneal residence time of FK506, thereby enhancing the bioavailability of FK506 for IIAODs therapy. FK506 CNE was prepared by high-pressure homogenization, and its composition was screened and optimized by single-factor experiments. The FK506 CNE showed spherical morphology with a mean diameter of 178.8 ± 2.7 nm and a zeta potential of +25.6 ± 0.6 mV. Results from in vivo gamma scintigraphy studies proved that the precorneal residence time of FK506 CNE was significantly increased, compared with FK506-loaded neutral nanoemulsions (FK506 NE) and saline. The data of aqueous humor pharmacokinetic study in rabbits showed that the relative bioavailability of FK506 CNE was 1.68-fold and 1.77-fold of FK506 NE and the marketed FK506 eye drops (Talymus®), respectively. Finally, hematoxylin and eosin staining images and in vitro cytotoxicity data confirmed the safety of the FK506 CNE. Taking all these into consideration, we propose that FK506 CNE is a promising topical ophthalmic nanoformulation for the management of IIAODs.