Design and ocular tolerance of flurbiprofen loaded ultrasound-engineered NLC

Antifungal Efficacy of Luliconazole-Loaded Nanostructured Lipid-Carrier Gel in an Animal Model of Dermatophytosis

Background:Trichophyton indotineae terbinafine-resistant infections are emerging in healthy individuals. Luliconazole, an imidazole antifungal that is effective against skin infections, faces challenges due to low water solubility and poor skin penetration. This study aimed to formulate a luliconazole-loaded nanostructured lipid-carrier (NLC) gel in a Carbopol-based system to enhance drug absorption and efficacy in a guinea pig model of dermatophytosis. Methods: Luliconazole-loaded nanostructured lipid carriers (NLCs) were prepared using a solvent evaporation method and gel formulation. Skin absorption and retention were assessed via Franz diffusion cells. The antifungal efficacy was tested against T. indotineae in thirty guinea pigs with induced tinea corporis, divided into five treatment groups. Mycological, clinical, and histopathological evaluations were conducted, along with skin irritation studies for safety. Results: LCZ-NLC demonstrated significantly better skin penetration than simple luliconazole gel, with cumulative drug penetration of 71.8 ± 3.7 μg/cm2 versus 50.9 ± 4.2 μg/cm2 after 24 h. Both formulations achieved complete infection resolution after 21 and 28 days, with reduced inflammation and no local irritations. On day 21, the LCZ-NLC 1% gel significantly reduced lesion scores and mycological evidence of infection compared to the terbinafine-treated groups, untreated controls, and NLC-gel-treated group (p < 0.05). Histopathological analysis indicated a reduction in both epidermal thickening and fungal burden in the models that received treatment with the LCZ-NLC 1% gel. Conclusions: Luliconazole-loaded lipid carriers enhance drug absorption and efficacy, suggesting shorter treatment durations and improved patient outcomes for resistant fungal infections. However, further studies are warranted to correlate these findings with clinical outcomes.

Hyaluronate-incorporated edaravone nanostructured lipid carriers for nose-to-brain targeting- biphasic DoE optimization, pharmacokinetic, and brain distribution studies

The present research aimed to develop nasal delivery for edaravone (EDR), a BCS class-IV neuroprotective agent. EDR nanostructured lipid carriers (EDR NLCs) were developed by melt-emulsification probe sonication using Geleol™ (solid lipid), Miglyol®812N and coconut oil (liquid lipid), Tween 20 (surfactant), Lipoid S75 (emulsifier) and sodium hyaluronate (SH) as mucoadhesive agent. A biphasic optimization approach for NLCs was implemented using the Plackett-Burman design and Box-Behnken design to comprehensively understand key formulation and process variables affecting critical attributes of NLCs. The mucoadhesive strength of optimized EDR-SH NLCs was 2.22-fold higher than EDR NLCs. Drug release of NLCs was 2-fold higher than EDR. The partial amorphous nature of EDR in the NLC matrix was evident from DSC and XRD results. A pharmacokinetic study in rats revealed that EDR-SH NLCs exhibited 4.42-fold, 1.27-fold and 8.75-fold enhanced AUC than EDR, EDR NLCs and marketed formulation. In brain distribution, drug targeting efficiency and direct transport percentage of EDR-SH NLCs were 2.4-fold, 1.17-fold higher than EDR, indicating efficient brain targeting via direct pathways. Thus, nasal delivery of EDR-SH NLCs improves brain targeting and provides a self-administration alternative for long-term use to mitigate neurological disorders.

Tolerogenic nanovaccines for the treatment of type I allergic diseases

The high prevalence of type I allergic diseases such as allergic rhinitis, allergic asthma, food allergies, allergic conjunctivitis, and atopic dermatitis has emerged as a significant public health concern globally. Failure of immune tolerance to ordinarily harmless substances or stimulation, and subsequent induction of T helper 2 cells by antigen-presenting cells evokes the allergic immune response, which results in persistent inflammation, tissue damage, and organ function impairment. Current therapeutic approaches for allergic diseases include avoiding allergen exposure, corticosteroids, biologics, etc. However, these strategies only relieve allergic symptoms but hardly prevent the deteriorative progression and may have adverse effects on patients. With the rapid development of nanotechnology and immunology, emerging tolerogenic nanovaccines represent novel approaches with the potential to cure type I allergic diseases rather than merely alleviate symptoms. In this review, we expound the burgeoning field of tolerogenic nanovaccines against type I allergic diseases, highlight various types of antigens employed in constructing allergen extracts, protein/peptide and nucleic acid-based tolerogenic nanovaccines, and discuss their application in allergic rhinitis, allergic asthma, food allergies, allergic conjunctivitis, and atopic dermatitis.

Transcutaneous delivery of disease-specific PI3K/Akt/mTOR inhibitor-based hybrid nanoparticles in hydrogel system for the management of psoriasis: Insights from in vivo studies

Psoriasis is a chronic autoimmune skin disorder characterized by excessive epidermis thickening, keratinocyte proliferation, and angiogenesis, driven by the PI3K/Akt/mTORC1, one of the key signalling axis of psoriasis. Corticosteroids used for treatment have limited efficacy and numerous side effects, thereby necessitating the development of safer, targeted therapeutic options for improved disease management and patient outcomes. Here we address this problem by encapsulating the PI3K/Akt/mTORC1 inhibitor Rapamycin in lipid-polymeric conjugated hybrid nanoparticles (RPMN) and incorporating these particles in a carbopol-based hydrogel system (RPMNGel), with enhanced release kinetics, long-term stability, better spreadability over reported literature for the treatment of psoriasis, and skin residence time. Using an in-vivo imiquimod-induced psoriatic model, in comparison to free drug-loaded gels, RPMNGel showed increased accumulation and deeper epidermal penetration, and slower diffusion within the psoriatic skin without causing any side effects to normal skin. The cumulative psoriasis area severity index score reduced from 10.5 to 5. 1 at day 7 in the group treated with RPMNGel. Overall, our studies establish the efficacy of RPMNGel for improved psoriasis treatment and management through enhanced drug penetration, prolonged drug release and reduced systemic toxicity.

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.

The role of metal nanocarriers, liposomes and chitosan-based nanoparticles in diabetic retinopathy treatment: A review study

Diabetic Retinopathy (DR) is a significant and progressive eye complication associated with diabetes mellitus, leading to potential vision loss. The pathophysiology of DR involves complex neurovascular changes due to prolonged hyperglycemia, resulting in microangiopathy and neurodegeneration. Current treatment modalities come with limitations such as low bioavailability of therapeutic agents, risk of side effects, and surgical complications. Consequently, the prevention and management of DR, particularly in its advanced stages, present ongoing challenges. This review investigates recent advancements in nanotechnology as a novel approach to enhance the treatment of DR. A comprehensive literature review of recent studies focusing on nanocarriers for drug delivery in DR treatment and an analysis of their efficacy compared to traditional methods was conducted for this study. The findings indicate that nanotechnology can significantly enhance the bioavailability of therapeutic agents while minimizing systemic exposure and associated side effects. The novelty of this study lies in its focus on the intersection of nanotechnology and ophthalmology, exploring innovative solutions that extend beyond existing literature on DR treatments. By highlighting recent advancements in this field, the study paves the way for future research aimed at developing more effective therapeutic strategies for managing DR.

Nanostructured Lipid Carrier-loaded In Situ Gel for Ophthalmic Drug Delivery: Preparation and In Vitro Characterization Studies

BACKGROUND

Nanostructured lipid carriers (NLCs) are explored as vehicles for ophthalmic drug delivery owing to their better drug loading, good permeation, and satisfactory safety profile.

OBJECTIVES

The purpose of the study was to fabricate and characterize an in situ ocular gel of loratadine as a model drug based on NLCs to enhance the drug residence time.

METHODS

NLCs were fabricated using the microemulsion method in which solid lipid as Compritol 888 ATO, lipid as oleic acid, surfactant as Tween 80, and isopropyl alcohol as co-surfactant as alcohol were used. Based on the evaluation of formulation batches of NLCs, the optimized batch was selected and further utilized for the formulation of in situ gel containing Carbopol 934 and HPMC K15M as gelling agents, and characterized Results: The optimized NLCs of loratadine exhibited entrapment efficiency of 83.13 ± 0.13% and an average particle size of 18.98 ± 1.22 nm. Drug content and drug release were found to be 98.67 and 92.48%, respectively. Excellent rheology and mucoadhesion were demonstrated by the loratadine NLC-loaded in situ gel to enhance its attachment to the mucosa. NLC-based in situ ocular gel showed the desired results for topical administration. The prepared gel was observed to be non-irritating to the eye.

CONCLUSION

The optimized NLC-based in situ gel formulation presented better corneal retention and it was found to be stable, offering sustained release of the drug. Thus, the joined system of sol-gel was found promising for ophthalmic drug delivery.

Nano-delivery Systems and Therapeutic Applications of Phytodrug Mangiferin

In order to cure a range of ailments, scientists have investigated a number of bioactive antioxidant compounds produced from natural sources. Mangiferin, a C-glycosyl xanthone-structured yellow polyphenol, is abundant in mangoes and other dietary sources. In-depth examinations found that it is effective in the treatment of a variety of disorders due to its antiviral, anti-inflammatory, antiproliferative, antigenotoxic, antiatherogenic, radioprotective, nephroprotective, antihyperlipidemic, and antidiabetic properties. However, it is recognised that mangiferin's poor bioavailability, volatility, and limited solubility restrict its therapeutic usefulness. Over time, effective solutions to these problems have arisen in the shape of effective delivery methods. The current articles present a summary of the several researches that have updated Mangiferin's biopharmaceutical characteristics. Additionally, strategies for enhancing the bioavailability, stability, and solubility of this phytodrug have been discussed. This review provides detailed information on the development of innovative Mangiferin delivery methods such as nanoparticles, liposomes, micelles, niosomes, microspheres, metal nanoparticles, and complexation, as well as its therapeutic applications in a variety of sectors. This article provides effective guidance for researchers who desire to work on the formulation and development of an effective delivery method for improved magniferin therapeutic effectiveness.

Augmented ocular uptake and anti-inflammatory efficacy of decorated Genistein-loaded NLCs incorporated in in situ gel

Genistein (Gen); a naturally occurring isoflavone, acts as a tyrosine kinase inhibitor and efficiently downregulates inflammatory cytokines, which are pivotal in eye inflammation. Also, Gen suffers from sparse ocular bioavailability due to poor solubility. In this work, nanostructured lipid carriers (NLCs) were successfully fabricated by using solid (stearic acid and compritol) and liquid (oleic acid) lipids. The optimized Gen-loaded NLCs showed a nanosize range of 140-246 nm, ≥ 98 % entrapment efficiency, and controlled release over 48 h. The ζ-potential of NLCs was increased from -27.3 mV to 25-27.4 mV due to surface modification with chitosan (CS) or eudragit RS100 (ERS 100). All NLCs showed prominent biocompatibility with enhanced cellular uptake on corneal stromal fibroblasts. Moreover, the different NLCs were incorporated into a mucoadhesive in situ gel. The optimized in situ gel (G9), containing 20 % poloxamers and 0.5 % hydroxyethyl cellulose, exhibited excellent gelling ability within 10.5 s, gelling temperature at 33.1 ± 0.6 ℃, spreadability diameter of 4.73 ± 0.12 cm, shear-thinning behavior, and 20 min ex vivo mucoadhesion time with drug release for 120 h. The in vivo results showed distinguished permeation and distribution potential for ocular delivery. In vivo anti-inflammatory effects after 3 days of treatment with CS-Gen-NLCs/G9 and ERS-Gen-NLCs/G9 revealed a downregulation of interleukin-6 levels in the cornea and retina compared to the untreated group. Our research highlights the promising anti-inflammatory potential of ERS-Gen-NLCs/G9 as an efficient, non-irritant Gen nanodelivery system for managing anterior and posterior ocular inflammation.

Formulation of hesperidin-loaded in situ gel for ocular drug delivery: a comprehensive study

BACKGROUND

Allergic conjunctivitis is one of the most common eye disorders. Different drugs are used for its treatment. Hesperidin is an active substance isolated from Citrus sinensis L. (Rutaceae) fruit peels, with known anti-inflammatory activity but low solubility. It was complexed with cyclodextrin and encapsulated in situ gel to extend its duration in the eye.

RESULTS

The optimized formulation comprised 1% hesperidin, 1.5% hydroxyethyl cellulose, and 16% poloxamer 407. The viscosity at 25 °C was 492 ± 82 cP, and at 35 °C it was 8875 ± 248 cP, the pH was 7.01 ± 0.03, gelation temperature was 34 ± 1.3 °C, and gelation time was 33 ± 1.2 s. There was a 66% in vitro release in the initial 2 h, with a burst effect. A lipoxygenase (LOX) inhibition test determined that hesperidin was active at high doses on leukotyrens seen in the body in allergic diseases. In cell-culture studies, the hesperidin cyclodextrin complex loaded in situ gel, BRN9-CD (poloxamer 16%, hydroxy ethyl cellulose (HEC) 1.5%), enhanced cell viability in comparison with the hesperidin solution. It was determined that BRN9-CD did not cause any irritation in the ocular tissues in the Draize test.

CONCLUSION

The findings of this study demonstrate the potential of the in situ gel formulation of hesperidin in terms of ease of application and residence time on the ocular surface. Due to its notable LOX inhibition activity and positive outcomes in the in vivo Draize test, it appears promising for incorporation into pharmaceutical formulations. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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.

Nanocomposite Gels Loaded with Flurbiprofen: Characterization and Skin Permeability Assessment in Different Skin Species

Nanocomposite gels consist of nanoparticles dispersed in a gel matrix. The main aim of this work was to develop nanocomposite gels for topical delivery of Flurbiprofen (FB) for humans and farm animals. Nanocomposite gels were prepared stemming from nanoparticles (NPs) freeze-dried with two different cryoprotectants, D-(+)-trehalose (NPs-TRE) and polyethylene glycol 3350 (NPs-PEG), sterilized by gamma (γ) irradiation, and gelled with Sepigel® 305. Nanocomposite gels with FB-NPs-TRE and FB-NPs-PEG were physiochemically characterized in terms of appearance, pH, morphological studies, porosity, swelling, degradation, extensibility, and rheological behavior. The drug release profile and kinetics were assessed, as well as, the ex vivo permeation of FB was assessed in human, porcine and bovine skin. In vivo studies in healthy human volunteers were tested without FB to assess the tolerance of the gels with nanoparticles. Physicochemical studies demonstrated the suitability of the gel formulations. The ex vivo skin permeation capacity of FB-NPs nanocomposite gels with different cryoprotectants allowed us to conclude that these formulations are suitable topical delivery systems for human and veterinary medicine. However, there were statistically significant differences in the permeation of each formulation depending on the skin. Results suggested that FB-NPs-PEG nanocomposite gel was most suitable for human and porcine skin, and the FB-NPs-TRE nanocomposite gel was most suitable for bovine skin.

Formulation development of Lornoxicam loaded heat triggered ocular in-situ gel using factorial design

OBJECTIVE

In the current research, lornoxicam-loaded in situ gels were developed, and their potential usage in ocular inflammation was evaluated.

SIGNIFICANCE

Lornoxicam cyclodextrin complex prepared with hydroxypropyl methylcellulose and poloxamer P407 because of the low viscosity of in situ gels to provide easy application. However, washing and removing it from the ocular surface becomes difficult due to the gelation formation with heat.

METHODS

A three-level factorial experimental design was used to evaluate the effects of poloxamer 407 concentration, polymer type, and polymer concentration on viscosity, pH, gelation capacity, gelation time, and gelation temperature, which were considered the optimal indicators of lornoxicam-containing formulations.

RESULTS

As a result of the three-level factorial experimental design, the optimized formulation contained 15 (%w/v) poloxamer 407 and 1 (%w/v) hydroxypropyl methylcellulose. The optimize formulation viscosity 25 °C = 504 ± 49cP, viscosity 35 °C = 11247 ± 214cP, pH = 6.80 ± 0.01, gelation temprature = 35 ± 0.2 °C, and gelation time= 34 ± 0.2 s was obtained. In the in vitro release studies, 68% of lornoxicam was released with a burst effect in the first three hours; then, the release continued for eight hours with controlled release. Release kinetics of the formulations were modeled mathematically, and it was found to be compatible with the Korsemeyer-Peppas and Weibull models. In cell culture studies, cell viability at 100 µg/mL was 83% and 96% for NL6 and NL6-CD, respectively. In Draize's in vivo test, no negative conditions occurred in rats.

CONCLUSIONS

Therefore, the NL6-CD formulation has the potential to be a favorable option for treating ocular inflammation.

Topical caffeine-loaded nanostructured lipid carriers for enhanced treatment of cellulite: A 32 full factorial design optimization and in vivo evaluation in rats

The goal of this study was the development and evaluation of semisolid caffeine (CAF) loaded nanostructured lipid carriers (NLCs) for topical treatment of cellulite. CAF-loaded NLC formulations were prepared via high-speed homogenization followed by ultrasonication. A 32 full factorial design was employed for formulation optimization. The total lipid content (%) and the liquid lipid content per total lipids (%) were chosen as factors, whereas particle size (PS), polydispersity index (PDI), zeta potential (|ZP|) and viscosity (VIS) were selected as responses. The design suggested CAF-NLC3 as the optimum formulation consisting of a total lipid content of 15% w/w (palmitic acid and soft paraffin/isopropyl myristate, 7:3 w/w) and a surfactant content of 10% w/w (Tween 80/lecithin, 8:1.2 w/w). CAF-NLC3 revealed PS, PDI, ZP, VIS and CAF content values of 318.8 nm, 0.253, -41.1 mV, 18.0 Pa.s and 97.57%, respectively. It showed a pseudoplastic rheological behavior, acceptable pH value (5.25), good spreadability (1.12 mm2/g) and spherical shape employing transmission electron microscopy. Differential scanning calorimetry and X-ray diffraction demonstrated the amorphization of CAF in CAF-NLC3. CAF-NLC3 remained stable for 3 months at room and refrigeration conditions. A single topical application of CAF-NLC3 on shaved abdominal skins of Wistar rats revealed enhanced skin retention of CAF by 2-fold and 1.4-fold after 4 h when compared with plain CAF gel (CAF-P) and marketed CAF gel (CAF-M), respectively. Furthermore, CAF-NLC3 exhibited a superior anti-cellulite activity in comparison with CAF-P and CAF-M through elevating extracellular matrix components (collagen 1, elastin and hyaluronic acid) and stimulating the brown adipose tissue thermogenesis via up-regulating UCP1 and PPAR-γ expression. In addition, CAF-NLC3 prominently increased lipolysis through HSL activity and decreased pro-inflammatory cytokines such as ICAM-1 and VCAM-1 after 30 days of treatment on a high fat diet-induced cellulite rat model. These findings were further confirmed by histopathological examination supported by morphometric analysis. Therefore, incorporation of CAF in a semisolid NLC formulation would be a promising cosmetic approach for the topical treatment of cellulite.

Gatifloxacin Loaded Nano Lipid Carriers for the Management of Bacterial Conjunctivitis

Bacterial conjunctivitis (BC) entails inflammation of the ocular mucous membrane. Early effective treatment of BC can prevent the spread of the infection to the intraocular tissues, which could lead to bacterial endophthalmitis or serious visual disability. In 2003, gatifloxacin (GTX) eyedrops were introduced as a new broad-spectrum fluoroquinolone to treat BC. Subsequently, GTX use was extended to other ocular bacterial infections. However, due to precorneal loss and poor ocular bioavailability, frequent administration of the commercial eyedrops is necessary, leading to poor patient compliance. Thus, the goal of the current investigation was to formulate GTX in a lipid-based drug delivery system to overcome the challenges with the existing marketed eyedrops and, thus, improve the management of bacterial conjunctivitis. GTX-NLCs and SLNs were formulated with a hot homogenization-probe sonication method. The lead GTX-NLC formulation was characterized and assessed for in vitro drug release, antimicrobial efficacy (against methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa), and ex vivo permeation. The lead formulation exhibited desired physicochemical characteristics, an extended release of GTX over a 12 h period, and was stable over three months at the three storage conditions (refrigerated, room temperature, and accelerated). The transcorneal flux and permeability of GTX from the GTX-NLC formulation were 5.5- and 6.0-fold higher in comparison to the commercial eyedrops and exhibited a similar in vitro antibacterial activity. Therefore, GTX-NLCs could serve as an alternative drug delivery platform to improve treatment outcomes in BC.

Chitosan-Coated SLN: A Potential System for Ocular Delivery of Metronidazole

Ophthalmic drops for ocular delivery exhibit inadequate residence time, which often requires multiple daily dosing that may result in patient non-adherence. In this study, the development of a once-daily-dosed chitosan-coated metronidazole (MTZ)-loaded solid lipid nanoparticles (SLNs) for ocular delivery was undertaken. Melt emulsification and ultrasonication were used to manufacture MTZ-loaded SLN, which were subsequently coated with chitosan (CS) by mechanical stirring using a 0.1% w/v solution. Gelucire^® 48/16 and Transcutol^® HP were used as the solid lipid and synthetic solvent, respectively, with Tween^® 20 included as a stabilizing agent. The critical quality attributes (CQA) of the optimized CS-coated SLN that was monitored included particle size, polydispersity index, Zeta potential, % entrapment efficiency, % MTZ loading, pH, and osmolarity. The optimized coated nanocarriers were evaluated using laser Doppler anemometry (LDA) and were determined to be stable, with particle sizes in the nanometre range. In vitro mucoadhesion, MTZ release and short-term stability, in addition to the determination of the shape of the optimized CS-coated SLN, were undertaken. The mucoadhesive properties of the optimized CS-coated MTZ-loaded SLN demonstrated increased ocular availability, which may allow dose reduction or longer intervals between doses by improving precorneal retention and ocular availability. Overall, our findings suggest that CS-coated MTZ-loaded SLNs have the potential for clinical application, to enhance ocular delivery through the release of MTZ.

Ocular Drug Delivery: a Comprehensive Review

The human eye is a sophisticated organ with distinctive anatomy and physiology that hinders the passage of drugs into targeted ophthalmic sites. Effective topical administration is an interest of scientists for many decades. Their difficult mission is to prolong drug residence time and guarantee an appropriate ocular permeation. Several ocular obstacles oppose effective drug delivery such as precorneal, corneal, and blood-corneal barriers. Routes for ocular delivery include topical, intravitreal, intraocular, juxtascleral, subconjunctival, intracameral, and retrobulbar. More than 95% of marketed products exists in liquid state. However, other products could be in semi-solid (ointments and gels), solid state (powder, insert and lens), or mixed (in situ gel). Nowadays, attractiveness to nanotechnology-based carries is resulted from their capabilities to entrap both hydrophilic and lipophilic drugs, enhance ocular permeability, sustain residence time, improve drug stability, and augment bioavailability. Different in vitro, ex vivo, and in vivo characterization approaches help to predict the outcomes of the constructed nanocarriers. This review aims to clarify anatomy of the eye, various ocular diseases, and obstacles to ocular delivery. Moreover, it studies the advantages and drawbacks of different ocular routes of administration and dosage forms. This review also discusses different nanostructured platforms and their characterization approaches. Strategies to enhance ocular bioavailability are also explained. Finally, recent advances in ocular delivery are described.

Development of Lipid Nanoparticles Containing Omega-3-Rich Extract of Microalga Nannochlorpsis gaditana

Microalgae are described as a new source of a wide range of bioactive compounds with health-promoting properties, such as omega-3 lipids. This biomass product is gaining attention mainly due to its potential to accumulate different compounds depending on the species and environment, and it has been commonly recognized as a valuable nutraceutical alternative to fish and krill oils. In this work, we obtained the extract of the microalga Nannochloropsis gaditana, selected on the basis of its content of eicosapentaenoic acid (EPA) and glycolipids, which were determined using GC-MS and high-performance liquid chromatography (HPLC), respectively. To develop an oral formulation for the delivery of the extract, we used a 2³ factorial design approach to obtain an optimal lipid nanoparticle formulation. The surfactant and solid lipid content were set as the independent variables, while the particle size, polydispersity index, and zeta potential were taken as the dependent variables of the design. To ensure the potential use of the optimum LN formulation to protect and modify the release of the loaded microalga extract, rheological and differential scanning calorimetry analyses were carried out. The developed formulations were found to be stable over 30 days, with an encapsulation efficiency over 60%.

Novel Strategies against Cancer: Dexibuprofen-Loaded Nanostructured Lipid Carriers

The aim of this work was to design innovative nanostructured lipid carriers (NLCs) for the delivery of dexibuprofen (DXI) as an antiproliferative therapy against tumoral processes, and overcome its side effects. DXI-NLC samples were prepared with beeswax, Miglyol 812 and Tween 80 using high-pressure homogenization. A two-level factorial design 2⁴ was applied to optimize the formulation, and physicochemical properties such as particle size, zeta potential, polydispersity index and entrapment efficiency were measured. Optimized parameters of DXI-NLCs exhibited a mean particle size of 152.3 nm, a polydispersity index below 0.2, and high DXI entrapment efficiency (higher than 99%). Moreover, DXI-NLCs provided a prolonged drug release, slower than the free DXI. DXI-NLCs were stable for 2 months and their morphology revealed that they possess a spherical shape. In vitro cytotoxicity and anticancer potential studies were performed towards prostate (PC-3) and breast (MDA-MB-468) cancer cell lines. The highest activity of DXI-NLCs was observed towards breast cancer cells, which were effectively inhibited at 3.4 μM. Therefore, DXI-NLCs constitute a promising antiproliferative therapy that has proven to be especially effective against breast cancer.

Nutraceuticals and Food-Grade Lipid Nanoparticles: From Natural Sources to a Circular Bioeconomy Approach

Nutraceuticals have gained increasing attention over the last years due to their potential value as therapeutic compounds formulated from natural sources. For instance, there is a wide range of literature about the cardioprotective properties of omega-3 lipids and the antioxidant value of some phenolic compounds, which are related to antitumoral activity. However, the value of nutraceuticals can be limited by their instability under gastric pH and intestinal fluids, their low solubility and absorption. That is why encapsulation is a crucial step in nutraceutical design. In fact, pharmaceutical nanotechnology improves nutraceutical stability and bioavailability through the design and production of efficient nanoparticles (NPs). Lipid nanoparticles protect the bioactive compounds from light and external damage, including the gastric and intestinal conditions, providing a retarded delivery in the target area and guaranteeing the expected therapeutic effect of the nutraceutical. This review will focus on the key aspects of the encapsulation of bioactive compounds into lipid nanoparticles, exploring the pharmaceutical production methods available for the synthesis of NPs containing nutraceuticals. Moreover, the most common nutraceuticals will be discussed, considering the bioactive compounds, their natural source and the described biological properties.

Applications and perspectives of polyphenol-loaded solid lipid nanoparticles and nanostructured lipid carriers for foods

Imbalanced nutrition in modern society is one of the reasons for disorders, such as cancer, cardiovascular disease, and diabetes, which have attracted the interest in bioactives (particularly polyphenols) to assist in the balanced diet of modern people. Although stability can be maintained during preparation and storage, the ingested polyphenols undergo harsh gastrointestinal digestion processes, resulting in limited bioaccessibility and low gut-epithelial permeation and bioavailability. Several lipid-based formulations have been proposed to overcome these issues. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) have also been highlighted as carrier systems for the oral delivery of lipophilic bioactives, including polyphenols. This paper summarizes the research on the ingredients, production methods, post-processing procedures, general characteristics, and advantages and disadvantages of SLNs and NLCs. Overall, this paper reviews the applications and perspectives of polyphenol-loaded SLNs and NLCs in foods, as well as their regulation, production, storage, and economic feasibility.

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.

Design of Besifloxacin HCl-Loaded Nanostructured Lipid Carriers: In Vitro and Ex Vivo Evaluation

Objective: In the treatment of severe cases of bacterial keratitis, conventional eye drops containing antibiotics should be applied daily and very frequently. The aim of this study is to develop low-dose high-effect formulations with the prepared nanostructured lipid carrier (NLC) formulations to reduce antibiotic resistance and increase patient compliance. Methods: NLC formulations were loaded with besifloxacin HCl (BHL) and the besifloxacin HCl: sulfobutyl ether beta-cyclodextrin (SBE-CD) complex. Positive charge was gained with chitosan, and corneal permeation and resolubility were increased with SBE-CD. In vitro characterization studies, permeability studies, and cytotoxicity and ex vivo transport studies were carried out. Results: In this study, it was found that SBE-CD increased BHL's solubility by 8-fold based on phase solubility studies. The optimized NLCs were small in size (13.63-16.09 nm) with a low polydispersity index (0.107-0.181) and adequate BHL drug loading efficiency. In vitro release studies showed that formulations were released approximately for 8 h and at levels over the minimum inhibitory concentration of Pseudomonas aeruginosa and Staphylococcus aureus. NLC formulations had a better corneal permeation rate than the marketed product during 6 h of ex vivo studies. Conclusions: According to in vitro and ex vivo data, it was determined that the most favorable NLC formulation was the formulation containing BHL/SBE-CD that was covered with chitosan. It has the highest drug loading capacity and one of the highest ex vivo corneal passage levels, along with desired drug release. The formulation containing BHL/SBE-CD and chitosan can be a potential alternative for the treatment of bacterial keratitis.

Delivery of Hydrophobic Drugs to the Posterior Ocular Region by Gel-in-Water Nanoemulsion

Purpose

The aim of this study was to develop a nanogel emulsion as a minimally invasive, safe, and effective treatment alternative for posterior ocular diseases.

Methods

A gel-in-water (G/W) nanoemulsion was developed by ultrasonication using beeswax as an organogelator. Different physicochemical properties were evaluated along with particle size analysis by dynamic light scattering. In vitro biocompatibility of G/W nanoemulsion using rat hepatocytes and human umbilical vein endothelial cells (HUVECs) and in vivo corneal permeability as eye drops were investigated.

Results

The nanogel emulsion was monodispersed with a polydispersity index and particle diameter of approximately 0.2 and 200 nm, respectively. The zeta potential value of −8.1 mV suggested enhanced stability and improved retinal permeability of nanoparticles. The prepared nanoemulsion was found to be biocompatible with hepatocytes and HUVECs in vitro. Moreover, in vivo study demonstrated high permeability of G/W nanoemulsion to the retinal layer with no ocular irritation.

Conclusions

G/W nanoemulsions have the potential for topical drug delivery in the posterior eye segment with maximum therapeutic efficacy.

Translational Relevance

Organogel nanodispersion is a new concept to deliver hydrophobic drugs to the posterior segment of eyes as a novel drug delivery system.

Formulation and Evaluation of Topical Biodegradable Films Loaded with Levofloxacin Lipid Nanocarriers

Skin ulcers have increased sharply due to rise in the incidence of obesity and diabetes. This study investigated lipid nanocarriers as a strategy to improve the efficacy of levofloxacin (LV) in penetrating skin. Two surfactant types and different lipid mixtures were used in preparation of lipid nanocarriers. Mean particle size, percentage entrapment efficiency (%EE), in vitro release, and antimicrobial activity were examined. The selected formula was incorporated into a chitosan (CS) film that was subjected to physic-chemical characterization and ex vivo permeation study. The selected formula showed particle size, PDI, and ZP: 80.3 nm, -0.21, and -26 mV, respectively, synchronized with 82.12 %EE. In vitro release study showed slow biphasic release of LV from lipid nanocarriers. The antimicrobial effect illustrated statistically significant effect of lipid nanocarriers on decreasing the minimum effective concentration (MIC) of LV, particularly against E. coli. The optimized nanocarriers' formula loaded into CS film was clear, colorless, translucent, and smooth in texture. Based on the release profiles, it could be speculated that the CS film loaded with LV nanocarriers can maintain the antibacterial activity for 4 consecutive days. Thus, the local delivery of the drug in a sustained release manner could be predicted to enhance the therapeutic effect. Further clinical studies are strongly recommended. Graphical Abstract.

Biocompatibility and Antimicrobial Activity of Nanostructured Lipid Carriers for Topical Applications Are Affected by Type of Oils Used in Their Composition

Nanostructured lipid carriers (NLCs) have gained significant attention as tools for the dermal delivery of therapeutics due to their stability, biocompatibility, and ability to improve drug bioavailability. The use of natural plant oils (NPO) in NLC formulations has numerous benefits for the skin due to their therapeutic potential. This work shows the effect of NLC composition on bioavailability in epidermal cells and antimicrobial activity against Staphylococcus aureus. Sixteen systems containing fixed (sunflower, olive, corn, peanut, coconut, castor, and sweet almond) and essential (eucalyptus) oils, with different solid lipid (SL): liquid lipid (LL) ratios, were engineered. The structural properties, bioavailability, and antimicrobial action of the particles was studied. The choice of NPO influenced the physicochemical stability by changing the diameter of NLC formulations (between 160 nm and 185 nm) and Z-potential (between −46 mV and −61 mV). All of the systems were characterized by concentration-dependent cytocompatibility with human epidermal keratinocytes (HaCaT) and human dermal fibroblasts (HDFn). The SL:LL ratio in some NLC systems impacted cell cytotoxicity differently. Antimicrobial properties were observed in all 16 systems; however, the type of oil and SL:LL ratio affected the activity of the formulations. Two NLC-NPO systems were found to be non-cytotoxic to human cells lines at concentrations that completely inhibited bacterial growth. These results present a strong argument that the use of natural oils in NLC formulations presents a promising tool for the treatment of skin infections.

Design, formulation and optimization of topical ethosomes using full factorial design: in-vitro and ex-vivo characterization

The present study aimed to develop lomefloxacin-loaded ethosomal vesicles intended to be applied topically for treating skin infections. Ethosomes were prepared using the cold method. The formulation variables were optimized using 2² factorial design and Design Expert^® software for analyzing the data statistically and graphically using response surface plots. Phosphatidylcholine (X1) and ethanol (X2) were chosen as the independent variables, while the dependent variables comprised entrapment efficiency (Y1), vesicles size (Y2) and zeta potential (Y3). The optimized ethosomes were subsequently incorporated into Carbopol^® 940 gel and characterized for rheological behaviour, in-vitro release, ex-vivo skin permeation and deposition. The ex-vivo permeation and skin deposition studies showed better results compared to drug solutions. In a nutshell, the ethosomal vesicles were found to be a promising carrier demonstrating enhanced topical delivery of lomefloxacin.

Colloidal nanosystems with mucoadhesive properties designed for ocular topical delivery

Over the last years, the scientific interest about topical ocular delivery targeting the posterior segment of the eye has been increasing. This is probably due to the fact that this is a non-invasive administration route, well tolerated by patients and with fewer local and systemic side effects. However, it is a challenging task due to the external ocular barriers, tear film clearance, blood flow in the conjunctiva and choriocapillaris and due to the blood-retinal barriers, amongst other features. An enhanced intraocular bioavailability of drugs can be achieved by either improving corneal permeability or by improving precorneal retention time. Regarding this last option, increasing residence time in the precorneal area can be achieved using mucoadhesive polymers such as xyloglucan, poly(acrylate), hyaluronic acid, chitosan, and carbomers. On the other hand, colloidal particles can interact with the ocular mucosa and enhance corneal and conjunctival permeability. These nanosystems are able to deliver a wide range of drugs, including macromolecules, providing stability and improving ocular bioavailability. New pharmaceutical approaches based on nanotechnology associated to bioadhesive compounds have emerged as strategies for a more efficient treatment of ocular diseases. Bearing this in mind, this review provides an overview of the current mucoadhesive colloidal nanosystems developed for ocular topical administration, focusing on their advantages and limitations.

Lipid nanoparticles loaded with butamben and designed to improve anesthesia at inflamed tissues

The most frequently used local anesthetics (LA) for local infiltration have an ionizable amine in the range of pH 7.6-8.9. Effective anesthesia of inflamed tissues is a great challenge, especially because the induced local acidosis decreases the fraction of the neutral (more potent) LA species in situ. To solve this limitation, the butyl-substituted benzocaine analogue butamben (BTB) - that has no ionizable amine group close to the physiological pH - could be useful if it was not for its low solubility. To overcome the solubility problem, an optimized formulation for BTB using nanostructured lipid carriers (NLC) was developed by a factorial design and characterized using DLS, XRD, DSC and cryo-EM. The release kinetics and cytotoxicity of the new formulation were measured in vitro, while the in vivo tests assessed its effectiveness on healthy and inflamed tissues, in rats. The optimized NLCBTB formulation showed desirable physicochemical properties (size = 235.6 ± 3.9 nm, polydispersity = 0.182 ± 0.006 and zeta potential = -23.6 ± 0.5 mV), high (99.5%) encapsulation efficiency and stability during 360 days of storage at room temperature. NLCBTB prolonged the release of butamben and decreased its in vitro cytotoxicity without inducing any in vivo toxic alteration. In the inflammatory hyperalgesia model, the NLCBTB formulation showed potential for the management of inflammatory pain, displaying greater analgesic effectiveness (40%) and a prolonged effect.

Lipid-Based Nanocarriers as Topical Drug Delivery Systems for Intraocular Diseases

Effective drug delivery to intraocular tissues remains a great challenge due to complex anatomical and physiological barriers that selectively limit the entry of drugs into the eye. To overcome these challenges, frequent topical application and regular intravitreal injections are currently used to achieve the desired drug concentrations into the eye. However, the repetitive installation or recurrent injections may result in several side effects. Recent advancements in the field of nanoparticle-based drug delivery have demonstrated promising results for topical ophthalmic nanotherapies in the treatment of intraocular diseases. Studies have revealed that nanocarriers enhance the intraocular half-life and bioavailability of several therapies including proteins, peptides and genetic material. Amongst the array of nanoparticles available nowadays, lipid-based nanosystems have shown an increased efficiency and feasibility in topical formulations, making them an important target for constant and thorough research in both preclinical and clinical practice. In this review, we will cover the promising lipid-based nanocarriers used in topical ophthalmic formulations for intraocular drug delivery.

Lipid-Based Nanocarriers for Ophthalmic Administration: Towards Experimental Design Implementation

Nanotherapeutics based on biocompatible lipid matrices allow for enhanced solubility of poorly soluble compounds in the treatment of ophthalmic diseases, overcoming the anatomical and physiological barriers present in the eye, which, despite the ease of access, remains strongly protected. Micro-/nanoemulsions, solid lipid nanoparticles (SLN) or nanostructured lipid carriers (NLC) combine liquid and/or solid lipids with surfactants, improving drug stability and ocular bioavailability. Current research and development approaches based on try-and-error methodologies are unable to easily fine-tune nanoparticle populations in order to overcome the numerous constraints of ocular administration routes, which is believed to hamper easy approval from regulatory agencies for these systems. The predictable quality and specifications of the product can be achieved through quality-by-design (QbD) implementation in both research and industrial environments, in contrast to the current quality-by-testing (QbT) framework. Mathematical modelling of the expected final nanoparticle characteristics by variation of operator-controllable variables of the process can be achieved through adequate statistical design-of-experiments (DoE) application. This multivariate approach allows for optimisation of drug delivery platforms, reducing research costs and time, while maximising the understanding of the production process. This review aims to highlight the latest efforts in implementing the design of experiments to produce optimised lipid-based nanocarriers intended for ophthalmic administration. A useful background and an overview of the different possible approaches are presented, serving as a starting point to introduce the design of experiments in current nanoparticle research.

Progress of Nanotechnology in Diabetic Retinopathy Treatment

Diabetic retinopathy (DR) is a chronic diabetes complication that progressively manifests itself as blurred vision, eye floaters, distorted vision, and even partial or total loss of vision as a result of retinal detachment in severe cases. Clinically, patients who have undergone variations in the microcirculation of the ocular fundus are treated with laser photocoagulation to improve the circulation of retina; but for patients with macular edema, anti-vascular endothelial growth factor (anti-VEGF) drugs are generally injected to eliminate macular edema and improve vision. The worst cases are patients with fundus hemorrhage or proliferative vitreoretinopathy, for whom vitrectomy has been performed. At present, these clinical treatment methods have widely been used, providing satisfactory results. However, considering the low bioavailability and potential side effects of drugs and the inevitable risks in major surgery, DR prevention, and treatment as well as nerve tissue regeneration in the later stage have always been the focus of research. In recent years, nanotechnology has been increasingly applied in the medical field, leading to new ideas for DR treatment. This study aims to systematically review the research progress of nanotechnology in DR treatment.

Characterization, Stability Assessment, Antioxidant Evaluation and Cell Proliferation Activity of Virgin Coconut Oil-based Nanostructured Lipid Carrier Loaded with Ficus deltoidea Extract

In this study, the Ficus deltoidea extract loaded nanostructured lipid carrier was prepared by using the melt emulsification homogenization method. Virgin coconut oil is used as liquid lipid, while glyceryl monostearate is the solid lipid. Particle size, zeta potential, entrapment efficiency, drug loading and morphology of the obtained nanostructured lipid carrier (NLC) were measured. The size of the nanostructured lipid carrier incorporated with Ficus deltoidea (FDNLC) is 158.0 ± 1.3 nm, with a polydispersity index of 0.15 ± 0.02. The zeta potential obtained is −42.3 ± 1.5 mV. The encapsulation efficiency and active ingredient loading capacity for FDNLC is 87.4% ± 1.3% and 8.5% ± 1.2%, respectively. The shape of FDNLC is almost spherical and the stability assessment showed that the obtained formulation is at least stable for 40 days. When compared with the positive controls, which are Trolox and ascorbic acid, FDNLC shows the highest antioxidant value. Cell proliferation activity study indicates that FDNLC is not toxic to cells, and FDNLC could potentially treat damage by ultraviolet B (UVB) irradiation.

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.

Therapeutic nanoemulsions in ophthalmic drug administration: Concept in formulations and characterization techniques for ocular drug delivery

The eye is the specialized part of the body and is comprised of numerous physiological ocular barriers that limit the drug absorption at the action site. Regardless of various efforts, efficient topical ophthalmic drug delivery remains unsolved, and thus, it is extremely necessary to advance the contemporary treatments of ocular disorders affecting the anterior and posterior cavities. Nowadays, the advent of nanotechnology-based multicomponent nanoemulsions for ophthalmic drug delivery has gained popularity due to the enhancement of ocular penetrability, improve bioavailability, increase solubility, and stability of lipophilic drugs. Nanoemulsions offer the sustained/controlled drug release and increase residence time which depend on viscosity, compositions, and stabilization process, etc.; hence, decrease the instillation frequency and improve patient compliance. Further, due to the nanosized of nanoemulsions, the sterilization process is easy as conventional solutions and cause no blur vision. The review aims to summarizes the various ocular barriers, manufacturing techniques, possible mechanisms to the retention and deep penetration into the eye, and appropriate excipients with their under-lying selection principles to prevent destabilization of nanoemulsions. This review also discusses the characterization parameters of ocular drug delivery to spike the interest of those contemplating a foray in this field. Here, in short, nanoemulsions are abridged with concepts to design clinically advantageous ocular drug delivery.

Nanopharmaceuticals for Eye Administration: Sterilization, Depyrogenation and Clinical Applications

Simple Summary

Nanopharmaceuticals have revolutionized the way ophthalmic drugs are administered to overcome ocular delivery barriers and improve drug bioavailability. The design and production of an efficient ocular drug delivery system still remain a challenge. In this review, we discuss the sterilization and depyrogenation methods, commonly used for ophthalmic nanopharmaceuticals, and their clinical applications.

Abstract

As an immune-privileged target organ, the eyes have important superficial and internal barriers, protecting them from physical and chemical damage from exogenous and/or endogenous origins that would cause injury to visual acuity or even vision loss. These anatomic, physiological and histologic barriers are thus a challenge for drug access and entry into the eye. Novel therapeutic concepts are highly desirable for eye treatment. The design of an efficient ocular drug delivery system still remains a challenge. Although nanotechnology may offer the ability to detect and treat eye diseases, successful treatment approaches are still in demand. The growing interest in nanopharmaceuticals offers the opportunity to improve ophthalmic treatments. Besides their size, which needs to be critically monitored, nanopharmaceuticals for ophthalmic applications have to be produced under sterilized conditions. In this work, we have revised the different sterilization and depyrogenation methods for ophthalmic nanopharmaceuticals with their merits and drawbacks. The paper also describes clinical sterilization of drugs and the outcomes of inappropriate practices, while recent applications of nanopharmaceuticals for ocular drug delivery are also addressed.

Natural Ergot Alkaloids in Ocular Pharmacotherapy: Known Molecules for Novel Nanoparticle-Based Delivery Systems

Several pharmacological properties are attributed to ergot alkaloids as a result of their antibacterial, antiproliferative, and antioxidant effects. Although known for their biomedical applications (e.g., for the treatment of glaucoma), most ergot alkaloids exhibit high toxicological risk and may even be lethal to humans and animals. Their pharmacological profile results from the structural similarity between lysergic acid-derived compounds and noradrenalin, dopamine, and serotonin neurotransmitters. To reduce their toxicological risk, while increasing their bioavailability, improved delivery systems were proposed. This review discusses the safety aspects of using ergot alkaloids in ocular pharmacology and proposes the development of lipid and polymeric nanoparticles for the topical administration of these drugs to enhance their therapeutic efficacy for the treatment of glaucoma.

Nanopharmaceutics: Part II-Production Scales and Clinically Compliant Production Methods

Due the implementation of nanotechnologies in the pharmaceutical industry over the last few decades, new type of cutting-edge formulations-nanopharmaceutics-have been proposed. These comprise pharmaceutical products at the nanoscale, developed from different types of materials with the purpose to, e.g., overcome solubility problems of poorly water-soluble drugs, the pharmacokinetic and pharmacodynamic profiles of known drugs but also of new biomolecules, to modify the release profile of loaded compounds, or to decrease the risk of toxicity by providing site-specific delivery reducing the systemic distribution and thus adverse side effects. To succeed with the development of a nanopharmaceutical formulation, it is first necessary to analyze the type of drug which is to be encapsulated, select the type matrix to load it (e.g., polymers, lipids, polysaccharides, proteins, metals), followed by the production procedure. Together these elements have to be compatible with the administration route. To be launched onto the market, the selected production method has to be scaled-up, and quality assurance implemented for the product to reach clinical trials, during which in vivo performance is evaluated. Regulatory issues concerning nanopharmaceutics still require expertise for harmonizing legislation and a clear understanding of clinically compliant production methods. The first part of this study addressing "Nanopharmaceutics: Part I-Clinical trials legislation and Good Manufacturing Practices (GMP) of nanotherapeutics in the EU" has been published in Pharmaceutics. This second part complements the study with the discussion about the production scales and clinically compliant production methods of nanopharmaceutics.

Sucupira Oil-Loaded Nanostructured Lipid Carriers (NLC): Lipid Screening, Factorial Design, Release Profile, and Cytotoxicity

Essential oils are odorant liquid oily products consisting of a complex mixture of volatile compounds obtained from a plant raw material. They have been increasingly proven to act as potential natural agents in the treatment of several human conditions, including diabetes mellitus (DM). DM is a metabolic disorder characterized by chronic hyperglycemia closely related to carbohydrate, protein and fat metabolism disturbances. In order to explore novel approaches for the management of DM our group proposes the encapsulation of sucupira essential oil, obtained from the fruits of the Brazilian plants of the genus Pterodon, in nanostructured lipid carriers (NLCs), a second generation of lipid nanoparticles which act as new controlled drug delivery system (DDS). Encapsulation was performed by hot high-pressure homogenization (HPH) technique and the samples were then analyzed by dynamic light scattering (DLS) for mean average size and polydispersity index (PI) and by electrophoretic light scattering (ELS) for zeta potential (ZP), immediately after production and after 24 h of storage at 4 °C. An optimal sucupira-loaded NLC was found to consist of 0.5% (m/V) sucupira oil, 4.5% (m/V) of Kollivax^® GMS II and 1.425% (m/V) of TPGS (formulation no. 6) characterized by a mean particle size ranging from 148.1 ± 0.9815 nm (0 h) to 159.3 ± 9.539 nm (at 24 h), a PI from 0.274 ± 0.029 (0 h) to 0.305 ± 0.028 (24 h) and a ZP from −0.00236 ± 0.147 mV (at 0 h) to 0.125 ± 0.162 (at 24 h). The encapsulation efficiency and loading capacity were 99.98% and 9.6%, respectively. The optimized formulation followed a modified release profile fitting the first order kinetics, over a period of 8 h. In vitro cytotoxicity studies were performed against Caco-2 cell lines, for which the cell viability above 90% confirmed the non-cytotoxic profile of both blank and sucupira oil-loaded NLC.

Effect of Formulation Variables and Gamma Sterilization on Transcorneal Permeation and Stability of Proniosomal Gels as Ocular Platforms for Antiglaucomal Drug

This study aims to evaluate the effect of different formulation variables (surfactant type and HLB value) adopting full factorial design (5¹. 2¹) using coacervation phase technique on in vitro characterization of dorzolamide hydrochloride (DZ)-loaded proniosomal gels, namely, entrapment efficiency percentage (EE%), vesicle size distribution, polydispersion index (PDI), and in vitro DZ release. The optimum formula F2 with a desirability value of 0.937 composed of 40 mg DZ, 500 mg span 60, 500 mg of L-α-Lethicin, and 55.5 mg cholesterol showing EE% of 84.5 ± 1.5%, PS of 189.5 ± 35.76 nm with PDI 0.8 ± 0.28 and 58.51% ± 1.00 of DZ released after 8 h was further evaluated using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The effect of gamma sterilization on transcorneal permeation and stability of DZ from the selected formulation (F2) revealed that F2 was significantly tolerable, stable, and competent to corneal permeation confirmed by histological examination, confocal laser microscopy, and intraocular pressure (IOP) measurement. Significant corneal bioavailability was attained from formula F2 (370.6 mg. h/m) compared to the market product Trusopt® eye drops (92.59 mg. h/ml) following IOP measurement, thereby proniosomal gels could be considered as tolerable and competent ocular platforms for improving the transcorneal permeation of DZ.

Design and Optimization of Nanostructured Lipid Carrier Containing Dexamethasone for Ophthalmic Use

The aim of this study was to perform a preformulation study of dexamethasone (DXM)-loaded nanostructured lipid carriers (NLCs) for ocular use. Lipid screening was applied to find the most suitable solid and liquid lipids and surfactant for the NLC formulation. The visual observation was proved with XRD measurements for the establishment of the soluble state of DXM. Thermoanalytical measurements indicated that the most relevant depression of the crystallinity index could be ensured when using a 7:3 solid lipid:oil ratio. In order to optimize the NLC composition, a 2³ full factorial experimental design was used. It was established that each independent factor (lipid, DXM, and surfactant concentration) had a significant effect on the particle size while in the case of entrapment efficiency, the DXM and surfactant concentrations were significant. Lower surfactant and lipid concentrations could be beneficial because the stability and the entrapment efficacy of NLCs were more favorable. The toxicity tests on human cornea cells indicated good ophthalmic tolerability of NLCs. The in vitro drug release study predicted a higher concentration of the solute DXM on the eye surface while the Raman mapping penetration study on the porcine cornea showed a high concentration of nanocarriers in the hydrophylic stroma layer.