Tacrolimus-Loaded Solid Lipid Nanoparticle Gel: Formulation Development and In Vitro Assessment for Topical Applications

Novel drug delivery systems in topical treatment of atopic dermatitis

Atopic dermatitis (AD), also known as eczema, is a chronic skin condition, affecting all ages, characterized by inflammation, itching, dryness, and redness, which can severely impact quality of life. Based on clinical features and symptoms, AD is of several types like contact dermatitis, dyshidrotic eczema, neurodermatitis, seborrheic dermatitis, stasis dermatitis, and nummular eczema. Its pathophysiology involves genetic, environmental, and immunological factors, leading to skin barrier dysfunction. Current treatments for AD involve a combination of pharmacological and non-pharmacological strategies tailored to individual needs. Management includes topical therapies of corticosteroids, calcineurin inhibitors, phosphodiesterase inhibitors, and janus kinase inhibitors in the form of gels, creams, ointments, and lotions. Systemic treatments like immunosuppressants and biologics are employed for severe cases. Long term and regular use of current treatments can lead to numerous adverse effects like skin thinning, atrophy, burning sensation, emergence of skin lymphomas, tolerance, and systemic side effects. Emerging topical nanoformulations, such as lipid-based nanoparticles, polymeric carriers, liposomes, cubosomes, ethosomes, nanoemulsions enhance drug delivery, improve therapeutic outcomes, and reduce toxicity, making them promising options for AD treatment. Clinical trials of nanoformulations for AD show significant improvements in treatment efficacy and skin absorption compared to conventional therapies. However, nanomedicine faces challenges in terms of inadequate evaluation studies and formulation instability, requiring stringent regulatory compliance and a thorough preclinical and clinical data investigation. This review aims to describe types of AD, its pathophysiology and current treatments and their challenges. The review further focuses on emerging trends of various nanoformulations for treatment of AD.

Central composite design (CCD) based formulation, optimization, in-vitro and ex-vivo characterization of 5-fluorouracil-loaded emulgel for enhanced dermal penetration and psoriasis management

OBJECTIVE

Psoriasis is a condition that mostly responds to topical remedies. 5-FU is promising since it is anti-proliferative but has poor permeability. The study aimed to fabricate a novel 5-FU emulgel in order to accomplish enhanced therapy of psoriasis.

METHODS

A central composite design (CCD) was employed to optimize the emulgel's key characteristics, including viscosity, spreadability, drug content, and in-vitro release profile. This statistical approach utilized a five-level, two-factor model to construct linear and quadratic relationships between the formulation variables and the desired responses. Design-Expert software version 13 facilitated this process, requiring 13 experimental runs (FU1-FU13) to achieve optimal formulation parameters. The emulgel consisted of an oil phase (oleic acid, Span 80, and Transcutol P) and an aqueous phase (5-FU and Tween 80). High shear homogenization was utilized for emulsification. The emulsion and gel were combined in a 1:1 ratio to form the emulgel. Finally, the optimized emulgel (FU13) underwent assessments for drug-excipient compatibility, ex-vivo drug permeability through the skin barrier, and long-term stability.

RESULTS

The results of optimized formulation FU13 showed viscosity of 5166 ± 9.01 Pa.s, spreadability of 27.56 ± 2.69 g.cm/s, extrudability of 28.49 ± 2.25 g/cm, drug content of 87.9 ± 3.16%, in-vitro drug release of 96.4 ± 1.25 up to 360 min and ex-vivo cumulative permeability of 1056.97 ± 10.33 µg/cm2. FU13 showed no significant chemical interactions and was stable throughout stability period.

CONCLUSION

It is within this context that the present study appears to possess significant potential for topical treatment of psoriasis, as it provides higher therapeutic gain over current treatment modalities with fewer undesired effects.

Gels as Promising Delivery Systems: Physicochemical Property Characterization and Recent Applications

Gels constitute a versatile class of materials with considerable potential for applications in both technical and medical domains. Physicochemical property characterization is a critical evaluation method for gels. Common characterization techniques include pH measurement, structural analysis, mechanical property assessment, rheological analysis, and phase transition studies, among others. While numerous research articles report characterization results, few reviews comprehensively summarize the appropriate numerical ranges for these properties. This lack of standardization complicates harmonized evaluation methods and hinders direct comparisons between different gels. To address this gap, it is essential to systematically investigate characterization methods and analyze data from the extensive body of literature on gels. In this review, we provide a comprehensive summary of general characterization methods and present a detailed analysis of gel characterization data to support future research and promote standardized evaluation protocols.

Deep-insights: Nanoengineered gel-based localized drug delivery for arthritis management

Arthritis is an inflammatory joint disorder that progressively impairs function and diminishes quality of life. Conventional therapies often prove ineffective, as oral administration lacks specificity, resulting in off-target side effects like hepatotoxicity and GIT-related issues. Intravenous administration causes systemic side effects. The characteristic joint-localized symptoms such as pain, stiffness, and inflammation make the localized drug delivery suitable for managing arthritis. Topical/transdermal/intra-articular routes have become viable options for drug delivery in treating arthritis. However, challenges with those localized drug delivery routes include skin barrier and cartilage impermeability. Additionally, conventional intra-articular drug delivery also leads to rapid clearance of drugs from the synovial joint tissue. To circumvent these limitations, researchers have developed nanocarriers that enhance drug permeability through skin and cartilage, influencing localized action. Gel-based nanoengineered therapy employs a gel matrix to incorporate the drug-encapsulated nanocarriers. This approach combines the benefits of gels and nanocarriers to enhance therapeutic effects and improve patient compliance. This review emphasizes deep insights into drug delivery using diverse gel-based novel nanocarriers, exploring their various applications embedded in hyaluronic acid (biopolymer)-based gels, carbopol-based gels, and others. Furthermore, this review discusses the influence of nanocarrier pharmacokinetics on the localization and therapeutic manipulation of macrophages mediated by nanocarriers. The ELVIS (extravasation through leaky vasculature and inflammatory cell-mediated sequestration) effect associated with arthritis is advantageous in drug delivery. Simply put, the ELVIS effect refers to the extravasation of nanocarriers through leaky vasculatures, which finally results in the accumulation of nanocarriers in the joint cavity.

Tacrolimus: Physicochemical stability challenges, analytical methods, and new formulations

Tacrolimus, a potent immunosuppressant, is widely used in several formulations to treat organ rejection in transplant patients. However, its physicochemical stability poses significant challenges, including thermal instability, photostability issues, low solubility, and drug-excipient incompatibility. This review article focuses on the details of these challenges and discusses the analytical methods employed to study tacrolimus stability, such as thermal, spectroscopic, and chromatographic methods in different formulations. New formulations to enhance tacrolimus stability are explored, including lipid-based nanocarriers, polymers, and thin film freezing. Researchers and formulators can optimize tacrolimus formulations to improve efficacy and patient outcomes by understanding and addressing these stability challenges.

Formulation and characterization of cholesterol-based nanoparticles of gabapentin protecting from retinal injury

Introduction

This study aimed to prepare cholesterol and stearic acid-based solid lipid nanoparticles of gabapentin (GAB-SLNs) for protection against streptozotocin (STZ)-induced retinal injury in rats.

Methods

We prepared four preparations of GAB-SLNs using a hot high-shear homogenization ultrasonication process, and the best formulation was selected and tested for biological activity. The retinal injury was brought in male adult albino rats while gabapentin doses continued for 6 weeks. Six groups of rats were assigned as the vehicle, diabetic, diabetic + gabapentin (10-20 mg/kg), and diabetic + GAB-SLNs (10-20 mg/kg). GAB-SLN#2 was selected as the optimized formulation with high entrapment efficacy (EE%, 98.64% ± 1.97%), small particle size (185.65 ± 2.41 nm), high negative Zeta potential (-32.18 ± 0.98 mV), low polydispersity index (0.28 ± 0.02), and elevated drug release (99.27% ± 3.48%). The TEM image of GAB-SLN#2 revealed a smooth surface with a spherical shape.

Results

GAB-SLNs provided greater protection against retinal injury than free gabapentin as indicated by the histopathology data which demonstrated more organization of retinal layers and less degeneration in ganglion cell layer in rats treated with GAB-SLN#2. Further, GAB-SLN#2 reduced the inflammatory proteins (IL-6/JAK2/STAT3) and vascular endothelial growth factor (VEGF).

Conclusion

The preparation of GAB-SLNs enhanced the physical properties of gabapentin and improved its biological activity as a neuroprotectant. Further studies are warranted to validate this technique for the use of oral gabapentin in other neurological disorders.

New Insight for Enhanced Topical Targeting of Caffeine for Effective Cellulite Treatment: In Vitro Characterization, Permeation Studies, and Histological Evaluation in Rats

Cellulite (CLT) is one of the commonly known lipodystrophy syndromes affecting post-adolescent women worldwide. It is topographically characterized by an orange-peel, dimpled skin appearance hence, it is an unacceptable cosmetic problem. CLT can be modulated by surgical procedures such as; liposuction and mesotherapy. But, these options are invasive, expensive and risky. For these reasons, topical CLT treatments are more preferred. Caffeine (CA), is a natural alkaloid that is well-known for its prominent anti-cellulite effects. However, its hydrophilicity hinders its cutaneous permeation. Therefore, in the present study CA was loaded into solid lipid nanoparticles (SLNs) by high shear homogenization/ultrasonication. CA-SLNs were prepared using Compritol® 888 ATO and stearic acid as solid lipids, and span 60 and brij™35, as lipid dispersion stabilizing agents. Formulation variables were adjusted to obtain entrapment efficiency (EE > 75%), particle size (PS < 350 nm), zeta potential (ZP < -25 mV) and polydispersity index (PDI < 0.5). CA-SLN-4 was selected and showed maximized EE (92.03 ± 0.16%), minimized PS (232.7 ± 1.90 nm), and optimum ZP (-25.15 ± 0.65 mV) and PDI values (0.24 ± 0.02). CA-SLN-4 showed superior CA release (99.44 ± 0.36%) compared to the rest CA-SLNs at 1 h. TEM analysis showed spherical, nanosized CA-SLN-4 vesicles. Con-LSM analysis showed successful CA-SLN-4 permeation transepidermally and via shunt diffusion. CA-SLN-4 incorporated into Noveon AA-1® hydrogel (CA-SLN-Ngel) showed accepted physical/rheological properties, and in vitro release profile. Histological studies showed that CA-SLN-Ngel significantly reduced mean subcutaneous fat tissue (SFT) thickness with 4.66 fold (p = 0.035) and 4.16 fold (p = 0.0001) compared to CA-gel, at 7th and 21st days, respectively. Also, significant mean SFT thickness reduction was observed compared to untreated group with 4.83 fold (p = 0.0005) and 3.83 fold (p = 0.0043), at 7th and 21st days, respectively. This study opened new avenue for CA skin delivery via advocating the importance of skin appendages. Hence, CA-SLN-Ngel could be a promising nanocosmeceutical gel for effective CLT treatment.

Topical calcineurin and mammalian target of rapamycin inhibitors in inflammatory dermatoses: Current challenges and nanotechnology‑based prospects (Review)

Topical therapy remains a critical component in the management of immune‑mediated inflammatory dermatoses such as psoriasis and atopic dermatitis. In this field, macrolactam immunomodulators, including calcineurin and mammalian target of rapamycin inhibitors, can offer steroid‑free therapeutic alternatives. Despite their potential for skin‑selective treatment compared with topical corticosteroids, the physicochemical properties of these compounds, such as high lipophilicity and large molecular size, do not meet the criteria for efficient penetration into the skin, especially with conventional topical vehicles. Thus, more sophisticated approaches are needed to address the pharmacokinetic limitations of traditional formulations. In this regard, interest has increasingly focused on nanoparticulate systems to optimize penetration kinetics and enhance the efficacy and safety of topical calcineurin and mTOR inhibitors in inflamed skin. Several types of nanovectors have been explored as topical carriers to deliver tacrolimus in both psoriatic and atopic skin, while preclinical data on nanocarrier‑based delivery of topical sirolimus in inflamed skin are also emerging. Given the promising preliminary outcomes and the complexities of drug delivery across inflamed skin, further research is required to translate these nanotherapeutics into clinical settings for inflammatory skin diseases. The present review outlined the dermatokinetic profiles of topical calcineurin and mTOR inhibitors, particularly tacrolimus, pimecrolimus and sirolimus, focusing on their penetration kinetics in psoriatic and atopic skin. It also summarizes the potential anti‑inflammatory benefits of topical sirolimus and explores novel preclinical studies investigating dermally applied nanovehicles to evaluate and optimize the skin delivery, efficacy and safety of these 'hard‑to‑formulate' macromolecules in the context of psoriasis and atopic dermatitis.

Formulation development of nanostructured lipid carrier-based nanogels encapsulating tacrolimus for sustained therapy of psoriasis

The goal of this study was to formulate tacrolimus nanogel based on nanostructured lipid carrier (NLC) in order to improve the efficacy, aesthetic, and patient compliance for the treatment of psoriasis. The microemulsion method was used to create phase diagrams and NLCs were prepared using points obtained from the microemulsion region and characterized. The gelling agent carbopol was used to develop an NLC-based nanogel. The pH, drug assay, viscosity, spreadability, and in vitro release of the nanogel, were evaluated. Ex vivo cytotoxicity of the formulation was assessed in murine fibroblast cells. Oxazolone and imiquimod models of psoriasis were used to assess the effectiveness of the nanogel. The NLCs exhibited a submicron particle size of 320 ± 10 nm, a low polydispersity index (<0.3), and a zeta potential of -19.4 mV. Morphological analysis revealed spherical nanoparticles with an encapsulation efficiency of 60 ± 3 %. The nanogel maintained a pH of 6.0 ± 0.5 and possessed a remarkable drug content of 99.73 ± 1.4 %. It exhibited pseudoplastic flow behaviour, ensuring easy spreadability, and demonstrated sustained drug release exceeding 90 % over a 24-hr period. Ex vivo cytotoxicity assessments revealed that the nanogel was safe because no cell death was induced. Nanogel resolved psoriatic blisters, was non-irritating and improved skin elasticity. The favorable properties, safety profile, and remarkable efficacy show the potential of the nanogel as a patient-friendly and effective therapeutic option for psoriasis treatment.

Tacrolimus-loaded chitosan-based nanoparticles as an efficient topical therapeutic for the effective treatment of atopic dermatitis symptoms

Atopic dermatitis (AD) is a chronic cutaneous disease with a complex underlying mechanism, and it cannot be completely cured. Thus, most treatment strategies for AD aim at relieving the symptoms. Although corticosteroids are topically applied to alleviate AD, adverse side effects frequently lead to the withdrawal of AD therapy. Tacrolimus (TAC), a calcineurin inhibitor, has been used to treat AD, but its high molecular weight and insolubility in water hinder its skin permeability. Herein, we developed and optimized TAC-loaded chitosan-based nanoparticles (TAC@CNPs) to improve the skin permeability of TAC by breaking the tight junctions in the skin. The prepared nanoparticles were highly loadable and efficient and exhibited appropriate characteristics for percutaneous drug delivery. TAC@CNP was stable for 4 weeks under physiological conditions. CNP released TAC in a controlled manner, with enhanced skin penetration observed. In vitro experiments showed that CNP was non-toxic to keratinocyte (HaCaT) cells, and TAC@CNP dispersed in an aqueous solution was as anti-proliferative as TAC solubilized in a good organic solvent. Importantly, an in vivo AD mouse model revealed that topical TAC@CNP containing ~1/10 of the dose of TAC found in commercially used Protopic® Ointment exhibited similar anti-inflammatory activity to that of the commercial product. TAC@CNP represents a potential therapeutic strategy for the management of AD.

Recent Advances in Phytochemical-Based Topical Applications for the Management of Eczema: A Review

Eczema (atopic dermatitis, AD) is a skin disease characterized by skin barrier dysfunction due to various factors, including genetics, immune system abnormalities, and environmental triggers. Application of emollients and topical drugs such as corticosteroids and calcineurin inhibitors form the mainstay of treatments for this challenging condition. This review aims to summarize the recent advances made in phytochemical-based topical applications to treat AD and the different carriers that are being used. In this review, the clinical efficacy of several plant extracts and bioactive phytochemical compounds in treating AD are discussed. The anti-atopic effects of the herbs are evident through improvements in the Scoring Atopic Dermatitis (SCORAD) index, reduced epidermal thickness, decreased transepidermal water loss, and alleviated itching and dryness in individuals affected by AD as well as in AD mouse models. Histopathological studies and serum analyses conducted in AD mouse models demonstrated a reduction in key inflammatory factors, including thymic stromal lymphopoietin (TSLP), serum immunoglobulin E (IgE), and interleukins (IL). Additionally, there was an observed upregulation of the filaggrin (FLG) gene, which regulates the proteins constituting the stratum corneum, the outermost layer of the epidermis. Carriers play a crucial role in topical drug applications, influencing dose delivery, retention, and bioavailability. This discussion delves into the efficacy of various nanocarriers, including liposomes, ethosomes, nanoemulsions, micelles, nanocrystals, solid-lipid nanoparticles, and polymeric nanoparticles. Consequently, the potential long-term side effects such as atrophy, eruptions, lymphoma, pain, and allergic reactions that are associated with current topical treatments, including emollients, topical corticosteroids, topical calcineurin inhibitors, and crisaborole, can potentially be mitigated through the use of phytochemical-based natural topical treatments.

Characterization of a human lesioned-skin model to assess the influence of skin integrity on drug permeability

The stratum corneum (SC) is the skin's outermost layer, organized by clusters of corneocytes among a lipid matrix, acting as a barrier. This "brick and mortar" organization is modified in many skin diseases. We proposed a lesioned-skin model for assessing the permeability of topical formulations and the impact of skin integrity on the permeability of molecules. We anticipate that removal of the SC compromises the skin barrier function, making it more permeable, affecting the biopharmaceutics of topical formulations. By stripping with 25 strips (Corneofix®), the thickness of the SC was considerably reduced, exposing the viable epidermis. Transversal and upper views of the skin by electronic microscopy and histology confirm the removal of the SC. After, we evaluated the permeability of tacrolimus (Protopic®, 0.1 % and 0.03 %) by HPLC-UV. The non-lesioned skin presented 20-25 % of tacrolimus in the SC and no drug permeated through the skin's inner layers. Contrary, the lesioned-skin model allowed the permeation of tacrolimus to the epidermis, dermis, and also in the receptor medium. These results highlight the importance of using diseased skin tissue as opposed to normal skin when assessing the permeability of pharmaceutical formulations for local topical delivery, closely mimicking the occurred events in clinical scenario.

Protective potential of frankincense essential oil and its loaded solid lipid nanoparticles against UVB-induced photodamage in rats via MAPK and PI3K/AKT signaling pathways; A promising anti-aging therapy

Frankincense oil has gained increased popularity in skin care, yet its anti-aging effect remains unclear. The current study aimed to investigate the anti-photoaging effect of frankincense (Boswellia papyrifera (Del.) Hochst., Family Burseraceae) essential oil in an in vivo model. The oil was initially extracted by two methods: hydro-distillation (HD) and microwave-assisted hydro-distillation (MAHD). GC/MS analysis revealed the dominance of n-octyl acetate, along with other marker compounds of B. papyrifera including octanol and diterpene components (verticilla 4(20) 7, 11-triene and incensole acetate). Thereafter, preliminary investigation of the anti-collagenase and anti-elastase activities of the extracted oils revealed the superior anti-aging effect of HD-extracted oil (FO), comparable to epigallocatechin gallate. FO was subsequently formulated into solid lipid nanoparticles (FO-SLNs) via high shear homogenization to improve its solubility and skin penetration characteristics prior to in vivo testing. The optimimal formulation prepared with 0.5% FO, and 4% Tween® 80, demonstrated nanosized spherical particles with high entrapment efficiency percentage and sustained release for 8 hours. The anti-photoaging effect of FO and FO-SLNs was then evaluated in UVB-irradiated hairless rats, compared to Vitamin A palmitate as a positive standard. FO and FO-SLNs restored the antioxidant capacity (SOD and CAT) and prohibited inflammatory markers (IL6, NFκB p65) in UVB-irradiated rats via downregulation of MAPK (pERK, pJNK, and pp38) and PI3K/AKT signaling pathways, alongside upregulating TGF-β expression. Subsequently, our treatments induced Procollagen I synthesis and downregulation of MMPs (MMP1, MMP9), where FO-SLNs exhibited superior anti-photoaging effect, compared to FO and Vitamin A, highlighting the use of SLNs as a promising nanocarrier for FO. In particular, FO-SLNs revealed normal epidermal and dermal histological structures, protected against UVβ-induced epidermal thickness and dermal collagen degradation. Our results indicated the potential use of FO-SLNs as a promising topical anti-aging therapy.

Preparation and In Vitro Evaluation of Levofloxacin-Loaded Floating Tables Using Various Rate-Controlling Agents

Floating tablets are a new approach to extending the time a drug is in the stomach to improve therapy outcomes. Floating tablets were formulated with the drug, the polymers hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose (CMC), and starch, fillers, and lubricants. The tablets were prepared using the direction compression method. The tablets' physical quality control tests were found to be within acceptable limits. The tablets extended drug release up to 12 h and were uniform in their drug contents. The swelling index of the tablets ranged from 60 ± 0.11 to 66 ± 0.14%, and the tablets were less dense than water. The floating lag time (10 ± 0.23 to 16 ± 0.09 s) and total floating time (>12 h) showed good floating behaviors. The kinetic modeling showed that the drug was released from the tablets by pseudo-diffusion, swelling, erosion, or anomalous non-Fickian diffusion. F6 (starch and CMC) showed higher n values (0.994 ± 0.04), exhibiting pseudo-zero-order drug release kinetics compared to those of other tablets. The dissolution data of the test and reference tables were not similar (P > 0.05). In terms of antimicrobial activity, the zones of inhibition of the test F6 tablet powders (5.3 ± 0.08 mm) and the reference tablet powders (5.9 ± 0.13 mm) were found to be significantly similar (P > 0.05). The study concluded that these floating tablets can improve the gastric residence time and therapeutic outcomes.

Rheological and Viscoelastic Analysis of Hybrid Formulations for Topical Application

The rheological and viscoelastic properties of hybrid formulations composed of vehicles designed for cutaneous topical application and loaded with ultradeformable liposomes (UDL) were assessed. UDL were selected for their established ability to transport both lipophilic and hydrophilic compounds through the skin, and are applicable in pharmaceuticals and cosmetics. Formulations underwent flow analysis and were fitted to the Herschel-Bulkley model due to their prevalent non-Newtonian behavior in most cases. Linear viscoelastic regions (LVR) were identified, and G' and G″ moduli were determined via frequency sweep steps, considering the impact of temperature and aging. The formulations exhibited non-Newtonian behavior with pseudoplastic traits in most cases, with UDL incorporation inducing rheological changes. LVR and frequency sweep tests indicated predominantly elastic solid behavior, with G' higher than G″, at different temperatures and post-production times. Tan δ values also illustrated a predominant solid-like behavior over liquid. This study provides pivotal insights into the rheological and viscoelastic features of topical formulations, emphasizing the crucial role of meticulous vehicle and formulation selection when incorporating UDL or analogous liposomal drug delivery systems.

A Reversibly Thermoresponsive, Theranostic Nanoemulgel for Tacrolimus Delivery to Activated Macrophages: Formulation and In Vitro Validation

Despite long-term immunosuppression, organ transplant recipients face the risk of immune rejection and graft loss. Tacrolimus (TAC, FK506, Prograf®) is an FDA-approved keystone immunosuppressant for preventing transplant rejection. However, it undergoes extensive first-pass metabolism and has a narrow therapeutic window, which leads to erratic bioavailability and toxicity. Local delivery of TAC directly into the graft, instead of systemic delivery, can improve safety, efficacy, and tolerability. Macrophages have emerged as promising therapeutic targets as their increased levels correlate with an increased risk of organ rejection and a poor prognosis post-transplantation. Here, we present a locally injectable drug delivery platform for macrophages, where TAC is incorporated into a colloidally stable nanoemulsion and then formulated as a reversibly thermoresponsive, pluronic-based nanoemulgel (NEG). This novel formulation is designed to undergo a sol-to-gel transition at physiological temperature to sustain TAC release in situ at the site of local application. We also show that TAC-NEG mitigates the release of proinflammatory cytokines and nitric oxide from lipopolysaccharide (LPS)-activated macrophages. To the best of our knowledge, this is the first TAC-loaded nanoemulgel with demonstrated anti-inflammatory effects on macrophages in vitro.

Solid Lipid Nanoparticles Embedded Hydrogels as a Promising Carrier for Retarding Irritation of Leflunomide

Leflunomide (LEF), a disease-modifying anti-rheumatic drug, has been widely explored for its anti-inflammatory potential in skin disorders such as psoriasis and melanoma. However, its poor stability and skin irritation pose challenges for topical delivery. To surmount these issues, LEF-loaded solid lipid nanoparticles (SLNs) integrated with hydrogels have been developed in the present investigation. SLNs developed by microemulsion techniques were found ellipsoidal with 273.1 nm particle size and -0.15 mV zeta potential. Entrapment and total drug content of LEF-SLNs were obtained as 65.25 ± 0.95% and 93.12 ± 1.72%, respectively. FTIR and XRD validated the successful fabrication of LEF-SLNs. The higher stability of LEF-SLNs (p < 0.001) compared to pure drug solution was observed in photostability studies. Additionally, in vitro anti-inflammatory activity of LEF-SLNs showed good potential in comparison to pure drugs. Further, prepared LEF-SLNs loaded hydrogel showed ideal rheology, texture, occlusion, and spreadability for topical drug delivery. In vitro release from LEF-SLN hydrogel was found to follow the Korsmeyer-Peppas model. To assess the skin safety of fabricated lipidic formulation, irritation potential was performed employing the HET-CAM technique. In conclusion, the findings of this investigation demonstrated that LEF-SLN hydrogel is capable of enhancing the photostability of the entrapped drug while reducing its skin irritation with improved topical delivery characteristics.

Solid lipid-based nanoparticulate system for sustained release and enhanced in-vitro cytotoxic effect of 5-fluorouracil on skin Melanoma and squamous cell carcinoma

The present study aimed to prepare solid lipid-based nanoparticles (SLNs) using Precirol® ATO 5 as solid lipid and Poloxamer 188 and Tween 80 as surfactant and co-surfactant respectively, and SLNs-derived gel for sustained delivery, enhanced in-vitro cytotoxicity, enhanced cellular uptake of 5-FU and enhanced permeation of 5-FU across the skin. The 5-FU-loaded SLNs were prepared by the hot melt encapsulation method and converted into SLN-derived gel using a gelling agent (Carbopol 940). The 5-FU-loaded SLNs had a particle size in the range of 76.82±1.48 to 327±4.46 nm, zeta potential between -11.3±2.11 and -28.4±2.40 mV, and entrapment efficiency (%) in range of 63.46±1.13 and 76.08±2.42. The FTIR analysis depicted that there was no chemical interaction between 5-FU and formulation components. Differential scanning calorimetric analysis showed thermal stability of 5-FU in the nanoparticles and powdered X-ray diffraction analysis revealed successful incorporation of 5-FU in nanoparticles. The in-vitro release study of 5-FU-loaded SLNs showed biphasic release behavior with initial burst release followed by sustained release over 48 hr. The 5-FU-loaded SLNs showed a greater cytotoxic effect on skin melanoma (B16F10 cells) and squamous cell carcinoma (A-431 cells) as compared to free 5-FU drug solution after 48 hr. Flow cytometry and fluorescence microscopy displayed enhanced quantitative and qualitative cellular uptake of SLNs. The SLNs formulation showed acceptable safety and biocompatible profile after an acute toxicity study in Wistar rats. Moreover, ex-vivo permeation studies depicted 2.13±0.076 folds enhanced flux of 5-FU-loaded SLN derived gel compared to 5-FU plain gel, and skin retention studies revealed target efficiency (%) 2.54±0.03 of 5-FU-loaded SLN derived gel compared to 5-FU plain gel.

Targeted delivery and anticancer effects of Chrysin-loaded chitosan-folic acid coated solid lipid nanoparticles in pancreatic malignant cells

The aim of this survey was to load Chrysin (CHY) on solid lipid nanoparticles (SLNs) and decorate the nanoparticles with folate-bound chitosan to increase the effectiveness of the treatment. CHY-SCF-NPs were synthesized by homogenizing and sonication methods and characterized. FA binding and encapsulation efficiency (HPLC), antioxidant capacity (ABTS and DPPH), cell viability assay (MTT), programmed cell death analysis (fluorescence staining, flow cytometry, and qPCR), and angiogenesis (CAM and molecular analysis) assay were done for assessment of therapeutic efficiency of CHY-SCF-NPs. Increases in size and change in surface charge of CHY-SLNs (PS: 84.3 nm and ZP: -18 mV) were reported after coating with folate-bound chitosan (PS: 125 nm and ZP: +34.9 mV). CHY-SCF-NPs inhibited PANC, MCF-7, A2780, and HepG2 as malignant cells and HFF as normal cells with IC₅₀∼53, 55, 249, and >250 µg/mL, respectively. Also, CHY-SCF-NPs scavenged ABTS (IC₅₀: 123.73 µg/mL), and DPPH (IC₅₀: 108.7 µg/mL) free radicals and suppressed angiogenesis in the CAM and qPCR assays. Up-regulation of Bax and caspase 9 genes as well as the fluorescence staining and cell cycle results confirmed the pro-apoptotic properties of CHY-SCF-NPs. CHY-SCF-NPs can be considered a promising anti-cancer candidate for preclinical and clinical studies of pancreatic cancer.

Erythropoietin-PLGA-PEG as a local treatment to promote functional recovery and neurovascular regeneration after peripheral nerve injury

BACKGROUND

Traumatic peripheral nerve injury (TPNI) is a major medical problem with no universally accepted pharmacologic treatment. We hypothesized that encapsulation of pro-angiogenic erythropoietin (EPO) in amphiphilic PLGA-PEG block copolymers could serve as a local controlled-release drug delivery system to enhance neurovascular regeneration after nerve injury.

METHODS

In this study, we synthesized an EPO-PLGA-PEG block copolymer formulation. We characterized its physiochemical and release properties and examined its effects on functional recovery, neural regeneration, and blood vessel formation after sciatic nerve crush injury in mice.

RESULTS

EPO-PLGA-PEG underwent solution-to-gel transition within the physiologically relevant temperature window and released stable EPO for up to 18 days. EPO-PLGA-PEG significantly enhanced sciatic function index (SFI), grip strength, and withdrawal reflex post-sciatic nerve crush injury. Furthermore, EPO-PLGA-PEG significantly increased blood vessel density, number of junctions, and myelinated nerve fibers after injury.

CONCLUSION

This study provides promising preclinical evidence for using EPO-PLGA-PEG as a local controlled-release treatment to enhance functional outcomes and neurovascular regeneration in TPNI.

Preparation and In Vitro Evaluation of Controlled-Release Matrices of Losartan Potassium Using Ethocel Grade 10 and Carbopol 934P NF as Rate-Controlling Polymers

Controlled-release formulations are essential for those drugs that require fine tuning of their activity to increase the ratio between therapeutic vs. adverse effects. Losartan potassium is among those drugs whose adverse effects may somehow impair its purported benefits. Previous investigations have been carried out to ascertain the suitability of several polymers for being associated with losartan. This study is focused on the effects of Ethocel grade 10 and Carbopol 934P NF on losartan release. Flow and physical properties were assessed according to the protocols standardized by the pharmacopeia (USP-NF 29), and the drug release in phosphate buffer (pH = 6.8) was measured for 24 h. Data evidenced good to excellent flow and physical properties according to the drug/polymer ratio and the addition of co-excipients. The release rate in 24 h was found to be 63-69% to 79-82% without or with the addition of co-excipients, respectively, following zero-order kinetics. The results also suggest a significant difference with the release profile of a traditional release losartan formulation. The results suggest the suitability of Ethocel grade 10 and Carbopol 934P NF as components of a controlled-release losartan formulation.

Design and Development of Neomycin Sulfate Gel Loaded with Solid Lipid Nanoparticles for Buccal Mucosal Wound Healing

Drug administration to the wound site is a potential method for wound healing. The drug retention duration should be extended, and drug permeability through the buccal mucosal layer should be regulated. Oral wounds can be caused by inflammation, ulcers, trauma, or pathological lesions; if these wounds are not treated properly, they can lead to pain, infection, and subsequent undesirable scarring. This study aimed to develop Kolliphor-407 P-based gel containing neomycin sulfate (NES) loaded in solid lipid nanoparticles (SLNs) and enhance the antimicrobial activity. By considering lipid concentrations and achieving the lowest particle size (Y1) and maximum entrapment (EE-Y2) effectiveness, the formulation of NES-SLN was optimized using the Box–Behnken design. For the selected responses, 17 runs were formulated (as anticipated by the Design-Expert software) and evaluated accordingly. The optimized formulation could achieve a particle size of 196.25 and EE of 89.27% and was further utilized to prepare the gel formulation. The NES-SLN-G formula was discovered to have a smooth, homogeneous structure and good mechanical and rheological properties. After 24 h of treatment, NES-SLN-G showed a regulated in vitro drug release pattern, excellent ex vivo permeability, and increased in vitro antibacterial activity. These findings indicate the potential application of NES-SLN-loaded gels as a promising formulation for buccal mucosal wound healing.