AEROSOL ASSISTED NANOSTRUCTURED LIPID CARRIEERS: A TOPICAL DRUG DELIVERY STRATEGY TO ALLEVIATE PSORASIS

Abstract

Psoriasis, a chronic, inflammatory disease affecting over 125 million people globally, is challenging to treat due to the lack of a unified pathogenesis mechanism. Its socioeconomic burden is particularly high in low and middle-income countries. Inadequate healthcare training and knowledge gaps lead to underdiagnosis and inadequate psoriasis therapy, affecting patients' quality of life and causing persistent psychosocial distress. The global burden of psoriasis is continuously rising due to high mortality and risk of associated comorbidities, impacting treatment response, and patients’ economic status. Currently, psoriasis is a life-long systemic inflammatory disease that necessitates prompt diagnosis and effective therapies to alleviate symptoms and prevent recurrence for a complete cure. Pharmacotherapies for mild to moderate psoriasis include topical agents, phototherapy, and systemic drugs, but they often cause detrimental adverse effects. Traditional topical carriers (ointment, cream, lotion, etc.) are preferred but have lower adherence and efficacy than systemic drugs, resulting in diminished outcomes, and patient noncompliance. Novel biological therapies, including Ustekinumab, Guselkumab, and Bimekizumab, effectively treat chronic psoriasis; however, their high costs and access disparities persist. Additionally, their continuous risk assessment and safety profiling are crucial for uncompromised long-term therapeutic efficacy. Furthermore, biologicals are not prescribed in mild to moderate psoriasis cases, which require rapid alleviation of manifestations. To mitigate the systemic drugs adverse effects and economic burden of biological therapies, cost-effective, and side-effectreducing innovative drug delivery strategies are required. Considering the aforementioned perspective, specifics of the thesis chapters (Chapters 1–5) are outlined as follows: At the outset, Chapter 1 presents an overview of the global burden, epidemiology, and clinical manifestations of psoriasis. It further explores the immunopathogenesis of psoriasis and other factors that contribute to its pathophysiology. The next section discusses the alarming impact of psoriasis comorbidities, emphasizing the interplay of immunopathophysiological events in psoriasis and its associated comorbidities. Next, we addressed existing challenges in the treatment of psoriasis and the significance of small-molecule drug discovery in advancing psoriasis treatment. The final section of this chapter highlights the potential of lipid nanoparticle technology to improve topical drug delivery for psoriasis therapy, overcoming the limitations of conventional carriers. The dysregulated NF-κB signaling pathway leads to the overexpression of target genes that code for pro-inflammatory chemical mediators in intracellular cascades. Dysfunctional NF-kB signaling amplifies and perpetuates autoimmune responses in psoriasis. Studies in Chapter 2 aim to identify therapeutically relevant NF-kB inhibitors and elucidate the mechanistic aspects behind NF-kB inhibition. After virtual screening and molecular docking, five hit NF-kB inhibitors were opted for, and their therapeutic efficacy was examined using cell-based assays in TNF-α stimulated human keratinocyte cells. To investigate the conformational changes of target protein and inhibitor-protein interaction mechanisms, molecular dynamics (MD) simulations, together with principal component analysis, dynamics cross-correlation matrix analysis, free energy landscape analysis, and quantum mechanical calculations were carried out. Among the identified NF-kB inhibitors, myricetin and hesperidin significantly scavenged intracellular reactive oxygen species and inhibited NF-kB activation. Analysis of the MD simulation trajectories of ligand-protein complexes revealed that myricetin and hesperidin formed energetically stabilized complexes with the target protein and were able to lock NF-kB in a closed conformation. The combinatorial approach employing in silico tools integrated with cell-based approaches substantiated the binding mechanism and NF-kB active site inhibition by the lead molecule myricetin as a viable antipsoriatic drug candidate. Based on the findings of the studies conducted in Chapter 2, the lead compound myricetin (MYR) demonstrated its potential as a viable antipsoriatic drug candidate. Due to its low solubility and penetration across epidermal barriers, myricetin has low bioavailability and efficacy in topical drug delivery. Studies in Chapter 3 assessed the FDA-approved leukotriene receptor antagonist montelukast sodium (MS) for possible use in topical psoriasis therapy, alongside myricetin. MYR and MS, being lipophilic and BCS class II drugs, have limitations for topical delivery, resulting in reduced therapeutic efficacy. To circumvent both drugs' biopharmaceutical limitations and improve their topical therapeutic efficacy in psoriasis, clinically advanced biocompatible lipid nanoparticle technology is used as a carrier system. To achieve high drug payloads, sustainable release, and synergistic antipsoriatic efficacy, we encapsulated MYR and MS into nanostructured lipid carriers (NLCs) as a co-delivery system (MYR-MS-NLCs). The US FDA and ICHQ8(R2) recommended Quality by Design (QbD) approach was utilized to optimize a robust manufacturing process, ensuring reproducible and scalable production of NLCs. To improve shelf life and long-term functional retention, cryoprotectant concentration and process parameters were optimized to freeze-dry NLC dispersions. Following ICHQ2(R2) and ISO/ASTM guidelines, orthogonal characterization of critical quality attributes and essential physicochemical properties of manufactured NLCs validated their successful production and topical drug delivery suitability. Furthermore, manufactured MYR-MS-NLCs revealed their excellent physical, chemical, and thermal stability, as well as improved cumulative drug release. A six-month stability study of freezedried MYR-MS-NLCs, following ICH Q1A(R2) guidelines, confirmed their optimal storage conditions at 4°C. Concisely, this study highlights the panegyrical aspects of implementing the QbD approach and orthogonal characterization methods in high-quality NLC production. Psoriasis, characterized by chronic inflammation and thick, scaly plaques, leads to increased transepidermal water loss, and dysregulated barrier function, affecting drug permeability and diffusion. Topical pharmacotherapies are preferred for psoriasis treatment, but their high viscosity and difficulty in removing leftovers from clothes and skin decrease therapy adherence and patient compliance. Due to inadequate penetration and distribution across thick, scaly psoriatic skin; conventional cream, lotion, ointment, and gel for targeted topical delivery of NLCs have been shown to reduce their therapeutic efficacy. Aerosol-based therapies for dermatological pathologies have earned global recognition and economic prosperity due to their cosmetic aesthetic and superior efficacy over traditional topical carriers. In Chapter 4, to improve the permeability and diffusion of MYR-MS-NLCs across dehydrated, and scaly psoriatic skin, we integrated them into pressurized aerosol spray and foam as an innovative topical drug delivery strategy. For aerosol spray and foam production, the container closure system was selected in compliance with CGMPs 21 CFR, Parts 210, and 211 regulations to assure its appropriateness for the intended purpose. The n-butane was used as a propellant, which is 'Generally Recognized as Safe' for usage as direct human food ingredients under 21 CFR § 184.1165. The aerosol spray and foam were physiochemically evaluated following the methods and recommendations outlined in the United States Pharmacopeia (USP). Both products, with their physical and chemical stability, demonstrated remarkable self-structuring and surface deposition characteristics, making them ideal for extended therapeutic evaluation. Since the foam is a thermodynamically unstable system that transforms over time, this study established the manufactured aerosol foam destabilization mechanism. Following the recommendations outlined in the USP General Chapter <1121>, finished aerosol spray and foam containers were labeled based on preliminary characterization findings. In Chapter 5, clinically relevant animal models were utilized to investigate the toxicological hazards and therapeutic potential of manufactured aerosol spray and foamassisted MYR-MS-NLCs. Following topical application, both products established their nontoxic nature in 14-day (fixed, single dose) and 28-day (graduated, repeated dosage) dermal toxicity studies on Wistar albino rats following OECD guidelines 402 and 410, respectively. In addition, 28-day repeated topical application of both products to Wistar albino rats did not significantly affect their physiological functions, nutritional sustenance measures, or vital organ functionality. A seven-day in vivo ocular irritancy test following OECD guideline no. 405 demonstrated that tested aerosol sprays were non-irritant to New Zealand rabbit eyes, and their UN GHS category was identified as “No hazard class”. Both products were further evaluated for anti-inflammatory activity in carrageenan-induced edema in a rat paw model. The findings confirmed that aerosol spray and foam assisted MYR-MS-NLCs mitigated the severity of acute inflammation in rats' paws more effectively than monotherapy. Subsequently, this study evaluated the therapeutic potential of both products in alleviating imiquimod (IMQ)- induced psoriasis-like inflammation in Swiss albino mice. The aerosol spray and foam-assisted MYR-MS-NLCs demonstrated superior efficacy in treating psoriasiform inflammation in Swiss albino mice, suggesting it as an alternative treatment strategy for psoriasis. Developing effective psoriasis treatments requires identifying shared pathophysiological patterns in comorbid diseases. Considering this, behavioral screening models were employed to study neurological complications in mice with IMQ-induced psoriasis and evaluate the neuroprotective efficacy of aerosol spray and foam. The study found that aerosol spray and foam therapies attenuated anxiety-like behavioral alterations in mice with psoriasis. To summarize, the investigations conducted in this thesis have deciphered the antipsoriatic and neuroprotective potential of manufactured aerosol spray or foam assisted MYR-MS-NLCs. Both the manufactured products are expected to enhance patient compliance and therapy outcomes, especially in geriatric and pediatric psoriasis patients, through their ease of application and non-sticky nature. Spray and foam can assist psoriasis patients with abraded skin and inflamed flexural and hirsute areas in preventing rubbing-induced pain and irritation.