Bioresponsive nanostructured systems for sustained naltrexone release and treatment of alcohol use disorder: Development and biological evaluation

DEVELOPMENT AND EVALUATION OF NANOSTRUCTURED SYSTEMS FOR CUTANEOUS DELIVERY OF H2S-RELEASING CORTICOSTEROIDS FOR SKIN INFLAMMATORY DISEASES

Psoriasis is an immune-mediated chronic inflammatory disease that causes major psychosocial impact. Topical corticosteroids represent the standard pharmacological treatment for mild-to-moderate disease, but their local and systemic adverse effects reinforce the need for treatment innovations. Here we developed lamellar phase-based formulations for topical delivery of a hybrid dexamethasone and hydrogen sulfide (H2S) donor molecule (Dexa-TBZ), aiming to potentiate the effects of the glucocorticoid with H2S. They offer the possibility to obtain precursor formulations free of water that originate lamellar phases upon water addition, preventing drug hydrolysis during storage. Two groups of formulations were developed varying the surfactants and oil phase types and content. Systems containing 20 and 70% of water formed, respectively, bulk lamellar phase and a more fluid formulation consisting of dispersed droplets (< 1000 nm) stabilized by lamellar phase. Both presented pseudoplastic behavior. Dexa-TBZ was incorporated at 1%, remaining stable for 8 h. Drug content decreased to ∼80% after 1 week in precursor formulations free of water, but remained stable after that. Without causing changes to the cutaneous barrier function ex vivo or to the histological structure of the skin in vivo, the formulation containing phosphatidylcholine as surfactant and 70% of water promoted 1.8- and 2.7-fold increases in Dexa-TBZ penetration in the stratum corneum and epidermis+dermis, respectively, compared to a control solution, demonstrating their potential applicability as topical delivery systems.

Evaluation of Pregabalin bioadhesive multilayered microemulsion IOP-lowering eye drops

In spite of available treatment options, glaucoma continues to be a leading cause of irreversible blindness in the world. Current glaucoma medications have multiple limitations including: lack of sustained action; requirement for multiple dosing per day, ocular irritation and limited options for drugs with different mechanisms of action. Previously, we demonstrated that pregabalin, a drug with high affinity and selectivity for CACNA2D1, lowered IOP in a dose-dependent manner. The current study was designed to evaluate pregabalin microemulsion eye drops and to estimate its efficacy in humans using in silico methods. Molecular docking studies of pregabalin against CACNA2D1 of mouse, rabbit, and human were performed. Pregabalin microemulsion eye drops were characterized using multiple in vivo studies and its stability was evaluated over one year at different storage conditions. Molecular docking analyses and QSPR of pregabalin confirmed its suitability as a new IOP-lowering medication that functions using a new mechanism of action by binding to CACNA2D1 in all species evaluated. Because of its prolonged corneal residence time and corneal penetration enhancement, a single topical application of pregabalin ME can provide an extended IOP reduction of more than day in different animal models. Repeated daily dosing for 2 months confirms the lack of any tachyphylactic effect, which is a common drawback among marketed IOP-lowering medications. In addition, pregabalin microemulsion demonstrated good physical stability for one year, and chemical stability for 3-6 months if stored below 25 °C. Collectively, these outcomes greatly support the use of pregabalin eye drops as once daily IOP-lowering therapy for glaucoma management.

Design and Characterization of Chitosan-Based Smart Injectable Hydrogel for Improved Sustained Release of Antinarcotics

The treatment adherence of narcotics-addicted individuals with reduced incidences of relapse can be enhanced by a sustained drug release formulation of antinarcotics. So far, different drug formulations have been reported with sustained drug release periods of 28 and 35 days. To further enhance this duration, different formulations of injectable hydrogels (IHs) have been developed by combining low molecular weight (LMW) and high molecular weight (HMW) chitosan (CS) with guar gum (GG) and crosslinking them by sodium bi phosphate dibasic. The structural, morphological, and physicochemical properties of LMW-CS IH, and HMW-CS IH were evaluated using Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and rheological, swelling, and biodegradation analysis. The HMW-CS IH showed high crosslinking, increased thermal stability, high mechanical strength, elevated swelling, and low biodegradation. The antinarcotic drugs naltrexone (NTX) and disulfiram (DSF) were loaded separately into the HMW-CS IH and LMW-CS IH. The release of NTX and DSF was investigated in phosphate buffer saline (PBS) and ethanol (0.3%, 0.4%, and 0.5%) over a 56-day period using an UV spectrophotometer. The drug release data were tested in zero-order, first-order, and Korsemeyer-Peppas mathematical models. In PBS, all prepared formulations followed non-Fickian drug release, while in ethanol, only NTX HMW-CS IH followed non-Fickian release in all three different concentrations of ethanol.

Topical delivery of seriniquinone for treatment of skin cancer and fungal infections is enabled by a liquid crystalline lamellar phase

Seriniquinone (SQ) was initially described by our group as an antimelanoma drug candidate and now also as an antifungal drug candidate. Despite its promising in vitro effects, SQ translation has been hindered by poor water-solubility. In this paper, we described the challenging nanoformulation process of SQ, which culminated in the selection of a phosphatidylcholine-based lamellar phase (PLP1). Liposomes and nanostructured lipid carriers were also evaluated but failed to encapsulate the compound. SQ-loaded PLP1 (PLP1-SQ) was characterized for the presence of sedimented or non-dissolved SQ, rheological and thermal behavior, and irritation potential with hen's egg test on the chorioallantoic membrane (HET-CAM). PLP1 influence on transepidermal water loss (TEWL) and skin penetration of SQ was assessed in a porcine ear skin model, while biological activity was evaluated against melanoma cell lines (SK-MEL-28 and SK-MEL-147) and C. albicans SC5314. Despite the presence of few particles of non-dissolved SQ (observed under the microscope 2 days after formulation obtainment), PLP1 tripled SQ retention in viable skin layers compared to SQ solution at 12 h. This effect did not seem to relate to formulation-induced changes on the barrier function, as no increases in TEWL were observed. No sign of vascular toxicity in the HET-CAM model was observed after cutaneous treatment with PLP1. SQ activity was maintained on melanoma cells after 48 h-treatment (IC50 values of 0.59-0.98 µM) whereas the minimum inhibitory concentration (MIC) against C. albicans after 24 h-treatment was 32-fold higher. These results suggest that a safe formulation for SQ topical administration was developed, enabling further in vivo studies.

Contributions of nanotechnology to the intraductal drug delivery for local treatment and prevention of breast cancer

Breast cancer is a major public health problem, affecting millions of people. It is a very heterogeneous disease, with localized and invasive forms, and treatment generally consists of a combination of surgery and radiotherapy followed by administration of estrogen receptor modulators or aromatase inhibitors. Given its heterogeneity, management strategies that take into consideration the type of disease and biological markers and can provide more personalized and local treatment are required. More recently, the intraductal administration (i.e., into the breast ducts) of drugs has attracted significant attention due to its ability of providing drug distribution through the ductal tree in a minimally invasive manner. Although promising, intraductal administration is not trivial, and difficulties in duct identification and cannulation are important challenges to the further development of this route. New drug delivery strategies such as nanostructured systems can help to achieve the full benefits of the route due to the possibility of prolonging tissue retention, improving targeting and selectivity, increasing cytotoxicity and reducing the frequency of administration. This review aims at discussing the potential benefits and challenges of intraductal administration, focusing on the design and use of nanocarriers as innovative and feasible strategies for local breast cancer therapy and prevention.

A Lipid-Based In Situ-Forming Hexagonal Phase for Prolonged Retention and Drug Release in the Breast Tissue

In this study, the addition of monoolein to phosphatidylcholine (PC), tricaprylin, and propylene glycol (PG) mixtures was studied to produce fluid precursor formulations (FIPs) that could transform into hexagonal phase (resistant to aqueous dilution) in vitro and in vivo. The overall goal was to obtain FIPs that could incorporate chemopreventive drugs for subcutaneous administration in the mammary tissue to inhibit the development and/or recurrence of breast cancer. Increasing PG content reduced FIP viscosity up to ~ 2.5-fold, while increases in PC (over monoolein) increased the formation of emulsified systems. The hexagonal phase was observed at 20% of water and higher, with the minimum amount of water necessary for this formation increasing with PG content. The selected FIP formed a depot in vivo after ~ 24 h of administration; its structure was compatible with the hexagonal phase and it remained in the mammary tissue for at least 30 days, prolonging the permanence of a fluorescent probe. In vitro, the release of the synthetic retinoid fenretinide was slow, with ~ 9% of the drug released in 72 h. Consistent with this slow release, fenretinide IC₅₀ in breast cancer cells was ~ 100-fold higher in the selected FIP compared to its solution. The FIP reduced cell migration and presented higher cytotoxicity towards tumor compared to non-tumor cells. Given the limited number of options for pharmacological prevention of breast cancer development and recurrences, this formulation could potentially find applicability to reduce the frequency of administration and improve local concentrations of chemopreventive drugs.

Sustained drug delivery strategies for treatment of common substance use disorders: Promises and challenges

Substance use disorders (SUDs) are a leading cause of death and other ill health effects in the United States and other countries in the world. Several approaches ranging from detoxification, behavioral therapy, and the use of antagonists or drugs with counter effects are currently being applied for its management. Amongst these, drug therapy is the mainstay for some drug abuse incidences, as is in place specifically for opioid abuse or alcohol dependence. The severity of the havocs observed with the SUDs has triggered constant interest in the discovery and development of novel medications as well as suitable or most appropriate methods for the delivery of these agents. The chronic need of such drugs in users warrants the need for their prolonged or sustained systemic availability. Further, the need to improve patient tolerance to medication, limit invasive drug use and overall treatment outcome are pertinent considerations for embracing sustained release designs for medications used in managing SUDs. This review aims to provide an overview on up-to-date advances made with regards to sustained delivery systems for the drugs for treatment of different types of SUDs such as opioid, alcohol, tobacco, cocaine, and cannabis use disorders. The clinical relevance, promises and the limitations of deployed sustained release approaches along with future opportunities are discussed.

Microemulsion for Prolonged Release of Fenretinide in the Mammary Tissue and Prevention of Breast Cancer Development

The need of pharmacological strategies to preclude breast cancer development motivated us to develop a non-aqueous microemulsion (ME) capable of forming a depot after administration in the mammary tissue and uptake of interstitial fluids for prolonged release of the retinoid fenretinide. The selected ME was composed of phosphatidylcholine/tricaprylin/propylene glycol (45:5:50, w/w/w) and presented a droplet diameter of 175.3 ± 8.9 nm. Upon water uptake, the ME transformed successively into a lamellar phase, gel, and a lamellar phase-containing emulsion in vitro as the water content increased and released 30% of fenretinide in vitro after 9 days. Consistent with the slow release, the ME formed a depot in cell cultures and increased fenretinide IC₅₀ values by 68.3- and 13.2-fold in MCF-7 and T-47D cells compared to a solution, respectively. At non-cytotoxic concentrations, the ME reduced T-47D cell migration by 75.9% and spheroid growth, resulting in ∼30% smaller structures. The depot formed in vivo prolonged a fluorochrome release for 30 days without producing any sings of local irritation. In a preclinical model of chemically induced carcinogenesis, ME administration every 3 weeks for 3 months significantly reduced (4.7-fold) the incidence of breast tumors and increased type II collagen expression, which might contribute to limit spreading. These promising results support the potential ME applicability as a preventive therapy of breast cancer.