Inhalable dry powder containing remdesivir and disulfiram: Preparation and in vitro characterization

Development of a proliposomal pretomanid dry powder inhaler as a novel alternative approach for combating pulmonary tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) continue as public health concerns. Inhaled drug therapy for TB has substantial benefits in combating the causal agent of TB (Mycobacterium tuberculosis). Pretomanid is a promising candidate in an optional combined regimen for XDR-TB. Pretomanid has demonstrated high potency against M. tuberculosis in both the active and latent phases. Conventional spray drying was used to formulate pretomanid as dry powder inhalers (DPIs) for deep lung delivery using a proliposomal system with a trehalose coarse excipient to enhance the drug solubility. Co-spray drying with L-leucine protected hygroscopic trehalose in formulations and improved powder aerosolization. Higher amounts of L-leucine (40-50 % w/w) resulted in the formation of mesoporous particles with high percentages of drug content and entrapment efficiency. The aerosolized powders demonstrated both geometric and median aerodynamic diameters < 5 µm with > 90 % emitted dose and > 50 % fine particle fraction. Upon reconstitution in simulated physiological fluid, the proliposomes completely converted to liposomes, exhibiting suitable particle sizes (130-300 nm) with stable colloids and improving drug solubility, leading to higher drug dissolution compared to the drug alone. Inhalable pretomanid showed higher antimycobacterial activity than pretomanid alone. The formulations were safe for all broncho-epithelial cell lines and alveolar macrophages, thus indicating their potential suitability for DPIs targeting pulmonary TB.

Preparation of poly(vinyl alcohol) nanofibers containing disulfiram-copper complex by electrospinning: a potential delivery system against melanoma

BACKGROUND

Melanoma poses a significant threat to human health, making the development of a safe and effective treatment a crucial challenge. Disulfiram (DS) is a proven anticancer drug that has shown effectiveness when used in combination with copper (DS-Cu complex).

OBJECTIVES

This study focuses on encapsulation of DS-copper complex into nanofiber scaffold from polyvinyl alcohol (PVA) (DS-Cu@PVA). In order to increase bioavailability towards melanoma cell lines and decrease its toxicity.

METHODS

The scaffold was fabricated through an electrospinning process using an aqueous solution, and subsequently analyzed using ART-Fourier transform infrared spectroscopy (ART-FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). Additionally, cellular cytotoxicity, flow cytometry analysis, and determination of caspase 3 activity were conducted to further characterize the scaffold.

RESULTS

The results confirmed that encapsulation of DS-Cu complex into PVA was successful via different characterization. The scanning electron microscopy (SEM) analysis revealed that the diameter of the nanofibers remained consistent despite the addition of DS-Cu. Additionally, ATR-FTIR confirmed that the incorporation of DS-Cu into PVA did not significantly alter the characteristic peaks of PVA. Furthermore, the cytotoxicity assessment of the DS-Cu@PVA nanofibrous scaffold using human normal skin cells (HFB4) demonstrated its superior biocompatibility compared to DS-Cu-free counterparts. Notably, the presence of DS-Cu maintained its effectiveness in promoting apoptosis by increasing cellular reactive oxygen species, proapoptotic gene expression, and caspase 3 activity, while simultaneously reducing glutathione levels and oncogene expression in human and mouse melanoma cell lines (A375 and B16F10, respectively). Overall, these findings suggest that the addition of DS-Cu to PVA nanofibers enhances their biocompatibility and cytotoxic effects on melanoma cells, making them a promising candidate for biomedical applications.

CONCLUSION

The findings indicate that the targeted delivery of DS-Cu onto a PVA nanofiber scaffold holds potential approach to enhance the efficacy of DS-Cu in combating melanoma.

Repurposing ebselen as an inhalable dry powder to treat respiratory tract infections

Respiratory tract infections (RTIs) are one of the leading causes of death globally, lately exacerbated by the increasing prevalence of antimicrobial resistance. While antimicrobial resistance could be overcome by developing new antimicrobial agents, the use of a safe repurposed agent having potent antimicrobial activity against various RTIs can be an efficient and cost-effective alternative to overcome the long and complex process of developing and testing new drugs. Ebselen, a synthetic organoselenium drug originally developed to treat noise-inducing hearing problems, has shown promising antimicrobial activity in vitro against several respiratory pathogens including viruses (e.g., SARS-CoV-2, influenza A virus) and bacteria (e.g., Mycobacterium tuberculosis, Streptococcus pneumoniae, and Staphylococcus aureus). Inhaled drug delivery is considered a promising approach for treating RTIs, as it can ensure effective drug concentrations at a lower dose, thereby minimizing the side effects that are often encountered by using oral or injectable drugs. In this study, we developed inhalable ebselen dry powder formulations using a spray-drying technique. The amino acids leucine, methionine, and tryptophan were incorporated with ebselen to enhance the yield and aerosolization of the dry powders. The amino acid-containing ebselen dry powders showed a better yield (37-56.4 %) than the amino acid-free formulation (30.9 %). All dry powders were crystalline in nature. The mass median aerodynamic diameter (MMAD) was less than 5 µm for amino acids containing dry powders (3-4 µm) and slightly higher (5.4 µm) for amino acid free dry powder indicating their suitability for inhalation. The aerosol performance was higher when amino acids were used, and the leucine-containing ebselen dry powder showed the highest emitted dose (84 %) and fine particle fraction (68 %). All amino acid formulations had similar cytotoxicity as raw ebselen, tested in respiratory cell line (A549 cells), with half-maximal inhibitory concentrations (IC50) between 100 and 250 μg/mL. Raw ebselen and amino acid-containing dry powders showed similar potent antibacterial activity against the Gram-positive bacteria S. aureus and S. pneumoniae with minimum inhibitory concentrations of 0.31 μg/mL and 0.16 μg/mL, respectively. On the other hand, raw ebselen and the formulations showed limited antimicrobial activity against the Gram-negative pathogens Pseudomonas aeruginosa and Klebsiella pneumoniae. In summary, in this study we were able to develop amino-acid-containing inhalable dry powders of ebselen that could be used against different respiratory pathogens, especially Gram-positive bacteria, which could ensure more drug deposition in the respiratory tract, including the lungs. DPIs are generally used to treat lung (lower respiratory tract) diseases. However, DPIs can also be used to treat both upper and lower RTIs. The deposition of the dry powder in the respiratory tract is dependent on its physicochemical properties and this properties can be modulated to target the intended site of infection (upper and/or lower respiratory tract). Further studies will allow the development of similar formulations of individual and/or combination of antimicrobials that could be used to inhibit a number of respiratory pathogens.