Formation of ciprofloxacin nanocrystals within liposomes by spray drying for controlled release via inhalation

Process development of inhalation powders containing simvastatin loaded liposomes using spray drying technology

The development of an inhalation powder (IP) for cancer therapy is desired to improve the therapeutic response and patient compliance. The latest studies highlighted that statins, a class of drugs used in hypercholesterolemia, can have anticancer and antiinflammatory properties. Therefore, the aim of the study was to develop an IP containing liposomes loaded with simvastatin using spray drying technology, as well as to investigate the influence of formulation factors on the quality attributes of the IP by means of experimental design. Results highlighted that the composition of liposomes, namely type of phospholipid and cholesterol concentration, highly influences the quality attributes of IP, and the use of optimal concentrations of excipients, i.e. D-mannitol and L-leucine, is essential to preserve the characteristics of liposomes throughout the spray drying process. The in vitro characterization of the optimal IP formulation revealed that the total percentage of released drug is higher from the IP formulation compared to the powder of active substance (53.38 vs. 42.76%) over a period of six hours, and 39.67% of dry particles have a size less than 5 µm, making them suitable for inhalation. As a conclusion, spray drying technology can be effectively used in the development and preparation of IP containing liposomes.

A Review on Micro and Nanoengineering in Powder-Based Pulmonary Drug Delivery

Pulmonary delivery of drugs has emerged as a promising approach for the treatment of both lung and systemic diseases. Compared to other drug delivery routes, inhalation offers numerous advantages including high targeting, fewer side effects, and a huge surface area for drug absorption. However, the deposition of drugs in the lungs can be limited by lung defence mechanisms such as mucociliary and macrophages' clearance. Among the delivery devices, dry powder inhalers represent the optimal choice due to their stability, ease of use, and absence of propellants. In the last decades, several bottom-up techniques have emerged over traditional milling to produce inhalable powders. Among these techniques, the most employed ones are spray drying, supercritical fluid technology, spray freeze-drying, and thin film freezing. Inhalable dry powders can be constituted by micronized drugs attached to a coarse carrier (e.g., lactose) or drugs embedded into a micro- or nanoparticle. Particulate-based formulations are commonly composed of polymeric micro- and nanoparticles, liposomes, solid lipid nanoparticles, dendrimers, nanocrystals, extracellular vesicles, and inorganic nanoparticles. Moreover, engineered formulations including large porous particles, swellable microparticles, nano-in-microparticles, and effervescent nanoparticles have been developed. Particle engineering has also a crucial role in tuning the physical-chemical properties of both carrier-based and carrier-free inhalable powders. This approach can increase powder flowability, deposition, and targeting by customising particle surface features.

Lipid-based nanomedicines for the treatment of bacterial respiratory infections: current state and new perspectives

The global threat posed by antimicrobial resistance demands urgent action and the development of effective drugs. Lower respiratory tract infections remain the deadliest communicable disease worldwide, often challenging to treat due to the presence of bacteria that form recalcitrant biofilms. There is consensus that novel anti-infectives with reduced resistance compared with conventional antibiotics are needed, leading to extensive research on innovative antibacterial agents. This review explores the recent progress in lipid-based nanomedicines developed to counteract bacterial respiratory infections, especially those involving biofilm growth; focuses on improved drug bioavailability and targeting and highlights novel strategies to enhance treatment efficacy while emphasizing the importance of continued research in this dynamic field.

Application of ensemble machine learning approach to assess the factors affecting size and polydispersity index of liposomal nanoparticles

Liposome nanoparticles have emerged as promising drug delivery systems due to their unique properties. Assessing particle size and polydispersity index (PDI) is critical for evaluating the quality of these liposomal nanoparticles. However, optimizing these parameters in a laboratory setting is both costly and time-consuming. This study aimed to apply a machine learning technique to assess the impact of specific factors, including sonication time, extrusion temperature, and compositions, on the size and PDI of liposomal nanoparticles. Liposomal solutions were prepared and subjected to sonication with varying values for these parameters. Two compositions: (A) HSPC:DPPG:Chol:DSPE-mPEG2000 at 55:5:35:5 molar ratio and (B) HSPC:Chol:DSPE-mPEG2000 at 55:40:5 molar ratio, were made using remote loading method. Ensemble learning (EL), a machine learning technique, was employed using the Least-squares boosting (LSBoost) algorithm to accurately model the data. The dataset was randomly split into training and testing sets, with 70% allocated for training. The LSBoost algorithm achieved mean absolute errors of 1.652 and 0.0105 for modeling the size and PDI, respectively. Under conditions where the temperature was set at approximately 60 °C, our EL model predicted a minimum particle size of 116.53 nm for composition (A) with a sonication time of approximately 30 min. Similarly, for composition (B), the model predicted a minimum particle size of 129.97 nm with sonication times of approximately 30 or 55 min. In most instances, a PDI of less than 0.2 was achieved. These results highlight the significant impact of optimizing independent factors on the characteristics of liposomal nanoparticles and demonstrate the potential of EL as a decision support system for identifying the best liposomal formulation. We recommend further studies to explore the effects of other independent factors, such as lipid composition and surfactants, on liposomal nanoparticle characteristics.

Engineering the right formulation for enhanced drug delivery

Dry powder inhalers (DPIs) can be used with a wide range of drugs such as small molecules and biologics and offer several advantages for inhaled therapy. Early DPI products were intended to treat asthma and lung chronic inflammatory disease by administering low-dose, high-potency drugs blended with lactose carrier particles. The use of lactose blends is still the most common approach to aid powder flowability and dose metering in DPI products. However, this conventional approach may not meet the high demand for formulation physical stability, aerosolisation performance, and bioavailability. To overcome these issues, innovative techniques coupled with modification of the traditional methods have been explored to engineer particles for enhanced drug delivery. Different particle engineering techniques have been utilised depending on the types of the active pharmaceutical ingredient (e.g., small molecules, peptides, proteins, cells) and the inhaled dose. This review discusses the challenges of formulating DPI formulations of low-dose and high-dose small molecule drugs, and biologics, followed by recent and emerging particle engineering strategies utilised in developing the right inhalable powder formulations for enhanced drug delivery.

Nanostructures for drug delivery in respiratory diseases therapeutics: Revision of current trends and its comparative analysis

Respiratory diseases are leading causes of death and disability in developing and developed countries. The burden of acute and chronic respiratory diseases has been rising throughout the world and represents a major problem in the public health system. Acute respiratory diseases include pneumonia, influenza, SARS-CoV-2 and MERS viral infections; while chronic obstructive pulmonary disease (COPD), asthma and, occupational lung diseases (asbestosis, pneumoconiosis) and other parenchymal lung diseases namely lung cancer and tuberculosis are examples of chronic respiratory diseases. Importantly, chronic respiratory diseases are not curable and treatments for acute pathologies are particularly challenging. For that reason, the integration of nanotechnology to existing drugs or for the development of new treatments potentially benefits the therapeutic goals by making drugs more effective and exhibit fewer undesirable side effects to treat these conditions. Moreover, the integration of different nanostructures enables improvement of drug bioavailability, transport and delivery compared to stand-alone drugs in traditional respiratory therapy. Notably, there has been great progress in translating nanotechnology-based cancer therapies and diagnostics into the clinic; however, researchers in recent years have focused on the application of nanostructures in other relevant pulmonary diseases as revealed in our database search. Furthermore, polymeric nanoparticles and micelles are the most studied nanostructures in a wide range of diseases; however, liposomal nanostructures are recognized to be some of the most successful commercial drug delivery systems. In conclusion, this review presents an overview of the recent and relevant research in drug delivery systems for the treatment of different pulmonary diseases and outlines the trends, limitations, importance and application of nanomedicine technology in treatment and diagnosis and future work in this field.

Combination and nanotechnology based pharmaceutical strategies for combating respiratory bacterial biofilm infections

Respiratory infections are one of the major global health problems. Among them, chronic respiratory infections caused by biofilm formation are difficult to treat because of both drug tolerance and poor drug penetration into the complex biofilm structure. A major part of the current research on combating respiratory biofilm infections have been focused on destroying the matrix of extracellular polymeric substance and eDNA of the biofilm or promoting the penetration of antibiotics through the extracellular polymeric substance via delivery technologies in order to kill the bacteria inside. There are also experimental data showing that certain inhaled antibiotics with simple formulations can effectively penetrate EPS to kill surficially located bacteria and centrally located dormant bacteria or persisters. This article aims to review recent advances in the pharmaceutical strategies for combating respiratory biofilm infections with a focus on nanotechnology-based drug delivery approaches. The formation and characteristics of bacterial biofilm infections in the airway mucus are presented, which is followed by a brief review on the current clinical approaches to treat respiratory biofilm infections by surgical removal and antimicrobial therapy, and also the emerging clinical treatment approaches. The current combination of antibiotics and non-antibiotic adjuvants to combat respiratory biofilm infections are also discussed.

Nanoparticle-Based Drug Delivery System: The Magic Bullet for the Treatment of Chronic Pulmonary Diseases

Chronic pulmonary diseases encompass different persistent and lethal diseases, including chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), cystic fibrosis (CF), asthma, and lung cancers that affect millions of people globally. Traditional pharmacotherapeutic treatment approaches (i.e., bronchodilators, corticosteroids, chemotherapeutics, peptide-based agents, etc.) are not satisfactory to cure or impede diseases. With the advent of nanotechnology, drug delivery to an intended site is still difficult, but the nanoparticle's physicochemical properties can accomplish targeted therapeutic delivery. Based on their surface, size, density, and physical-chemical properties, nanoparticles have demonstrated enhanced pharmacokinetics of actives, achieving the spotlight in the drug delivery research field. In this review, the authors have highlighted different nanoparticle-based therapeutic delivery approaches to treat chronic pulmonary diseases along with the preparation techniques. The authors have remarked the nanosuspension delivery via nebulization and dry powder carrier is further effective in the lung delivery system since the particles released from these systems are innumerable to composite nanoparticles. The authors have also outlined the inhaled particle's toxicity, patented nanoparticle-based pulmonary formulations, and commercial pulmonary drug delivery devices (PDD) in other sections. Recently advanced formulations employing nanoparticles as therapeutic carriers for the efficient treatment of chronic pulmonary diseases are also canvassed.

Storage stability of inhalable, controlled-release powder formulations of ciprofloxacin nanocrystal-containing liposomes

Novel inhalable and controlled release powder formulations of ciprofloxacin nanocrystals inside liposomes (CNL) were recently developed. In the present study, the storage stability of CNL powders consisting of lyoprotectant (i.e. sucrose or lactose), lipids, ciprofloxacin (CIP), and magnesium stearate or isoleucine was investigated. These powders were produced by spray drying, collected in a dry box at <15% relative humidity (RH), then stored at room temperature and either 4 or 20 %RH. Liposomal integrity, CIP encapsulation efficiency (EE), in vitro drug release (IVR), aerosol performance, and solid-state properties were examined over six months. Sucrose CNL powder exhibited consistent liposomal integrity, aerosol performance, and controlled release of CIP over six months of storage at 4 %RH. However, storage of the powder at 20 %RH for the same period caused sucrose crystallization and consequently a significant drop in EE and aerosol performance (p-values < 0.05), along with the IVR of CIP becoming similar to that of the non-crystalline CIP liposomal dispersions (f2 > 50). Lactose CNL maintained superior aerosol performance over the six months irrespective of the storage RH. However, liposomal instability occurred at both RHs within the first month of storage with a significant drop in EE and an increase in liposome size (p-values < 0.05). Moreover, the IVR assay of CIP from lactose CNL showed a less controlled release and a substantial difference (f2 < 50) from its initial value after six months regardless of the storage RHs. In conclusion, dry powder inhalers of CNL were physiochemically stable in sucrose lyoprotectant when stored below 4 %RH at room temperature for six months.

In Vitro Drug Release, Permeability, and Structural Test of Ciprofloxacin-Loaded Nanofibers

Nanofibers of the poorly water-soluble antibiotic ciprofloxacin (CIP) were fabricated in the form of an amorphous solid dispersion by using poly(vinyl pyrrolidone) as a polymer matrix, by the low-cost electrospinning method. The solubility of the nanofibers as well as their in vitro diffusion were remarkably higher than those of the CIP powder or the physical mixture of the two components. The fiber size and morphology were optimized, and it was found that the addition of the CIP to the electrospinning solution decreased the nanofiber diameter, leading to an increased specific surface area. Structural characterization confirmed the interactions between the drug and the polymer and the amorphous state of CIP inside the nanofibers. Since the solubility of CIP is pH-dependent, the in vitro solubility and dissolution studies were executed at different pH levels. The nanofiber sample with the finest morphology demonstrated a significant increase in solubility both in water and pH 7.4 buffer. Single medium and two-stage biorelevant dissolution studies were performed, and the release mechanism was described by mathematical models. Besides, in vitro diffusion from pH 6.8 to pH 7.4 notably increased when compared with the pure drug and physical mixture. Ciprofloxacin-loaded poly(vinyl pyrrolidone) (PVP) nanofibers can be considered as fast-dissolving formulations with improved physicochemical properties.

Administration of dry powders during respiratory supports

Inhaled drugs are routinely used for the treatment of respiratory-supported patients. To date, pressurized metered dose inhalers and nebulizers are the two platforms routinely employed in the clinical setting. The scarce utilization of the dry powder inhaler (DPI) platform is partly due to the lack of in vivo data that proves optimal delivery and drug efficacy are achievable. Additionally, fitting a DPI in-line to the respiratory circuit is not as straightforward as with the other aerosol delivery platforms. Importantly, there is a common misconception that the warm and humidified inspiratory air in respiratory supports, even for a short exposure, will deteriorate powder formulation compromising its delivery and efficacy. However, some recent studies have dispelled this myth, showing successful delivery of dry powders through the humidified circuit of respiratory supports. Compared with other aerosol delivery devices, the use of DPIs during respiratory supports possesses unique advantages such as rapid delivery and high dose. In this review, we presented in vitro studies showing various setups employing commercial DPIs and effects of ventilator parameters on the aerosol delivery. Inclusion of novel DPIs was also made to illustrate characteristics of an ideal inhaler that would give high lung dose with low powder deposition loss in tracheal tubes and respiratory circuits. Clinical trials are urgently needed to confirm the benefits of administration of dry powders in ventilated patients, thus enabling translation of powder delivery into practice.

Modeling of a spray drying method to produce ciprofloxacin nanocrystals inside the liposomes utilizing a response surface methodology: Box-Behnken experimental design

Spray drying was previously used to modify the physical form of the encapsulated ciprofloxacin drug to produce ciprofloxacin nanocrystals inside the liposomes (CNL). The purpose of the present study was to optimize CNL powder production by evaluating the response surface via design of experiments (DoE). Using the Box-Behnken (BB) design, the study independent variables were the protectant type (sucrose, trehalose or lactose), protectant amount, drying temperature, and spray gas flow. Individual spray drying experiments were performed at various set points for each variable followed by characterization of the produced powders. Liposomal particle size, drug encapsulation efficiency (EE%), liposomal surface zeta potential, and nanocrystal dimensions were the design dependant variables. By applying the least square regression method on the experimental data, mathematical models were developed using the mathematical software package MATLAB R2018b. Model reliability and the significance of the model's factors were estimated using analysis of variance (ANOVA). The generated CNL powders showed spherical to elliptical liposomal vesicles with particle sizes ranging from 98 to 159 nm. The EE (%) ranged from 30 to 95% w/w while the zeta potential varied between -3.5 and -10.5 mV. The encapsulated ciprofloxacin nanocrystals were elongated cylindrical structures with an aspect ratio of 4.0-7.8. Coefficients of determination (R² > 0.9) revealed a good agreement between the predicted and experimental values for all responses except for the nanocrystal dimensions. Sucrose and lactose were superior to trehalose in protecting the liposomes during spray drying. The amount of sugar significantly affected the characteristics of the CNL powders (p-value < 0.05). In conclusion, the DoE approach using BB design has efficiently modelled the generation of CNL by spray drying. The optimum processing conditions which produced high drug encapsulation (90%) after formation of nanocrystals and a vesicle size of ~125 nm utilized 57% (w/w) sucrose, an 80 °C inlet temperature, and an atomization rate of 742 L/hr.

Targeted drug nanocrystals for pulmonary delivery: a potential strategy for lung cancer therapy

INTRODUCTION

Lung cancer and metastases are major concerns worldwide. Although systemic chemotherapy is the recommended treatment, it is associated with various disadvantages, including nonselective drug distribution and systemic toxicity. In contrast, the pulmonary route ensures the localized delivery of drugs to the lung. Still, the pulmonary route is prone to clearance, limited drug dissolution, and local toxicity to healthy lung cells. Drug nanocrystals provide a potential strategy to enhance the therapeutic efficacy and mitigate the limitations of pulmonary delivery.

AREAS COVERED

The development and potential application of nanocrystals in pulmonary delivery, their role in overcoming associated barriers, and strategies for site-specific and stimuli-responsive pulmonary delivery are outlined. This review also traces different in-vitro pulmonary models for assessments of the performance of drug nanocrystals and nanocrystals loaded carriers in pulmonary delivery.

EXPERT OPINION

Enhanced stability, high aerosolization performance, better particle size distribution, improved penetration, sustained release of the drug, and minimal excipients usage makes drug nanocrystal an ideal candidate for pulmonary delivery. Besides, drug nanocrystals may provide selective cellular internalization with minimum clearance and maximum deposition. Furthermore, surface modified nanocrystals and nanocrystals in nanocarriers can exhibit a more prolonged, and site-specific release of the drug to cancer cells in the lungs.