Demonstrating Biological Fate of Nanoparticle-Loaded Dissolving Microneedles with Aggregation-Caused Quenching Probes: Influence of Application Sites

Integrating dissolving microneedles (DMNs) and nanocarriers (NC) holds great potential in transdermal drug delivery because it can simultaneously overcome the stratum corneum barrier and achieve efficient and controlled drug delivery. However, different skin sites with different thicknesses and compositions can affect the transdermal diffusion of NC-loaded DMNs. There are few reports on the biological fate (especially transdermal diffusion) of NC-loaded DMNs, and inaccurate bioimaging information of intact NC limits the accurate understanding of the in vivo fate of NC-loaded DMNs. The aggregation-caused quenching (ACQ) probes P4 emitted intense fluorescence signals in intact NC while quenched after the degradation of NC, had been demonstrated the feasibility of label intact NC. In this study, P4 was loaded in solid lipid nanoparticles (SLNs), and further encapsulated into DMNs, to track the transdermal diffusion of SLNs delivered at different skin sites. The results showed that SLNs had excellent stability after being loaded into DMNs with no significant changes in morphology and fluorescence properties. The in vivo live and ex vivo imaging showed that the transdermal diffusion rate of NC-loaded DMNs was positively correlated with skin thickness, with the order ear > abdomen > back. In conclusion, this study confirmed the site-dependency of transdermal diffusion in NC-loaded DMNs.

Updates on the applications of iron-based nanoplatforms in tumor theranostics

With the development of biomedicine and materials science, the emerging research of iron-based nanoplatforms (INPs) have provided a bright future for tumor theranostics. Thanks to its excellent biocompatibility and diverse application potential, some INPs have successfully transformed from the laboratory to the clinic and market, making it one of the most successful nanoplatforms. Further investigations associated with its enormous biomedical potential is continuing, and new features of them are being demonstrated. The discovery of ferroptosis therapy opens up new avenue for the applications of INPs in tumor therapy, which is attracting tremendous attention from worldwide. It is well established that some of the INPs are capable of triggering the tumor cell ferroptosis efficiently, accelerating the tumor cell death process. Combined with anti-tumor drugs or other tumor therapy approaches, the INPs-induced ferroptosis are expected to break the bottleneck in the treatment of drug-resistant malignant tumors. In addition, other applications of INPs in tumor theranostics field are still active. Featured with the catalase-like ability, INPs were also well documented to reverse the tumor hypoxia as nanozymes, assisting and enhancing the oxygen-consuming tumor therapy approaches. And the unique magnetic property of INPs endow it with great potential in tumor diagnosis, hyperthermal therapy and target drug delivery. It is of great significance to summarize these new advances. Herein, the latest reports of the applications of INPs in tumor theranostics are classified to expound the trend of its research and development. The featured functions of it will be discussed in detail to provide a new insight. The key issues needing to be addressed and the development prospective will be put forward. We hope that this review will be helpful to understand the ample potential of INPs in tumor theranostics field.

Novel Inhalable Ciprofloxacin Dry Powders for Bronchiectasis Therapy: Mannitol-Silk Fibroin Binary Microparticles with High-Payload and Improved Aerosolized Properties

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic respiratory disease associated with the high morbidity and mortality. Long-term intermittent therapy by inhalable antibiotics has recently emerged as an effective approach for NCFB treatment. However, the effective delivery of antibiotics to the lung requires administering a high dose to the site of infection. Herein, we investigated the novel inhalable silk-based microparticles as a promising approach to deliver high-payload ciprofloxacin (CIP) for NCFB therapy. Silk fibroin (SF) was applied to improve drug-payload and deposit efficiency of the dry powder particles. Mannitol was added as a mucokinetic agent. The dry powder inhaler (DPI) formulations of CIP microparticles were evaluated in vitro in terms of the aerodynamic performance, particle size distribution, drug loading, morphology, and their solid state. The optimal formulation (highest drug loading, 80%) exhibited superior aerosolization performance in terms of fine particle fraction (45.04 ± 0.84%), emitted dose (98.10 ± 1.27%), mass median aerodynamic diameter (3.75 ± 0.03 μm), and geometric standard deviation (1.66 ± 0.10). The improved drug loading was due to the electrostatic interactions between the SF and CIP by adsorption, and the superior aerosolization efficiency would be largely attributed to the fluffy and porous cotton-like property and low-density structure of SF. The presented results indicated the novel inhalable silk-based DPI microparticles of CIP could provide a promising strategy for the treatment of NCFB.

Nanomedicines for targeted pulmonary delivery: receptor-mediated strategy and alternatives

Pulmonary drug delivery of nanomedicines is promising for the treatment of lung diseases; however, their lack of specificity required for targeted delivery limit their applications. Recently, a variety of pulmonary delivery targeting nanomedicines (PDTNs) has been developed for enhancing drug accumulation in lung lesions and reducing systemic side effects. Furthermore, with the increasing profound understanding of the specific microenvironment of different local lung diseases, multiple targeting strategies have been employed to promote drug delivery efficiency, which can be divided into the receptor-mediated strategy and alternatives. In this review, the current publication trend on PDTNs is analyzed and discussed, revealing that the research in this area has been attracting much attention. According to the different unique microenvironments of lung lesions, the reported PDTNs based on the receptor-mediated strategy for lung cancer, lung infection, lung inflammation and pulmonary fibrosis are listed and summarized. In addition, several other well-established strategies for the design of these PDTNs, such as charge regulation, mucus delivery enhancement, stimulus-responsive drug delivery and magnetic force-driven targeting, are introduced and discussed. Besides, bottlenecks in the development of PDTNs are discussed. Finally, we highlight the challenges and opportunities in the development of PDTNs. We hope that this review will provide an overview of the available PDTNs for guiding the treatment of lung diseases.

Endotracheal Aerosolization Device for Laboratory Investigation of Pulmonary Delivery of Nanoparticle Suspensions: In Vitro and in Vivo Validation

The objective of this study was to perform the in vitro and in vivo validation of an endotracheal aerosolization (ETA) device (HRH MAG-4, HM). Solid lipid nanoparticle suspension (SLNS) formulations with particle sizes of approximately 120, 240, 360, and 480 nm were selected as model nanoparticle suspensions for the validation. The emission rate (ER) of the in vitro aerosolization and the influence of aerosolization on the physicochemical properties were investigated. A high ER of up to 90% was obtained, and no significant alterations in physicochemical properties were observed after the aerosolization. The pulmonary deposition of model drug budesonide in Sprague-Dawley rats was determined to be approximately 80%, which was satisfactory for pulmonary delivery. Additionally, a fluorescent probe with aggregation-caused quenching property was encapsulated in SLNS formulations for in vivo bioimaging, after excluding the effect of aerosolization on its fluorescence spectrum. It was verified that SLNS formulations were deposited in the lung region. The results demonstrated the feasibility and reliability of the HM device for ETA in laboratory investigation.

Chitosan-based binary dry powder inhaler carrier with nanometer roughness for improving in vitro and in vivo aerosolization performance

Suitable nanometer roughness favors interactions between drugs and carriers, and it is a promising approach to enhance the aerosolization performance of carrier-based dry powder inhalers (DPIs). In this study, by altering the molecular migration rates, chitosan-based binary carriers (CBBCs) with nanometer roughness were fabricated for DPIs. Comprehensive physicochemical characterizations were conducted to elucidate the formation mechanism of the CBBCs. It was hypothesized that different constituent ratios in the formulations would result in different assembling of the particles and diverse roughness scales. The fine particle fractions (FPF, approximately 40~60%) of nanometer roughness CBBC-based DPI formulations were satisfactory, demonstrating the enhancement of the in vitro aerodynamic performance. The positive correlation (R2 = 0.9883) between the nanometer roughness and FPF was revealed, and the surface roughness of 20 nm might achieve the best aerosolization performance. CBBCs (optimal formulations) showed no difference in cytotoxicity on A549 and Calu-3 cells (p > 0.05). Additionally, the increased Cmax and AUC0-8h of the formulation with the nanometer roughness (p < 0.05) were observed in pharmacokinetic studies, which resulted from the improved in vivo aerosolization performance. In summary, the CBBCs were a prospective tool to improve the in vitro and in vivo aerosolization performance of DPIs. Graphical abstract ᅟ.

Formation Mechanism and In Vitro Evaluation of Risperidone-Containing PLGA Microspheres Fabricated by Ultrafine Particle Processing System

Ultrafine particle processing system (UPPS) was developed previously by our group to provide a new solution to microsphere fabrication. The UPPS was supposed to possess many featured advantages, but the microsphere formation mechanism during UPPS processing was still unknown. The objective of this study was to perform the formation mechanism investigation and in vitro evaluation on risperidone-containing poly(d, l-lactic-co-glycolic acid) microspheres (RIS-PLGA MS) fabricated by UPPS. Evaporation profile and viscosity of the PLGA-containing solutions were considered as the critical factors for the microsphere formation mechanism and were determined in present study. The formation mechanism of RIS-PLGA MS was put forward by semiquantitative analysis on the basis of the evaporation profile, viscosity, and scanning electron microscopy results. It was established that the evaporation profile and viscosity would have an impact on the evaporation velocity and PLGA molecular diffusion velocity during solidification process, resulting in different appearance of the microspheres. Furthermore, comprehensive in vitro evaluations of RIS-PLGA MS were conducted, including particle size distribution, micromeritics, morphology, drug loading, encapsulation efficiency, residual organic solvent, syringeability, and in vitro release behavior. The results revealed that RIS-PLGA MS was a promising candidate for intramuscular administration, and meanwhile UPPS was a qualified technology for microsphere production.

Dual peptides-modified cationic liposomes for enhanced Lung cancer gene therapy by a gap junction regulating strategy

BACKGROUND

Gene therapy for lung cancer has emerged as a novel tumor-combating strategy for its superior tumor specificity, low systematical toxicity and huge clinical translation potential. Especially, the applications of microRNA shed led on effective tumor ablation by directly interfering with the crucial gene expression, making it one of the most promising gene therapy agents. However, for lung cancer therapy, the microRNA treatment confronted three bottlenecks, the poor tumor tissue penetration effect, the insufficient lung drug accumulation and unsatisfied gene transfection efficiency. To address these issues, an inhalable RGD-TAT dual peptides-modified cationic liposomes loaded with microRNA miR-34a and gap junction (GJ) regulation agent all-trans retinoic acid (ATRA) was proposed, which was further engineered into dry powder inhalers (DPIs).

RESULTS

Equipped with a rough particle surface and appropriate aerodynamic size, the proposed RGD-TAT-CLPs/ARTA@miR-34a DPIs were expected to deposit into the deep lung and reach lung tumor lesions guided by targeting peptide RGD. Assisted by cellular transmembrane peptides TAT, the RGD-TAT-CLPs/ARTA@miR-34a was proven to be effectively internalized by cancer cells, enhancing gene transfection efficiency. Then, the GJ between tumor cells was upregulated by ARTA, facilitating the intercellular transport of miR-34a and boosting the gene expression in the deep tumor.

CONCLUSION

Overall, the proposed RGD-TAT-CLPs/ARTA@miR-34a DPIs could enhance tumor tissue penetration, elevate lung drug accumulation and boost gene transfection efficiency, breaking the three bottlenecks to enhancing tumor elimination in vitro and in vivo. We believe that the proposed RGD-TAT-CLPs/ARTA@miR-34a DPIs could serve as a promising pulmonary gene delivery platform for multiple lung local disease treatments.

In-situ synchrotron wide-angle X-ray diffraction as a rapid method for cocrystal/salt screening

The purpose of this work was to explore in-situ synchrotron wide-angle X-ray diffraction (WAXD) as a rapid and accurate tool to screen and monitor the formation of cocrystal/salts during heating. The active pharmaceutical ingredients (caffeine, carbamazepine and lamotrigine) were respectively mixed with the coformer (saccharin), and then heated by the hot stage. Real-time process monitoring was performed using synchrotron WAXD to assess cocrystal formation and subsequently compared to differential scanning calorimetry (DSC) measurements. The effect of heating rates and cocrystal growth behavior were investigated. Synchrotron WAXD was fast and sensitive to detect cocrystal formation with the appearance of characteristic diffraction rings, even at the heating rate of 30°C/min, while DSC curves showed overlapped peaks. Unlike the indirect characterization of DSC on endo/exothermic peaks, synchrotron WAXD can directly and qualitatively determine cocrystal by diffraction peaks. The diffraction intensity-temperature curves and the corresponding first-derivative curves clearly exhibited the growth behavior of cocrystal upon heating, providing useful information to optimize the process temperature of hot melt extrusion to continuously manufacture cocrystal. The study suggests that in-situ synchrotron WAXD could provide a one-step process to screen cocrystal at high efficiency and reveal the details of cocrystal/salts growth behavior.

Development of Aggregation-Caused Quenching Probe-Loaded Pressurized Metered-Dose Inhalers with Fluorescence Tracking Potentials

Recently, pressurized metered-dose inhalers (pMDIs) are getting more attention as an effective approach of pulmonary drug delivery, and nanoparticle-based formulations have become a new generation of pMDIs, especially for water insoluble drugs. Up until now, there is no clinical application of nanoparticle-based pMDIs. The main hurdle remains in the lack of knowledge of the in vivo fate of those systems. In this study, a fluorescent probe named P4 with aggregation-caused quenching (ACQ) effect was loaded in the nanoparticle-based pMDIs to track the in vivo fate. P4 probe expressed strong fluorescence when distributed in intact nanoparticles, but quenched in the in vivo aqueous environment due to molecular aggregation. Experimentally, P4 probe was encapsulated into solid lipid nanoparticles (SLN) as P4-SLN, and then, the formulation of pMDIs was optimized. The content (w/w) of the optimal formulation (P4-SLN-pMDIs) was as follows: 6.02% Pluronic® L64, 12.03% ethanol, 0.46% P4-SLN, and 81.49% 1,1,1,2-tetrafluoroethane (HFA-134a). P4-SLN-pMDI was transparent in appearance, possessed a particle size of 132.07 ± 3.56 nm, and the fine particle fraction (FPF) was 39.53 ± 1.94%, as well good stability was shown within 10 days. The results indicated P4-SLN-pMDI was successfully prepared. Moreover, the ACQ property of P4-SLN-pMDIs was verified, which ensured the fluorescence property as a credible tool for in vivo fate study. Taken together, this work established a platform that could provide a firm theoretical support for exploration of the in vivo fate of nanoparticle-based pMDIs in subsequent studies. Grapical abstract.

Enhancing Stability of Exenatide-Containing Pressurized Metered-Dose Inhaler Via Reverse Microemulsion System

The dispersibility and stability issues of peptide drugs during preparation and storage hinder the widespread adoption of pressurized metered-dose inhaler (pMDI). This study aimed to develop a reverse microemulsion (RM) of exenatide (EXE) pMDI through a liquid-based bottom-up method, thus to overcome the stability issue of peptide drugs encountered in traditional top-down methods, such as milling down and high-pressure homogenization. In this study, Pluronic® L64 (L64) was chosen as a surfactant to prepare the EXE-RM pMDI formulations with the assistance of ethanol. The results showed RM possessed a particle size of 123.80 ± 2.91 nm with 0.121 ± 0.024 PdI and a satisfied fine-particle fraction of 41.30 ± 3.73% measured by a next-generation impactor. In addition, the dispersion stability of RM pMDI was maintained after storage at 4 °C for 50 days. The secondary structure of EXE was maintained during the preparation process. Moreover, the results indicated that L64 was compatible with cells and could improve the penetration of EXE through cell monolayers. Through the liquid-based bottom-up method, EXE-RM pMDI was successfully prepared and exhibited favorable stability and aerodynamic performance. This study offers a preparation strategy to enhance the stability of peptides in pMDIs.

Near-Infrared Spectroscopy Assay of Key Quality-Indicative Ingredients of Tongkang Tablets

The objective of this paper is to develop an easy and fast near-infrared spectroscopy (NIRS) assay for the four key quality-indicative active ingredients of Tongkang tablets by comparing the true content of the active ingredients measured by high performance liquid chromatography (HPLC) and the NIRS data. The HPLC values for the active ingredients content of Cimicifuga glycoside, calycosin glucoside, 5-O-methylvisamminol and hesperidin in Tongkang tablets were set as reference values. The NIRS raw spectra of Tongkang tablets were processed using first-order convolution method. The iterative optimization method was chosen to optimize the band for Cimicifuga glycoside and 5-O-methylvisamminol, and correlation coefficient method was used to determine the optimal band of calycosin glucoside and hesperidin. A near-infrared quantitative calibration model was established for each quality-indicative ingredient by partial least-squares method on the basis of the contents detected by HPLC and the obtained NIRS spectra. The correlation coefficient R 2 values of the four models of Cimicifuga glycoside, calycosin glucoside, 5-O-methylvisamminol and hesperidin were 0.9025, 0.8582, 0.9250, and 0.9325, respectively. It was demonstrated that the accuracy of the validation values was approximately 90% by comparison of the predicted results from NIRS models and the HPLC true values, which suggested that NIRS assay was successfully established and validated. It was expected that the quantitative analysis models of the four indicative ingredients could be used to rapidly perform quality control in industrial production of Tongkang tablets.

Major difference in particle size, minor difference in release profile: a case study of solid lipid nanoparticles

Solid lipid nanoparticles (SLN) have been widely used in a variety of drug delivery routes, which have the outstanding advantage of controlled drug release. The release of SLN is dominated by many factors, among which the particle size of SLN is a critical one. The aim of this project was to explore the relationship between drug release profile and particle size of SLN. SLN were synthesized via the hot high-pressure homogenization (HPH) method, budesonide (BUD) was used as the model drug, and BUD-SLN1-BUD-SLN4 with increasing particle size was obtained, i.e. 120, 240, 360, and 480 nm. The prepared SLN has good encapsulation efficiency, drug loading capacity, and stability. In vitro release behavior studies showed that the cumulative release of BUD-SLN in Tris-Maleate (Tris-M) media was negligible, while that in Tris-M plus pancreatin media or Tris-M-ethanol media obeyed Ritger-Peppas model or first-order kinetic model, respectively. Noticeably, the release behavior of SLN was to some extent related to the average particle size of SLN, but the correlation was insignificant when the intersection degree of particle size distribution was great. This study provides a new idea for the understanding of in vitro release of SLN and has a certain referencing value for the research and development of novel nanomedicines.

Unraveling the publication trends in inhalable nano-systems

Nano-systems (size range: 1 ~ 1000 nm) have been widely investigated as pulmonary drug delivery carriers, and the safety of inhaled nano-systems has aroused general interests. In this work, bibliometric analysis was performed to describe the current situation of related literature, figure out the revolutionary trends, and eventually forecast the possible future directions. The relevant articles and reviews from 2001 to 2020 were retrieved from the Web of Science Core Collection. The documents were processed by Clarivate Analytic associated with Web of Science database, Statistical Analysis Toolkit for Informetric, bibliometric online platform and VOSviewer, and the data were visualized. The bibliometric overview of the literature was described, citation analysis was performed, and research hotspots were showcased. The bibliometric analysis of 3362 documents of interest indicated that most of the relevant source titles were in the fields of toxicology, pharmacy, and materials science. The three research hotspots were the biological process of inhalable nano-systems in vivo, the manufacture of inhalable nano-systems, and the impact of nano-systems on human health in the environment. Toxicity and safety have always been the keywords. The USA was the major contributing country, and international collaboration and co-authorship were common phenomena. The general situation and development trend of literature of inhalable nano-systems were summarized. It was anticipated that bibliometrics analysis could provide new ideas for the future research of inhalable nano-systems.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11051-021-05384-1.

Development of Paroxetine Hydrochloride Single Layer Controlled-Release Tablets Based on 3² Factorial Design

Major depressive disorder (MDD) is one of the main contributors to disability and suicide mortality globally. Paroxetine hydrochloride (PHH) is the most potent antidepressant used for MDD treatment. Due to its reduced side effects PAXIL® CR is a widely-used controlled-release formulation of PHH. However, the complicated double-layer production of PAXIL® CR faces the risk of layer separation. In this study, PHH enteric coating single layer controlled-release tablets (PHH-EC-SLTs) were designed as a simplified substitution of PAXIL® CR through a rational formulation screening. The optimized PHH-EC-SLTs showed similar release behaviors in vitro to PAXIL® CR and the release profiles corresponded to a zero-order release model (R² = 0.9958). Polymer matrix erosion was the main release mechanism, according to the fitting exponents n > 1 in the Korsmeyer-Pappas model. Crucial pharmacokinetic parameters including peak-reaching time (Tmax), peak concentration (Cmax) and the area under the blood level-time curve (AUC0-48) of PHH-EC-SLTs and PAXIL® CR had no significant difference (p > 0.05) and the relative bioavailability (F = 97.97%) of PHH-EC-SLTs demonstrated their similar pharmacokinetic profiles in vivo. In view of avoiding layer separation risk and simplifying the preparation processing, the self-made PHH-EC-SLTs could be considered as a safe and economic alternative to PAXIL® CR.

Supersaturable organic-inorganic hybrid matrix based on well-ordered mesoporous silica to improve the bioavailability of water insoluble drugs

Mesoporous silica with uniform 2-D hexagonal pores has been newly employed as facile reservoir to impove the dissolution rate of water insoluble drugs. However, rapid drug release from mesoporous silica is usually accompanied by the generation of supersaturated solution, which leads to the drug precipitation and compromised absorption. To address this issue, a supersaturated ternary hybrid system was constructed in this study by utilizing inorganic mesoporous silica and organic precipitation inhibitor. Vinylprrolidone-vinylacetate copolymer (PVP VA64) with similar solubility parameter to model drug fenofibrate (FNB) was expected to well inhibit the precipitation. Mesoporous silica Santa Barbara amorphous-15 (SBA-15) was synthesized in acidic media and hybrid matrix was produced by hot melt extrusion technique. The results of in vitro supersaturation dissolution test obviously revealed that the presence of PVP VA64 could effectively sustain a higher apparent concentration. PVP VA64 was suggested to simultaneously reduce the rate of nucleation and crystal growth and subsequently maintain a metastable supersaturated state. The absorption of FNB delivered by the organic-inorganic hybrid matrix was remarkably enhanced in beagle dogs, and its AUC value was 1.92-fold higher than that of FNB loaded mesoporous silica without PVP VA 64. In conclusion, the supersaturated organic-inorganic hybrid matrix can serve as a modular strategy to enhance the oral availability of water insoluble drugs.