Spray-Dried Amorphous Solid Dispersions of Griseofulvin in HPC/Soluplus/SDS: Elucidating the Multifaceted Impact of SDS as a Minor Component

This study aimed to elucidate the impact of a common anionic surfactant, sodium dodecyl sulfate (SDS), along with hydroxypropyl cellulose (HPC) and Soluplus (Sol) on the release of griseofulvin (GF), a poorly soluble drug, from amorphous solid dispersions (ASDs). Solutions of 2.5% GF and 2.5%–12.5% HPC/Sol with 0.125% SDS/without SDS were prepared in acetone–water and spray-dried. The solid-state characterization of the ASDs suggests that GF–Sol had better miscibility and stronger interactions than GF–HPC and formed XRPD-amorphous GF, whereas HPC-based ASDs, especially the ones with a lower HPC loading, had crystalline GF. The dissolution tests show that without SDS, ASDs provided limited GF supersaturation (max. 250%) due to poor wettability of Sol-based ASDs and extensive GF recrystallization in HPC-based ASDs (max. 50%). Sol-based ASDs with SDS exhibited a dramatic increase in supersaturation (max. 570%), especially at a higher Sol loading, whereas HPC-based ASDs with SDS did not. SDS did not interfere with Sol’s ability to inhibit GF recrystallization, as confirmed by the precipitation from the supersaturated state and PLM imaging. The favorable use of SDS in a ternary ASD was attributed to both the wettability enhancement and its inability to promote GF recrystallization when used as a minor component along with Sol.

Hydroxypropyl beta cyclodextrin: a water-replacement agent or a surfactant upon spray freeze-drying of IgG with enhanced stability and aerosolization

The great potential of hydroxypropyl beta-cyclodextrin (HPßCD), as a dried-protein stabilizer, has been attributed to various mechanisms namely water-replacement, vitrification and surfactant-like effects. Highlighting the best result in our previous study (weight ratio IgG: HPßCD of 1:0.4), herein we designed to evaluate the efficacy of upper (1:2) and lower (1:0.05) ratios of HPßCD in stabilization and aerosol properties of spray freeze-dried IgG. The protective effect of HPβCD, as measured by size exclusion chromatography (SEC-HPLC) was most pronounced at C3' and C3″, IgG:trehalose:HPβCD ratios of 1:2:0.25 and 1:2:0.05 with aggregation rate constants of 0.46 ± 0.02 and 0.58 ± 0.01 (1/month), respectively. The secondary conformations were analyzed through Fourier transform infrared spectroscopy (FTIR) and all powders well-preserved with the lack of any visible fragments qualified through sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PPAGE). Scanning electron microscopy (SEM) and twin stage impinger (TSI) were employed to characterize the suitability of particles for further inhalation therapy of antibodies and the highest values of fine particle fraction (FPF) were achieved by C3' and C3″, 56.43 and 48.12%. The powders produced at the current ratio 1:2:0.25 and 1:2:0.05 are superior to our previous examination with regards to manifesting lower aggregation and comparable FPF values.

Advances and limitations of drug delivery systems formulated as eye drops

Topical instillation of eye drops remains the most common and easiest route of ocular drug administration, representing the treatment of choice for many ocular diseases. Nevertheless, low ocular bioavailability of topically applied drug molecules can considerably limit their efficacy. Over the last several decades, numerous drug delivery systems (DDS) have been developed in order to improve drug bioavailability on the ocular surfaces. This review systematically covers the most recent advances of DDS applicable by topical instillation, that have shown better performance in in vivo models compared to standard eye drop formulations. These delivery systems are based on in situ forming gels, nanoparticles and combinations of both. Most of the DDS have been developed using natural or synthetic polymers. Polymers offer many advantageous properties for designing advanced DDS including biocompatibility, gelation properties and/or mucoadhesiveness. However, despite the high number of studies published over the last decade, there are several limitations for clinical translation of DDS. This review article focuses on the recent advances for the development of ocular drug delivery systems. In addtion, the potential challenges for commercialization of new DDS are presented.

A Systematic Safety Evaluation of Nanoporous Mannitol Material as a Dry-Powder Inhalation Carrier System

For carrier-based dry-powder inhaler (DPI) formulations, the adhesion between carrier particles and active pharmaceutical ingredients (API) particles have a significant influence on the aerosolization performance of the API-carrier complexes and the desired detachment of the API for efficient pulmonary delivery. In our previous study, nanoporous mannitol material was successfully fabricated as carriers by a one-step nonorganic solvent spray drying method with the thermal degradation of ammonium carbonate. These carriers were shown to achieve excellent aerosolization performance. In addition, no residue of ammonium carbonate was detected on the powder surface. However, the safety of nanoporous mannitol carriers (Nano-PMCs) during pulmonary administration/delivery was still unknown because the lung is vulnerable to the inhaled particles. To address this question, the present study was conducted to construct a systematic safety evaluation for DPIs carriers to investigate the safety of Nano-PMCs in the whole inhalation, which would make up for the lack of detailed and standardized method in this field. In vitro safety evaluation was carried out using respiratory and pulmonary cytotoxicity tests, hemolysis assay, and ciliotoxicity test. In vivo safety evaluation was studied by measuring inflammatory indicators in the bronchoalveolar lavage fluid, assessing the pulmonary function and observing pulmonary pathological changes. Nano-PMCs showed satisfactory biocompatibility on respiratory tracts and lungs in vitro and in vivo. It was suggested that Nano-PMCs were safe for intrapulmonary delivery and potential as DPI carriers.

Poly(L-Glutamic Acid)-Based Brush Copolymers: Fabrication, Self-assembly, and Evaluation as Efficient Nanocarriers for Cationic Protein Drug Delivery

Protein drugs were considered to be the first choice to treat many human diseases, but their clinical application was usually limited by their short half-life and lack of validated targeted therapy. Here, a series of folate-functionalized poly(ethylene glycol)-b-(poly(2-aminoethyl-L-glutamate)-g-poly(L-glutamic acid))s (FA-PEG-b-(PELG-g-PLGA)s) were designed as tumor-targeted carriers for cationic protein delivery. Compared with traditional copolymers consisting of PEG and linear charged hydrophilic blocks, FA-PEG-b-(PELG-g-PLGA) with brush-like polyelectrolyte segments were beneficial to improving their electrostatic interactions with loading protein molecules, thus increasing drug-loading stability and protecting encapsulated proteins from degradation. The designed polymer brushes could efficiently encapsulate cytochrome C (CytC), a cationic model protein, to form polyion complex (PIC) micelles with an average particle size of approximately 200 nm. An in vitro drug release study showed that the drug-loading stability of the formed PIC micelles was largely improved. The functionalization of the block copolymer carriers with a targeting folate group enhanced the tumor cell growth inhibition and total apoptotic rates induced by CytC. Our results shed light on the unique advantages of brush-like polymer carriers in delivering cationic proteins, and the poly(L-glutamic acid)-based linear-brush diblock copolymers could be applied as a versatile delivery platform for molecular targeting in cancer therapy.

Influence of Composition and Spray-Drying Process Parameters on Carrier-Free DPI Properties and Behaviors in the Lung: A review

Although dry powder inhalers (DPIs) have attracted great interest compared to nebulizers and metered-dose inhalers (MDIs), drug deposition in the deep lung is still insufficient to enhance therapeutic activity. Indeed, it is estimated that only 10–15% of the drug reaches the deep lung while 20% of the drug is lost in the oropharyngeal sphere and 65% is not released from the carrier. The potentiality of the powders to disperse in the air during the patient’s inhalation, the aerosolization, should be optimized. To do so, new strategies, in addition to classical lactose-carrier, have emerged. The lung deposition of carrier-free particles, mainly produced by spray drying, is higher due to non-interparticulate forces between the carrier and drug, as well as better powder uniformity and aerosolization. Moreover, the association of two or three active ingredients within the same powder seems easier. This review is focused on a new type of carrier-free particles which are characterized by a sugar-based core encompassed by a corrugated shell layer produced by spray drying. All excipients used to produce such particles are dissected and their physico-chemical properties (Péclet number, glass transition temperature) are put in relation with the lung deposition ability of powders. The importance of spray-drying parameters on powders’ properties and behaviors is also evaluated. Special attention is given to the relation between the morphology (characterized by a corrugated surface) and lung deposition performance. The understanding of the closed relation between particle material composition and spray-drying process parameters, impacting the final powder properties, could help in the development of promising DPI systems suitable for local or systemic drug delivery.

Physical stability of dry powder inhaler formulations

Introduction: Dry powder inhalers (DPIs) are popular for pulmonary drug delivery. Various techniques have been employed to produce inhalation drug particles and improve the delivery efficiency of DPI formulations. Physical stability of these DPI formulations is critical to ensure the delivery of a reproducible dose to the airways over the shelf-life.Areas covered: This review focuses on the impact of solid-state stability on aerosolization performance of DPI drug particles manufactured by powder production approaches and particle-engineering techniques. It also highlights the different analytical tools that can be used to characterize the physical instability originating from production and storage.Expert opinion: A majority of the DPI literature focuses on the effects of physico-chemical properties such as size, morphology, and density on aerosolization. While little has been reported on the physical stability, particularly the stability of engineered drug particles for use in DPIs. Literature data have shown that different particle-engineering methods and storage conditions may cause physical instability of dry powders for inhalation and can significantly change the aerosol performance. A systematic examination of physical instability mechanisms in DPI formulations is necessary during formulation development in order to select the optimum formulation with satisfactory stability. In addition, the use of appropriate characterization tools is critical to detect and understand physical instability during the development of DPI formulations.

PLGA Porous Microspheres Dry Powders for Codelivery of Afatinib-Loaded Solid Lipid Nanoparticles and Paclitaxel: Novel Therapy for EGFR Tyrosine Kinase Inhibitors Resistant Nonsmall Cell Lung Cancer

Combination therapy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR TKIs) with other chemotherapeutic agents is a feasible strategy to overcome resistance that often occurs after 9-13 months of EGFR TKIs administration in nonsmall cell lung cancer (NSCLC). In this study, a pulmonary microspheres system that codelivers afatinib and paclitaxel (PTX) is developed for treatment of EGFR TKIs resistant NSCLC. In this system, afatinib is loaded in stearic acid-based solid lipid nanoparticles, then these nanoparticles and PTX are loaded in poly-lactide-co-glycolide-based porous microspheres. These inhaled microspheres systems are characterized including geometric particle size, drug encapsulation efficiency, morphology by scanning electron microscopy, specific surface area, in vitro drug release, and aerodynamic particle size. Cell experiments indicate that afatinib and PTX have a synergistic effect and the codelivery system shows a superior treatment effect in drug-resistant NSCLC cells. The biocompatibility, pharmacokinetic, and tissue distribution experiments in Sprague-Dawley rats show that afatinib and PTX in the system can maintain 96 h of high lung concentration but low concentration in other tissues, with acceptable safety. These results demonstrate that this system may be a prospective delivery strategy for drug combination treatment in cancers developing resistance, especially drug-resistant lung cancer.

Proniosomal gel-derived niosomes: an approach to sustain and improve the ocular delivery of brimonidine tartrate; formulation, in-vitro characterization, and in-vivo pharmacodynamic study

Brimonidine tartrate (BRT) is a hydrophilic α2 adrenergic agonist used for the treatment of glaucoma. Glaucoma is an ocular disease affecting the anterior segment of the eye requiring lifetime treatment. Owing to the obstacles facing ocular delivery systems and hydrophilicity of BRT, frequent administration of the eye drops is required. Niosomes have been widely used to improve the ocular bioavailability of the topically applied drugs and to enhance the ocular residence time. However, they have drawbacks as physical instability, aggregation, and loss of the entrapped drug. For this reason, BRT proniosomes were prepared to overcome niosomal instability issues. A D-optimal design was utilized to determine the optimum conditions for preparation of the proniosomal gels. Independent variables were amount of surfactant, surfactant:cholesterol ratio, and type of surfactant used. The dependent variables were entrapment efficiency (EE%), particle size, percentage of drug released after 2 h (Q2h), and percentage of drug released after 24 h (Q24h). The optimum formula was suggested with desirability 0.732 and the composition of 540 mg Span 60 and 10:1 surfactant:cholesterol ratio. The results obtained after reconstitution were; EE% of 79.23 ± 1.12% particle size of 810.95 ± 16.758 nm, polydispersity index (PDI) 0.6785 ± 0.213, zeta potential 59.1 ± 0.99 mV, Q2h40.98 ± 1.29%, Q8h 63.35 ± 6.07%, and Q24h = 91.11 ± 1.76%. Transmission electron microscope imaging of the formula showed the typical spherical shape of niosomes. In-vivo pharmacodynamic study assured the improved ocular bioavailability of BRT selected formula when compared with Alphagan®P with relative AUC0-24 of 5.024 and 7.90 folds increase in the mean residence time (MRT). Lack of ocular irritation of the formula was assured by Draize test.

Therapeutic efficacy of nanoparticles and routes of administration

In modern-day medicine, nanotechnology and nanoparticles are some of the indispensable tools in disease monitoring and therapy. The term “nanomaterials” describes materials with nanoscale dimensions (< 100 nm) and are broadly classified into natural and synthetic nanomaterials. However, “engineered” nanomaterials have received significant attention due to their versatility. Although enormous strides have been made in research and development in the field of nanotechnology, it is often confusing for beginners to make an informed choice regarding the nanocarrier system and its potential applications. Hence, in this review, we have endeavored to briefly explain the most commonly used nanomaterials, their core properties and how surface functionalization would facilitate competent delivery of drugs or therapeutic molecules. Similarly, the suitability of carbon-based nanomaterials like CNT and QD has been discussed for targeted drug delivery and siRNA therapy. One of the biggest challenges in the formulation of drug delivery systems is fulfilling targeted/specific drug delivery, controlling drug release and preventing opsonization. Thus, a different mechanism of drug targeting, the role of suitable drug-laden nanocarrier fabrication and methods to augment drug solubility and bioavailability are discussed. Additionally, different routes of nanocarrier administration are discussed to provide greater understanding of the biological and other barriers and their impact on drug transport. The overall aim of this article is to facilitate straightforward perception of nanocarrier design, routes of various nanoparticle administration and the challenges associated with each drug delivery method.

Self-assembling in situ gel based on lyotropic liquid crystals containing VEGF for tissue regeneration

Current tissue-regenerative biomaterials confront two critical issues: the uncontrollable delivery capacity of vascular endothelial growth factor (VEGF) for adequate vascularization and the poor mechanical properties of the system for tissue regeneration. To overcome these two issues, a self-assembling in situ gel based on lyotropic liquid crystals (LLC) was developed. VEGF-LLC was administrated as a precursor solution that would self-assemble into an in situ gel with well-defined internal inverse bicontinuous cubic phases when exposed to physiological fluid at a defect site. The inverse cubic phase with a 3D bicontinuous water channel enabled a 7-day sustained release of VEGF. The release profile of VEGF-LLC was controlled using octyl glucoside (OG) as a hydration-modulating agent, which could enlarge the water channel, yielding a 2-fold increase in water channel size and a 7-fold increase in VEGF release. For the mechanical properties, the elastic modulus was found to decrease from ∼100 kPa to ∼1.2 kPa, which might be more favorable for angiogenesis. Furthermore, the self-recovery ability of the VEGF-LLC gel was confirmed by quick recovery of the inner network in step-strain measurements. In vitro, VEGF-LLC considerably promoted the proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs) as compared to free VEGF (p < 0.05). Furthermore, angiogenesis was successfully induced in rats after subcutaneous injection of VEGF-LLC. The self-assembling LLC gel showed satisfactory degradability and mild inflammatory response with little impact on the surrounding tissue. The controllable release profile and unique mechanical properties of VEGF-LLC offer a new approach for tissue regeneration. STATEMENT OF SIGNIFICANCE: The potential clinical use of currently available biomaterials in tissue regeneration is limited by their uncontrollable drug delivery capacity and poor mechanical properties. Herein, a self-assembling in situ gel based on lyotropic liquid crystals (LLC) for induced angiogenesis was developed. The results showed that the addition of octyl glucoside (OG) could change the water channel size of LLC, which enabled the LLC system to release VEGF in a sustained manner and to possess a suitable modulus to favor angiogenesis simultaneously. Moreover, the self-recovery capability allowed the gel to match the deformation of surrounding tissues during body motion to maintain its properties and reduce discomfort. In vivo, angiogenesis was induced by VEGF-LLC 14 days after administering subcutaneous injection. These results highlight the potential of LLC as a promising sustained protein drug delivery system for vascular formation and tissue regeneration.

Understanding the effect of lipid formulation loading and ethanol as a diluent on solidification of pitavastatin super-saturable SNEDDS using factorial design approach

Solidification of a preconcentrate lipid formulation namely self-nano emulsifying drug delivery system (SNEDDS) is required to achieve feasibility, flexibility, and a new concept of “dry nano-emulsion”. The purpose of this study was to assess the effect of SNEDDS loading and ethanol as a diluent on the solidification of pitavastatin supersaturable SNEDDS (S-SNEDDS). A 2² full factorial design approach with a center point addition as a curvature was implemented to determine the effect of S-SNEDDS loading and ethanol on the physical characteristics, namely flowability, compactibility, and drug release behavior. Vibrational spectra, thermal behavior, and morphology of solid S-SNEDDS formulation were also evaluated. The results indicated that there was no interaction between S-SNEDDS and carrier, based on vibrational spectra. However, thermal behaviors (enthalpy and weight loss) were depending on SNEDDS loading. Thereafter, the ethanol as a diluent of preconcentrated formulation had no effect on the morphology of carrier structure. However, the S-SNEDDS loading altered the structure of carrier owing to either solubilization or abrasion processes. The statistical model suggested that ethanol as diluent reduced the flowability, compactibility, and drug releases. Meanwhile, the liquid SNEDDS loading affected the reducing of flowability and compactibility. Finally, solidification without diluent and 20% lipid formulation load was recommended. In addition, it was very useful because of ease on handling, flexibility for further formulation, and desired characteristics of final solid dosage form.

Cubic and hexagonal liquid crystal gels for ocular delivery with enhanced effect of pilocarpine nitrate on anti-glaucoma treatment

The objective of this work was to investigate phytantriol-based liquid crystal (LC) gels including cubic (Q₂) and hexagonal (H₂) phase for ocular delivery of pilocarpine nitrate (PN) to treat glaucoma. The gels were produced by a vortex method and confirmed by crossed polarized light microscopy, small-angle X-ray scattering, and rheological measurements. Moreover, the release behaviors and permeation results of PN from the gels were estimated using in vitro studies. Finally, the anti-glaucoma effect of LC gels was evaluated by in vivo animal experiments. The inner structure of the gels was Pn3m-type Q₂ and H₂ phase, and both of them showed pseudoplastic fluid properties based on characterization techniques. In vitro release profiles suggested that PN could be sustainably released from LC gels within 48 h. Compared with eye drops, Q₂ and H₂ gel produces a 5.25-fold and 6.23-fold increase in the P_app value (p < .05), respectively, leading to a significant enhancement of corneal penetration. Furthermore, a good biocompatibility and longer residence time on precorneal for LC gels confirmed by in vivo animal experiment. Pharmacokinetic studies showed that LC gels could maintain PN concentration in aqueous humor for at least 12 h after administration and remarkably improve the bioavailability of drug. Additionally, in vivo pharmacodynamics studies indicated that LC gels had a more significant intraocular pressure-lowering and miotic effect compared to eye drops. These research findings hinted that LC gels would be a promising pharmaceutical strategy for ocular application to enhance the efficacy of anti-glaucoma.

Spray-Dried Amorphous Solid Dispersions of Atorvastatin Calcium for Improved Supersaturation and Oral Bioavailability

Over the past few decades, the amorphous solid dispersions (ASDs) technique has emerged as a promising strategy to enhance the in vitro/in vivo characteristic of hydrophobic drugs. The low aqueous solubility and poor bioavailability of atorvastatin calcium (ATO), a lipid-lowering drug, present challenges for effective drug delivery. The objective of this work was to improve the aqueous solubility, in vitro dissolution, and oral absorption of ATO with amorphous solid dispersion technique prepared by spray-drying method. The optimized ternary formulation comprising of ATO; hydroxypropyl methylcellulose (HPMC), as a hydrophilic polymer; and sodium lauryl sulfate (SLS), as a surfactant, at a weight ratio of 1/1/0.1, showed significant improvement in aqueous solubility by ~18-fold compared to that of the free drug, and a cumulative release of 94.09% compared to a release of 59.32% of the free drug. Further, physicochemical studies via scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction revealed a change from the crystalline state of the free drug to its amorphous state in the ASD. Pharmacokinetic analysis in rats demonstrated 1.68- and 2.39-fold increments in AUC and Cmax, respectively, in the ASD over the free drug. Altogether, hydrophilic carrier-based ASDs prepared by the spray-drying technique represent a promising strategy to improve the biopharmaceutical performance of poorly soluble drugs.

In silico Tools at Early Stage of Pharmaceutical Development: Data Needs and Software Capabilities

In early drug development, the selection of a formulation platform and decisions on formulation strategies have to be made within a short timeframe and often with minimal use of the active pharmaceutical ingredient (API). The current work evaluated the various physicochemical parameters required to improve the prediction accuracy of simulation software for immediate release tablets in early drug development. DDDPlus™ was used in simulating dissolution test profiles of immediate release tablets of ritonavir and all simulations were compared with experimental results. The minimum data requirements to make useful predictions were assessed using the ADMET predictor (part of DDDPlus) and Chemicalize (an online resource). A surfactant model was developed to estimate the solubility enhancement in media containing surfactant and the software's transfer model based on the USP two-tiered dissolution test was assessed. One measured data point was shown to be sufficient to make predictive simulations in DDDPlus. At pH 2.0, the software overestimated drug release while at pH 1.0 and 6.8, simulations were close to the measured values. A surfactant solubility model established with measured data gave good dissolution predictions. The transfer model uses a single-vessel model and was unable to predict the two in vivo environments separately. For weak bases like ritonavir, a minimum of three solubility data points is recommended for in silico predictions in buffered media. A surfactant solubility model is useful when predicting dissolution behavior in surfactant media and in silico predictions need measured solubility data to be predictive.

Successful oral delivery of poorly water-soluble drugs both depends on the intraluminal behavior of drugs and of appropriate advanced drug delivery systems

Poorly water-soluble drugs continue to be a problematic, yet important class of pharmaceutical compounds for treatment of a wide range of diseases. Their prevalence in discovery is still high, and their development is usually limited by our lack of a complete understanding of how the complex chemical, physiological and biochemical processes that occur between administration and absorption individually and together impact on bioavailability. This review defines the challenge presented by these drugs, outlines contemporary strategies to solve this challenge, and consequent in silico and in vitro evaluation of the delivery technologies for poorly water-soluble drugs. The next steps and unmet needs are proposed to present a roadmap for future studies for the field to consider enabling progress in delivery of poorly water-soluble compounds.

Surface Modification of Poly(lactic-co-glycolic acid) Microspheres with Enhanced Hydrophilicity and Dispersibility for Arterial Embolization

In this study, a series of poly(lactic-co-glycolic acid) (PLGA) microspheres with different particle sizes for arterial embolization surgery were prepared. The polydopamine (PDA) and polydopamine/polyethyleneimine (PDA/PEI) were respectively coated on the PLGA microspheres as shells, in order to improve the hydrophilicity and dispersibility of PLGA embolization microspheres. After modification, with the introduction of PDA and PEI, many hydrophilic hydroxyl and amine groups appeared on the surface of the PLGA@PDA and PLGA@PDA/PEI microspheres. SEM images showed the morphologies, sizes, and changes of the as-prepared microspheres. Meanwhile, the XPS and FT-IR spectra demonstrated the successful modification of the PDA and PEI. Water contact angles (WCAs) of the PLGA@PDA and PLGA@PDA/PEI microspheres became smaller, indicating a certain improvement in surface hydrophilicity. In addition, the results of in vitro cytotoxicity showed that modification had little effect on the biosafety of the microspheres. The modified PLGA microspheres suggest a promising prospective application in biomedical field, as the modified microspheres can reduce difficulties in embolization surgery.

β-Carotene solid dispersion prepared by hot-melt technology improves its solubility in water

β-Carotene is a member of the carotenoid family and is a red-orange pigment abundantly present in many vegetables and fruits. As an antioxidant, it eliminates excessive reactive oxygen species generated in the body. Accordingly, it has potential to be used in the pharmaceutical, food, and cosmetic industries. β-Carotene has a very low water solubility and low bioavailability; thus, there is a need to develop techniques to overcome these issues. In this study, we aimed to enhance the water solubility of β-carotene by using hot-melt technology, a type of solid dispersions technology. When preparing β-carotene solid dispersion using this method, suitable conditions for the emulsifiers and mixing ratios were investigated using water solubility as an index. Setting the weight ratio of β-carotene:polyvinylpyrrolidone:sucrose fatty acid ester to 10%:70%:20% resulted in the poorly-water soluble β-carotene showing improved water solubility (120 μg/mL). The physicochemical properties of the optimized β-carotene solid dispersion were analyzed using field emission scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction. The solid dispersion was found to have an amorphous structure. The improved solubility observed for β-carotene in the solid dispersions developed in this work may make these dispersions useful as additives in foods or in nutraceutical formulations.

Comparison of ELISA and HPLC-MS methods for the determination of exenatide in biological and biotechnology-based formulation matrices

The development of biotechnology-based active pharmaceutical ingredients, such as GLP-1 analogs, brought changes in type 2 diabetes treatment options. For better therapeutic efficiency, these active pharmaceutical ingredients require appropriate administration, without the development of adverse effects or toxicity. Therefore, it is required to develop several quantification methods for GLP-1 analogs products, in order to achieve the therapeutic goals, among which ELISA and HPLC arise. These methods are developed, optimized and validated in order to determine GLP-1 analogs, not only in final formulation of the active pharmaceutical ingredient, but also during preclinical and clinical trials assessment. This review highlights the role of ELISA and HPLC methods that have been used during the assessment for GLP-1 analogs, especially for exenatide.

Itraconazole lipid nanocapsules gel for dermatological applications: In vitro characteristics and treatment of induced cutaneous candidiasis

There is a growing clinical demand for topical itraconazole (ITC) delivery systems because of the expanding potential of the drug for topical fungal and non-fungal applications. Lipid-based nanocarriers offer great promise in this respect. In the present study, a new topical ITC gel based on lipid nanocapsules (LNC) was developed. ITC-LNC were compared to ITC-loaded nanostructured lipid carriers (ITC-NLC) with more established benefits as topical vectors. Both nanocarriers showed high entrapment efficiency (EE > 98%). Compared to ITC-NLC, the ITC-LNC showed a significantly smaller particle size (∼50 vs 155 nm), narrower size distribution (0.09 vs 0.38), faster initial release rate under sink conditions and greater in vitro antifungal activity against Candida albicans (C. albicans) (inhibition zone 29.4 vs 26.4 mm). ITC-LNC and ITC-NLC-based gels significantly enhanced the dermal retention of ITC in excised human skin relative to a conventional ITC gel. Histopathological assessment of a 14-day treatment of induced cutaneous candidiasis in a rat model indicated efficacy of the gel preparations. Fungal elements developed in the superficial epidermal skin layer were cleared by the end of treatment. Equally important, no histopathological changes in the epidermal and dermal layers of rat skin were observed. Findings of this study verified efficacy of topical ITC in the treatment of superficial fungal infections as well as effectiveness of LNC as biomimetic nanocarrier for dermal drug delivery. Combining ITC and LNC would present a bioactive nanocarrier system with good potentials for fungal infections and other skin applications.

Effect of USP Induction Ports, Glass Sampling Apparatus, and Inhaler Device Resistance on Aerodynamic Patterns of Fluticasone Propionate-Loaded Engineered Mannitol Microparticles

The present investigation is to study the effect of two different induction ports (IP), i.e., USP IP and USP-modified IP equipped with andersen cascade impactor on in vitro aerodynamic performance along with the impact of USP-modified glass sampling apparatus on delivered dose uniformity of fluticasone propionate (FP) dry powder inhaler (DPI). FP DPI was fabricated by spray drying technique using engineered mannitol microparticles (EMP) with different force controlling agents, i.e., leucine and magnesium stearate. Additionally, commercially available two DPI inhaler devices namely Handihaler® and Breezhaler® were used to aerosolize the FP blends. Spherical smooth surface of EMP showed good powder flow properties and acceptable percentage content uniformity (> 95%). Amounts of FP deposited in cascade assembly using USP-modified IP with the Breezhaler® device was significantly higher (1.32-fold) as compared with the Handihaler® device. Moreover, USP-modified IP showed better deposition as compared with USP IP. Additionally, both inhaler devices showed a satisfactory delivered dose (> 105%) for FP using modified glass sampling apparatus at a flow rate of 60 L/min for 2 s. It was interesting to note that not only formulation properties but also IP geometry and device resistance have significant impact on DPI deposition pattern. This study is a first detailed account of aerodynamic performance of FP using USP-modified IP and USP-modified glass sampling apparatus. Thus, it can be of potential importance for both the academic and industry perspective.

Towards more accurate bioimaging of drug nanocarriers: turning aggregation-caused quenching into a useful tool

One of the current challenges in the monitoring of drug nanocarriers lies in the difficulties in discriminating the carrier-bound signals from the bulk signals of probes. Environment-responsive probes that enable signal switching are making steps towards a solution to this problem. Aggregation-caused quenching (ACQ), a phenomenon generally regarded as unfavorable in bioimaging, has turned out to be a promising characteristic for achieving environment-responsiveness and eliminating free-probe interference. So-called ACQ probes emit fluorescence when dispersed molecularly within the carrier matrix but quench immediately and absolutely once they are released into the ambient aqueous environment upon the degradation of the nanocarriers. Therefore, the fluorescence observed represents integral nanocarriers. Based on this rationale, the in vivo fates of various nanocarriers have been explored using live imaging equipment, with very interesting findings revealing the role of the particles. The current applications are however restricted to nanocarriers with highly hydrophobic matrices (lipid or polyester nanoparticles) or with a hydrophobic core-hydrophilic shell structure (micelles). The ACQ-based bioimaging strategy is emerging as a promising tool to achieve more accurate bioimaging of drug nanocarriers. This review article provides an overview of the ACQ phenomenon and the rationale for and examples of applications, as well as the limitations of the ACQ-based strategy, with a focus on improving the accuracy of bioimaging of nanoparticles.

In situ gelation of rhEGF-containing liquid crystalline precursor with good cargo stability and system mechanical properties: a novel delivery system for chronic wounds treatment

The objective of this study was to develop a novel delivery system for recombinant human epidermal growth factor (rhEGF) for chronic wound treatment. Such a delivery system should be of good cargo stability and system mechanical properties in order to guarantee a satisfactory wound-healing effect. rhEGF-containing lyotropic liquid crystalline precursors (rhEGF-LLCPs) with in situ gelation capability were considered as a promising candidate to achieve this aim. Various properties of the optimal formulations (rhEGF-LLCP1 and rhEGF-LLCP2) were characterized, including apparent viscosity, gelation time, in vitro release and phase behavior. The stability of rhEGF and system mechanical properties (i.e. mechanical rigidity and bioadhesive force) were verified. Interestingly, rhEGF-LLCP2 with a larger internal water channel diameter exhibited faster release rate in vitro and then better bioactivity in Balb/c 3T3 and HaCaT cell models. Moreover, rhEGF-LLCP2 showed distinct promotion effects on wound closure, inflammatory recovery and re-epithelization process in Sprague-Dawley rat models. In conclusion, rhEGF-LLCP emerged as a prospective candidate to preserve the stability and enhance the wound-healing effect of rhEGF, which might serve as a new delivery system for chronic wound therapies.

Folate Ligand Orientation Optimized during Cell Membrane Mimetic Micelle Formation for Enhanced Tumor Cell Targeting

Nanocarriers with strong tumor cell targeting ability have been expected to overcome limitations of cancer chemotherapy. Herein, cell membrane mimetic micelles were prepared from a random copolymer (PMNCF) containing cell membrane phosphorylcholine zwitterion, cholesterol, and tumor cell targeting folic acid (FA) at the side chain ends. Surface orientation of the FA ligand was optimized during PMNCF micelle preparation by controlling solvent solubility for FA. The out-oriented ligands on the micelles were immobilized by the strongly associated hydration layer around the closely packed phosphorylcholine zwitterions. The doxorubicin (DOX) loaded PMNCF micelles were demonstrated to reduce normal cell toxicity to less than 20%. More significantly, HeLa and MCF-7 tumor cell killing efficacy of the optimized formulation was enhanced to 160% compared with that of free DOX. The excellent performances of the drug loaded PMNCF micelles on both tumor cell killing and normal cell toxicity reducing efficacies reveal great potential for developing advanced drug delivery system.

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.

Formation Mechanism, In vitro and In vivo Evaluation of Dimpled Exenatide Loaded PLGA Microparticles Prepared by Ultra-Fine Particle Processing System

Spherical poly (D, L-lactic-co-glycolic acid) microparticles (PLGA-MPs) have long been investigated in order to achieve sustained delivery of proteins/peptides. However, the formation mechanism and release characteristics of the specific shape MPs were still unknown. This study aimed to develop a novel-dimpled exenatide-loaded PLGA-MPs (Exe-PLGA-MPs) using an ultra-fine particle processing system (UPPS) and investigate the formation mechanism and release characteristics. Exe-PLGA-MPs were prepared by UPPS and optimized based on their initial burst within the first 24 h and drug release profiles. Physicochemical properties of Exe-PLGA-MPs, including morphology, particle size, and structural integrity of Exe extracted from Exe-PLGA-MPs, were evaluated. Furthermore, pharmacokinetic studies of the optimal formulation were conducted in Sprague-Dawley (SD) rats to establish in vitro-in vivo correlations (IVIVC) of drug release. Exe-PLGA-MPs with dimpled shapes and uniform particle sizes achieved a high encapsulation efficiency (EE%, 91.50 ± 2.65%) and sustained drug release for 2 months in vitro with reduced initial burst (20.42 ± 1.64%). Moreover, the pharmacokinetic studies revealed that effective drug concentration could be maintained for 3 weeks following a single injection of dimpled Exe-PLGA-MPs with high IVIVC. Dimpled PLGA-MPs prepared using the UPPS technique could thus have great potential for sustained delivery of macromolecular proteins/peptides.

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.

Moisture-Resistant Co-Spray-Dried Netilmicin with l-Leucine as Dry Powder Inhalation for the Treatment of Respiratory Infections

Netilmicin (NTM) is one of the first-line drugs for lower respiratory tract infections (LRTI) therapy, but its nephrotoxicity and ototoxicity caused by intravenous injection restrict its clinical application. Dry powder inhalation (DPI) is a popular local drug delivery system that is introduced as a solution. Due to the nature of NTM hygroscopicity that hinders its direct use through DPI, in this study, L-leucine (LL) was added into NTM dry powder to reduce its moisture absorption rate and improve its aerosolization performance. NTM DPIs were prepared using spray-drying with different LL proportions. The particle size, density, morphology, crystallinity, water content, hygroscopicity, antibacterial activity, in vitro aerosolization performance, and stability of each formulation were characterized. NTM DPIs were suitable for inhalation and amorphous with a corrugated surface. The analysis indicated that the water content and hygroscopicity were decreased with the addition of LL, whilst the antibacterial activity of NTM was maintained. The optimal formulation ND₂ (NTM:LL = 30:1) showed high fine particle fraction values (85.14 ± 8.97%), which was 2.78-fold those of ND₀ (100% NTM). It was stable after storage at 40 ± 2 °C, 75 ± 5% relative humidity (RH). The additional LL in NTM DPI successfully reduced the hygroscopicity and improved the aerosolization performance. NTM DPIs were proved to be a feasible and desirable approach for the treatment of LRTI.

Dry powder inhaler formulations of poorly water-soluble itraconazole: A balance between in-vitro dissolution and in-vivo distribution is necessary

Formulating poorly water-soluble drug, itraconazole (ITZ), as dry powder inhaler (DPI) may be more effective for the treatment of invasive pulmonary Aspergillosis than intravenous injection and oral administration. It is necessary to improve the dissolution of ITZ because the alveolar lining fluid is limited and thus the dissolution of ITZ in the lung may be slow and incomplete. However, too fast dissolution may result in over-absorption into the circulation and thus insufficient distribution in the lung. The purpose of this study is to understand the relationship between in-vitro dissolution and in-vivo distribution of ITZ from DPI formulations. Two DPI formulations (F1 and F2) with identical compositions and similar aerodynamic behaviors were fabricated by hot melt extrusion and thus jet-milling. ITZ was formulated with mannitol as fine solid crystal suspension system to effectively improve its dissolution. In-vitro dissolution tests and in-vivo pharmacokinetic studies indicated that F1 released faster than F2 under both sink and non-sink conditions, but exhibited a lower lung retention and higher plasma absorption than F2. These results suggested that although dissolution enhancement of poorly water-soluble drugs in pulmonary delivery may be necessary to overcome problems such as local irritation and quick elimination by macrophages, it may have an impact on the distribution of the drug between the lung and the plasma. A balance between airway dissolution and systemic absorption should be taken into consideration when developing DPI formulations of poorly water-soluble ITZ.

Fragmented particles containing octreotide acetate prepared by spray drying technique for dry powder inhalation

Dry powder inhalers (DPIs) have been proposed as an alternative administration route for protein and peptide drugs. However, DPI particles are easy to aggregate due to the strong interactions between the particles, leading to poor aerosolization performance. In this study, fragmented particles containing octreotide acetate (OA) were prepared by spray drying technique for dry powder inhalation, which were expected to decrease the particle-particle interaction by reducing the contact sites. Mannitol and ammonium carbonate were used as protein stabilizer and fragment-forming agent, respectively. The obtained fragmented particles presented larger particle size, lower density, better dispersibility, and well in vitro aerodynamic behavior (emitted dose > 97%, fine particle fraction ≈ 40%). The circular dichroism spectrum results indicated that OA maintained the stability throughout the spray drying process. The relative bioavailability of dry powder inhalation (DPI) compared with subcutaneous injection of commercial product was up to 88.0%, demonstrating the feasibility of DPI for OA delivery. These results confirmed that the proposed fragmented particles had great potential for pulmonary delivery of protein and peptide drugs in a painless, rapid, and convenient manner.

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.

Drying Technologies for the Stability and Bioavailability of Biopharmaceuticals

Solid dosage forms of biopharmaceuticals such as therapeutic proteins could provide enhanced bioavailability, improved storage stability, as well as expanded alternatives to parenteral administration. Although numerous drying methods have been used for preparing dried protein powders, choosing a suitable drying technique remains a challenge. In this review, the most frequent drying methods, such as freeze drying, spray drying, spray freeze drying, and supercritical fluid drying, for improving the stability and bioavailability of therapeutic proteins, are discussed. These technologies can prepare protein formulations for different applications as they produce particles with different sizes and morphologies. Proper drying methods are chosen, and the critical process parameters are optimized based on the proposed route of drug administration and the required pharmacokinetics. In an optimized drying procedure, the screening of formulations according to their protein properties is performed to prepare a stable protein formulation for various delivery systems, including pulmonary, nasal, and sustained-release applications.

Risperidone Controlled Release Microspheres Based on Poly(Lactic Acid)-Poly(Propylene Adipate) Novel Polymer Blends Appropriate for Long Acting Injectable Formulations

The present study evaluates the preparation of risperidone controlled release microspheres as appropriate long-acting injectable formulations based on a series of novel biodegradable and biocompatible poly(lactic acid)⁻poly(propylene adipate) (PLA/PPAd) polymer blends. Initially, PPAd was synthesized using a two-stage melt polycondensation method (esterification and polycondensation) and characterized by 1H-NMR, differential scanning calorimetry (DSC), and powder X-ray diffraction (XRD) analyses. DSC and XRD results for PLA/PPAd blends (prepared by the solvent evaporation method) showed that these are immiscible, while enzymatic hydrolysis studies performed at 37 °C showed increased mass loss for PPAd compared to PLA. Risperidone-polyester microparticles prepared by the oil⁻water emulsification/solvent evaporation method showed smooth spherical surface with particle sizes from 1 to 15 μm. DSC, XRD, and Fourier-transformed infrared (FTIR) analyses showed that the active pharmaceutical ingredient (API) was dispersed in the amorphous phase within the polymer matrices, whereas in vitro drug release studies showed risperidone controlled release rates in all PLA/PPAd blend formulations. Finally, statistical moment analysis showed that polyester hydrolysis had a major impact on API release kinetics, while in PLA/PPAd blends with high PLA content, drug release was mainly controlled by diffusion.

Fast Dissolving of Ferulic Acid via Electrospun Ternary Amorphous Composites Produced by a Coaxial Process

Enhancing the dissolution of insoluble active ingredients comprises one of the most important issues in the pharmaceutical and biomaterial fields. Here, a third generation solid dispersion (3rd SD) of ferulic acid was designed and fabricated by a modified coaxial electrospinning process. A traditional second generation SD (2nd SD) was also prepared by common one-fluid blending electrospinning and was used as a control. With poly(vinyl alcohol) as the fiber matrix and polyvinylpyrrolidone K10 as an additive in the 3rd SDs, the two electrospinning processes were investigated. The prepared 2nd and 3rd SDs were subjected to a series of characterizations, including X-ray diffraction (XRD), scanning electron microscope (SEM), hydrophilicity and in vitro drug dissolving experiments. The results demonstrate that both SDs were monolithic nanocomposites and that the drugs were amorphously distributed within the matrix. However, the 3rd SDs had better morphology with smaller size, narrower size distribution, and smaller water contact angles than the 2nd SDs. Dissolution tests verified that the 3rd SDs could release their loaded cargoes within 60 s, which was over three times faster than the 2nd SDs. Therefore, a combined strategy based on the modified coaxial electrospinning and the logical selections of drug carriers is demonstrated for creating advanced biomaterials.

The potential to treat lung cancer via inhalation of repurposed drugs

Lung cancer is a highly invasive and prevalent disease with ineffective first-line treatment and remains the leading cause of cancer death in men and women. Despite the improvements in diagnosis and therapy, the prognosis and outcome of lung cancer patients is still poor. This could be associated with the lack of effective first-line oncology drugs, formation of resistant tumors and non-optimal administration route. Therefore, the repurposing of existing drugs currently used for different indications and the introduction of a different method of drug administration could be investigated as an alternative to improve lung cancer therapy. This review describes the rationale and development of repositioning of drugs for lung cancer treatment with emphasis on inhalation. The review includes the current progress of repurposing non-cancer drugs, as well as current chemotherapeutics for lung malignancies via inhalation. Several potential non-cancer drugs such as statins, itraconazole and clarithromycin, that have demonstrated preclinical anti-cancer activity, are also presented. Furthermore, the potential challenges and limitations that might hamper the clinical translation of repurposed oncology drugs are described.

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.

Photoresponsive endosomal escape enhances gene delivery using liposome-polycation-DNA (LPD) nanovectors

Lipid-based nanocarriers with stimuli responsiveness have been utilized as controlled release systems for gene/drug delivery applications. In our work, by taking advantage of the high complexation capability of polycations and the light triggered properties, we designed a novel photoresponsive liposome-polycation-DNA (LPD) platform. This LPD carrier incorporates verteporfin (VP) in lipid bilayers and the complex of polyethylenimine (PEI)/plasmid DNA (pDNA) encoding EGFP (polyplex) in the central cavities of the liposomes. The liposomes were formulated with cationic lipids, PEGylated neutral lipids and cholesterol molecules, which improve their stability and cellular uptake in the serum-containing media. We evaluated the nanocomplex stability by monitoring size changes over six days, and the cellular uptake of the nanocomplex by imaging the intracellular route. We also demonstrated that light triggered the cytoplasmic release of pDNA upon irradiation with a 690 nm LED light source. Furthermore, this light triggered mechanism has been studied at the subcellular level. The activated release is driven by the generation of reactive oxygen species (ROS) from VP after light illumination. These ROS oxidize and destabilize the liposomal and endolysosomal membranes, leading to the release of pDNA into the cytosol and subsequent gene transfer activities. Light-triggered endolysosomal escape of pDNA at different time points was confirmed by a quantitative analysis of colocalization between pDNA and endolysosomes. The increased expression of the reporter EGFP in human colorectal cancer cells was also quantified after light illumination at various time points. The efficiency of this photo-induced gene transfection was demonstrated to be more than double compared to non-irradiated controls. Additionally, we observed a reduced cytotoxicity of the LPDs compared with the polyplexes alone. This study has thus shown that light-triggered and biocompatible LPDs enable an improved control of efficient gene delivery, which will be beneficial for future gene therapies.

Low density, good flowability cyclodextrin-raffinose binary carrier for dry powder inhaler: anti-hygroscopicity and aerosolization performance enhancement

BACKGROUND

The hygroscopicity of raffinose carrier for dry powder inhaler (DPI) was the main obstacle for its further application. Hygroscopicity-induced agglomeration would cause deterioration of aerosolization performance of raffinose, undermining the delivery efficiency.

METHODS

Cyclodextrin-raffinose binary carriers (CRBCs) were produced by spray-drying so as to surmount the above issue. Physicochemical attributes and formation mechanism of CRBCs were explored in detail. The flow property of CRBCs was examined by FT4 Powder Rheometer. Hygroscopicity of CRBCs was elucidated by dynamic vapor sorption study. Aerosolization performance was evaluated by in vitro deposition profile and in vivo pharmacokinetic profile of CRBC based DPI formulations.

RESULTS

The optimal formulation of CRBC (R4) was proven to possess anti-hygroscopicity and aerosolization performance enhancement properties. Concisely, the moisture uptake of R4 was c.a. 5% which was far lower than spray-dried raffinose (R0, c.a. 65%). R4 exhibited a high fine particle fraction value of 70.56 ± 0.61% and it was 3.75-fold against R0. The pulmonary and plasmatic bioavailability of R4 were significantly higher than R0 (p < 0.05).

CONCLUSION

CRBC with anti-hygroscopicity and aerosolization performance enhancement properties was a promising approach for pulmonary drug delivery, which could provide new possibilities to the application of hygroscopic carriers for DPI.