Application of Quality by Design to the robust preparation of a liposomal GLA formulation by DELOS-susp method.

Fabry disease is a lysosomal storage disease arising from a deficiency of the enzyme α-galactosidase A (GLA). The enzyme deficiency results in an accumulation of glycolipids, which over time, leads to cardiovascular, cerebrovascular, and renal disease, ultimately leading to death in the fourth or fifth decade of life. Currently, lysosomal storage disorders are treated by enzyme replacement therapy (ERT) through the direct administration of the missing enzyme to the patients. In view of their advantages as drug delivery systems, liposomes are increasingly being researched and utilized in the pharmaceutical, food and cosmetic industries, but one of the main barriers to market is their scalability. Depressurization of an Expanded Liquid Organic Solution into aqueous solution (DELOS-susp) is a compressed fluid-based method that allows the reproducible and scalable production of nanovesicular systems with remarkable physicochemical characteristics, in terms of homogeneity, morphology, and particle size. The objective of this work was to optimize and reach a suitable formulation for in vivo preclinical studies by implementing a Quality by Design (QbD) approach, a methodology recommended by the FDA and the EMA to develop robust drug manufacturing and control methods, to the preparation of α-galactosidase-loaded nanoliposomes (nanoGLA) for the treatment of Fabry disease. Through a risk analysis and a Design of Experiments (DoE), we obtained the Design Space in which GLA concentration and lipid concentration were found as critical parameters for achieving a stable nanoformulation. This Design Space allowed the optimization of the process to produce a nanoformulation suitable for in vivo preclinical testing.

Liposome-based multifunctional nanoplatform as effective therapeutics for the treatment of retinoblastoma.

Photothermal therapy has the characteristics of minimal invasiveness, controllability, high efficiency, and strong specificity, which can effectively make up for the toxic side effects and tumor resistance caused by traditional drug treatment. However, due to the limited tissue penetration of infrared light, it is difficult to promote and apply in clinical practice. The eye is the only transparent tissue in human, and infrared light can easily penetrate the eye tissue, so it is expected that photothermal therapy can be used to treat fundus diseases. Here in, a new nano-platform assembled by liposome and indocyanine green (ICG) was used to treat retinoblastoma. ICG was assembled in liposomes to overcome some problems of ICG itself. For example, ICG is easily quenched, self-aggregating and instability. Moreover, liposomes can prevent free ICG from being cleared through the systemic circulation. The construction of the nano-platform not only ensured the stability of ICG in vivo, but also realized imaging-guide photothermal therapy, which created a new strategy for the treatment of retinoblastoma.

Photoacoustic nanodroplets for oxygen enhanced photodynamic therapy of cancer.

Photodynamic therapy (PDT) is a well-known cancer therapy that utilizes light to excite a photosensitizer and generate cytotoxic reactive oxygen species (ROS). The efficacy of PDT primarily depends on the photosensitizer and oxygen concentration in the tumor. Hypoxia in solid tumors promotes treatment resistance, resulting in poor PDT outcomes. Hence, there is a need to combat hypoxia while delivering sufficient photosensitizer to the tumor for ROS generation. Here we showcase our unique theranostic perfluorocarbon nanodroplets as a triple agent carrier for oxygen, photosensitizer, and indocyanine green that enables light triggered spatiotemporal delivery of oxygen to the tumors. We evaluated the characteristics of the nanodroplets and validated their ability to deliver oxygen via photoacoustic monitoring of blood oxygen saturation and subsequent PDT efficacy in a murine subcutaneous tumor model. The imaging results were validated with an oxygen sensing probe, which showed a 9.1 fold increase in oxygen content inside the tumor, following systemic administration of the nanodroplets. These results were also confirmed with immunofluorescence. In vivo studies showed that nanodroplets held higher rates of treatment efficacy than a clinically available benzoporphyrin derivative formulation. Histological analysis showed higher necrotic area within the tumor with perfluoropentane nanodroplets. Overall, the photoacoustic nanodroplets can significantly enhance image-guided PDT and has demonstrated substantial potential as a valid theranostic option for patient-specific photodynamic therapy-based treatments.

Pulmonary delivery of siRNA against acute lung injury/acute respiratory distress syndrome.

The use of small interfering RNAs (siRNAs) has been under investigation for the treatment of several unmet medical needs, including acute lung injury/acute respiratory distress syndrome (ALI/ARDS) wherein siRNA may be implemented to modify the expression of pro-inflammatory cytokines and chemokines at the mRNA level. The properties such as clear anatomy, accessibility, and relatively low enzyme activity make the lung a good target for local siRNA therapy. However, the translation of siRNA is restricted by the inefficient delivery of siRNA therapeutics to the target cells due to the properties of naked siRNA. Thus, this review will focus on the various delivery systems that can be used and the different barriers that need to be surmounted for the development of stable inhalable siRNA formulations for human use before siRNA therapeutics for ALI/ARDS become available in the clinic.

A homogenous nanoporous pulmonary drug delivery system based on metal-organic frameworks with fine aerosolization performance and good compatibility.

Pulmonary drug delivery has attracted increasing attention in biomedicine, and porous particles can effectively enhance the aerosolization performance and bioavailability of drugs. However, the existing methods for preparing porous particles using porogens have several drawbacks, such as the inhomogeneous and uncontrollable pores, drug leakage, and high risk of fragmentation. In this study, a series of cyclodextrin-based metal-organic framework (CD-MOF) particles containing homogenous nanopores were delicately engineered without porogens. Compared with commercial inhalation carrier, CD-MOF showed excellent aerosolization performance because of the homogenous nanoporous structure. The great biocompatibility of CD-MOF in pulmonary delivery was also confirmed by a series of experiments, including cytotoxicity assay, hemolysis ratio test, lung function evaluation, in vivo lung injury markers measurement, and histological analysis. The results of ex vivo fluorescence imaging showed the high deposition rate of CD-MOF in lungs. Therefore, all results demonstrated that CD-MOF was a promising carrier for pulmonary drug delivery. This study may throw light on the nanoporous particles for effective pulmonary administration.

Delivery strategies for macromolecular drugs in cancer therapy.

With the development of biotherapy, biomacromolecular drugs have gained tremendous attention recently, especially in drug development field due to the sophisticated functions in vivo. Over the past few years, a motley variety of drug delivery strategies have been developed for biomacromolecular drugs to overcome the difficulties in the druggability, e.g., the instability and easily restricted by physiologic barriers. The application of novel delivery systems to deliver biomacromolecular drugs can usually prolong the half-life, increase the bioavailability, or improve patient compliance, which greatly improves the efficacy and potentiality for clinical use of biomacromolecular drugs. In this review, recent studies regarding the drug delivery strategies for macromolecular drugs in cancer therapy are summarized, mainly drawing on the development over the last five years.

Liposomes modified with cardiolipin can act as a platform to regulate the potential flux of NADP+-dependent isocitrate dehydrogenase.

Cardiolipin (CL) is a phospholipid found in the outer mitochondrial membrane (OMM) and inner mitochondrial membrane (IMM) in animal cells. Isocitrate dehydrogenase (ICDH) is an important catalytic enzyme that is localized at the cytosol and mitochondria; the metabolic pathway catalyzed by ICDH differs between the OMM and IMM. To estimate the possible role of lipid membrane in the enzymatic activity of NADP+-dependent ICDH, CL-modified liposomes were prepared using CL/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/cholesterol (Ch), and their characteristics were analyzed based on the fluorescent probe method. The relative enzymatic activity of ICDH decreased in the presence of CL/DPPC/Ch=(30/50/20) liposome, whereas activity increased in the presence of CL/DPPC/Ch=(5/75/20) liposome. NADP+ had the greatest substrate affinity and was dominant in the regulation of ICDH activity. Analysis of membrane properties indicated that membranes in CL-modified liposomes were dehydrated by ICDH binding. Using circular dichroism analysis, CL/DPPC/Ch=(30/50/20) liposome induced a conformational change in ICDH, indicating that CL-rich membrane domains could inhibit ICDH activity. These results suggest that lipid membranes, including CL molecules, could act as a platform to regulate ICDH-related metabolic pathways such as the tricarboxylic acid cycle and lipid synthesis.

Disperse Orange 3 as a resonance Raman probe for measuring membrane order.

Resonance Raman spectra of azobenzene derivatives were examined in the presence of lipid membranes to find a probe that can distinguish different membrane phases. The NO2 symmetric stretching band of 4-(4-nitrophenylazo)aniline, also known as Disperse Orange 3 (DO3), is downshifted by about 4 cm(-1) on the phase transition of phosphatidylcholine membranes from the liquid crystalline to the gel phase. A comparable downshift also occurs when DO3 is bound to cholesterol-containing membranes in the liquid-ordered phase. Our results demonstrate that Raman spectrum of DO3 is a unique tool for measuring the molecular order of lipids in membranes.

Purification, characterization, molecular cloning and extracellular production of a phospholipase A1 from Streptomyces albidoflavus NA297.

A novel metal ion-independent phospholipase A1 of Streptomyces albidoflavus isolated from Japanese soil has been purified and characterized. The enzyme consists of a 33-residue N-terminal signal secretion sequence and a 269-residue mature protein with a deduced molecular weight of 27,199. Efficient and extracellular production of the recombinant enzyme was successfully achieved using Streptomyces lividans cells and an expression vector. A large amount (25 mg protein, 14.7 kU) of recombinant enzyme with high specific activity (588 U/mg protein) was purified by simple purification steps. The maximum activity was found at pH 7.2 and 50 °C. At pH 7.2, the enzyme preferably hydrolyzed phosphatidic acid and phosphatidylserine; however, the substrate specificity was dependent on the reaction pH. The enzyme hydrolyzed lysophosphatidylcholine and not triglyceride and the p-nitrophenyl ester of fatty acids. At the reaction equilibrium, the molar ratio of released free fatty acids (sn-1:sn-2) was 63:37. The hydrolysis of phosphatidic acid at 50 °C and pH 7.2 gave apparent V max and k cat values of 1389 µmol min(-1) mg protein(-1) and 630 s(-1), respectively. The apparent K m and k cat/K m values were 2.38 mM and 265 mM(-1) s(-1), respectively. Mutagenesis analysis showed that Ser11 is essential for the catalytic function of the enzyme and the active site may include residues Ser216 and His218.