A new method for liposome preparation using a membrane contactor

Nanoliposomes as nonviral vectors in cancer gene therapy

Nonviral vectors, such as liposomes, offer potential for targeted gene delivery in cancer therapy. Liposomes, composed of phospholipid vesicles, have demonstrated efficacy as nanocarriers for genetic tools, addressing the limitations of off-targeting and degradation commonly associated with traditional gene therapy approaches. Due to their biocompatibility, stability, and tunable physicochemical properties, they offer potential in overcoming the challenges associated with gene therapy, such as low transfection efficiency and poor stability in biological fluids. Despite these advancements, there remains a gap in understanding the optimal utilization of nanoliposomes for enhanced gene delivery in cancer treatment. This review delves into the present state of nanoliposomes as carriers for genetic tools in cancer therapy, sheds light on their potential to safeguard genetic payloads and facilitate cell internalization alongside the evolution of smart nanocarriers for targeted delivery. The challenges linked to their biocompatibility and the factors that restrict their effectiveness in gene delivery are also discussed along with exploring the potential of nanoliposomes in cancer gene therapy strategies by analyzing recent advancements and offering future directions.

Liposome-Hydrogel Composites for Controlled Drug Delivery Applications

Various controlled delivery systems (CDSs) have been developed to overcome the shortcomings of traditional drug formulations (tablets, capsules, syrups, ointments, etc.). Among innovative CDSs, hydrogels and liposomes have shown great promise for clinical applications thanks to their cost-effectiveness, well-known chemistry and synthetic feasibility, biodegradability, biocompatibility and responsiveness to external stimuli. To date, several liposomal- and hydrogel-based products have been approved to treat cancer, as well as fungal and viral infections, hence the integration of liposomes into hydrogels has attracted increasing attention because of the benefit from both of them into a single platform, resulting in a multifunctional drug formulation, which is essential to develop efficient CDSs. This short review aims to present an updated report on the advancements of liposome-hydrogel systems for drug delivery purposes.

Recent advancements in nanotechnology-based bacteriophage delivery strategies against bacterial ocular infections

Antibiotic resistance is growing as a critical challenge in a variety of disease conditions including ocular infections leading to disastrous effects on the human eyes. Staphylococcus aureus (S. aureus) mediated ocular infections are very common affecting different parts of the eye viz. vitreous chamber, conjunctiva, cornea, anterior and posterior chambers, tear duct, and eyelids. Blepharitis, dacryocystitis, conjunctivitis, keratitis, endophthalmitis, and orbital cellulitis are some of the commonly known ocular infections caused by S. aureus. Some of these infections are so fatal that they could cause bilateral blindness like panophthalmitis and orbital cellulitis, which is caused by methicillin-resistant S. aureus (MRSA) and vancomycin-resistance S. aureus (VRSA). The treatment of S. aureus infections with known antibiotics is becoming gradually difficult because of the development of resistance against multiple antibiotics. Apart from the different combinations and formulation strategies, bacteriophage therapy is growing as an effective alternative to treat such infections. Although the superiority of bacteriophage therapy is well established, yet physical factors (high temperatures, acidic pH, UV-rays, and ionic strength) and pharmaceutical barriers (poor stability, low in-vivo retention, controlled and targeted delivery, immune system neutralization, etc.) have the greatest influence on the viability of phage virions (also phage proteins). A variety of Nanotechnology based formulations such as polymeric nanoparticles, liposomes, dendrimers, nanoemulsions, and nanofibres have been recently reported to overcome the above-mentioned obstacles. In this review, we have compiled all these recent reports and discussed bacteriophage-based nanoformulations techniques for the successful treatment of ocular infections caused by multidrug-resistant S. aureus and other bacteria.

Current Applications of Liposomes for the Delivery of Vitamins: A Systematic Review

Liposomes have been used for several decades for the encapsulation of drugs and bioactives in cosmetics and cosmeceuticals. On the other hand, the use of these phospholipid vesicles in food applications is more recent and is increasing significantly in the last ten years. Although in different stages of technological maturity-in the case of cosmetics, many products are on the market-processes to obtain liposomes suitable for the encapsulation and delivery of bioactives are highly expensive, especially those aiming at scaling up. Among the bioactives proposed for cosmetics and food applications, vitamins are the most frequently used. Despite the differences between the administration routes (oral for food and mainly dermal for cosmetics), some challenges are very similar (e.g., stability, bioactive load, average size, increase in drug bioaccessibility and bioavailability). In the present work, a systematic review of the technological advancements in the nanoencapsulation of vitamins using liposomes and related processes was performed; challenges and future perspectives were also discussed in order to underline the advantages of these drug-loaded biocompatible nanocarriers for cosmetics and food applications.

An emerging era in manufacturing of drug delivery systems: Nanofabrication techniques

Nanotechnology has the capability of making significant contributions to healthcare. Nanofabrication of multifunctional nano- or micro-character systems is becoming incredibly influential in various sectors like electronics, photonics, energy, and biomedical gadgets worldwide. The invention of such items led to the merger of moderate cost and excellent quality nano or micro-characters into 3D structures. Nanofabrication techniques have many benefits as the primary technology for manipulating cellular surroundings to research signaling processes. The inherent nanoscale mechanisms of cyto-reactions include the existence and death of cells, stem cell segmentation, multiplication, cellular relocation, etc. Nanofabrication is essential in developing various nano-formulations like solid lipid nanoparticles, nanostructured lipid carriers, liposomes, niosomes, nanoemulsions, microemulsions etc. Despite the initial development cost in designing the nanofabrication-based products, it has also reduced the total cost of the healthcare system by considering the added benefits compared to the other standard formulations. Thus, the current review mainly focuses on nanofabrication techniques, advantages, disadvantages, applications in developing various nanocarrier systems, challenges and future perspectives.

Liposomes: structure, composition, types, and clinical applications

Liposomes are now considered the most commonly used nanocarriers for various potentially active hydrophobic and hydrophilic molecules due to their high biocompatibility, biodegradability, and low immunogenicity. Liposomes also proved to enhance drug solubility and controlled distribution, as well as their capacity for surface modifications for targeted, prolonged, and sustained release. Based on the composition, liposomes can be considered to have evolved from conventional, long-circulating, targeted, and immune-liposomes to stimuli-responsive and actively targeted liposomes. Many liposomal-based drug delivery systems are currently clinically approved to treat several diseases, such as cancer, fungal and viral infections; more liposomes have reached advanced phases in clinical trials. This review describes liposomes structure, composition, preparation methods, and clinical applications.

Methods of Liposomes Preparation: Formation and Control Factors of Versatile Nanocarriers for Biomedical and Nanomedicine Application

Liposomes are nano-sized spherical vesicles composed of an aqueous core surrounded by one (or more) phospholipid bilayer shells. Owing to their high biocompatibility, chemical composition variability, and ease of preparation, as well as their large variety of structural properties, liposomes have been employed in a large variety of nanomedicine and biomedical applications, including nanocarriers for drug delivery, in nutraceutical fields, for immunoassays, clinical diagnostics, tissue engineering, and theranostics formulations. Particularly important is the role of liposomes in drug-delivery applications, as they improve the performance of the encapsulated drugs, reducing side effects and toxicity by enhancing its in vitro- and in vivo-controlled delivery and activity. These applications stimulated a great effort for the scale-up of the formation processes in view of suitable industrial development. Despite the improvements of conventional approaches and the development of novel routes of liposome preparation, their intrinsic sensitivity to mechanical and chemical actions is responsible for some critical issues connected with a limited colloidal stability and reduced entrapment efficiency of cargo molecules. This article analyzes the main features of the formation and fabrication techniques of liposome nanocarriers, with a special focus on the structure, parameters, and the critical factors that influence the development of a suitable and stable formulation. Recent developments and new methods for liposome preparation are also discussed, with the objective of updating the reader and providing future directions for research and development.

Computational and Experimental Approaches to Investigate Lipid Nanoparticles as Drug and Gene Delivery Systems

Lipid nanoparticles (LNPs) have been widely applied in drug and gene delivery. More than twenty years ago, DoxilTM was the first LNPs-based drug approved by the US Food and Drug Administration (FDA). Since then, with decades of research and development, more and more LNP-based therapeutics have been used to treat diverse diseases, which often offer the benefits of reduced toxicity and/or enhanced efficacy compared to the active ingredients alone. Here, we provide a review of recent advances in the development of efficient and robust LNPs for drug/gene delivery. We emphasize the importance of rationally combining experimental and computational approaches, especially those providing multiscale structural and functional information of LNPs, to the design of novel and powerful LNP-based delivery systems.

Towards Green Nanoscience: From extraction to nanoformulation

The use of nanotechnology has revolutionized many biotechnological sectors, from bioengineering to medicine, passing through food and cosmetic fields. However, their clinic and industrial application has been into the spotlight due to their safety risk and related side effects. As a result, Green Nanoscience/Nanotechnology emerged as a strategy to prevent any associated nanotoxicity, via implementation of sustainable processes across the whole lifecycle of nanoformulation. Notwithstanding its success across inorganic nanoparticles, the green concept for organic nanoparticle elaboration is still at its infancy. This, coupled with the organic nanoparticles being the most commonly used in biomedicine, highlights the need to implement specific green principles for their elaboration. In this review, we will discuss the possible green routes for the proper design of organic nanoparticles under the umbrella of Green Nanoscience: from the extraction of nanomaterials and active compounds to their final nanoformulation.

Formulation and Application of Nanoemulsions for Nutraceuticals and Phytochemicals

:

Recent trends in research and investigation on nanoemulsion based products is the result of many reasons such as food security as a global concern, increasing demand for highly efficient food and agricultural products and technological need for products with the ability of manipulation and optimization in their properties. Nanoemulsions are defined as emulsions made up of nano sized droplets dispersed in another immiscible liquid which exhibit properties distinguishing them from conventional emulsions and making them suitable for encapsulation, delivery and formulations of bioactive ingredients in different fields including drugs, food and agriculture. The objective of this paper is to present a general overview of nanoemulsions definition, their preparation methods, properties and applications in food and agricultural sectors. Due to physicochemical properties of the nanoemulsion composition, creating nanosized droplets requires high/low energy methods that can be supplied by special devices or techniques. An overview about the mechanisms of these methods is also presented in this paper which are commonly used to prepare nanoemulsions. Finally, some recent works about the application of nanoemulsions in food and agricultural sectors along with challenges and legislations restricting their applications is discussed in the last sections of the current study.

3D-printed microfluidic chip for the preparation of glycyrrhetinic acid-loaded ethanolic liposomes

18-α-Glycyrrhetinic acid (GA) is a bioactive compound extracted from licorice that exhibits many biological and pharmacological effects such as anti-inflammatory and antioxidant activities on the skin. However, its lipophilic nature results in poor bioavailability that limits clinical applications. Liposomes, presenting the ability to carry both hydrophobic and hydrophilic payloads and a good cytocompatibility, are effective to overcome this barrier. Furthermore, the addition of permeation enhancers such as ethanol into liposomal formulations helps the diffusion of these systems through the skin barrier. Here, we aimed to formulate GA-loaded ethanolic liposomes, using a natural soybean lecithin via a microfluidic approach. Using a fused deposition modeling (FDM) 3D printer we customized a microfluidic chip, and manufactured vesicles that presented spherical shape with a size of 202 ± 5.2 nm, a narrow size distribution and a good stability over a period of 30 days. After reaching a drug encapsulation efficiency of 63.15 ± 2.2%, liposomes were evaluated for their cytocompatibility and skin permeation potentiality after hydrogelation using xanthan gum. The in vitro release and permeation studies were performed using Franz diffusion cells comparing two different media and three synthetic membranes including a polymeric skin-mimicking membrane. The selected formulation presented no cytotoxicity and an increased permeation compared to GA saturated hydrogel. It could perform therapeutically better effects than conventional formulations containing free GA, as prolonged and controlled release topical dosage forms, which may lead to improved efficiency and better patient compliance.

Vesicle formation mechanisms: an overview

Vesicle structures primarily embody spherical capsules composed of a single or multiple bilayers, entrapping a pool of aqueous solution in their interior. The bilayers can be synthesised by phospholipids or other amphiphiles (surfactants, block copolymers, etc.). Vesicles with broad-spectrum applications in numerous scientific disciplines, including biochemistry, biophysics, biology, and various pharmaceutical industries, have attracted widespread attention. Consequently, a multitude of protocols have been devised and proposed for their fabrication. In this review, with a motivation to derive the basic conditions for the formation of vesicles, the associated thermodynamic and kinetic aspects are comprehensively appraised. Contextually, an all-purpose overview of the underlying thermodynamics of bilayer/membrane generation and deformation, including the chemical potential of aggregates, geometric packing and the concept of elastic properties, is presented. Additionally, the current review highlights the probable, inherent mechanisms of vesicle formation under distinct modes of manufacturing. We lay focus on vesicle formation from pre-existing bilayers, as well as from bilayers, which form when lipids from an organic solvent are transferred into an aqueous medium. Furthermore, we outline the kinetic effects on vesicle formation from the lamellar phase, with and without the presence of shearing force. Wherever required, the experimental and/or theoretical outcomes, the driving forces for vesicle size selection, and various scaling laws are also reviewed, all of which facilitate an overall improved understanding of the vesicle formation mechanisms.

Extracellular Vesicles as Drug Delivery Systems - Methods of Production and Potential Therapeutic Applications

Drug delivery systems are created to achieve the desired therapeutic effect of a specific pharmaceutical compound. Numerous drawbacks and side effects such as unfavorable pharmacokinetics, lack of tissue selectivity, immunogenicity, increased systemic clearance and toxicity, have been observed for currently available drug delivery systems (DDSs). The use of natural and artificial extracellular vesicles (EVs) in drug delivery may help to solve the aforementioned problems faced by different DDSs. Due to their self-origin, small size, flexibility, the presence of multiple adhesive molecules on their surfaces as well as their function as biomolecules carriers, EVs are the perfect candidates for DDSs. Currently, several drug delivery systems based on EVs have been proposed. While the great potential of these particles in targeted drug delivery has been recognized in cancer, hepatitis C, neurodegenerative diseases, inflammatory states etc., this field is still in the early stage of development. Unfortunately, the use of EVs from natural sources (cell cultures, body fluids) results in numerous problems in terms of the heterogeneity of isolated vesicle population as well as the method of isolation thereof, which may influence vesicle composition and properties. Therefore, there is a significant need for the synthesis of artificial EV-based DDSs under strictly controlled laboratory conditions and from well-defined biomolecules (proteins and lipids). Vesicle-mimetic delivery systems, characterized by properties similar to natural EVs, will bring new opportunities to study the mechanisms of DDS internalization and their biological activity after delivering their cargo to a target cell.

The Why, Where, Who, How, and What of the vesicular delivery systems

Though vesicular delivery systems have been widely explored and reviewed, no comprehensive review exists that covers their development from the inception of the concept to its culmination in the form of regulated marketed formulations. With the advancement of scientific research in the field of nanomedicine, certain category of vesicular delivery systems have successfully reached the global market. Despite extensive research and highly encouraging results in a plethora of pathological conditions in the preclinical studies, translation of these nanomedicines from laboratory to market has been very limited. Aim of this review is to describe comprehensively the various colloidal delivery systems, focusing mainly on their conventional and advanced methods of preparation, different characterization techniques and main success stories of their journey from bench to bedside of the patient. The review also touches the finer nuances of the use of modern formulation approach of DoE (Design of Experiments) in their formulation and the status of regulatory guidelines for the approval of these nanomedicines.

Propolis loaded liposomes: evaluation of antimicrobial and antioxidant activities

Propolis, a natural bee product, has both antimicrobial/antifungal and antioxidant characteristics. Active substances having antimicrobial and antifungal effects are used to avoid infections, which develop during long treatment process of chronic wounds. Antioxidant substances protect wound areas against the effect of free radicals and accelerate the healing process. For this purpose, propolis was used to develop topical liposome formulations for wound treatment. Characterization studies (particle size distribution, polydispersity index, Zeta Potential, morphology pH, loading capacity, encapsulation efficiency, in-vitro release behaviour) as well as stability studies were performed. Then in-vitro antioxidant (free radical scavenging capacity and trolox equivalent antioxidant capacity) and antimicrobial/antifungal activities of formulations have been evaluated. The particle size of formulations was found within the range of 300-750 nm depending on the concentration of lipid and water phase in the formulation. The Zeta Potential and pH values of optimum formulation were -23.0 ± 0.666 and 6.34, respectively. Loading capacity and encapsulation efficiency were 66.535 ± 2.705% and 57.321 ± 2.448%. At the end of 8 h, 48.16% of propolis was released and the formulations were found stable during 3 months at +4 °C. Drug loaded liposome formulations significantly scavenged the ABTS⁺ radical in a dose-dependent manner of propolis when compared with unloaded liposome formulations (p < 0.05). The minimum inhibitory concentration (MIC) values of liposomes ranged from 512 to 128 μg/mL for bacteria and 256 to 128 μg/mL for fungi. Overall results showed that effective and innovative alternative was developed for topical application in wound treatment with propolis loaded liposomal formulations having antioxidant and antimicrobial effects.

Liposomes for delivery of antioxidants in cosmeceuticals: Challenges and development strategies

Antioxidants (AOs) play a crucial role in the protection and maintenance of health and are also integral ingredients in beauty products. Unfortunately, most of them are sensitive due to their instability and insolubility. The use of liposomes to protect AOs and expand their applicability to cosmeceuticals, thereby, is one of the most effective solutions. Notwithstanding their offered advantages for the delivery of AOs, liposomes, in their production and application, present many challenges. Here, we provide a critical review of the major problems complicating the development of liposomes for AO delivery. Along with issues related to preparation techniques and encapsulation efficiency, the loss of protective function and inefficiency of skin permeability are the main disadvantages of liposomes. Corresponding development strategies for resolving these problems, with their respective advantages and drawbacks, are introduced, discussed in some depth, and summarized in these pages as well. Advanced liposomes have a vital role to play in the development and delivery of AOs in practical cosmeceutical product applications.

Proliposome Powders for the Generation of Liposomes: the Influence of Carbohydrate Carrier and Separation Conditions on Crystallinity and Entrapment of a Model Antiasthma Steroid

Formulation effects on the entrapment of beclometasone dipropionate (BDP) in liposomes generated by hydration of proliposomes were studied, using the high-density dispersion medium deuterium oxide in comparison to deionized water (DW). Proliposomes incorporating BDP (2 mol% of the lipid phase consisting of soya phosphatidylcholine (SPC) and cholesterol; 1:1) were manufactured, using lactose monohydrate (LMH), sorbitol or D-mannitol as carbohydrate carriers (1:5 w/w lipid to carrier). Following hydration of proliposomes, separation of BDP-entrapped liposomes from the unentrapped (free) BDP at an optimized centrifugation duration of 90 min and a centrifugation force of 15,500g were identified. The dispersion medium was found to have a major influence on separation of BDP-entrapped liposomes from the unentrapped drug. Entrapment efficiency values were higher than 95% as estimated when DW was used. By contrast, the entrapment efficiency was 19.69 ± 5.88, 28.78 ± 4.69 and 34.84 ± 3.62% upon using D₂O as a dispersion medium (for LMH-, sorbitol- and D-mannitol-based proliposomes, respectively). The similarity in size of liposomes and BDP crystals was found to be responsible for co-sedimentation of liposomes and free BDP crystals upon centrifugation in DW, giving rise to the falsely high entrapment values estimated. This was remedied by the use of D₂O as confirmed by light microscopy, nuclear magnetic resonance (¹HNMR), X-ray diffraction (XRD) and entrapment studies. This study showed that carrier type has a significant influence on the entrapment of BDP in liposomes generated from proliposomes, and using D₂O is essential for accurate determination of steroid entrapment in the vesicles.

Encapsulation and Controlled Release of Rapamycin from Polycaprolactone Nanoparticles Prepared by Membrane Micromixing Combined with Antisolvent Precipitation

Rapamycin-loaded polycaprolactone nanoparticles (RAPA-PCL NPs) with a polydispersity index of 0.006-0.073 were fabricated by antisolvent precipitation combined with micromixing using a ringed stainless steel membrane with 10 μm diameter laser-drilled pores. The organic phase composed of 6 g L^-1 PCL and 0.6-3.0 g L^-1 RAPA in acetone was injected through the membrane at 140 L m^-2 h^-1 into 0.2 wt % aqueous poly(vinyl alcohol) solution stirred at 1300 rpm, resulting in a Z-average mean of 189-218 nm, a drug encapsulation efficiency of 98.8-98.9%, and a drug loading in the NPs of 9-33%. The encapsulation of RAPA was confirmed by UV-vis spectroscopy, XRD, DSC, and ATR-FTIR. The disappearance of sharp characteristic peaks of crystalline RAPA in the XRD pattern of RAPA-PCL NPs revealed that the drug was molecularly dispersed in the polymer matrix or RAPA and PCL were present in individual amorphous domains. The rate of drug release in pure water was negligible due to low aqueous solubility of RAPA. RAPA-PCL NPs released more than 91% of their drug cargo after 2.5 h in the release medium composed of 0.78-1.5 M of the hydrotropic agent N,N-diethylnicotinamide, 10 vol % ethanol, and 2 vol % Tween 20 in phosphate buffered saline. The dissolution of RAPA was slower when the drug was embedded in the PCL matrix of the NPs than dispersed in the form of pure RAPA nanocrystals.

Biodegradable liposome-encapsulated hydrogels for biomedical applications: a marriage of convenience

Liposome-encapsulated hydrogels have emerged as an attractive strategy for medical and pharmaceutical applications.

Clove essential oil-in-cyclodextrin-in-liposomes in the aqueous and lyophilized states: From laboratory to large scale using a membrane contactor

This work is dedicated to prepare liposomal dry powder formulations of inclusion complexes of clove essential oil (CEO) and its main component eugenol (Eug). Ethanol injection method and membrane contactor were applied to prepare liposomes at laboratory and large scale, respectively. Various liposomal formulations were tested: (1) free hydroxypropyl-β-cyclodextrin loaded liposomes; (2) drug in hydroxypropyl-β-cyclodextrin in liposomes (DCL); (3) DCL2 obtained by double loading technique, where the drug is added in the organic phase and the inclusion complex in the aqueous phase. Liposomes were characterized for their particle size, polydispersity index, Zeta potential, morphology, encapsulation efficiency of CEO components and Eug loading rate. Reproducible results were obtained with both injection devices. Compared to Eug-loaded liposomes, DCL and DCL2 improved the loading rate of Eug and possessed smaller vesicles size. The DPPH(•) scavenging activity of Eug and CEO was maintained upon incorporation of Eug and CEO into DCL and DCL2. Contrary to DCL2, DCL formulations were stable after 1 month of storage at 4°C and upon reconstitution of the dried lyophilized cakes. Hence, DCL in aqueous and lyophilized forms, are considered as a promising carrier system to preserve volatile and hydrophobic drugs enlarging their application in cosmetic, pharmaceutical and food industries.

Large-scale preparation of clove essential oil and eugenol-loaded liposomes using a membrane contactor and a pilot plant

Based on our previous study where optimal conditions were defined to encapsulate clove essential oil (CEO) into liposomes at laboratory scale, we scaled-up the preparation of CEO and eugenol (Eug)-loaded liposomes using a membrane contactor (600 mL) and a pilot plant (3 L) based on the principle of ethanol injection method, both equipped with a Shirasu Porous Glass membrane for injection of the organic phase into the aqueous phase. Homogenous, stable, nanometric-sized and multilamellar liposomes with high phospholipid, Eug loading rates and encapsulation efficiency of CEO components were obtained. Saturation of phospholipids and drug concentration in the organic phase may control the liposome stability. Liposomes loaded with other hydrophobic volatile compounds could be prepared at large scale using the ethanol injection method and a membrane for injection.

Enhancement of microbial hydroxylation of 13-ethyl-gon-4-ene-3,17-dione by Metarhizium anisopliae using nano-liposome technique

The introduction of 11α-hydroxy to 13-ethyl-gon-4-ene-3,17-dione (GD) by microbial transformation is a key step in the synthesis of oral contraceptive desogestrel, while low substrate solubility and uptake into cells are tough problems influencing biotransformation efficiency greatly. Nano-liposome technique was used in the hydroxylation of GD by Metarhizium anisopliae. The substrate GD was processed to be GD-loaded nano-liposomes (GNLs) with high stability and encapsulation efficiency, and then applied in microbial hydroxylation by M. anisopliae. The results proved that the yield of the main product 11α-hydroxy-13-ethyl-gon-4-ene-3,17-dione (HGD) tripled compared to regular solvent dimethylformamide dispersion method at 2 g/l of substrate feeding concentration, and the HGD conversion rate showed no obvious reduction when the substrate feeding concentration increased from 2 to 6 g/l, which indicated the improvement of GNL addition method on biotransformation. Furthermore, the main byproduct changed from 6β-hydroxy derivative of GD (with similar polarity to HGD) to 6β,11α-dihydroxy derivative, which benefits the following purification of HGD from fermentation broth. These advantages suggest a great potential for the application of nano-liposome technique in microbial steroid transformation.

Emerging research and clinical development trends of liposome and lipid nanoparticle drug delivery systems

Liposomes are spherical-enclosed membrane vesicles mainly constructed with lipids. Lipid nanoparticles are loaded with therapeutics and may not contain an enclosed bilayer. The majority of those clinically approved have diameters of 50-300 nm. The growing interest in nanomedicine has fueled lipid-drug and lipid-protein studies, which provide a foundation for developing lipid particles that improve drug potency and reduce off-target effects. Integrating advances in lipid membrane research has enabled therapeutic development. At present, about 600 clinical trials involve lipid particle drug delivery systems. Greater understanding of pharmacokinetics, biodistribution, and disposition of lipid-drug particles facilitated particle surface hydration technology (with polyethylene glycol) to reduce rapid clearance and provide sufficient blood circulation time for drug to reach target tissues and cells. Surface hydration enabled the liposome-encapsulated cancer drug doxorubicin (Doxil) to gain clinical approval in 1995. Fifteen lipidic therapeutics are now clinically approved. Although much research involves attaching lipid particles to ligands selective for occult cells and tissues, preparation procedures are often complex and pose scale-up challenges. With emerging knowledge in drug target and lipid-drug distribution in the body, a systems approach that integrates knowledge to design and scale lipid-drug particles may further advance translation of these systems to improve therapeutic safety and efficacy.

Preparation of Bovine Serum Albumin (BSA) nanoparticles by desolvation using a membrane contactor: a new tool for large scale production

Albumin nanoparticles are attractive drug delivery systems as they can be prepared under soft conditions and incorporate several kinds of molecules. The aim of this study was to upscale the desolvation process for preparing Bovine Serum Albumin (BSA) nanoparticles using a membrane contactor. At a first step, the BSA nanoparticles were prepared at small scale using a syringe pump. BSA nanoparticles of 139 nm in size, with a polydispersity index of 0.046, were obtained at the optimal conditions: pH 8.2, 100 mg mL(-1) BSA albumin solution (2 mL), and 1 mL min(-1) flow rate of ethanol addition (8 mL). The upscaling with a membrane contactor was achieved by permeating ethanol through the pores of a Shirasu Porous Glass (SPG Technology Co., Japan) membrane and circulating the aqueous phase tangentially to the membrane surface. By increasing the pressure of the ethanol from 1 to 2.7 bars, a progressive decrease in nanoparticle size was obtained with a high nanoparticles yield (around 94-96%). In addition, the flow rate of the circulating phase did not affect the BSA nanoparticle characteristics. At the optimal conditions (pH 8.2, 100 mg mL(-1) BSA albumin solution, pressure of ethanol 2.7 bars, flow rate of the circulating phase 30.7 mL s(-1)), the BSA nanoparticles showed similar characteristics to those obtained with the syringe pump. Large batches of BSA nanoparticles were prepared up to 10 g BSA. The BSA nanoparticles were stable at least during 2 months at 4 °C, and their characteristics were reproducible. It was then concluded that the membrane contactor technique could be a suitable method for the preparation of albumin nanoparticles at large scale with properties similar to that obtained at small scale.

The shape/morphology balance: a study of stealth liposomes via fractal analysis and drug encapsulation

PURPOSE

Fractal analysis was used as a tool in order to study the morphological characteristics of PEGylated liposomes. We report on the morphological characteristics of stealth liposomes composed of DPPC and DPPE-PEG 3000 in two dispersion media using fractal analysis.

METHODS

Light scattering techniques were used in order to elucidate the size, the morphology and the surface charge of PEGylated liposomes as a function of PEGylated lipid concentration and temperature. Fluorescence spectroscopy studies revealed a microenvironment of low polarity inside the liposomal membranes.

RESULTS

All formulations were found to retain their physicochemical characteristics for at least 3 weeks. The hydrodynamic radii (Rh) of stealth liposomes were stable in the process of heating up to 50°C; while the fractal dimension values (df) which correspond to their morphology, have been changed during heating. Hence, these results are a first indication of the presence of a heterogeneous microdomain structure of the stealth liposomal system. The amphiphilic drug indomethacin (IND) was successfully encapsulated within the liposomes and led to an increased size of stealth liposomes, while the morphology of liposomal vectors changed significantly at the highest molar ratio of PEGylated lipid.

CONCLUSIONS

We can state that this approach can promote a new analytical concept based on the morphological characteristics and quantify the shape of drug carriers complementary to that of the conventional analytical techniques.