Lipid nanoparticles with different oil/fatty ester ratios as carriers of buprenorphine and its prodrugs for injection

Buprenorphine is a promising drug for the treatment of chronic pain and opioid dependence. The aim of the present work was to evaluate the feasibility of lipid nanoparticles with different oil/fatty ester ratios for injection of buprenorphine. To improve the release properties and analgesic duration of the drug, ester prodrugs were also incorporated into the nanoparticles for evaluation. Linseed oil and cetyl palmitate were respectively chosen as the liquid lipid and solid lipid in the inner phase of the nanoparticulate systems. Differential scanning calorimetry (DSC) was performed, and the particle size, zeta potential, molecular environment, and lipid/water partitioning were determined to characterize the state of the drug/prodrug and lipid modification. The in vitro release kinetics were measured by a Franz assembly. DSC showed that systems without oil (solid lipid nanoparticles, SLNs) had a more ordered crystalline lattice in the inner matrix compared to those with oil (nanostructured lipid carriers, NLCs and lipid emulsion, LE). The mean diameter of the nanoparticles ranged between 180 and 200 nm. The in vitro drug/prodrug release occurred in a delayed manner in decreasing order as follows: SLN > NLC > LE. It was found that the release rate was reduced following an increase in alkyl ester chains in the prodrugs. The in vivo antinociception was examined by a cold ethanol tail-flick test in rats. Compared to an aqueous solution, a prolonged analgesic duration was detected after an intravenous injection of buprenorphine-loaded SLNs and buprenorphine propionate (Bu-C3)-loaded NLCs (with 10% linseed oil in the lipid phase). The Bu-C3 in NLCs even showed a maximum antinociceptive activity for 10 h. In vitro erythrocyte hemolysis and lactate dehydrogenase (LDH) release from neutrophils demonstrated a negligible toxicity of these carriers. Our results indicate the feasibility of using lipid nanoparticles, especially SLNs and NLCs, as parenteral delivery systems for buprenorphine and its prodrugs.     

Perspectives on cutting-edge nanoparticulate drug delivery technologies based on lipids and their applications

Numerous nanotech arenas in therapeutic biology have recently provided a scientific platform to manufacture a considerable swath of unique chemical entities focusing on drugs. Recently, nanoparticulate drug delivery systems have emerged to deliver a specific drug to a specified site. Among all other carriers, lipids possess features exclusive to nanostructured dosage forms. The bioavailability of orally administered drugs is typically negatively affected by their poor water solubility, resulting from the unique chemical moieties introduced. Because of their unique advantages, lipid nanoparticles must become increasingly predictable as a robust delivery mechanism. The enhanced biopharmaceutical properties and significance of lipid-based targeting technologies such as liposomes, niosomes, solid lipid nanoparticles and micelles are highlighted in this review. Pharmaceutical implications of lipid nanocarriers for the transport and distribution of various therapeutic agents, such as biotechnological products and small pharmaceutical molecules, is a booming topic. Lipid nanoparticles as drug delivery systems have many appealing properties, including high biocompatibility, ease of preparation, tissue specificity, avoidance of reticuloendothelial systems, delayed drug release, scale-up feasibility, nontoxicity and targeted delivery. The use of lipid nanoparticles to enhance the transport of biopharmaceuticals is currently considered state-of-the-art. Similarly, we critically examine the upcoming guidelines that therapeutic scientists should handle.     

Application of lipid nanoparticles to ocular drug delivery

ABSTRACT

Introduction: Although eye drops are widely used as drug delivery systems for the anterior segment of the eye, they are also associated with poor drug bioavailability due to transient contact time and rapid washout by tearing. Moreover, effective drug delivery to the posterior segment of the eye is challenging, and alternative routes of administration (periocular and intravitreal) are generally needed, the blood–retinal barrier being the major obstacle to systemic drug delivery.

Areas covered: Nanotechnology, and especially lipid nanoparticles, can improve the therapeutic efficiency, compliance and safety of ocular drugs, administered via different routes, to both the anterior and posterior segment of the eye. This review highlights the main ocular barriers to drug delivery, as well as the most common eye diseases suitable for pharmacological treatment in which lipid nanoparticles have proved efficacious as alternative delivery systems.

Expert opinion: Lipid-based nanocarriers are among the most biocompatible and versatile means for ocular delivery. Mucoadhesion with consequent increase in pre-corneal retention time, and enhanced permeation due to cellular uptake by corneal epithelial cells, are the essential goals for topical lipid nanoparticle delivery. Gene delivery to the retina has shown very promising results after intravitreal administration of lipid nanoparticles as non-viral vectors.     

mRNA delivery in cancer immunotherapy

Messenger RNA (mRNA) has drawn much attention in the medical field. Through various treatment approaches including protein replacement therapies, gene editing, and cell engineering, mRNA is becoming a potential therapeutic strategy for cancers. However, delivery of mRNA into targeted organs and cells can be challenging due to the unstable nature of its naked form and the low cellular uptake. Therefore, in addition to mRNA modification, efforts have been devoted to developing nanoparticles for mRNA delivery. In this review, we introduce four categories of nanoparticle platform systems: lipid, polymer, lipid-polymer hybrid, and protein/peptide-mediated nanoparticles, together with their roles in facilitating mRNA-based cancer immunotherapies. We also highlight promising treatment regimens and their clinical translation.     

Solid lipid nanoparticles suspension versus commercial solutions for dermal delivery of minoxidil

Solid lipid nanoparticles have been reported as possible carrier for skin drug delivery. Solid lipid nanoparticles are produced from biocompatible and biodegradable lipids. Solid lipid nanoparticles made of semi-synthetic triglycerides stabilized with a mixture of polysorbate and sorbitan oleate were loaded with 5% of minoxidil. The prepared systems were characterized for particle size, pH and drug content. Ex vivo skin penetration studies were performed using Franz-type glass diffusion cells and pig ear skin. Ex vivo skin corrosion studies were realized with a method derived from the Corrositex^® test. Solid lipid nanoparticles suspensions were compared to commercial solutions in terms of skin penetration and skin corrosion. Solid lipid nanoparticles suspensions have been shown as efficient as commercial solutions for skin penetration; and were non-corrosive while commercial solutions presented a corrosive potential. Solid lipid nanoparticles suspensions would constitute a promising formulation for hair loss treatment.     

Nanostructured lipid carriers,solid lipid nanoparticles,and polymeric nanoparticles: which kind of drug delivery system is better for glioblastoma chemotherapy?

Context: Glioblastoma is a malignant brain tumor originating in the central nervous system. Successfully therapy of this disease required the efficient delivery of therapeutic agents to the tumor cells and tissues. Delivery of anticancer drugs using novel nanocarriers is promising in glioma treatment.

Objective: Polymeric nanoparticles (PNPs), solid lipid nanoparticles (SLNs), and nanostructured lipid carriers (NLCs) were constructed for the delivery of temozolomide (TMZ). The anti-tumor effects of the three kinds of nanocarriers were compared to provide the optimum choice for gliomatosis cerebri treatment.

Methods: TMZ-loaded PNPs (T-PNPs), SLNs (T-SLNs), and NLCs (T-NLCs) were formulated. Their particle size, zeta potential, drug encapsulation efficiency (EE), and drug loading (DL) capacity were evaluated. Anti-tumor efficacies of the three kinds of nanocarriers were evaluated on U87 malignant glioma cells (U87?MG cells) and mice-bearing malignant glioma model.

Results: T-NLCs displayed the best anti-tumor activity than other formulations in vivo and in vitro. The most significantly glioma inhibition was observed on NLCs formulations than PNPs and SLNs.

Conclusion: This work demonstrates that NLCs can deliver TMZ into U87MG cells more efficiently, with higher inhibition efficacy than PNPs and SLNs. T-NLCs could be an excellent drug delivery system for glioblastoma chemotherapy.     

Solid Lipid Nanoparticles as Delivery Systems for Bromocriptine

PURPOSE: The present investigation describes a formulative study for the development of innovative drug delivery systems for bromocriptine. METHODS: Solid lipid nanoparticles (SLN) based on different lipidic components have been produced and characterized. Morphology and dimensional distribution have been investigated by electron microscopy and Photon Correlation Spectroscopy. The antiparkinsonian activities of free bromocriptine and bromocriptine encapsulated in nanostructured lipid carriers were evaluated in 6-hydroxydopamine hemilesioned rats, a model of Parkinson's disease. RESULTS: Tristearin/tricaprin mixture resulted in nanostructured lipid carriers with stable mean diameter up to 6 months from production. Bromocriptine was encapsulated with high entrapment efficiency in all of the SLN samples, particularly in the case of tristearin/tricaprin mixture. Bromocriptine encapsulation did not change nanoparticle dimensions. In vitro release kinetics based on a dialysis method demonstrated that bromocriptine was released in a prolonged fashion for 48 h. Tristearin/tricaprin nanoparticles better controlled bromocriptine release. Both free and encapsulated bromocriptine reduced the time spent on the blocks (i.e. attenuated akinesia) in the bar test, although the action of encapsulated bromocriptine was more rapid in onset and prolonged. CONCLUSIONS: It can be concluded that nanostructured lipid carriers encapsulation may represent an effective strategy to prolong the half-life of bromocriptine.     

Nanostructured lipid carriers system: Recent advances in drug delivery

Nanostructured lipid carrier (NLC) is second generation smarter drug carrier system having solid matrix at room temperature. This carrier system is made up of physiological, biodegradable and biocompatible lipid materials and surfactants and is accepted by regulatory authorities for application in different drug delivery systems. The availability of many products in the market in short span of time reveals the success story of this delivery system. Since the introduction of the first product, around 30 NLC preparations are commercially available. NLC exhibit superior advantages over other colloidal carriers viz., nanoemulsions, polymeric nanoparticles, liposomes, SLN etc. and thus, have been explored to more extent in pharmaceutical technology. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes NLC versatile delivery system for various routes of administration. The present review gives insights on the definitions and characterization of NLC as colloidal carriers including the production techniques and suitable formulations. This review paper also highlights the importance of NLC in pharmaceutical applications for the various routes of drug delivery viz., topical, oral, pulmonary, ocular and parenteral administration and its future perspective as a pharmaceutical carrier.     

Fabrication and Evaluation of Curcumin-loaded Nanoparticles Based on Solid Lipid as a New Type of Colloidal Drug Delivery System

Curcumin has very broad spectrum of biological activities; however, photodegradation, short half-life and low bioavailability have limited its clinical application. Curcumin-loaded solid lipid nanoparticles were studied to overcome these problems. The aim of this study was to optimize the best formulation on curcumin-loaded solid lipid nanoparticles. Emulsion-evaporation and low temperature-solidification technique was applied with monostearin as lipid carriers. The single factor analysis and orthogonal design were used to optimize formulation and various parameters were investigate. By the optimisation of a single factor analysis and orthogonal test, the particles size, polydispersity index, zeta potential, encapsulation efficiency and drug loading capacity of the optimised formulation were 99.99 nm, 0.158, −19.9 mV, 97.86%, and 4.35%, respectively. The differential scanning calorimetry and X-ray diffraction analysis results demonstrated new structure was formed in nanoparticles. The release kinetics in vitro demonstrated curcumin-loaded solid lipid nanoparticles can control drug release. These studies confirmed that curcumin-loaded solid lipid nanoparticles could be prepared successfully with high drug entrapment efficiency and loading capacity. Curcumin-loaded solid lipid nanoparticles may be a promising drug delivery system to control drug release and improve bioavailability.     

Strategies for delivering local anesthetics to the skin: focus on liposomes,solid lipid nanoparticles,hydrogels and patches

Introduction: Dermal and transdermal drug delivery systems offer the possibility to control the release of the drug for an extended period of time. In particular, skin-delivery of local anesthetics (LA) is one of the most important strategies to increase the local drug concentration and to reduce systemic adverse reactions.

Areas covered: During the development phase of new formulations for skin-delivery of LA one should consider a set of desirable features such providing suitable adhesion, easy application/removal and also to be biocompatible, biodegradable and non-toxic. This review emphasizes the main strategies for skin-delivery of LA considering those features in relation to the composition of the delivery systems described. The topics highlight the relationships between physico-chemical studies and pharmaceutical applications for liposomes and solid lipid nanoparticles as well as the formulation and clinical applications for hydrogels and patches.

Expert opinion: The development of LA skin-delivery systems using hydrogels and different permeation enhancers, liposomes or lipid nanoparticles (as isolated carrier systems or as their dispersion in a gel-base) and patches have been explored as alternatives to commercial formulations, modifying the release rate of LA, increasing bioadhesive properties and reducing toxicity, resulting in an improved therapeutic efficacy. This review should provide to the reader a special emphasis on four delivery-systems, comprising the group of liposomes and lipid nanoparticles, hydrogels and patches technologies looking forward their application for skin anesthesia.     

新型纳米结构脂质载体系统的研究进展

目的介绍新型的纳米结构脂质载体系统的研究进展,为其研究和应用提供参考。方法查阅相关文献33篇,进行整理和归纳。结果新型的纳米结构脂质载体能够克服固体脂质纳米粒的一些不足,并具有独特的结构特征,药物的包封机理和释放特征。结论纳米结构脂质载体作为药物传递系统的一种新剂型,具有广阔的发展前景。     

固体脂质纳米粒和纳米结构脂质载体在经皮给药系统中的研究进展

目的介绍固体脂质纳米粒和纳米结构脂质载体在经皮给药系统中的应用与优势,为其开发利用提供参考。方法查阅国内外相关文献共30余篇,从固体脂质纳米粒和纳米结构脂质载体用于经皮给药系统的优势、药物在固体脂质纳米粒和纳米结构脂质载体中的分布形式及固体脂质纳米粒和纳米结构脂质载体在经皮给药领域中的应用等方面进行综述。结果固体脂质纳米粒和纳米结构脂质载体可以增强药物稳定性,能在皮肤表面产生包封效应,增加皮肤水合作用,具有药物靶向性。结论固体脂质纳米粒和纳米结构脂质载体是极有发展前景的新型经皮给药系统。     

Lipid nanoparticles for chemotherapeutic applications: strategies to improve anticancer efficacy

Introduction: Chemotherapy remains the major form of treatment for cancer. However, chemotherapy often fails due to a variety of barriers, resulting in a limited intratumoral drug disposition. Recently, lipid nanoparticles (LNs, i.e., solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs)) have been shown to provide a favorable means for efficiently delivering drugs to tumor sites, while minimizing their side effects.

Areas covered: The delivery of drugs to tumors is restricted by a series of barriers, including the tumor abnormalities, strong adverse effects and poor specificity of cytotoxic drugs, and the induction of multidrug resistance (MDR). The present review summarizes the strategies using SLNs and/or NLCs to improve the anticancer efficacy of cytotoxic drugs, including passive targeting, active targeting, long circulating and MDR reversing. Specifically, the most significant in vitro and in vivo results on the use of SLNs and/or NLCs are highlighted.

Expert opinion: The future success of SLNs and NLCs for administration of cytotoxic drugs will depend on their ability to efficiently encapsulate and release drugs, the possibility for large-scale production, selective tumor cells targeting and increased antitumor efficacy with reduced tissue toxicity.     

Solid lipid nanoparticles formed by solvent-in-water emulsion–diffusion technique: Development and influence on insulin stability

Insulin-loaded solid lipid nanoparticles (SLN), obtained by the solvent-in-water emulsion–diffusion technique, were produced using isovaleric acid (IVA) as organic phase, glyceryl mono-stearate (GMS) as lipid, soy lecithin and sodium taurodeoxycholate (TDC) as emulsifiers. IVA, a partially water-miscible solvent with low toxicity, was used to dissolve both insulin and lipids. SLN of spherical shape were obtained by simple water dilution of the O/W emulsion. Analysis of SLN content after processing showed interesting encapsulation efficiency with respect to therapeutic doses; moreover, insulin did not undergo any chemical modification within the nanoparticles and most of it remained stable after incubation of the SLN with trypsin solution. The biological activity of insulin, i.e. the ability to decrease glycemia in rats, was not negatively influenced by the SLN production process, as after subcutaneous administration of insulin extracted from SLN to animals, the blood glucose levels were quite similar to those obtained after administration of a conventional insulin suspension. Consequently, SLN seem to have interesting possibilities as delivery systems for oral administration of insulin.     

固脂纳米粒(SLN)药物释放系统的研究进展

目的综述固脂纳米粒作为药物释放系统的最新研究进展。方法依据近年来国内外文献资料 ,将固脂纳米粒的制备方法、药物载入、药物释放、特性分析及其在药学领域的应用情况进行了概括。结果固脂纳米粒的主要制备方法为乳化法和微乳法 ;通过调整制备工艺参数可调整药物的包封率和释药曲线 ;固脂纳米粒可供多途径给药。结论固脂纳米粒在药学领域有广阔的发展前景     

Formulation and Targeting Efficiency of Cisplatin Engineered Solid Lipid Nanoparticles

The present study is aimed at the overall improvement in the efficacy, reduced toxicity and enhancement of therapeutic index of cisplatin. Solid lipid nanoparticulate delivery system of cisplatin has been developed by microemulsification method by using stearic acid, soy lecithin 95% and sodium glycolate. The formulations were then characterized with respect to size and its surface morphology, zeta potential, entrapment efficiency, in vitro drug release profile, in vivo drug targeting studies and its stability under specific conditions. The formulated solid lipid nanoparticles were oval with a diameter ranging from 250 nm to 500 nm. The lowest entrapment efficiency was found to be 47.59% and highest was found to be 74.53%. The zeta potential was in the range of -9.8 to -11.2 mv. In vitro release study was analyzed using various mathematical models. Highest cumulative percent drug release was observed with F-1 (97.22 %) and lowest with F-4 (78.43%) in 16 h. The in vivo result of formulated solid lipid nanoparticles of cisplatin reveals that the drug is preferentially targeting to liver followed by brain and lungs.     

Development of nitrosyl ruthenium complex-loaded lipid carriers for topical administration: improvement in skin stability and in nitric oxide release by visible light irradiation

The prominent nitric oxide (NO) donor [Ru(terpy)(bdqi)NO](PF₆)₃ has been synthesized and evaluated with respect to noteworthy biological effects due to its NO photorelease, including vascular relaxation and melanoma cell culture toxicity. The potential for delivering NO in therapeutic quantities is tenable since the nitrosyl ruthenium complex (NRC) must first reach the “target tissue” and then release the NO upon stimulus. In this context, NRC-loaded lipid carriers were developed and characterized to further explore its topical administration for applications such as skin cancer treatment. NRC-loaded solid lipid nanoparticles (SLN) and nanostructured lipid carriers were prepared via the microemulsification method, with average diameters of 275 ± 15 nm and 211 ± 31 nm and zeta potentials of −40.7 ± 10.4 mV and −50.0 ± 7.5 mV, respectively. In vitro kinetic studies of NRC release from nanoparticles showed sustained release of NRC from the lipid carriers and illustrated the influence of the release medium and the lyophilization process. Stability studies showed that NO is released from NRC as a function of temperature and time and due to skin contact. The encapsulation of NRC in SLN followed by its lyophilization, significantly improved the complex stability. Furthermore, of particular interest was the fact that in the NO photorelease study, the NO release from the NRC-loaded SLN was approximately twice that of just NRC in solution. NRC-loaded SLN performs well enough at releasing and protecting NO degradation in vitro that it is a promising carrier for topical delivery of NO.     

Skin permeation of buprenorphine and its ester prodrugs from lipid nanoparticles: lipid emulsion,nanostructured lipid carriers and solid lipid nanoparticles

The aim of this study was to develop and characterize lipid nanoparticle systems for the transdermal delivery of buprenorphine and its prodrugs. A panel of three buprenorphine prodrugs with ester chains of various lengths was synthesized and characterized by solubility, capacity factor (log K′), partitioning between lipids and water and the ability to penetrate nude mouse skin. Colloidal systems made of squalene (lipid emulsion, LE), squalene + Precirol (nanostructured lipid carriers, NLC) and Precirol (solid lipid nanoparticles, SLN) as the lipid core material were prepared. Differential scanning calorimetry showed that the SLN had a more-ordered crystalline lattice in the inner matrix compared to the NLC. The particle size ranged from 220–300 nm, with NLC showing the smallest size. All prodrugs were highly lipophilic and chemically stable, but enzymatically unstable in skin homogenate and plasma. The in vitro permeation results exhibited a lower skin delivery of drug/prodrug with an increase in the alkyl chain length. SLN produced the highest drug/prodrug permeation, followed by the NLC and LE. A small inter-subject variation was also observed with SLN carriers. SLN with soybean phosphatidylcholine (SLN-PC) as the lipophilic emulsifier showed a higher drug/prodrug delivery across the skin compared to SLN with Myverol, a palmitinic acid monoglyceride. The in vitro permeation of the prodrugs occurred in a sustained manner for SLN-PC. The skin permeation of buprenorphine could be adjusted within a wide range by combining a prodrug strategy and lipid nanoparticles.     

Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC) for pulmonary application: A review of the state of the art

Drug delivery by inhalation is a noninvasive means of administration that has following advantages for local treatment for airway diseases: reaching the epithelium directly, circumventing first pass metabolism and avoiding systemic toxicity. Moreover, from the physiological point of view, the lung provides advantages for systemic delivery of drugs including its large surface area, a thin alveolar epithelium and extensive vasculature which allow rapid and effective drug absorption. Therefore, pulmonary application is considered frequently for both, the local and the systemic delivery of drugs. Lipid nanoparticles – Solid Lipid Nanoparticles and Nanostructured Lipid Carriers – are nanosized carrier systems in which solid particles consisting of a lipid matrix are stabilized by surfactants in an aqueous phase. Advantages of lipid nanoparticles for the pulmonary application are the possibility of a deep lung deposition as they can be incorporated into respirables carriers due to their small size, prolonged release and low toxicity. This paper will give an overview of the existing literature about lipid nanoparticles for pulmonary application. Moreover, it will provide the reader with some background information for pulmonary drug delivery, i.e., anatomy and physiology of the respiratory system, formulation requirements, application forms, clearance from the lung, pharmacological benefits and nanotoxicity.