Enhanced stability and skin permeation of ibuprofen-loaded solid lipid nanoparticles based binary solid lipid matrix: Effect of surfactant and lipid compositions

Hypothesis

The type of emulsifier selected has an impact on the physicochemical properties of solid lipid nanoparticles (SLNs). This study was designed to compare the effects of emulsifiers on the physicochemical properties and in vitro skin performance of SLNs prepared from a binary mixture of Softisan® 378 (S378) and cetyl palmitate (CP) to those of SLNs prepared from only CP and S378.

Experiments

SLNs were prepared from CP, S378, or a binary mixture of CP and S378 (1:1 w/w) as the lipid phase and stabilized with Tego®Care 450 (TG450) or poloxamer 188 (P188) containing 1.0% w/w ibuprofen loading. The physicochemical properties including the particle size, polydispersity index (PDI), zeta potential (ZP), encapsulation efficiency (E.E.), crystallinity (%CI), and polymorphism were determined after production and after storage for 180 days under different conditions. In addition, in vitro drug release and permeation through human skin was studied after production and storage at room temperature for 180 days.

Finding

The particle sizes of ibuprofen-loaded SLNs (IBSLNs) stabilized with P188 (IBSLN-P188) were smaller than those of SLNs stabilized with TG450 (IBSLN-TG450) (p < 0.05). After 180 days, the particle sizes of the IBSLNs were slightly increased compared to those at the initial time but were <250 nm. The IBSLN-TG450 sample showed a higher %CI than IBSLN-P188 prepared with similar propotions of CP and S378, and ibuprofen crystals were observed in the IBSLN1-TG450 sample after storage at 4 °C for 180 days. Based on the result of the in vitro release study and the in vitro skin permeation test, the addition of S378 into the CP-matrix modified ibuprofen release and skin permeation both permeated ibuprofen through the epidermis and retained ibuprofen in the epidermis. In addition, the storage time affected the release and skin permeation of ibuprofen from the SLNs, which depended on the composition of the IBSLNs.

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.

Nanodelivery of antiretroviral drugs to nervous tissues

Despite the development of effective combined antiretroviral therapy (cART), the neurocognitive impairments associated with human immunodeficiency virus (HIV) remain challenging. The presence of the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCFB) impedes the adequate penetration of certain antiretroviral drugs into the brain. In addition, reports have shown that some antiretroviral drugs cause neurotoxicity resulting from their interaction with nervous tissues due to long-term systemic exposure. Therefore, the research into the effective therapeutic modality that would cater for the HIV-associated neurocognitive disorders (HAND) and ART toxicity is now receiving broad research attention. Thus, this review explores the latest information in managing HAND using a nanoparticle drug delivery system (NDDS). We discussed the neurotoxicity profile of various approved ART. Also, we explained the applications of silver nanoparticles (AgNPs) in medicine, their different synthesis methods and their interaction with nervous tissues. Lastly, while proposing AgNPs as useful nanoparticles in properly delivering ART to enhance effectiveness and minimize neurocognitive disorders, we hypothesize that the perceived toxicity of AgNPs could be minimized by taking appropriate precautions. One such precaution is using appropriate reducing and stabilizing agents such as trisodium citrate to reduce silver ion Ag + to ground state Ag0 during the synthesis. Also, the usage of medium-sized, spherical-shaped AgNPs is encouraged in AgNPs-based drug delivery to the brain due to their ability to deliver therapeutic agents across BBB. In addition, characterization and functionalization of the synthesized AgNPs are required during the drug delivery approach. Putting all these factors in place would minimize toxicity and enhance the usage of AgNPs in delivering therapeutic agents across the BBB to the targeted brain tissue and could cater for the HIV-associated neurocognitive disorders and neurotoxic effects of antiretroviral drugs (ARDs).

Lipid-Drug Conjugates and Nanoparticles for the Cutaneous Delivery of Cannabidiol

Lipid nanoparticles are currently used to deliver drugs to specific sites in the body, known as targeted therapy. Conjugates of lipids and drugs to produce drug-enriched phospholipid micelles have been proposed to increase the lipophilic character of drugs to overcome biological barriers. However, their applicability at the topical level is still minimal. Phospholipid micelles are amphiphilic colloidal systems of nanometric dimensions, composed of a lipophilic nucleus and a hydrophilic outer surface. They are currently used successfully as pharmaceutical vehicles for poorly water-soluble drugs. These micelles have high in vitro and in vivo stability and high biocompatibility. This review discusses the use of lipid-drug conjugates as biocompatible carriers for cutaneous application. This work provides a metadata analysis of publications concerning the conjugation of cannabidiol with lipids as a suitable approach and as a new delivery system for this drug.

Antimicrobial Activity Enhancers: Towards Smart Delivery of Antimicrobial Agents

The development of effective treatments against infectious diseases is an extensive and ongoing process due to the rapid adaptation of bacteria to antibiotic-based therapies. However, appropriately designed activity enhancers, including antibiotic delivery systems, can increase the effectiveness of current antibiotics, overcoming antimicrobial resistance and decreasing the chance of contributing to further bacterial resistance. The activity/delivery enhancers improve drug absorption, allow targeted antibiotic delivery, improve their tissue and biofilm penetration and reduce side effects. This review provides insights into various antibiotic activity enhancers, including polymer, lipid, and silver-based systems, designed to reduce the adverse effects of antibiotics and improve formulation stability and efficacy against multidrug-resistant bacteria.

Advanced drug delivery systems containing herbal components for wound healing

Management of chronic wound has an immense impact on social and economic conditions in the world. Healthcare costs, aging population, physical trauma, and comorbidities of diabetes and obesity seem to be the major factors of this increasing incidence of chronic wounds. Conditions of chronic wound could not restore functional epidermis; thus, delaying the closure of the wound opening in an expected manner. Failures in restoration of skin integrity delay healing due to changes in skin pathology, such as chronic ulceration or nonhealing. The role of different traditional medicines has been explored for use in the healing of cutaneous wounds, where several phytochemicals, such as flavonoids, alkaloids, phenolic acids, tannins are known to provide potential wound healing properties. However, the delivery of plant-based therapeutics could be improved by the novel platform of nanotechnology. Thus, the objectives of novel delivery strategies of principal bioactive from plant sources are to accelerate the wound healing process, avoid wound complications and enhance patient compliance. Therefore, the opportunities of nanotechnology-based drug delivery of natural wound healing therapeutics have been included in the present discussion with special emphasis on nanofibers, vesicular structures, nanoparticles, nanoemulsion, and nanogels.

Solid Lipid Nanoparticles (SLNs): An Advanced Drug Delivery System Targeting Brain through BBB

The blood-brain barrier (BBB) plays a vital role in the protection and maintenance of homeostasis in the brain. In this way, it is an interesting target as an interface for various types of drug delivery, specifically in the context of the treatment of several neuropathological conditions where the therapeutic agents cannot cross the BBB. Drug toxicity and on-target specificity are among some of the limitations associated with current neurotherapeutics. In recent years, advances in nanodrug delivery have enabled the carrier system containing the active therapeutic drug to target the signaling pathways and pathophysiology that are closely linked to central nervous system (CNS) disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), multiple sclerosis (MS), brain tumor, epilepsy, ischemic stroke, and neurodegeneration. At present, among the nano formulations, solid lipid nanoparticles (SLNs) have emerged as a putative drug carrier system that can deliver the active therapeutics (drug-loaded SLNs) across the BBB at the target site of the brain, offering a novel approach with controlled drug delivery, longer circulation time, target specificity, and higher efficacy, and more importantly, reducing toxicity in a biomimetic way. This paper highlights the synthesis and application of SLNs as a novel nontoxic formulation strategy to carry CNS drugs across the BBB to improve the use of therapeutics agents in treating major neurological disorders in future clinics.

Challenges in Oral Drug Delivery and Applications of Lipid Nanoparticles as Potent Oral Drug Carriers for Managing Cardiovascular Risk Factors

BACKGROUND

The oral application of drugs is the most popular route through which the systemic effect can be achieved. Nevertheless, oral administration is limited by difficulties related to the physicochemical properties of the drug molecule, including low aqueous solubility, instability, low permeability, and rapid metabolism, all of which result in low and irregular oral bioavailability.

OBJECTIVE

The enhancement of oral bioavailability of drug molecules with such properties could lead to extreme complications in drug preparations. Oral lipid-based nanoparticles seem to possess extensive advantages due to their ability to increase the solubility, simplifying intestinal absorption and decrease or eradicate the effect of food on the absorption of low soluble, lipophilic drugs and therefore improving the oral bioavailability.

METHODS

The present review provides a summary of the general theory of lipid-based nanoparticles, their preparation methods, as well as their oral applications. Moreover, oral drug delivery challenges are discussed.

RESULTS

According to this review, the most frequent types of lipid-based nanoparticle, the solid lipid nanoparticles and nanostructured lipid carriers are potent oral carriers due to their ability to penetrate the oral drug adsorption barriers. Moreover, such lipid nanoparticles can be beneficial drug carriers against cardiovascular risk disorders as diabetes, hypertension, etc. Conclusion: In this review, the most current and promising studies involving Solid Lipid Nanoparticles and Nanostructured Lipid Carriers as oral drug carriers are reported aiming to assist researchers who focus their research on lipid-based nanoparticles.

S. SK. Nanotechnology: an emerging approach to combat COVID-19

The recent outbreak of coronavirus disease (COVID-19) has challenged the survival of human existence in the last 1 year. Frontline healthcare professionals were struggling in combating the pandemic situation and were continuously supported with literature, skill set, research activities, and technologies developed by various scientists/researchers all over the world. To handle the continuously mutating severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) requires amalgamation of conventional technology with emerging approaches. Nanotechnology is science, engineering, and technology dealing at the nanoscale level. It has made possible the development of nanomaterials, nano-biosensors, nanodrugs, and vaccines for diagnosis, therapy, and prevention of COVID-19. This review has elaborately highlighted the role of nanotechnology in developing various detection kits such as nanoparticle-assisted diagnostics, antibody assay, lateral flow immunoassay, nanomaterial biosensors, etc., in detection of SARS-CoV-2. Similarly, various advancements supervene through nanoparticle-based therapeutic drugs for inhibiting viral infection by blocking virus attachment/cell entry, multiplication/replication, and direct inactivation of the virus. Furthermore, information on vaccine development and the role of nanocarriers/nanoparticles were highlighted with a brief outlining of nanomaterial usage in sterilization and preventive mechanisms engineered to combat COVID-19 pandemic.

Oxiconazole nitrate solid lipid nanoparticles: formulation, in-vitro characterization and clinical assessment of an analogous loaded carbopol gel

The aim of the present work was to develop a promising drug delivery system of oxiconazole nitrate-loaded solid lipid nanoparticles (SLNs) topical gel to enhance the drug effectiveness for the treatment of Tinea infection. SLNs were prepared by emulsification-solvent evaporation method. Particle size and entrapment efficiency of the prepared SLNs were investigated. An appropriate formulation was selected and examined for morphology and physicochemical characterization adopting Scanning electron microscope and Differential scanning colorimetry. In-vitro drug release was also investigated. The selected SLNs were loaded into 1% Carbopol 934 gel that was investigated for homogeneity, pH, grittiness, spreadability, viscosity and in vitro drug release. Clinical study for the developed gel system compared to the corresponding marketed product was conducted on 28 patients. The results revealed that the prepared oxiconazole nitrate SLNs had drug entrapment efficiency ranging from 41.34% to 75.07% and zeta potential lying between -13 and -50. Physicochemical characterization revealed a decrease in the drug crystallinity in the prepared SLNs. The gel formulation showed appropriate physical characteristics and sustained in-vitro drug release. Clinical study for the prepared oxiconazole nitrate SLNs gel showed significantly less side effects, better patient satisfaction and superior clinical improvement compared with the corresponding marketed product.

Nutraceuticals' Novel Formulations: The Good, the Bad, the Unknown and Patents Involved

Traditional nutraceuticals and cosmeceuticals hold pragmatic nature with respect to their definitions, claims, purposes and marketing strategies. Their definitions are not well established worldwide. They also have different regulatory definitions and registration regulatory processes in different parts of the world. Global prevalence of nutraceuticals and cosmeceuticals is noticeably high with large market share with minimal regulation compared to traditional drugs. The global market is flooded with nutraceuticals and cosmeceuticals claiming to be of natural origin and sold with a therapeutic claim by major online retail stores such as Amazon and eBay. Apart from the traditional formulations, many manufacturers and researchers use novel formulation technologies in nutraceutical and cosmeceutical formulations for different reasons and objectives. Manufacturers tend to differentiate their products with novel formulations to increase market appeal and sales. On the other hand, researchers use novel strategies to enhance nutraceuticals and cosmeceuticals activity and safety. The objective of this review is to assess the current patents and research adopting novel formulation strategies in nutraceuticals and cosmeceuticals. Patents and research papers investigating nutraceutical and cosmeceutical novel formulations were surveyed for the past 15 years. Various nanosystems and advanced biotechnology systems have been introduced to improve the therapeutic efficacy, safety and market appeal of nutraceuticals and cosmeceuticals, including liposomes, polymeric micelles, quantum dots, nanoparticles, and dendrimers. This review provides an overview of nutraceuticals and cosmeceuticals current technologies, highlighting their pros, cons, misconceptions, regulatory definitions and market. This review also aims in separating the science from fiction in the nutraceuticals and cosmeceuticals development, research and marketing.

Solid Lipid Nanoparticles: Emerging Colloidal Nano Drug Delivery Systems

Solid lipid nanoparticles (SLNs) are nanocarriers developed as substitute colloidal drug delivery systems parallel to liposomes, lipid emulsions, polymeric nanoparticles, and so forth. Owing to their unique size dependent properties and ability to incorporate drugs, SLNs present an opportunity to build up new therapeutic prototypes for drug delivery and targeting. SLNs hold great potential for attaining the goal of targeted and controlled drug delivery, which currently draws the interest of researchers worldwide. The present review sheds light on different aspects of SLNs including fabrication and characterization techniques, formulation variables, routes of administration, surface modifications, toxicity, and biomedical applications.

Topical phenytoin nanostructured lipid carriers: design and development

Phenytoin (PHT) is an antiepileptic drug that was reported to exhibit high wound healing activity. Nevertheless, its limited solubility, bioavailability, and inefficient distribution during topical administration limit its use. Therefore, this study aims to develop, characterize nanostructured lipid carriers (NLCs), and evaluate their potential in topical delivery of PHT to improve the drug entrapment efficiency and sustained release. The NLCs were prepared by hot homogenization followed by ultra sonication method using 2³ factorial design. NLC formulations were characterized regarding their particle size (PS), zeta potential (ZP), entrapment efficiency percent (%EE), surface morphology, physicochemical stability, and in vitro release studies. The optimized NLC (F7) was further incorporated in 1%w/v carbopol gel and then characterized for appearance, pH, viscosity, stability, and in vitro drug release. The prepared NLCs were spherical in shape and possessed an average PS of 121.4-258.2 nm, ZP of (-15.4)-(-32.2) mV, and 55.24-88.80 %EE. Solid-state characterization revealed that the drug is dispersed in an amorphous state with hydrogen bond interaction between the drug and the NLC components. NLC formulations were found to be stable at 25 °C for six months. The stored F7-hydrogel showed insignificant changes in viscosity and drug content (p>.05) up to six months at 25 °C that pave a way for industrial fabrication of efficient PHT products. In vitro release studies showed a sustained release from NLC up to 48 h at pH 7.4 following non-Fickian Higuchi kinetics model. These promising findings encourage the potential use of phenytoin loaded lipid nanoparticles for future topical application.

Development of olmesartan medoxomil lipid-based nanoparticles and nanosuspension: preparation, characterization and comparative pharmacokinetic evaluation

The aim was to enhance the oral bioavailability of olmesartan medoxomil (OM) by preparing solid lipid nanoparticles (SLNs) and comparing with nanosuspension (OM-NS). OM-SLNs and OM-NS were prepared by known methods. Prepared SLNs were evaluated for physical characters and in vivo pharmacokinetic (PK) performance in rats. OM-NS showed more than four-fold increase in the solubility. During DSC and XRD studies, drug incorporated in SLNs was found to be in amorphous form. The relative bioavailability of OM-SLN and OM-NS was 7.21- and 3.52-fold when compared with that of coarse suspension. Further, OM-SLNs also increased the oral bioavailability by two-fold over that of OM-NS.

Phospholipid complex enriched micelles: A novel drug delivery approach for promoting the antidiabetic effect of repaglinide

To enhance the oral antidiabetic effect of repaglinide (RG), a newly emerging approach, based on the combination of phospholipid complexation and micelle techniques, was employed. Repaglinide-phospholipid complex (RG-PLC) was prepared by the solvent-evaporation method then characterized using Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction (XPRD). The results revealed obvious disappearance of the characteristic peaks of the prepared RG-PLCs confirming the formation of drug-phospholipid complex. RG-PLC enriched micelles (RG-PLC-Ms) were prepared by the solvent-evaporation technique employing poloxamer 188 as surfactant. The prepared RG-PLC-Ms showed high drug encapsulation efficiencies (93.81-99.38%), with nanometric particle diameters (500.61-665.32nm) of monodisperse distribution and high stability (Zeta potential < -29.8mV). The in vitro release of RG from RG-PLC-Ms was pH-dependant according to the release media. A higher release pattern was reported in pH=1.2 compared to a more retarded release in pH=6.8 owing to two different kinetics of drug release. Oral antidiabetic effect of two optimized RG-PLC-M formulations was evaluated in an alloxan-induced diabetic rat model for 7-day treatment protocol. The two investigated formulations depicted normal blood glucose, serum malondialdehyde and insulin levels as well as an improved lipid profile, at the end of daily oral treatment, in contrast to RG marketed tablets implying enhanced antidiabetic effect of the drug. Hence, phospholipid-complex enriched micelles approach holds a promising potential for promoting the antidiabetic effect of RG.

Surface Modified Multifunctional and Stimuli Responsive Nanoparticles for Drug Targeting: Current Status and Uses

Nanocarriers, due to their unique features, are of increased interest among researchers working with pharmaceutical formulations. Polymeric nanoparticles and nanocapsules, involving non-toxic biodegradable polymers, liposomes, solid lipid nanoparticles, and inorganic-organic nanomaterials, are among the most used carriers for drugs for a broad spectrum of targeted diseases. In fact, oral, injectable, transdermal-dermal and ocular formulations mainly consist of the aforementioned nanomaterials demonstrating promising characteristics such as long circulation, specific targeting, high drug loading capacity, enhanced intracellular penetration, and so on. Over the last decade, huge advances in the development of novel, safer and less toxic nanocarriers with amended properties have been made. In addition, multifunctional nanocarriers combining chemical substances, vitamins and peptides via coupling chemistry, inorganic particles coated by biocompatible materials seem to play a key role considering that functionalization can enhance characteristics such as biocompatibility, targetability, environmental friendliness, and intracellular penetration while also have limited side effects. This review aims to summarize the "state of the art" of drug delivery carriers in nanosize, paying attention to their surface functionalization with ligands and other small or polymeric compounds so as to upgrade active and passive targeting, different release patterns as well as cell targeting and stimuli responsibility. Lastly, future aspects and potential uses of nanoparticulated drug systems are outlined.

Solid lipid nanoparticles as attractive drug vehicles: Composition, properties and therapeutic strategies

This work briefly reviews up-to-date developments in solid lipid nanoparticles (SLNs) as effective nanocolloidal system for drug delivery. It summarizes SLNs in terms of their preparation, surface modification and properties. The application of SLNs as a carrier system enables to improve the therapeutic efficacy of drugs from various therapeutic groups. Present uses of SLNs include cancer therapy, dermatology, bacterial infections, brain targeting and eye disorders among others. The usage of SLNs provides enhanced pharmacokinetic properties and modulated release of drugs. SLN ubiquitous application results from their specific features such as possibility of surface modification, increased permeation through biological barriers, resistance to chemical degradation, possibility of co-delivery of various therapeutic agents or stimuli-responsiveness. This paper will be useful to the scientists working in the domain of SLN-based drug delivery systems.

Identifying lipidic emulsomes for improved oxcarbazepine brain targeting: In vitro and rat in vivo studies

Lipid-based nanovectors offer effective carriers for brain delivery by improving drug potency and reducing off-target effects. Emulsomes are nano-triglyceride (TG) carriers formed of lipid cores supported by at least one phospholipid (PC) sheath. Due to their surface active properties, PC forms bilayers at the aqueous interface, thereby enabling encapsulated drug to benefit from better bioavailability and stability. Emulsomes of oxcarbazepine (OX) were prepared, aimed to offer nanocarriers for nasal delivery for brain targeting. Different TG cores (Compritol(®), tripalmitin, tristearin and triolein) and soya phosphatidylcholine in different amounts and ratios were used for emulsomal preparation. Particles were modulated to generate nanocarriers with suitable size, charge, encapsulation efficiency and prolonged release. Cytotoxicity and pharmacokinetic studies were also implemented. Nano-spherical OX-emulsomes with maximal encapsulation of 96.75% were generated. Stability studies showed changes within 30.6% and 11.2% in the size and EE% after 3 months. MTT assay proved a decrease in drug toxicity by its encapsulation in emulsomes. Incorporation of OX into emulsomes resulted in stable nanoformulations. Tailoring emulsomes properties by modulating the surface charge and particle size produced a stable system for the lipophilic drug with a prolonged release profile and mean residence time and proved direct nose-to-brain transport in rats.

Targeting of eugenol-loaded solid lipid nanoparticles to the epidermal layer of human skin

Aim: The purpose of this study was to formulate carbopol hydrogels containing eugenol-loaded solid lipid nanoparticles (EG–SLNs) for epidermal targeting to treat fungal infections in skin. Materials & methods: EG–SLNs were incorporated into carbopol hydrogels and the physiochemical characteristics of EG–SLN in hydrogels were investigated by dynamic light scattering, transmission electron microscopy and atomic force microscopy. Rheological behavior and mechanical properties of hydrogels were also studied before and after incorporation of EG–SLNs. The epidermal-targeting ability of EG–SLN-enriched hydrogels was evaluated by estimation of eugenol in the epidermis of human cadaver skin. An occlusion (hydration) study was also performed to elucidate the mechanism of epidermal targeting of EG–SLN-enriched hydrogels. Results: The particle size (d90) and morphology of EG–SLNs were not significantly changed after incorporation into the hydrogel. EG–SLN of stearic acid-enriched hydrogels follow the Carreau model that describes pseudoplastic flow. The hydrogel containing EG–SLN of stearic acid and of Compritol® (Gattefose, Mumbai, India) showed significantly greater accumulation of eugenol in the epidermis (62.65 ± 4.35 and 52.86 ± 3.76 µg/cm2, respectively) than that of eugenol–hydroxypropyl-β–cyclodextrin complex in hydrogel (9.77 ± 1.16 µg/cm2) and almond oil solution of eugenol (3.45 ± 0.6 µg/cm2). The occlusion study demonstrated greater hydration of human cadaver skin treated with EG–SLN-enriched hydrogel compared with that of hydrogel and intact skin. Conclusion: Hydrogels containing EG–SLNs could be a promising formulation for epidermal targeting to treat fungal infections in skin.

Original submitted 26 March 2012; Revised submitted 29 January 2013

Development of vorinostat-loaded solid lipid nanoparticles to enhance pharmacokinetics and efficacy against multidrug-resistant cancer cells

PURPOSE

To investigate whether delivery of a histone deacetylase inhibitor, vorinostat (VOR), by using solid lipid nanoparticles (SLNs) enhanced its bioavailability and effects on multidrug-resistant cancer cells.

METHODS

VOR-loaded SLNs (VOR-SLNs) were prepared by hot homogenization using an emulsification-sonication technique, and the formulation parameters were optimized. The cytotoxicity of the optimized formulation was evaluated in cancer cell lines (MCF-7, A549, and MDA-MB-231), and pharmacokinetic parameters were examined following oral and intravenous (IV) administration to rats.

RESULTS

VOR-SLNs were spherical, with a narrowly distributed average size of ~100 nm, and were physically stable for 3 months. Drug release showed a typical bi-phasic pattern in vitro, and was independent of pH. VOR-SLNs were more cytotoxic than the free drug in both sensitive (MCF-7 and A549) and resistant (MDA-MB-231) cancer cells. Importantly, SLN formulations showed prominent cytotoxicity in MDA-MB-231 cells at low doses, suggesting an ability to effectively counter the P-glycoprotein-related drug efflux pumps. Pharmacokinetic studies clearly demonstrated that VOR-SLNs markedly improved VOR plasma circulation time and decreased its elimination rate constant. The areas under the VOR concentration-time curve produced by oral and IV administration of VOR-SLNs were significantly greater than those produced by free drug administration. These in vivo results clearly highlighted the remarkable potential of SLNs to augment the bioavailability of VOR.

CONCLUSIONS

VOR-SLNs successfully enhanced the oral bioavailability, circulation half-life, and chemotherapeutic potential of VOR.

Targeting of diacerein loaded lipid nanoparticles to intra-articular cartilage using chondroitin sulfate as homing carrier for treatment of osteoarthritis in rats

Targeted delivery of antiosteoarthritic drug diacerein to articular tissue could be a major achievement and soluble polysaccharide chondroitin sulfate (ChS) may be a suitable agent for this. Therefore, diacerein loaded solid lipid nanoparticles modified with ChS (ChS-DC-SLN) were prepared for synergistic effect of these agents to combat multidimensional pathology of osteoarthritis (OA). Prepared formulation were of size range 396±2.7nm, showed extended release up to 16h and increased bioavailability of diacerein by 2.8 times. ChS-DC-SLN were evaluated for their effect on histopathology of femoro-tibial joint of rat knee and amount of ChS and rhein (an active metabolite of diacerein) at targeted site. Concentration of rhein was significantly higher in case of ChS-DC-SLN (7.8±1.23μg/ml) than that of drug dispersion (2.9±0.45μg/ml). It can be stated that ChS served as homing to articular cartilage for targeting of drug. Thus, ChS-DC-SLN have great potential to enhance the overall efficacy of treatment for OA.

FROM THE CLINICAL EDITOR

This study demonstrates the feasibility of targeted delivery of diacerein to articular tissue using soluble polysaccharide chondroitin sulfate as the targeting vector. This approach has the potential to significantly increase anti-arthritic drug concentration in joints without leading to systemic toxicity.

Preparation and optimization of triptolide-loaded solid lipid nanoparticles for oral delivery with reduced gastric irritation

Triptolide (TP) often causes adverse reactions in the gastrointestinal tract when it is administered orally. This study aimed to prepare and optimize triptolide-loaded solid lipid nanoparticles (TP-SLN) with reduced gastric irritation. The microemulsion technique was used to formulate TP-SLN employing a five-level central composite design (CCD) that was developed for exploring the optimum levels of three independent variables on particle size, encapsulation efficiency (EE) and drug loading (DL). Quadratic polynomial models were generated to predict and evaluate the three independent variables with respect to the three responses. The optimized TP-SLN was predicted to comprise fraction of lipid of 49.73%, surfactant to co-surfactant ratio of 3.25, and lipid to drug ratio of 55.27, which showed particle size of 179.8 ± 5.7 nm, EE of 56.5 ± 0.18% and DL of 1.02 ± 0.003% that were in good agreement with predicted values. In addition, the optimized nanoparticles manifested a sustained-release pattern in vitro and were stable during 3 h of incubation in simulated gastric fluids without significant size change and the majority (91%) of the drug was protected. Furthermore, the nanoparticles did not show obvious gastric irritation caused by oral administration of TP in rats.

A comparison between use of spray and freeze drying techniques for preparation of solid self-microemulsifying formulation of valsartan and in vitro and in vivo evaluation

The objective of the present study was to develop self micro emulsifying formulation (SMEF) of valsartan to improve its oral bioavailability. The formulations were screened on the basis of solubility, stability, emulsification efficiency, particle size and zeta potential. The optimized liquid SMEF contains valsartan (20% w/w), Capmul MCM C8 (16% w/w), Tween 80 (42.66% w/w) and PEG 400 (21.33% w/w) as drug, oil, surfactant and co-surfactant, respectively. Further, Liquid SMEF was adsorbed on Aerosol 200 by spray and freeze drying methods in the ratio of 2 : 1 and transformed into free flowing powder. Both the optimized liquid and solid SMEF had the particle size <200 nm with rapid reconstitution properties. Both drying methods are equally capable for producing stable solid SMEF and immediate release of drug in in vitro and in vivo conditions. However, the solid SMEF produced by spray drying method showed high flowability and compressibility. The solid state characterization employing the FTIR, DSC and XRD studies indicated insignificant interaction of drug with lipid and adsorbed excipient. The relative bioavailability of solid SMEF was approximately 1.5 to 3.0 folds higher than marketed formulation and pure drug. Thus, the developed solid SMEF illustrates an alternative delivery of valsartan as compared to existing formulations with improved bioavailability.

Formulation optimization and topical delivery of quercetin from solid lipid based nanosystems

The presence of large amounts of reactive oxygen species (ROS) leads to oxidative stress that can damage cell membranes, lead to DNA breakage and cause inactivation of free radical scavenger enzymes, eventually resulting in skin damage. Quercetin is a natural flavonoid that has been shown to have the highest anti-radical activity, along with the ability to act as a scavenger of free radicals and an inhibitor of lipid peroxidation. In this research work, a solvent-free solid lipid based nanosystem has been developed and evaluated for topical delivery of quercetin. Systematic screening of the formulation and process parameters led to the development of a solid lipid (glyceryl dibehenate) based nanosystem using a probe ultrasonication method. The selected variant demonstrated good physical stability for up to 8 weeks at 2-8 °C. Transmission electron microscopy (TEM) images showed spherical particles in the nanometer range. In vitro release studies showed biphasic release of quercetin from the SLN formulation, with an initial burst release followed by prolonged release for up to 24h. In vitro permeation studies using full thickness human skin showed higher amounts of quercetin to be localized within the skin compared to a control formulation with particles in the micrometer range. Such accumulation of quercetin in the skin is highly desirable since the efficacy of quercetin in delaying ultra-violet radiation mediated cell damage and eventual necrosis mainly occurs in the epidermis.

Current State-of-Art and New Trends on Lipid Nanoparticles (SLN and NLC) for Oral Drug Delivery

Lipids and lipid nanoparticles are extensively employed as oral-delivery systems for drugs and other active ingredients. These have been exploited for many features in the field of pharmaceutical technology. Lipids usually enhance drug absorption in the gastrointestinal tract (GIT), and when formulated as nanoparticles, these molecules improve mucosal adhesion due to small particle size and increasing their GIT residence time. In addition, lipid nanoparticles may also protect the loaded drugs from chemical and enzymatic degradation and gradually release drug molecules from the lipid matrix into blood, resulting in improved therapeutic profiles compared to free drug. Therefore, due to their physiological and biodegradable properties, lipid molecules may decrease adverse side effects and chronic toxicity of the drug-delivery systems when compared to other of polymeric nature. This paper highlights the importance of lipid nanoparticles to modify the release profile and the pharmacokinetic parameters of drugs when administrated through oral route.