Solid lipid nanoparticles comprising internal Compritol 888 ATO, tripalmitin and cacao butter for encapsulating and releasing stavudine, delavirdine and saquinavir

New Insight for Enhanced Topical Targeting of Caffeine for Effective Cellulite Treatment: In Vitro Characterization, Permeation Studies, and Histological Evaluation in Rats

Cellulite (CLT) is one of the commonly known lipodystrophy syndromes affecting post-adolescent women worldwide. It is topographically characterized by an orange-peel, dimpled skin appearance hence, it is an unacceptable cosmetic problem. CLT can be modulated by surgical procedures such as; liposuction and mesotherapy. But, these options are invasive, expensive and risky. For these reasons, topical CLT treatments are more preferred. Caffeine (CA), is a natural alkaloid that is well-known for its prominent anti-cellulite effects. However, its hydrophilicity hinders its cutaneous permeation. Therefore, in the present study CA was loaded into solid lipid nanoparticles (SLNs) by high shear homogenization/ultrasonication. CA-SLNs were prepared using Compritol® 888 ATO and stearic acid as solid lipids, and span 60 and brij™35, as lipid dispersion stabilizing agents. Formulation variables were adjusted to obtain entrapment efficiency (EE > 75%), particle size (PS < 350 nm), zeta potential (ZP < -25 mV) and polydispersity index (PDI < 0.5). CA-SLN-4 was selected and showed maximized EE (92.03 ± 0.16%), minimized PS (232.7 ± 1.90 nm), and optimum ZP (-25.15 ± 0.65 mV) and PDI values (0.24 ± 0.02). CA-SLN-4 showed superior CA release (99.44 ± 0.36%) compared to the rest CA-SLNs at 1 h. TEM analysis showed spherical, nanosized CA-SLN-4 vesicles. Con-LSM analysis showed successful CA-SLN-4 permeation transepidermally and via shunt diffusion. CA-SLN-4 incorporated into Noveon AA-1® hydrogel (CA-SLN-Ngel) showed accepted physical/rheological properties, and in vitro release profile. Histological studies showed that CA-SLN-Ngel significantly reduced mean subcutaneous fat tissue (SFT) thickness with 4.66 fold (p = 0.035) and 4.16 fold (p = 0.0001) compared to CA-gel, at 7th and 21st days, respectively. Also, significant mean SFT thickness reduction was observed compared to untreated group with 4.83 fold (p = 0.0005) and 3.83 fold (p = 0.0043), at 7th and 21st days, respectively. This study opened new avenue for CA skin delivery via advocating the importance of skin appendages. Hence, CA-SLN-Ngel could be a promising nanocosmeceutical gel for effective CLT treatment.

Solid lipid nanoparticles: a versatile approach for controlled release and targeted drug delivery

Solid Lipid Nanoparticles (SLN), the first type of lipid-based solid carrier systems in the nanometer range, were introduced as a replacement for liposomes. SLN are aqueous colloidal dispersions with solid biodegradable lipids as their matrix. SLN is produced using processes like solvent diffusion method and high-pressure homogenization, among others. Major benefits include regulated release, increased bioavailability, preservation of peptides and chemically labile compounds like retinol against degradation, cost-effective excipients, better drug integration, and a broad range of applications. Solid lipid nanoparticles can be administered via different routes, such as oral, parenteral, pulmonary, etc. SLN can be prepared by using high shear mixing as well as low shear mixing. The next generation of solid lipids, nanostructured lipid carriers (NLC), can reduce some of the drawbacks of SLN, such as its restricted capacity for drug loading and drug expulsion during storage. NLC are controlled nanostructured lipid particles that enhance drug loading. This review covers a brief introduction of solid lipid nanoparticles, manufacturing techniques, benefits, limitations, and their characterization tests.

Taste Masking of Promethazine Hydrochloride Using l-Arginine Polyamide-Based Nanocapsules

Promethazine hydrochloride (PMZ), a potent H1-histamine blocker widely used to prevent motion sickness, dizziness, nausea, and vomiting, has a bitter taste. In the present study, taste masked PMZ nanocapsules (NCs) were prepared using an interfacial polycondensation technique. A one-step approach was used to expedite the synthesis of NCs made from a biocompatible and biodegradable polyamide based on l-arginine. The produced NCs had an average particle size of 193.63 ± 39.1 nm and a zeta potential of −31.7 ± 1.25 mV, indicating their stability. The NCs were characterized using differential scanning calorimetric analysis and X-ray diffraction, as well as transmission electron microscopy that demonstrated the formation of the NCs and the incorporation of PMZ within the polymer. The in vitro release study of the PMZ-loaded NCs displayed a 0.91 ± 0.02% release of PMZ after 10 min using artificial saliva as the dissolution media, indicating excellent taste masked particles. The in vivo study using mice revealed that the amount of fluid consumed by the PMZ-NCs group was significantly higher than that consumed by the free PMZ group (p < 0.05). This study confirmed that NCs using polyamides based on l-arginine and interfacial polycondensation can serve as a good platform for the effective taste masking of bitter actives.

Antiviral role of nanomaterials: a material scientist's perspective

The present world continues to face unprecedented challenges caused by the COVID-19 pandemic. Collaboration between researchers of multiple disciplines is the need of the hour. There is a need to develop antiviral agents capable of inhibiting viruses and tailoring existing antiviral drugs for efficient delivery to prevent a surge in deaths caused by viruses globally. Biocompatible systems have been designed using nanotechnological principles which showed appreciable results against a wide range of viruses. Many nanoparticles can act as antiviral therapeutic agents if synthesized by the correct approach. Moreover, nanoparticles can act as carriers of antiviral drugs while overcoming their inherent drawbacks such as low solubility, poor bioavailability, uncontrolled release, and side effects. This review highlights the potential of nanomaterials in antiviral applications by discussing various studies and their results regarding antiviral potential of nanoparticles while also suggesting future directions to researchers.

Physicochemical and biopharmaceutical aspects influencing skin permeation and role of SLN and NLC for skin drug delivery

The skin is a complex and multifunctional organ, in which the static versus dynamic balance is responsible for its constant adaptation to variations in the external environment that is continuously exposed. One of the most important functions of the skin is its ability to act as a protective barrier, against the entry of foreign substances and against the excessive loss of endogenous material. Human skin imposes physical, chemical and biological limitations on all types of permeating agents that can cross the epithelial barrier. For a molecule to be passively permeated through the skin, it must have properties, such as dimensions, molecular weight, pKa and hydrophilic-lipophilic gradient, appropriate to the anatomy and physiology of the skin. These requirements have limited the number of commercially available products for dermal and transdermal administration of drugs. To understand the mechanisms involved in the drug permeation process through the skin, the approach should be multidisciplinary in order to overcome biological and pharmacotechnical barriers. The study of the mechanisms involved in the permeation process, and the ways to control it, can make this route of drug administration cease to be a constant promise and become a reality. In this work, we address the physicochemical and biopharmaceutical aspects encountered in the pathway of drugs through the skin, and the potential added value of using solid lipid nanoparticles (SLN) and nanostructured lipid vectors (NLC) to drug permeation/penetration through this route. The technology and architecture for obtaining lipid nanoparticles are described in detail, namely the composition, production methods and the ability to release pharmacologically active substances, as well as the application of these systems in the vectorization of various pharmacologically active substances for dermal and transdermal applications. The characteristics of these systems in terms of dermal application are addressed, such as biocompatibility, occlusion, hydration, emollience and the penetration of pharmacologically active substances. The advantages of using these systems over conventional formulations are described and explored from a pharmaceutical point of view.

Compritol solid lipid nanoparticle formulations enhance the protective effect of betulinic acid derivatives in human Müller cells against oxidative injury

Müller cells maintain homeostatic functions in the retina. Their dysfunction leads to irreversible retinal diseases. Oxidative injury is a leading cause of retinal cytotoxicity. Our previous studies reported several betulinic acid (BA) derivatives can protect Müller cells from oxidative injury but achieving pharmacologically effective concentrations in the Müller cells could be a limitation. To optimise cellular delivery, we encapsulated the BA analogues H3, H5 and H7 into the clinically approved Compritol 888 and HD5 ATO solid lipid nanoparticles (SLNs) using the micro-emulsion method. The cytoprotective effects of these SLN-formulations were determined in human MIO-M1 cells. We found cytoprotection by H3 and H5 SLN-formulations was significantly enhanced, which was evident at concentrations much lower than those required with the free agents. Both SLN-formulations prolonged the duration of action of these agents. The most effective agent H5 delivered in 888 ATO SLNs attenuated glutamate-induced ROS formation and the associated necrosis in MIO-M1 cells. Overall, SLNs have emerged as promising delivery carriers for BA derivatives enhancing their protective effects against oxidative injury in human Müller cells. Our study is the first to show SLNs can be a viable route to delivery agents with improved efficacy and stability into human Müller cells favoring the treatment/prevention of retinal diseases.

Lipid Nanocarriers for Anti-HIV Therapeutics: A Focus on Physicochemical Properties and Biotechnological Advances

Since HIV was first identified, and in a relatively short period of time, AIDS has become one of the most devastating infectious diseases of the 21st century. Classical antiretroviral therapies were a major step forward in disease treatment options, significantly improving the survival rates of HIV-infected individuals. Even though these therapies have greatly improved HIV clinical outcomes, antiretrovirals (ARV) feature biopharmaceutic and pharmacokinetic problems such as poor aqueous solubility, short half-life, and poor penetration into HIV reservoir sites, which contribute to the suboptimal efficacy of these regimens. To overcome some of these issues, novel nanotechnology-based strategies for ARV delivery towards HIV viral reservoirs have been proposed. The current review is focused on the benefits of using lipid-based nanocarriers for tuning the physicochemical properties of ARV to overcome biological barriers upon administration. Furthermore, a correlation between these properties and the potential therapeutic outcomes has been established. Biotechnological advancements using lipid nanocarriers for RNA interference (RNAi) delivery for the treatment of HIV infections were also discussed.

Development and Evaluation of Cocoa Butter Taste Masked Ibuprofen Using Supercritical Carbon Dioxide

Masking the unpleasant taste of the pharmaceutically active ingredients plays a critical role in patient acceptance, particularly for children. This work's primary objective was the preparation of taste-masked ibuprofen microparticles using cocoa butter with the assistance of supercritical fluid technology. Microparticles were prepared by dissolving ibuprofen in melted cocoa butter at 40 °C. The solution was then introduced into a supercritical fluid unit and processed at 10 MPa CO₂ pressure for 30 min. The product was collected after depressurizing the system. The effect of the drug to cocoa butter ratio and the supercritical fluid units' configuration on product quality was evaluated and compared with the sample prepared by a conventional method. Physicochemical characterization of the prepared product, including particle size, crystallinity, entrapment efficiency, in vitro drug release, and product taste using a human volunteer panel was conducted. The produced microparticles were in the range of 1.42 to 15.28 μm. The entrapment efficiency of the formulated microparticles ranged from 66 to 81%. The drug:polymer ratio, the configuration of the supercritical fluid unit, and the method of preparation were found to have a critical role in the formulation of ibuprofen microparticles. Taste evaluation using human volunteers showed that microparticles containing 20% drug and processed with supercritical fluid technology were capable of masking the bitter taste of ibuprofen. In conclusion, the dispersion of ibuprofen in cocoa butter using supercritical fluid technology is a a promising innovative method to mask the bitter taste of ibuprofen.

Design of Chitosan Nanocapsules with Compritol 888 ATO® for Imiquimod Transdermal Administration. Evaluation of Their Skin Absorption by Raman Microscopy

PURPOSE

Design imiquimod-loaded chitosan nanocapsules for transdermal delivery and evaluate the depth of imiquimod transdermal absorption as well as the kinetics of this absorption using Raman Microscopy, an innovative strategy to evaluate transdermal absorption. This nanovehicle included Compritol 888ATO®, a novel excipient for formulating nanosystems whose administration through the skin has not been studied until now.

METHODS

Nanocapsules were made by solvent displacement method and their physicochemical properties was measured by DLS and laser-Doppler. For transdermal experiments, newborn pig skin was used. The Raman spectra were obtained using a laser excitation source at 532 nm and a 20/50X oil immersion objective.

RESULTS

The designed nanocapsules, presented nanometric size (180 nm), a polydispersity index <0.2 and a zeta potential +17. The controlled release effect of Compritol was observed, with the finding that half of the drug was released at 24 h in comparison with control (p < 0.05). It was verified through Raman microscopy that imiquimod transdermal penetration is dynamic, the nanocapsules take around 50 min to penetrate the stratum corneum and 24 h after transdermal administration, the drug was in the inner layers of the skin.

CONCLUSIONS

This study demonstrated the utility of Raman Microscopy to evaluate the drugs transdermal penetration of in the different layers of the skin. Graphical Abstract New imiquimod nanocapsules: evaluation of their skin absorption by Raman Microscopy and effect of the compritol 888ATO® in the imiquimod release profile.

Taste-masked nanoparticles containing Saquinavir for pediatric oral administration

This research has aimed to improve the stability and taste-masking properties by developing nanostructured dosage forms containing Saquinavir. Liquid formulations were developed using Eudragit RS100® and Pullulan as polymers. The physicochemical characteristics, stability, in vitro drug release, morphology, mucoadhesion and taste masking capacity were evaluated. The Saquinavir-nanoparticles had average diameters between 136 and 158 nm, with a Span below 1.4. These formulations presented a drug content above 80%, a high encapsulation efficiency (>97%), slightly acidic pH levels, low dynamic viscosity and controlled drug release. Electron microscopy revealed irregular spherical nanoparticles. The formulations prepared with higher amounts of Eudragit RS100® had greater mucoadhesion. Both polymers were able to improve drug stabilization, taste-masking properties and protection against drug cytotoxicity. The Saquinavir-nanoparticles exhibited stability and control releasing properties, thus making it a promising liquid dosage form with taste-masking properties intended for application in pediatric treatment.

Lyophilized SLN of Cinnacalcet HCl: BBD enabled optimization, characterization and pharmacokinetic study

Objective: The objective of the present research is to formulate solid lipid nanoparticles (SLN) of CH to improve its oral bioavailability.Methods: Cinnacalcet hydrochloride (CH) exhibits poor oral bioavailability of 20 to 25% because of low aqueous solubility and first pass metabolism. The SLN formulations were optimized using Box-Behnken Design. SLN formulation was prepared using hot homogenization technique followed by ultra-sonication and evaluated. The optimized SLN formulation was lyophilized to improve the stability of the formulation further.Results: Compritol 888 ATO (COM), Soya lecithin (SL) and poloxamer 188 (POL) were selected as lipid, surfactant and co-surfactant respectively. For optimistaion, the desirable goal was fixed for variour responses vis-a-vis entrapment efficiency (EE), particle size (PS) and (time taken for diffusion of 85% drug) T85%. The optimized single dose of SLN obtained using BBD consisting of 30 mg of CH, 100 mg of COM, 150 mg of SL and 0.1% w/v of POL. The pharmacokinetic study revealed that optimized SLN and lyophilized SLN were found to increase the oral bioavailability nearly two times compared to an aqueous suspension of pure drug.Conclusion: Thus lyophilized SLN formulation explicated the potential of lipid-based nanoparticles as a potential carrier in improving the oral delivery and stability of CH.

Plant-Derived Butters as Lipid Nanocarriers: A Systematic and Prospective Review

BACKGROUND

Pharmaceutical nanotechnology represents an efficient alternative for the delivery of pharmacologically active plant-derived compounds, considering their protective capacity, oral bioavailability and drug vectorization capacity. In this context, butters obtained from plant seeds have emerged as promising products for the development of pharmacologically active nanostructures. They possess a complex lipid composition, allowing the formation of different emulsion systems with solid cores, since this mixture of different triglycerides is solid at room temperature and body temperature. Therefore, the systematic mapping around the technological development of nanostructures produced from plant-derived butters is potentially valuable for researchers interested in novel alternative formulations for pharmacological therapy, with potential industrial, economic, health and societal impacts.

METHODS

Systematic review was carried out by the search of scientific papers and patents deposited in official databases concerning the development of nanostructured pharmaceutical products using plantderived butters as starting material. The publications obtained were subjected to sorting and analysis by applying the following inclusion/exclusion criteria.

RESULTS

The Solid Lipid Nanoparticle (SLN) was the type of nanostructure produced in all the analyzed scientific papers, due to the physicochemical characteristics of the lipid constituents of plantderived butters. In this sense, 54% of the articles have reported the use of Cocoa Butter for the production of nanostructures; 28% for Shea Butter; 6% for Cupuacu Butter, 6% for Murumuru Butter and 6% for Bacuri Butter.

DISCUSSION

In the technological prospection, only two patents exhibited SLN as an invention based on cocoa butter and on shea butter, respectively. The production methods employed have included: phase inversion temperature, microemulsion, hot high pressure homogenization, high shear homogenization and ultrasonication.

CONCLUSION

In light of this prospective review, the encouragement of novel studies in lipids-based nanotechnology is evident, considering the small number of findings so far, in order to stimulate new research involving plant-derived butters from easily cultivated fruits in tropical regions, then stimulating the pharmaceutical development of new therapeutic alternatives using biocompatible and sustainable raw materials.

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.

Encapsulation of ritonavir in solid lipid nanoparticles: in-vitro anti-HIV-1 activity using lentiviral particles

Objectives

In this study, ritonavir was entrapped into solid lipid nanoparticles (SLNs) employing two production methods. The prepared SLNs were characterized and antiretroviral activity was investigated for more efficient formulation.

Methods

Ritonavir-loaded SLNs were produced by solvent emulsification evaporation (SE) and double emulsion methods (DE), and the effects of Tween80 and poloxamer188 as external phase surfactant were compared. Prepared SLNs were characterized in terms of size, surface charge, entrapment efficiency (EE), release profile and thermal behaviour. Moreover, the activity of drug-loaded SLNs was investigated on the lentiviral-based pseudo-HIV-1 particles.

Key findings

The average size of negatively charged SLNs was 170–250 nm with polydispersity index (PDI) of 0.2. The most EE% was about 53.2% achieved by DE method in the presence of poloxamer188. It was found that addition of poloxamer188 in the process led to increased entrapment efficiency and particle size. The in-vitro antiviral experiment showed ritonavir SLNs can actively maintain inhibition of virus production as well as free drug.

Conclusions

In this study, we showed the SLNs not only can encapsulate ritonavir efficiently but also can maintain its antiviral activity and modulate drug release as promising nanocarrier.

Physicochemical characterization of chitosan-hyaluronan-coated solid lipid nanoparticles for the targeted delivery of paclitaxel: a proof-of-concept study in breast cancer cells

Aim: To investigate the potential of modified solid lipid nanoparticles (SLN) for the delivery of paclitaxel (PAX). Materials & methods: SLN loaded with PAX were prepared via modified high-pressure hot homogenization. Formulation parameters were optimized to obtain a high-quality delivery system. SLN cores were coated, layer-by-layer, with a chitosan and hyaluronan (HA) shell. Selectivity toward HA receptors was tested in a breast cancer cell line, MCF-7. Results: Stable and reproducible nano-sized and negatively charged nanoparticles resulted. Findings reveal that chitosan-HA-coated SLN facilitated the targeting, cellular uptake and the time-/dose-controlled delivery and release of PAX, enhancing intrinsic chemotherapeutic activities. Conclusion: SLN are suitable carrier candidates for nano-oncology given their localized, and potent cytotoxic potential overcoming multidrug-resistant cancer cells.

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.

Solid lipid nanoparticles for transdermal delivery of avanafil: optimization, formulation, in-vitro and ex-vivo studies

CONTEXT

Avanafil (AVA) is used in the treatment of erectile dysfunction, but is reported for its poor aqueous solubility. Solid lipid nanoparticles (SLNs) are lipid carriers that can greatly enhance drug solubility and bioavailability.

OBJECTIVE

This work was aimed to formulate and optimize AVA SLNs with subsequent loading into hydrogel films for AVA transdermal delivery.

MATERIALS AND METHODS

AVA SLNs were prepared utilizing homogenization followed by ultra-sonication technique. The prepared SLNs were characterized for particle size, charge, surface morphology and drug content. The optimized SLNs formulation was incorporated into transdermal films prepared using HPMC and chitosan. Hydrogel films were evaluated for ex-vivo rat skin permeation using automated Franz diffusion cells. The permeation parameters and the release mechanism were evaluated. The transdermal permeation of the prepared AVA SLNs through the skin layers was studied using confocal laser scanning microscope.

RESULTS

Lipid concentration and % of oil in lipid had a pronounced effect on particle size while, entrapment efficiency was significantly affected by lipid concentration and % of cholesterol. The optimized AVA SLNs showed particle size and entrapment efficiency of 86 nm and 85.01%, respectively. TEM images revealed spherecity of the particles. High permeation parameters were observed from HPMC films loaded with AVA SLNs. The release data were in favor of Higuchi diffusion model. The prepared AVA SLNs were able to penetrate deeper in skin layers.

CONCLUSION

HPMC transdermal film-loaded AVA SLNs is an effective and alternative to per-oral drug administration.

Improved intestinal lymphatic drug targeting via phospholipid complex-loaded nanolipospheres of rosuvastatin calcium

The present work describes the systematic development and characterization of nanolipospheres (NLPs) loaded with phospholipid complex of rosuvastatin for enhanced oral drug absorption trough lymphatic pathways.

Solid Lipid Nanoparticles as Efficient Drug and Gene Delivery Systems: Recent Breakthroughs

In recent years, nanomaterials have been widely applied as advanced drug and gene delivery nanosystems. Among them, solid lipid nanoparticles (SLNs) have attracted great attention as colloidal drug delivery systems for incorporating hydrophilic or lipophilic drugs and various macromolecules as well as proteins and nucleic acids. Therefore, SLNs offer great promise for controlled and site specific drug and gene delivery. This article includes general information about SLN structures and properties, production procedures, characterization. In addition, recent progress on development of drug and gene delivery systems using SLNs was reviewed.

Anti-HIV drug-combination nanoparticles enhance plasma drug exposure duration as well as triple-drug combination levels in cells within lymph nodes and blood in primates

HIV patients on combination oral drug therapy experience insufficient drug levels in lymph nodes, which is linked to viral persistence. Following success in enhancing lymph node drug levels and extending plasma residence time of indinavir formulated in lipid nanoparticles, we developed multidrug anti-HIV lipid nanoparticles (anti-HIV LNPs) containing lopinavir (LPV), ritonavir (RTV), and tenofovir (PMPA). These anti-HIV LNPs were prepared, characterized, scaled up, and evaluated in primates with a focus on plasma time course and intracellular drug exposure in blood and lymph nodes. Four macaques were subcutaneously administered anti-HIV LNPs and free drug suspension in a crossover study. The time course of the plasma drug concentration as well as intracellular drug concentrations in blood and inguinal lymph nodes were analyzed to compare the effects of LNP formulation. Anti-HIV LNPs incorporated LPV and RTV with high efficiency and entrapped a reproducible fraction of hydrophilic PMPA. In primates, anti-HIV LNPs produced over 50-fold higher intracellular concentrations of LPV and RTV in lymph nodes compared to free drug. Plasma and intracellular drug levels in blood were enhanced and sustained up to 7 days, beyond that achievable by their free drug counterpart. Thus, multiple antiretroviral agents can be simultaneously incorporated into anti-HIV lipid nanoparticles to enhance intracellular drug concentrations in blood and lymph nodes, where viral replication persists. As these anti-HIV lipid nanoparticles also prolonged plasma drug exposure, they hold promise as a long-acting dosage form for HIV patients in addressing residual virus in cells and tissue.

Potential of Nanomaterials as Movers and Packers for Drug Molecules

As the development of nanotechnology has extended to the world of biomolecules, a revolution has occurred in the design and assembly of nanomaterials for drug delivery with a significant potential to impact drug efficacy and patient outcomes. Currently a number of nanomaterials are under investigation for their suitability as sustained, controlled and targeted drug carriers. Leading edge of the rapidly developing nanosciences is the development and assessment of these nanomaterials, with specific physicochemical properties different from their larger/ bulk counterparts, as vehicles for transport of small and large drug molecules. The characteristics such as size, shape, chemical composition, surface structure and charge, aggregation and agglomeration, and solubility, can greatly influence interactions of these nanostructured systems or carriers with biomembranes and cells. The selectivity and reactivity achieved due to the very small size assigns these systems with a wide spectrum of applications. In this review, nanomaterials are considered in terms of the physical attributes or pharmaceutical effects allocated by them to the all-inclusive carrier or vehicle system (s). However we will limit our discussion to lipidic and polymeric nanomaterials, the two most commonly promoted, and safe nanosystems for delivery of both, the chemical or small molecular entities (SME) and the macromolecules including genes and siRNA.Contents of Paper

Compritol 888 ATO: a multifunctional lipid excipient in drug delivery systems and nanopharmaceuticals

INTRODUCTION

Compritol® 888 ATO is a lipid excipient that is generally used in cosmetic industry as a surfactant, emulsifying agent and viscosity-inducing agent in emulsions or creams. Based on its chemical composition, Compritol 888 ATO is a blend of different esters of behenic acid with glycerol.

AREAS COVERED

Recently, there has been great interest in the multiple roles that Compritol 888 ATO plays in various pharmaceutical delivery systems. Accordingly, this review aimed at summarizing the current and potential applications of Compritol 888 ATO in various drug delivery areas.

EXPERT OPINION

Different researches have highlighted the feasibility of using Compritol 888 ATO as a lubricant or coating agent for oral solid dosage formulations. It has also been explored as a matrix-forming agent for controlling drug release. At present, the most common pharmaceutical application of Compritol 888 ATO is in lipid-based colloidal drug delivery system such as solid lipid microparticles, solid lipid nanoparticles and nanostructured lipid carriers. Although, Compritol 888 ATO has acceptable regulatory and safety profiles and although the number of articles that emphasize on its applicability as an innovative excipient in pharmaceutical technology is continuously increasing, it is not widely used in the pharmaceutical market products and its use is limited to its sustain release ability in extended release tablets.

Effect of surface charge on the brain delivery of nanostructured lipid carriers in situ gels via the nasal route

The aim of this study was to investigate the influence of the nanocarrier surface charge on brain delivery of a model hydrophilic drug via the nasal route. Anionic and cationic nanostructured lipid carriers (NLCs) were prepared and optimized for their particle size and zeta potential. The optimum particles were incorporated in poloxamer in situ gels and their in vivo behavior was studied in the plasma and brain after administration to rats. Optimum anionic and cationic NLCs of size <200 nm and absolute zeta potential value of ≈ 34 mV were obtained. Toxicity study revealed mild to moderate reversible inflammation of the nasal epithelium in rats treated with the anionic NLCs (A7), and destruction of the lining mucosal nasal epithelium in rats treated with the cationic NLCs (C7L). The absolute bioavailability of both drug loaded anionic and cationic NLCs in situ gels was enhanced compared to that of the intranasal solution (IN) of the drug with values of 44% and 77.3%, respectively. Cationic NLCs in situ gel showed a non significant higher Cmax (maximum concentration) in the brain compared to the anionic NLCs in situ gel. Anionic NLCs in situ gel gave highest drug targeting efficiency in the brain (DTE%) with a value of 158.5 which is nearly 1.2 times that of the cationic NLCs in situ gel.

Evaluation of the cytotoxic effect of camptothecin solid lipid nanoparticles on MCF7 cells

Camptothecin (CPT) and its analogs exhibit remarkable anti-tumor activity, due to their ability to inhibit DNA topoisomerase I. However, its use is limited by the lack of solubility and stability of the active lactone form. An attractive alternative is the encapsulation of CPT within liposomes. In this study, CPT was incorporated into solid lipid nanoparticles (SLN) based on the triglyceride, Compritol 888 ATO, using supercritical fluid technology without requiring the use of harmful solvents. This drug delivery system was characterized and its cytotoxicity effect was evaluated by measuring MCF7 and MCF10A cell viability as a function of drug loading during a 48-h treatment. Results showed that after 10 h of treatment, MCF7 cells displayed an IC50 of 0.23±0.034 μM at a 1:5 (CPT:SLN) loading and 0.22±0.027 μM at a 1:10 loading, whereas MCF10A cells displayed an IC50 of 0.40±0.036 μM at 1:5 and 0.60±0.063 μM at 1:10. On the other hand, the IC50 of free CPT was 0.57±0.035 μM and 1.07±0.077 μM for MCF7 and MCF10A cells, respectively. Cellular uptake and retention measurements in both cells displayed a two-fold increase when using the SLN formulation. The results from this study showed that the cytotoxic effects of CPT in a SLN formulation improved when compared with those seen with free CPT. The results of this study showed that delivery of CPT as a SLN formulation could be a promising strategy for enhancing its chemotherapeutic effects.

Drug solubilisation in lipid nanoparticles containing high melting point triglycerides

The effect of lipid (either the triglyceride trilaurin or tripalmitin, melting points of 43 and 64 °C, respectively) on the properties of lipid nanoparticles (LN) stabilised by the surfactant, polyoxyethylene-10-oleyl ether (C18:1E10) at a temperature of 22 °C, has been determined. LN were prepared by heating lipid, surfactant and water to 70 °C and cooling to ambient temperature with constant stirring. While lipid type influenced LN formation in that trilaurin-containing LN formed over the greatest range of compositions, phase inversion studies suggested that both lipids formed a core within the LN while light scattering studies indicated that the size of both types of LN varied with lipid concentration: in an approximately linear fashion for clear or opalescent LN and exponentially for cloudy LN. Additionally, both types of preformed LN exhibited an increase in solubilisation capacity of the hydrophobic drug, testosterone propionate compared to C18:1E10 micelles, although the trilaurin-containing LN exhibited the greatest increase. Differential scanning calorimetry studies demonstrated that trilaurin formed a 'fluid-like' core and therefore liquefied-lipid nanoparticles, which allowed dissolution of testosterone propionate in the lipid core. In contrast, tripalmitin was present in a 'solid-like' state forming solid lipid nanoparticles which did not allow testosterone propionate dissolution in the core.

Anti-HIV-1 nanotherapeutics: promises and challenges for the future

The advent of highly active antiretroviral therapy (HAART) has significantly improved the prognosis for human immunodeficiency virus (HIV)-infected patients, however the adverse side effects associated with prolonged HAART therapy use continue. Although systemic viral load can be undetectable, the virus remains sequestered in anatomically privileged sites within the body. Nanotechnology-based delivery systems are being developed to target the virus within different tissue compartments and are being evaluated for their safety and efficacy. The current review outlines the various nanomaterials that are becoming increasingly used in biomedical applications by virtue of their robustness, safety, multimodality, and multifunctionality. Nanotechnology can revolutionize the field of HIV medicine by not only improving diagnosis, but also by improving delivery of antiretrovirals to targeted regions in the body and by significantly enhancing the efficacy of the currently available antiretroviral medications.

Methylmethacrylate-sulfopropylmethacrylate nanoparticles with surface RMP-7 for targeting delivery of antiretroviral drugs across the blood-brain barrier

This study investigates the capability of methylmethacrylate-sulfopropylmethacrylate (MMA-SPM) nanoparticles (NPs) with grafted RMP-7 (RMP-7/MMA-SPM NPs) to deliver stavudine (D4T), delavirdine (DLV), and saquinavir (SQV) across the blood-brain barrier (BBB). The permeability coefficients of the three drugs across the BBB were evaluated by a co-culture model containing human brain-microvascular endothelial cells and human astrocytes. An increase in the concentration of ammonium persulfate (APS), the polymerization initiator, enhanced the particle size of drug-loaded RMP-7/MMA-SPM NPs. When the concentration of APS was 0.6%, the average particle diameter was smaller than 50 nm. These spherical drug carriers were uniform in size and displayed a dominant topography of discrete hillocks and deep pits in deposited film. Smaller RMP-7/MMA-SPM NPs yielded a larger drug loading efficiency. The order of drug in the loading efficiency and in the particle uptake was, respectively, D4T>DLV>SQV and D4T>SQV>DLV. Endocytosis of RMP-7/MMA-SPM NPs and tight junction mediation can improve the permeability of D4T, DLV, and SQV across the BBB.