Design, characterization and in vivo evaluation of nanostructured lipid carriers (NLC) as a new drug delivery system for hydrochlorothiazide oral administration in pediatric therapy

Systematic Characterization of Nanostructured Lipid Carriers from Cetyl Palmitate/Caprylic Triglyceride/Tween 80 Mixtures in an Aqueous Environment

Nanostructured lipid carriers (NLCs) are gaining attention as the new generation of lipid vehicles. These carriers consist of saturated lipids with small drops of liquid oil dispersed into the inner lipid matrix and are stabilized by a surfactant. Conventionally, NLC-based drug delivery systems have been widely studied, and many researchers are looking into the composition of NLC properties to improve the performance of NLCs. The membrane fluidity and polarity of self-assembling lipids are also essential properties that must be affected by membrane compositions; however, such fundamental characteristics have not been studied yet. In this study, NLCs were prepared from cetyl palmitate (CP), caprylic triglyceride (CaTG), and Tween 80 (T80). Structural properties, such as particle size and ζ-potential of the CP/CaTG/T80 ternary mixtures, were investigated. Then, the systematic characterization of self-assembly properties using fluorescence-based analysis was applied for the first time to the NLC system. As a final step, the ternary diagram was developed based on the self-assembly properties to summarize the possible structures formed at different compositions. The results showed four states: micelle-like, oil-in-water (O/W) emulsion-like, solid lipid nanoparticle-like, and intermediate (solid-liquid coexistence). For the purpose of making the lipid matrix more liquified, the heterogeneous state and the disordered state of the O/W emulsion-like structure might fulfill the criteria of NLCs. Finally, the ternary diagram provides new information about the assembly state of NLC constituents that could become an important reference for developing high-performance NLCs.

Fabrication of Mupirocin-Loaded Nanostructured Lipid Carrier and Its In Vitro Characterization

In the present study, mupirocin (MP), an antimicrobial agent, was formulated as a nanostructured lipid carrier (NLC) by using a novel method named as melt emulsion ultrafiltration method. For the formulation of NLC, glyceryl monostearate and watermelon seed oil were used as solid and liquid lipids, respectively. The method was optimized for various parameters by Taguchi design of experiment and prepared NLCs were characterized for particle size, polydispersity index (PDI), shape, zeta potential, % drug loading, and in vitro release profile. The optimized NLCs were found to be smooth, monodisperse with PDI 0.229 ± 0.093. NLCs were found to have an average particle size of 139 ± 0.75 nm and +21.9 ± 0.98 mV as zeta potential. The % drug loading of optimized NLCs was found to be 59% ± 0.13%. The optimized NLCs were able to release the drug up to 24 h. The release kinetic study revealed mixed-order kinetics. Hence, it was concluded that the novel method is simple and able to fabricate MP-loaded NLCs with sustained release property and being stable in terms of particle size, PDI, and % drug loading.

Current strategies for oral delivery of BCS IV drug nanocrystals: challenges, solutions and future trends

INTRODUCTION

Oral absorption of BCS IV drug benefits little from improved dissolution. Therefore, the absorption of BCS IV drug nanocrystals 'as a whole' strategy is preferred, and structural modification of nanocrystals is required. Surface modification helps the nanocrystals maintain particle structure before drug dissolution is needed, thus enhancing the oral absorption of BCS IV drugs and promoting therapeutic effect. Here, the main challenges and solutions of oral BCS IV drug nanocrystals delivery are discussed. Moreover, strategies for nanocrystal surface modification that facilitates oral bioavailability of BCS IV drugs are highlighted, and provide insights for the innovation in oral drug delivery.

AREAS COVERED

Promising size, shape, and surface modification of nanocrystals have gained interests for application in oral BCS IV drugs.

EXPERT OPINION

Nanocrystal surface modification is a feasible method to maintain the structural integrity of nanocrystals, and the introduced materials can also be modified to integrate additional functions to further facilitate the absorption of nanocrystals. It is expected that the absorption 'as a whole' strategy of nanocrystals will provide different choices for the oral BCS IV drugs.

Evaluation and Comparison of Solid Lipid Nanoparticles (SLNs) and Nanostructured Lipid Carriers (NLCs) as Vectors to Develop Hydrochlorothiazide Effective and Safe Pediatric Oral Liquid Formulations

The aim of this study was the optimization of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) in terms of physicochemical and biopharmaceutical properties, to develop effective and stable aqueous liquid formulations of hydrochlorothiazide, suitable for paediatric therapy, overcoming its low-solubility and poor-stability problems. Based on solubility studies, Precirol® ATO5 and Transcutol® HP were used as solid and liquid lipids, respectively. The effect of different surfactants, also in different combinations and at different amounts, on particle size, homogeneity and surface-charge of nanoparticles was carefully investigated. The best formulations were selected for drug loading, and evaluated also for entrapment efficiency and release behaviour. For both SLN and NLC series, the use of Gelucire® 44/14 as surfactant rather than PluronicF68 or Tween® 80 yielded a marked particle size reduction (95-75 nm compared to around 600-400 nm), and an improvement in entrapment efficiency and drug release rate. NLC showed a better performance than SLN, reaching about 90% entrapped drug (vs. 80%) and more than 90% drug released after 300 min (vs. about 65%). All selected formulations showed good physical stability during 6-month storage at 4 °C, but a higher loss of encapsulated drug was found for SLNs (15%) than for NLCs (<5%). Moreover, all selected formulations revealed the absence of any cytotoxic effect, as assessed by a cell-viability test on Caco-2 cells and are able to pass the intestinal epithelium as suggested by Caco-2 uptake experiments.

Effect of the Surfactant and Liquid Lipid Type in the Physico-chemical Characteristics of Beeswax-based Nanostructured Lipid Carrier (NLC) of Metformin

BACKGROUND

Metformin (MF) is an antidiabetic drug that belongs to class III of the biopharmaceutical classification system (BCS) characterized by high solubility and low permeability.

OBJECTIVE

The study aimed to prepare metformin as nanostructured lipid carriers (MF-NLCs) to control the drug release and enhance its permeability through the biological membrane.

METHODS

2² full factorial design was used to make the design of MF-NLCs formulations. MFNLCs were prepared by hot-melt homogenization-ultra sonication technique using beeswax as solid lipid in the presence of liquid lipid (either capryol 90 or oleic acid) and surfactant (either poloxamer 188 or tween 80).

RESULTS

The entrapment efficiency (EE%) of MF-NLCs was ranged from 85.2±2.5 to 96.5±1.8%. The particle size was in the nanoscale (134.6±4.1 to 264.1±4.6 nm). The value of zeta potential has a negative value ranged from -25.6±1.1 to -39.4±0.9 mV. The PDI value was in the range of 0.253±0.01 to 0.496±0.02. The cumulative drug release was calculated for MF-NLCs and it was found that Q_12h ranged from 90.5±1.7% for MF-NLC1 to 99.3±2.8 for MF-NLC4. Infra-red (IR) spectroscopy and differential scanning calorimetry (DSC) studies revealed the compatibility of the drug with other ingredients. MF-NLC4 was found to be the optimized formulation with the best responses.

CONCLUSION

2² full factorial design succeed to obtain an optimized formulation which controls the drug release and increases the drug penetration.

Physicochemical characteristics and in vitro permeation of loratadine solid lipid nanoparticles for transdermal delivery

Aim: To prepare loratadine-loaded solid lipid nanoparticles (SLNs) using a modified two-step ultrasound-assisted phase inversion temperature (PIT) process. Results/methodology: Loratadine was dissolved in beeswax and Tween 80 was dissolved in water. The two phases were mixed together to prepare a water-in-oil emulsion preconcentrate (w/o) at a PIT of 85°C, followed by gradual water addition at 25°C to trigger nanoparticles formation (o/w). Kinetic stability was investigated. No change in the size was observed within 6 months. Fourier-transform infrared spectroscopy demonstrated stability of the emulsions via molecular structure of water at the interface of the o/w nanoemulsions. SLNs enhanced the in vitro skin permeation of loratadine. Conclusion: Stable SLNs were successfully prepared by ultrasound-assisted PIT.

Nano Carrier Drug Delivery Systems for the Treatment of Neuropsychiatric Disorders: Advantages and Limitations

Neuropsychiatric diseases are one of the main causes of disability, affecting millions of people. Various drugs are used for its treatment, although no effective therapy has been found yet. The blood brain barrier (BBB) significantly complicates drugs delivery to the target cells in the brain tissues. One of the problem-solving methods is the usage of nanocontainer systems. In this review we summarized the data about nanoparticles drug delivery systems and their application for the treatment of neuropsychiatric disorders. Firstly, we described and characterized types of nanocarriers: inorganic nanoparticles, polymeric and lipid nanocarriers, their advantages and disadvantages. We discussed ways to interact with nerve tissue and methods of BBB penetration. We provided a summary of nanotechnology-based pharmacotherapy of schizophrenia, bipolar disorder, depression, anxiety disorder and Alzheimer's disease, where development of nanocontainer drugs derives the most active. We described various experimental drugs for the treatment of Alzheimer's disease that include vector nanocontainers targeted on β-amyloid or tau-protein. Integrally, nanoparticles can substantially improve the drug delivery as its implication can increase BBB permeability, the pharmacodynamics and bioavailability of applied drugs. Thus, nanotechnology is anticipated to overcome the limitations of existing pharmacotherapy of psychiatric disorders and to effectively combine various treatment modalities in that direction.

Tailoring lipid nanoconstructs for the oral delivery of paliperidone: Formulation, optimization and in vitro evaluation

PURPOSE

The present research work involves Quality by Design (QbD)-based fabrication of lipid nanoconstructs (LNC) of paliperidone (PPD) bearing superior biopharmaceutical attributes.

METHODS

LNC of paliperidone was prepared by melt emulsification-probe sonication and high-pressure homogenization method followed by optimization using QbD approach. Preparing LNC by both these methods will give the benefit of identifying the best optimized formulation which will be further evaluated for in vitro studies.

RESULTS

The best optimized formulation was obtained using melt emulsification-probe sonication technique with small particle size (86.35 nm), high entrapment efficiency (90.07 %), and high loading capacity (8.49 %). The drug release from LNC was found to be 5, 8, and 9-folds greater than drug suspension in pH 1.2, 6.8, and 7.4 respectively (p < 0.001). Stability studies of LNC in simulated gastric fluid pH 1.2 and fasted state simulated intestinal fluid depicted no alteration in particle size and polydispersity index of LNC but were found to increase in fed state simulated intestinal fluid. The drug permeability through rat intestine for LNC was found to be approximately 6-folds (p < 0.05) greater as compared to the drug suspension which was further confirmed by confocal microscopy. The in vitro lipolysis study presented significantly highest solubilization (p < 0.001) in the aqueous phase thereby anticipating higher in vivo absorption.

CONCLUSION

Thus, it was concluded that LNC bears the knack of improving the solubilization and permeation potential of an otherwise hydrophobic drug, paliperidone."

Enhancing the Oral Bioavailability of Candesartan Cilexetil Loaded Nanostructured Lipid Carriers: In Vitro Characterization and Absorption in Rats after Oral Administration

Candesartan Cilexetil (CC) is a prodrug widely used in the treatment of hypertension and heart failure, but it has some limitations, such as very poor aqueous solubility, high affinity to P-glycoprotein efflux mechanism, and hepatic first-pass metabolism. Therefore, it has very low oral bioavailability. In this study, glyceryl monostearate (GMS) and Capryol™ 90 were selected as solid and liquid lipids, respectively, to develop CC-NLC (nanostructured lipid carrier). CC was successfully encapsulated into NLP (CC-NLC) to enhance its oral bioavailability. CC-NLC was formulated using a hot homogenization-ultrasonication technique, and the physicochemical properties were characterized. The developed CC-NLC formulation was showed in nanometric size (121.6 ± 6.2 nm) with high encapsulation efficiency (96.23 ± 3.14%). Furthermore, it appeared almost spherical in morphology under a transmission electron microscope. The surgical experiment of the designed CC-NLC for absorption from the gastrointestinal tract revealed that CC-NLC absorption in the stomach was only 15.26% of that in the intestine. Otherwise, cellular uptake study exhibit that CC-NLCs should be internalized through the enterocytes after that transported through the systemic circulation. The pharmacokinetic results indicated that the oral bioavailability of CC was remarkably improved above 2-fold after encapsulation into nanostructured lipid carriers. These results ensured that nanostructured lipid carriers have a highly beneficial effect on improving the oral bioavailability of poorly water-soluble drugs, such as CC.

Nanostructured Lipid Carriers Delivering Sorafenib to Enhance Immunotherapy Induced by Doxorubicin for Effective Esophagus Cancer Therapy

The tumor microenvironment (TME) plays a significant role in weakening the effect of cancer immunotherapy, which calls for the remodeling of TME. Herein, we fabricated a nanostructured lipid carrier (NLC) to codeliver doxorubicin (Dox) and sorafenib (Sfn) as a drug delivery system (NLC/D-S). The Sfn was expected to regulate the TME of esophagus cancer. As a result, the immune response induced by Dox-related immunogenicity cell death could be fully realized. Our results demonstrated that Sfn was able to remodel the TME through downregulation of regulatory T cells (Treg), activation of effector T cells, and relieving of PD-1 expression, which achieved synergistic effect on the inhibition of primary tumor but also subsequent strong immune response on the regeneration of distant tumor.

Systematic development and characterization of curcumin-loaded nanogel for topical application

Curcumin (CUR) conventional formulation has poor oral bioavailability due to low solubility and low stability. Also, it extensively undergoes first-pass-metabolism showing low biological activity. The present work focuses on the systematic development and characterization of CUR-loaded Nanostructured Lipid Carrier (CUR-NLCs) having promising topical applications for skin diseases such as psoriasis. CUR-NLCs were prepared by using high-speed homogenization method. Quality by design approach was exploited to select out Critical Process Parameters i.e. homogenization speed (X1), homogenization time (X2), amount of lipid (X3), solid lipids (SL): liquid lipids (LL) (X4), and surfactant conc. (X5) using Plackett-Burman design and for obtaining critical quality attributes i.e. particle size (Y1) and entrapment efficiency (Y2) using Box-Behnken design. The developed NLCs were found to be nano-metric in size (189.4 ± 2.6 nm) with a low polydispersity index (0.262 ± 0.24), zeta potential (-21.45 ± 1.3 mV), and showed good encapsulation efficiency (86.72 ± 09%). Surface morphology determined by SEM and AFM revealed the spherical shape of the NLCs with a smooth surface. XRD studies showed NLCs in the amorphous state. After incorporation of NLCs into a nanogel, it was characterized for pH, rheological behavior, spreadability, in vitro occlusion, and in vitro release kinetics. The drug release from NLC in 24 h was found to be 60.2 ± 0.45% indicating a sustained release pattern. Ex vivo permeation studies revealed a good permeation flux (0.453 ± 0.76 µg/cm2.h) and retention (60.2 ± 0.45%) of CUR in the skin epidermis. Thus, developed CUR-NLCs can be a potential delivery system and a promising therapeutic approach for the effective treatment of psoriasis.

Development of a stable oral pediatric solution of hydrochlorothiazide by the combined use of cyclodextrins and hydrophilic polymers

Hydrochlorothiazide (HCT) is widely used in pediatrics for hypertension management. Due to the lack of pediatric commercial forms, community or hospital pharmacies generally prepare HCT extemporaneous pediatric suspensions by dispersing in water a portion of a crushed tablet or the drug powder; however, any dose or stability control is usually done on these preparations. Obtaining stable HCT solutions is very challenging, due to its low water-solubility and pH-dependent degradation. The aim of this work was to develop a stable 2 mg/mL-HCT oral pediatric solution without using co-solvents. Combined use of cyclodextrins (CD) and hydrophilic polymers was exploited to improve poor HCT solubility and stability. HPβCD and SBEβCD were selected, considering their safe toxicological profiles, while PVP resulted the best among the tested polymers. Low PVP concentrations (0.2-1.0%) improved the solubilizing efficiency of both CDs, allowing to reach the prefixed HCT concentration. Different CD-PVP concentrations were used to prepare several 2 mg/mL-HCT solutions in pH 5.5 buffer. The best stability was shown by solutions containing the highest SBEβCD concentration (25 mM), which allowed a 3-months stability at 4 °C. In vivo studies on rats showed that such formulation allowed a more pronounced and more reproducible diuretic effect than the corresponding HCT suspension.

Advances in drug delivery systems: Work in progress still needed?

A new era of science and technology has emerged in pharmaceutical research with focus on developing novel drug delivery systems for oral administration. Conventional dosage forms like tablets and capsules are associated with a low bioavailability, frequent application, side effects and hence patient noncompliance. By developing novel strategies for drug delivery, researchers embraced an alternative to traditional drug delivery systems. Out of those, fast dissolving drug delivery systems are very eminent among pediatrics and geriatrics. Orally disintegrating films are superior over fast dissolving tablets as the latter are assigned with the risk of suffocation. Due to their ability of bypassing the dissolution and the first pass effect after oral administration, self-emulsifying formulations have also become increasingly popular in improving oral bioavailability of hydrophobic drugs. Osmotic devices enable a controlled drug delivery independent upon gastrointestinal conditions using osmosis as driving force. The advances in nanotechnology and the variety of possible materials and formulation factors enable a targeted delivery and triggered release. Vesicular systems can be easily modified as required and provide a controlled and sustained drug delivery to a specific site.

This work provides an insight of the novel approaches in drug delivery covering the critical comparison between traditional and novel “advanced-designed” systems.

Development of tamoxifen-loaded surface-modified nanostructured lipid carrier using experimental design: in vitro and ex vivo characterisation

The present study aimed to develop a surface-modified biocompatible nanostructured lipid carrier (NLCs) system using polyoxyethylene (40) stearate (POE-40-S) to improve the oral bioavailability of poorly water-soluble Biopharmaceutics Classification System class-II drug like tamoxifen (TMX). Also aimed to screen the most influential factors affecting the particle size (PS) using Taguchi (L₁₂ (2¹¹)) orthogonal array design (TgL₁₂OA). Then, to optimize the TMX loaded POE-40-S (P) surface-modified NLCs (TMX-loaded-PEG-40-S coated NLC (PNLCs) or PNLCs) by central composite design (CCD) using a four-factor, five-level model. The most influential factors affecting the PS was screened and optimized. The in-vitro study showed that increased drug-loading (DL) and encapsulation efficiency (EE), decreased PS and charge, sustained drug release for the prolonged period of the time with good stability and suppressed protein adsorption. The Ex-vivo study showed that decreased mucous binding with five-fold enhanced permeability of PNLC formulation after surface modification with POE-40-S. The in-vitro cytotoxicity study showed that the blank carrier is biocompatible and cytotoxicity of the formulation was dependent on the concentration of the drug. Finally, it can be concluded that the surface-modified PNLCs formulation was an effective, biocompatible, stable formulation in the enhancement of dissolution rate, solubility, stability with reduced mucus adhesion and increased permeability thereby which indicates its enhanced oral bioavailability.

Omar M, A. Mahmoud H, A. Abou-Taleb H. Nanostructured Lipid Carriers to Mediate Brain Delivery of Temazepam: Design and In Vivo Study

The opposing effect of the blood–brain barrier against the delivery of most drugs warrants the need for an efficient brain targeted drug delivery system for the successful management of neurological disorders. Temazepam-loaded nanostructured lipid carriers (NLCs) have shown possibilities for enhancing bioavailability and brain targeting affinity after oral administration. This study aimed to investigate these properties for insomnia treatment. Temazepam-NLCs were prepared by the solvent injection method and optimized using a 4² full factorial design. The optimum formulation (NLC-1) consisted of; Compritol^® 888 ATO (75 mg), oleic acid (25 mg), and Poloxamer^® 407 (0.3 g), with an entrapment efficiency of 75.2 ± 0.1%. The average size, zeta potential, and polydispersity index were determined to be 306.6 ± 49.6 nm, −10.2 ± 0.3 mV, and 0.09 ± 0.10, respectively. Moreover, an in vitro release study showed that the optimized temazepam NLC-1 formulation had a sustained release profile. Scintigraphy images showed evident improvement in brain uptake for the oral ^99mTc-temazepam NLC-1 formulation versus the ^99mTc-temazepam suspension. Pharmacokinetic data revealed a significant increase in the relative bioavailability of ^99mTc-temazepam NLC-1 formulation (292.7%), compared to that of oral ^99mTc-temazepam suspension. Besides, the NLC formulation exhibited a distinct targeting affinity to rat brain. In conclusion, our results indicate that the developed temazepam NLC formulation can be considered as a potential nanocarrier for brain-mediated drug delivery in the out-patient management of insomnia.

Nanostructured Lipid Carriers for Delivery of Chemotherapeutics: A Review

The efficacy of current standard chemotherapy is suboptimal due to the poor solubility and short half-lives of chemotherapeutic agents, as well as their high toxicity and lack of specificity which may result in severe side effects, noncompliance and patient inconvenience. The application of nanotechnology has revolutionized the pharmaceutical industry and attracted increasing attention as a significant means for optimizing the delivery of chemotherapeutic agents and enhancing their efficiency and safety profiles. Nanostructured lipid carriers (NLCs) are lipid-based formulations that have been broadly studied as drug delivery systems. They have a solid matrix at room temperature and are considered superior to many other traditional lipid-based nanocarriers such as nanoemulsions, liposomes and solid lipid nanoparticles (SLNs) due to their enhanced physical stability, improved drug loading capacity, and biocompatibility. This review focuses on the latest advances in the use of NLCs as drug delivery systems and their preparation and characterization techniques with special emphasis on their applications as delivery systems for chemotherapeutic agents and different strategies for their use in tumor targeting.

Development, skin targeting and antifungal efficacy of topical lipid nanoparticles containing itraconazole

Considering the increased incidence of sporotrichosis and other fungal infections in rural and urban areas, and the limitations and adverse effects of oral itraconazole therapy, we studied nanostructured lipid carriers (NLC) as topical delivery systems to increase itraconazole localization in skin lesions and associate efficacy with reduced systemic exposure. Unloaded and itraconazole-loaded NLC showed nanometric size (~216-340 nm), negative zeta potential (~ -17 mV), and high entrapment efficiency (~97%). NLC treatment decreased transepidermal water loss, an index of cutaneous barrier function, in intact skin and in tissues damaged with a linear incision (to mimic lesions) by 23-36%, and reduced drug transdermal delivery by ~2-fold, demonstrating its ability to localize itraconazole within the skin. The unloaded and itraconazole-loaded NLC were considered safe, as indicated by scores of 0.5 and 0.6 in HET-CAM models, respectively, and lack of toxicity (measured by survival and health index) on the Galleria mellonella larvae. The values obtained for minimum inhibitory concentration and minimum fungicidal concentration on Sporothrix brasiliensis yeasts were 0.25 and 32 μg/mL, respectively. The drug in solution displayed similar values, indicating that encapsulation does not hinder itraconazole antifungal effect. NLC treatment improved the survival rate and health index of G. mellonella larvae infected with S. brasiliensis yeasts and C. albicans, demonstrating antifungal efficacy. Taken together, itraconazole encapsulation in NLC represents a viable strategy to optimize cutaneous localization without compromising its efficacy against fungal infections.

Advantages of the combined use of cyclodextrins and nanocarriers in drug delivery: A review

Complexation with cyclodextrins (CDs) has been widely and successfully used in pharmaceutical field, mainly for enhancing solubility, stability and bioavailability of a variety of drugs. However, some important drawbacks, including rapid removal from the bloodstream after in vivo administration, or possible replacement, in biological media, of the entrapped drug moieties by other molecules with higher affinity for the CD cavity, can limit the CDs effectiveness as drug carriers. This review is focused on combined strategies simultaneously exploiting CD complexation, and loading of the complexed drug into various colloidal carriers (liposomes, niosomes, polymeric nanoparticles, lipid nanoparticles, nanoemulsions, micelles) which have been investigated as a possible means for circumventing the problems associated with both such carriers, when used separately, and join their relative benefits in a unique delivery system. Several examples of applications have been reported, to illustrate the possible advantages achievable by such a dual strategy, depending on the CD-nanocarrier combination, and mainly resulting in enhanced performance of the delivery system and improved biopharmaceutical properties and therapeutic efficacy of drugs. The major problems and/or drawbacks found in the development of such systems, as well as the (rare) case of failures in achieving the expected improvements have also been highlighted.

The use of quantitative analysis and Hansen solubility parameter predictions for the selection of excipients for lipid nanocarriers to be loaded with water soluble and insoluble compounds

The aim of these studies was to determine the miscibility of different API with lipid excipients to predict drug loading and encapsulation properties for the production of solid lipid nanoparticles and nanostructured lipid carriers. Five API exhibiting different physicochemical characteristics, viz., clarithromycin, efavirenz, minocycline hydrochloride, mometasone furoate, and didanosine were used and six solid lipids in addition to four liquid lipids were investigated. Determination of solid and liquid lipids with the best solubilization potential for each API were performed using a traditional shake-flask method and/or a modification thereof. Hansen solubility parameters of the API and different solid and liquid lipids were estimated from their chemical structure using Hiroshi Yamamoto’s molecular breaking method of Hansen Solubility Parameters in Practice software. Experimental results were in close agreement with solubility parameter predictions for systems with ΔδT < 4.0 MPa^1/2. A combination of Hansen solubility parameters with experimental drug-lipid miscibility tests can be successfully applied to predict lipids with the best solubilizing potential for different API prior to manufacture of solid lipid nanoparticles and nanostructured lipid carriers.

Synthesis of Tilmicosin Nanostructured Lipid Carriers for Improved Oral Delivery in Broilers: Physiochemical Characterization and Cellular Permeation

This study aimed to develop nanostructured lipid carriers (NLCs) for improved oral absorption of tilmicosin (TMS) in broilers. Thus, palmitic acid, lauric acid, and stearic acid were selected as solid lipids to formulate TMS-pNLCs, TMS-lNLCs, and TMS-sNLCs, respectively. They showed similar physicochemical properties and meanwhile possessed excellent storage and gastrointestinal stability. The TMS interacted with the lipid matrix and was encapsulated efficiently in NLCs in an amorphous structure. NLCs could enhance oral absorption of TMS compared to 10% tilmicosin phosphate solution in broilers, among which the TMS-sNLCs were the most efficient drug delivery carriers, with a relative oral bioavailability of 203.55%. NLCs could inhibit the efflux of P-glycoprotein (P-pg) toward TMS, which may be involved with improved oral absorption. Taken together, these types of solid lipids influenced the enhanced level of NLCs toward oral bioavailability of TMS, and the sNLCs proved to be the most promising oral delivery carriers of TMS.

Lipid Nanocarriers for Enhanced Delivery of Temozolomide to the Brain

Brain disorders, a diverse range of conditions comprising of neurological and psychiatric conditions, are the leading cause of disability, severely affect the quality of life, and in many cases lead to mortality. The prime challenge in treatment of brain disorders is to deliver therapeutics by overcoming the blood-brain barrier (BBB), a unique anatomical and physiological barrier which restricts the passage of a number of molecules, proteins, and cells from the bloodstream. Lipid nanoparticles have emerged as promising drug delivery systems primarily because of biodegradability, low toxicity potential, and the ability to cross physiological barriers especially the BBB even without surface modifications.In this chapter we discuss the preparation and characterization of nanostructured lipid carriers of temozolomide, a chemotherapeutic drug. Evaluation of pharmacokinetics and biodistribution of the nanocarrier system in rats revealed improved delivery of the chemotherapeutic agent to the brain with the potential of lesser side effects.

Formation of stable nanoemulsions by ultrasound-assisted two-step emulsification process for topical drug delivery: Effect of oil phase composition and surfactant concentration and loratadine as ripening inhibitor

Nanoemulsions are very interesting systems as they offer capacity to encapsulate both hydrophilic and lipophilic molecules in a single particle, as well as the controlled release of chemical moieties initially entrapped in the internal droplets. In this study, we propose a new two-step modified ultrasound-assisted phase inversion approaches-phase inversion temperature (PIT) and self-emulsification, to prepare stable o/w nanoemulsions from a fully water-dilutable microemulsion template for the transdermal delivery of loratadine (a hydrophobe and as Ostwald ripening inhibitor). Firstly, the primary water-in-oil microemulsion concentrate (w/o) was formed using loratadine in the oil phase (oleic acid or coconut oil) and Tween 80 in the aqueous phase and by adjusting the PIT around 85 °C followed by stepwise dilution with water at 25 °C to initiate the formation the nanoemulsions (o/w). To assure the long-term stability, a brief application of low frequency ultrasound was employed. Combining the two low energy methods resulted in nanoemulsions prepared by mixing constant surfactant/oil ratios above the PIT with varying water volume fraction (self-emulsification) during the PIT by stepwise dilution. The kinetic stability was evaluated by measuring the droplet size with time by dynamic light scattering (DLS). The droplet size ranged 15-43 nm and did not exceed 100 nm over the period of 6 months indicating the system had high kinetic stability. Cryo-TEM showed that the nanoemulsions droplets were monodispersed and approaching micellar structure and scale. All nanoemulsions had loratadine crystals formed within 20 days after preparation, which tended to sediment during storage. Nanoemulsions improved the in vitro permeation of loratadine through porcine skin up to 20 times compared to the saturated solution.

A novel self-nanoemulsifying drug delivery system for curcumin used in the treatment of wound healing and inflammation

The main objective of this study was to develop and evaluate self-nanoemulsifying drug delivery system (SNEDDS) of curcumin (Cur) to enhance their solubility as well as improve skin permeation; and evaluate wound healing potential of Cur via SNEDDS in comparison with standards pure eucalyptus oil-SNEDDS (Euc-SNEDDS), pure curcumin suspension (Cur-S), and standard fusidic acid followed by their anti-inflammatory action. Curcumin-loaded different SNEDDS formulations were formulated through aqueous phase titration method and the zones of SNEDDS were recognized by the construction of phase diagrams. Eucalyptus oil, Tween 80 (surfactant), and Transcutol HP (co-surfactant) were selected on the basis of their solubility and highest nanoemulsion region. Characterization of thermodynamic stability for Cur-loaded SNEDDS was evaluated by its globule size, zeta potential, polydispersity index, viscosity, % transmittance, refractive index, and surface morphology. Cur-SNEDDS (Cur-SN4) was optimized and selected on the basis of their excellent physicochemical parameters for in vivo activity. The particle size (59.56 ± 0.94 nm), % transmittance (99.08 ± 0.07%), and PDI (0.207 ± 0.011 were observed for optimized Cur-SNEDDS. TEM and SEM showed their smooth and spherical shape of the morphological characterization with zeta potential (- 21.41 ± 0.89), refractive index (1.341 ± 0.06), and viscosity (11.64 ± 1.26 cp) for optimized Cur-SNEDDS. Finally, optimized Cur-SNEDDS was used to enhance skin permeation with improvement in the solubility of Cur. However, optimized Cur-SNEDDS showed significant wound healing activity as compared with pure eucalyptus oil and Cur-S on topical application. Optimized Cur-SNEDDS showed healing of wound as compared to standard fusidic acid. Optimized Cur-SNEDDS exhibited no signs of inflammatory cells on the histopathological studies of treated rats which were recommended the safety and non-toxicity of Cur-SNEDDS. Newly developed Cur-SNEDDS could be successfully used to enhance Cur-solubility and skin permeation, as well as suggested a potential role of Cur-SNEDDS for better improvement of wound healing activity followed by anti-inflammatory action of Cur via topical application.

Combined Approach of Cyclodextrin Complexationand Nanostructured Lipid Carriers for the Development of a Pediatric Liquid Oral Dosage Form of Hydrochlorothiazide

The development of specific and age-appropriate pediatric formulations is essential to assure that all children and their care-givers can easily access to safe and effective dosage forms. The need for developing specific pediatric medicinal products has been highlighted by the European Medicines Agency. The aim of this study was to investigate the effectiveness of combining the advantages of both cyclodextrin (CD) complexation and loading into nanostructured lipid carriers (NLC), to obtain a liquid oral pediatric formulation of hydrochlorothiazide (HCT), endowed with safety, dosage accuracy, good stability and therapeutic efficacy. Equimolar drug combinations as physical mixture (P.M.) or coground product (GR) with hydroxypropyl-β-cyclodextrin (HPβCD) or sulfobutylether-β-cyclodextrin (SBEβCD) were loaded into NLC, then characterized for particle size, homogeneity, Zeta potential, entrapment efficiency, gastric and storage stability. The presence of HPβCD allowed higher entrapment efficacy than NLC loaded with the plain drug, and enabled, in the case of GR systems a complete and sustained drug release, attributable to the wetting and solubilising properties of HPβCD toward HCT. In vivo studies on rats proved the superior therapeutic effectiveness of HCT-in HPβCD-in NLC formulations compared to the corresponding free HCT-loaded NLC, thus confirming the successfulness of the proposed approach in the development of an efficacious liquid oral formulation of the drug.