Formulation and optimization of raloxifene-loaded solid lipid nanoparticles to enhance oral bioavailability

Noninvasive and Microinvasive Nanoscale Drug Delivery Platforms for Hard Tissue Engineering

Bone tissue plays a crucial role in protecting internal organs and providing structural support and locomotion of the body. Treatment of hard tissue defects and medical conditions due to physical injuries, genetic disorders, aging, metabolic syndromes, and infections is more often a complex and drawn out process. Presently, dealing with hard-tissue-based clinical problems is still mostly conducted via surgical interventions. However, advances in nanotechnology over the last decades have led to shifting trends in clinical practice toward noninvasive and microinvasive methods. In this review article, recent advances in the development of nanoscale platforms for bone tissue engineering have been reviewed and critically discussed to provide a comprehensive understanding of the advantages and disadvantages of noninvasive and microinvasive methods for treating medical conditions related to hard tissue regeneration and repair.

Intranasal Polymeric and Lipid-Based Nanocarriers for CNS Drug Delivery

Nanomedicine is currently focused on the design and development of nanocarriers that enhance drug delivery to the brain to address unmet clinical needs for treating neuropsychiatric disorders and neurological diseases. Polymer and lipid-based drug carriers are advantageous for delivery to the central nervous system (CNS) due to their safety profiles, drug-loading capacity, and controlled-release properties. Polymer and lipid-based nanoparticles (NPs) are reported to penetrate the blood–brain barrier (BBB) and have been extensively assessed in in vitro and animal models of glioblastoma, epilepsy, and neurodegenerative disease. Since approval by the Food and Drug Administration (FDA) of intranasal esketamine for treatment of major depressive disorder, intranasal administration has emerged as an attractive route to bypass the BBB for drug delivery to the CNS. NPs can be specifically designed for intranasal administration by tailoring their size and coating with mucoadhesive agents or other moieties that promote transport across the nasal mucosa. In this review, unique characteristics of polymeric and lipid-based nanocarriers desirable for drug delivery to the brain are explored in addition to their potential for drug repurposing for the treatment of CNS disorders. Progress in intranasal drug delivery using polymeric and lipid-based nanostructures for the development of treatments of various neurological diseases are also described.

Design and evaluation of hyaluronic acid-coated PLGA nanoparticles of raloxifene hydrochloride for treatment of breast cancer

CONTEXT

In the present study, hyaluronic acid (HA)-coated raloxifene-loaded poly(l-lactic-co-glycolic acid) (PLGA) nanoparticles have been developed to improve the anticancer potential and reduce side effects associated with the drug.

AIM AND OBJECTIVES

The investigation was aimed to formulate and optimize raloxifene hydrochloride (RALH)-loaded PLGA nanoparticles with surface modification using HA as a targeting moiety. To perform physicochemical characterization, in vitro cytotoxicity study (using MCF-7), in vitro drug release study and in vivo pharmacodynamic study of optimized formulation.

METHODOLOGY

Raloxifene hydrochloride-loaded PLGA nanoparticles were prepared by nanoprecipitation technique, followed by surface modification with HA. Formulation was optimized by using 23 factorial design and characterized by physicochemical, in vitro drug release, in vitro cytotoxicity studies, and in vivo pharmacokinetics.

RESULTS AND DISCUSSION

The particle size, PDI, zeta potential, entrapment efficiency, and loading capacity of spherically shaped RALH-loaded nanoparticles were 207.3 ± 4.2 d.nm, 0.218 ± 0.127, -.127 mV, 43.75 ± 1.2%, and 7.55 ± 1.14%, respectively. The in vitro drug release showed sustained release and followed Korsmeyer-Peppas model with non-Fickian release pattern. The in vitro cytotoxicity study of drug-loaded NPs by MTT assay on MCF-7 breast carcinoma cell showed anti-cancer activity after 48 h of treatment.

CONCLUSION

The results of the present investigation suggested that RALH-loaded HA-modified PLGA nanoparticles showed sustained drug release with anticancer activity and can be a promising approach for treatment of breast cancer.

Nano-strategies as Oral Drug Delivery Platforms for Treatment of Cancer: Challenges and Future Perspectives

Oral drug administration is the oldest and widely used method for drug administration. The objectives behind developing an oral drug delivery for the treatment of cancer are to achieve low cost treatment by utilizing novel techniques to target cancer through gut-associated lymphoid tissue (GALT) and to enhance patient comfort and compliance through a hospital-free treatment leading to "Chemotherapy at Home." Unfortunately, due to the physiological environment of the GIT and physicochemical properties of drug candidate, the efficacy of oral drug delivery methods is limited in the treatment of cancer. Due to their low hydrophilicity, high P-gp efflux and restricted intestinal permeability most of the anti-cancer drugs fail to achieve oral bioavailability. The review focuses on the efforts, challenges, opportunities and studies conducted by scientists worldwide on the oral administration of anticancer medications via nanocarriers such as liposomes, SLNs and dendrimers, because of their potential to overcome the epithelial barrier associated with GALT, as well as the applications of different polymers in targeting the cancer. The oral delivery can set newer horizons in cancer therapy to make it more patient friendly.

Lipid-Based Nanocarriers via Nose-to-Brain Pathway for Central Nervous System Disorders

Neurodegenerative disorders are distinguished by the gradual deterioration of the nervous system's structure and function due to oxidative stress, mitochondrial dysfunction, protein misfolding, excitotoxicity, and neuroinflammation. Among these NDs, Alzheimer's disease, Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis characterized an increasing dysfunction and loss of neuronal structure leading to neuronal cell death. Although there is currently no drug to totally reverse the effects of NDs, such novel formulations and administration routes are developed for better management and nose-to-brain delivery is one of delivery for treating NDs. This review aimed to highlight advances in research on various lipid based nanocarriers such as liposomes, solid lipid nanoparticles, nanostructured lipid carriers, microemulsion, nanoemulsion, and cubosomes which are reported to treat and alleviate the symptoms of NDs via nose-to-brain route. The challenges during clinical translation of lipid nanocarriers from bench to bed side is also discussed.

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.

Raloxifene-loaded SLNs with enhanced biopharmaceutical potential: QbD-steered development, in vitro evaluation, in vivo pharmacokinetics, and IVIVC

Raloxifene hydrochloride, a second-generation selective estrogen receptor modulator, has been approved for the management of breast cancer. However, it is known to exhibit poor (~ 2%) and inconsistent oral bioavailability in humans, primarily ascribable to its low aqueous solubility, extensive first-pass metabolism, P-gp efflux, and presystemic glucuronide conjugation. The present research work entails the systematic development and evaluation of SLNs of RLX for its enhanced biopharmaceutical performance against breast cancer. Factor screening studies were conducted using Taguchi design, followed by optimization studies employing Box-Behnken design. Preparation of SLNs was carried out using glyceryl monostearate and Compritol® 888 ATO (i.e., lipid), Phospholipid S-100 (i.e., co-surfactant), and TPGS-1000 (i.e., surfactant) employing solvent diffusion method. The optimized formulation was evaluated for zeta potential, average particle size, field emission scanning electron microscope, transmission electron microscopy, and in vitro release study. Further, MCF-7 cells (cell cytotoxicity assay, apoptosis assay, and reactive oxygen species assay) and Caco-2 cells (cell uptake studies and P-gp efflux assay) were employed to evaluate the in vitro anticancer potential of the developed optimized formulation. In vivo pharmacokinetic studies were conducted in Sprague-Dawley rats to evaluate the therapeutic profile of the developed formulation. The optimized SLN formulations exhibited a mean particle size of 109.7 nm, PDI 0.289 with a zeta potential of - 13.7 mV. In vitro drug dissolution studies showed Fickian release, with release exponent of 0.137. Cell cytotoxicity assay, apoptosis assay, and cellular uptake indicated 6.40-, 5.40-, and 3.18-fold improvement in the efficacy of RLX-SLNs vis-à-vis pure RLX. Besides, the pharmacokinetic studies indicated quite significantly improved biopharmaceutical performance of RLX-SLNs vis-à-vis pure drug, with 4.06-fold improvement in C_max, 4.40-fold in AUC_(0-72 h), 4.56-fold in AUC_(0-∞), 1.53-fold in K_a, 2.12-fold in t_1/2, and 1.22-fold in T_max. Further, for RLX-SLNs and pure drug, high degree of level A linear correlation was established between fractions of drug dissolved (in vitro) and of drug absorbed (in vivo) at the corresponding time-points. Stability studies indicated the robustness of RLX-SLNs when stored at for 3 months. Results obtained from the different studies construe promising the anticancer potential of the developed RLX-SLNs, thereby ratifying the lipidic nanocarriers as an efficient drug delivery strategy for improving the biopharmaceutical attributes of RLX.

Optimization of Nanostructured Lipid Carriers of Fenofibrate Using a Box-Behnken Design for Oral Bioavailability Enhancement

BACKGROUND

Fenofibrate (FNB) is a commonly used hypolipidemic agent. However, the oral bioavailability of FNB is limited by slow dissolution due to its low solubility. Thus, investigations on novel FNB formulations are necessary for their use.

OBJECTIVE

To enhance the oral bioavailability of FNB using optimized Nanostructured Lipid Carrier (NLC) formulations.

METHODS

Hot homogenization followed by ultrasonication was used to prepare FNB-NLCs. These formulations were optimized using a Box-Behnken design, where the amount of FNB (X1), a ratio of solid lipid/liquid lipid (X2), and the percentage of emulsifier (X3), were set as independent variables, while the particle size (Y1), and Entrapment Efficiency (EE%) (Y2), were used as dependent factors. An in vitro dissolution test was then performed using a paddle method, while an in vivo pharmacokinetic study of FNB-NLC formulation was performed in rats.

RESULTS

FNB-NLCs were successfully prepared and optimized using a Box-Behnken design. The particle size and EE% of the FNB-NLC had less than 5% difference from predicted values. The in vitro dissolution and oral bioavailability of the FNB-NLC were both higher than those of raw FNB.

CONCLUSION

A Box-Behnken design was successfully applied to optimize FNB-NLC formulation for the enhancement of the dissolution and bioavailability of FNB, a poorly water-soluble drug.

Nanostructured lipid carrier potentiated oral delivery of raloxifene for breast cancer treatment

Nanotherapeutics in cancer treatment are dominating global science and research, and have been recognized as the pioneering medical care regimen. Raloxifene (RLN) has been used for its anti-proliferative action on mammary tissue, however, it suffers from poor oral bioavailability. This investigation gives an account of the design and development of RLN-loaded nanostructured lipid carriers (RLN-NLCs) using a simple and scalable ultrasonication method for improved oral efficacy and limited offsite toxicity using Compritol^® 888 ATO as a solid lipid and Transcutol^® HP as a liquid lipid. In addition, the optimized RLN-NLCs were in the nanometric range (121 nm) with high % entrapment efficiency (%EE) (81%) for RLN, and were further freeze-dried in the presence of mannitol to enhance the stability of RLN-NLCs in the dry state for long-term use. Morphological observation under a transmission electron microscope and scanning electron microscope revealed the spherical smooth surface nanometric size of RLN-NLCs. Powder x-ray diffraction confirmed the encapsulation of RLN into the RLN-NLC's matrix with reduced crystallinity of the drug. The in vitro release study showed a burst release for an initial 4 h, and sustained release for up to 24 h. Furthermore, the RLN-NLCs showed higher cytotoxicity towards MCF-7 cells in vitro in comparison to RLN suspension, and an ex vivo intestinal permeation study demonstrated improved intestinal permeability of RLN-NLCs. Moreover, the in vivo pharmacokinetic study in female Wistar rats showed a 4.79-fold increment in oral bioavailability of RLN from RLN-NLCs compared to RLN suspension. Taken together, our results pave the way for a new nanotherapeutic approach towards breast cancer treatment.

Solid Lipid Nanoparticles for Drug Delivery: Pharmacological and Biopharmaceutical Aspects

In the golden age of pharmaceutical nanocarriers, we are witnessing a maturation stage of the original concepts and ideas. There is no doubt that nanoformulations are extremely valuable tools for drug delivery applications; the current challenge is how to optimize them to ensure that they are safe, effective and scalable, so that they can be manufactured at an industrial level and advance to clinical use. In this context, lipid nanoparticles have gained ground, since they are generally regarded as non-toxic, biocompatible and easy-to-produce formulations. Pharmaceutical applications of lipid nanocarriers are a burgeoning field for the transport and delivery of a diversity of therapeutic agents, from biotechnological products to small drug molecules. This review starts with a brief overview of the characteristics of solid lipid nanoparticles and discusses the relevancy of performing systematic preformulation studies. The main applications, as well as the advantages that this type of nanovehicles offers in certain therapeutic scenarios are discussed. Next, pharmacokinetic aspects are described, such as routes of administration, absorption after oral administration, distribution in the organism (including brain penetration) and elimination processes. Safety and toxicity issues are also addressed. Our work presents an original point of view, addressing the biopharmaceutical aspects of these nanovehicles by means of descriptive statistics of the state-of-the-art of solid lipid nanoparticles research. All the presented results, trends, graphs and discussions are based in a systematic (and reproducible) bibliographic search that considered only original papers in the subject, covering a 7 years range (2013-today), a period that accounts for more than 60% of the total number of publications in the topic in the main bibliographic databases and search engines. Focus was placed on the therapeutic fields of application, absorption and distribution processes and current efforts for the translation into the clinical practice of lipid-based nanoparticles. For this, the currently active clinical trials on lipid nanoparticles were reviewed, with a brief discussion on what achievements or milestones are still to be reached, as a way of understanding the reasons for the scarce number of solid lipid nanoparticles undergoing clinical trials.

Oral Bioavailability Enhancement of Raloxifene with Nanostructured Lipid Carriers

Raloxifene hydrochloride (RLX) shows poor bioavailability (<2%), high inter-patient variability and extensive gut metabolism (>90%). The objective of this study was to develop nanostructured lipid carriers (NLCs) for RLX to enhance its bioavailability. The NLC formulations were produced with glyceryl tribehenate and oleic acid. The particle characteristics, entrapment efficiency (EE), differential scanning calorimetry (DSC), in vitro drug release, oral bioavailability (in rats) and stability studies were performed. The optimized nanoparticles were 120 ± 3 nm in size with positive zeta potential (14.4 ± 0.5 mV); % EE was over 90% with the drug loading of 5%. The RLX exists in an amorphous form in the lipid matrix. The optimized RLX-NLC formulation showed sustained release in vitro. The RLX-NLC significantly (p < 0.05) enhanced oral bioavailability 3.19-fold as compared to RLX-free suspension in female Wistar rats. The RLX-NLC can potentially enhance the oral bioavailability of RLX. It can also improve the storage stability.

Low density lipoprotein receptor (LDLR)-targeted lipid nanoparticles for the delivery of sorafenib and Dihydroartemisinin in liver cancers

AIMS

Liver cancer is one of the leading causes of cancer mortality worldwide. Inspired by the biological structure and function of low-density lipoprotein (LDL), in this study, an ApopB-100 based targeted lipid nanoparticles was synthesized to improve the therapeutic efficacy in liver cancer treatment.

MAIN METHODS

The biological composition of ApopB is similar to LDL which can effectively increase the targeting efficiency of nanoparticles in LDL receptor (LDLR)-overexpressed liver tumors.

KEYFINDINGS

We have demonstrated that the co-administration of sorafenib (SRF) and Dihydroartemisinin (DHA) could exhibit synergistic anticancer effect in HepG2 liver cancer cells. DHA produced excessive cellular reactive oxygen species (ROS) and induced greater apoptosis of cancer cells. LDL-based SRF/DHA-loaded lipid nanoparticles (LD-SDN) showed remarkable decrease in the cell viability compared to that of either of single drug treated cancer cells. Combination of SRF+DHA resulted in predominant SubG1 proportion of cells. LD-SDN exhibited the highest SubG1 (%) of cells compared to that of any of the individual drugs. Most importantly, robust antitumor response and delayed tumor growth was observed for LD-SDN treated xenograft tumor model. Ki67 proliferation index of LD-SDN (22.1 ± 5.6%) is significantly lesser compared to that of either control (86.2 ± 6.9%) or SRF (75.4 ± 4.89%) or DHA (69.4 ± 6.9%).

SIGNIFICANCES

These data provide strong evidence that LDL-mimetic lipid nanoformulations could be utilized as a biocompatible and tumor targeted platform for the delivery of multiple anticancer drugs in cancer treatment.

Investigation of in vitro permeability and in vivo pharmacokinetic behavior of bare and functionalized MCM-41 and MCM-48 mesoporous silica nanoparticles: a burst and controlled drug release system for raloxifene

In the present work, MCM-41 and MCM-48 type of nanoparticles were successfully engineered. Effect of nanosize and amine functionalization on drug release, in vitro intestinal absorption and in vivo pharmacokinetic behavior was investigated in a comprehensive manner. The tailor-made bare and surface decorated MCM-41 and MCM-48 were synthesized and evaluated for their mesoporous skeleton, pore size, particle size, surface area, zeta potential, etc. by nitrogen sorption, DLS, TEM, etc. Incorporation of raloxifene (RLF) was affirmed using optimized immersion-solvent evaporation technique and its success confirmed by DSC, IR, and XRD analysis. TGA analysis revealed higher %grafting of amine groups on the exterior and larger RLF encapsulation into mesoporous derivate. The detailed in vitro release study revealed SGF to be the most compatible media for RLF showing an initial burst release from pristine nanoparticles and a delayed release from surface coated nanoparticles. Furthermore, release kinetics model data demonstrated Weibull and Higuchi as the best fit models for bare and amine-functionalized nanoparticles respectively. Moreover, an in vitro permeability study on Caco-2 cell line revealed higher absorption by engineered nanoparticle as compared to pure RLF and its marketed formulation. The supremacy in the in vivo pharmacokinetic parameters of RLF-41 and RLF-48 was demonstrated with 3.33 and 3.50 times enhancement in the bioavailability of RLF with respect to RLF suspension. To sum up, the results obtained were superior and promising for synthesized nanoparticles and more precisely for MCM-48 amongst them.

Solid Lipid Nanoparticles of Dronedarone Hydrochloride for Oral Delivery: Optimization, In Vivo Pharmacokinetics and Uptake Studies

BACKGROUND

Dronedarone HCl (DRD), owing to its poor aqueous solubility and extensive presystemic metabolism shows low oral bioavailability of about 4% without food, which increases to approximately 15% when administered with a high fat meal.

OBJECTIVE

Solid lipid nanoparticles (SLN) were designed with glyceryl monstearate (GMS) in order to improve oral bioavailability of DRD.

METHODS

Hot homogenization followed by probe sonication was used to prepare SLN dispersions. Box-Behnken design was used to optimize manufacturing conditions. SLN were characterized for particle size, zeta potential, entrapment efficiency, physical state and in vitro drug release. Pharmacokinetics and intestinal uptake study of dronedarone HCl loaded solid lipid nanoparticles (DRD-SLN) in the presence and absence of endocytic uptake inhibitor, chlorpromazine (CPZ) was performed with conscious male Wistar rats.

RESULTS

Optimized formulation of SLN showed particle size of 233 ± 42 nm and entrapment efficiency of 87.4 ± 1.29%. Results of pharmacokinetic studies revealed enhancement of bioavailability of DRD by 2.68 folds from SLN as compared to DRD suspension. Significantly reduced bioavailability of DRD-SLNs in the presence of chlorpromazine, demonstrated the role of endocytosis in uptake of SLN formulation.

CONCLUSION

These results indicated that dronedarone HCl loaded SLN could potentially be exploited as a delivery system for improving oral bioavailability by minimizing first pass metabolism.

PEGylated mBPEI-rGO nanocomposites facilitate hepotocarcinoma treatment combining photothermal therapy and chemotherapy

Despite chemotherapy has been widely used for tumor therapy, the serious side effect is still a major challenge. Recently, two dimensional nanomaterial-based drug delivery systems have attracted wide concern due to their high drug loading and low side effect. In addition, some kinds of nanomaterials can directly act as a photosensitizer to induce cancer destruction. In this study, we developed a drug delivery system of mixture of high/low molecular weight branched polyethylenimine-polyethylene glycol-reduced graphene oxide (mBPEI-PEG-rGO) using reduced graphene oxide as matrix. A model drug of doxorubicin (DOX) was loaded on the nanocomposites with the efficiency of 81% and the release rate of more than 50% at acidic environment. In vitro experiments indicated that mBPEI-PEG-rGO-DOX with enhanced stability and biocompatibility efficiently delivered and released DOX into cells mainly through micropinocytosis and killed SMMC-7721 cells by inducing reactive oxygen species (ROS) and cell apoptosis. Furthermore, in vivo experiments indicated that the combination of intratumoral injection of mBPEI-PEG-rGO-DOX and local laser irradiation nearly ablated hepatocarcinoma. In conclusion, this new drug delivery system provided an alternative for combinational photothermal and chemotherapy against hepatocarcinoma.

Pomegranate extract-loaded solid lipid nanoparticles: design, optimization, and in vitro cytotoxicity study

Background

Pomegranate extract (PE) is a natural product with potent antioxidant and anticancer activity because of its polyphenols content. The main purpose of this study was to maximize the PE chemotherapeutic efficacy by loading it in an optimized solid lipid nanoparticles (SLNs) formula.

Materials and methods

The influence of independent variables, which were lipid concentration (X₁), surfactant concentration (X₂) and cosurfactant concentration (X₃), on dependent ones, which were particle size (Y₁), polydispersity index (Y₂), zeta potential (Y₃), entrapment efficiency (Y₄) and cumulative % drug release (Y₅), were studied and optimized using the Box–Behnken design. Fifteen formulations of PE-SLNs were prepared using hot homogenization followed by ultra-sonication technique. Response surface plots, Pareto charts and mathematical equations were produced to study the impact of independent variables on the dependent quality parameters. The anti-proliferative activity of the optimized formula was then evaluated in three different cancer cell lines, namely, MCF-7, PC-3 and HepG-2, in addition to one normal cell line, HFB-4.

Results

The results demonstrated that the particle sizes ranged from 407.5 to 651.9 nm and the entrapment efficiencies ranged from 56.02 to 65.23%. Interestingly, the 50% inhibitory concentration of the optimized formula had more than a 40-fold improved effect on the cell growth inhibition in comparison with its free counterpart. Furthermore, it was more selective against cancer cells than normal cells particularly in MCF-7 breast cancer cells.

Conclusion

These data proved that nanoencapsulation of PE enhanced its anticancer efficacy. Therefore, our results suggested that a PE-loaded SLNs optimized-formula could be a promising chemo therapeutic agent.

Enhanced solubility, oral bioavailability and anti-osteoporotic effects of raloxifene HCl in ovariectomized rats by Igepal CO-890 nanomicelles

The purpose of the present study was to enhance the bioavailability and anti-osteoporotic effects of raloxifene HCl (RH) by increasing its solubility and inhibition of the p-glycoprotein pump using surfactant micelles of Igepal CO-890. The micelles were prepared by the direct method and their critical micellar concentration, drug dissolution rate, saturated solubility, drug loading and surface morphology were defined. The cytotoxicity of Igepal CO-890 and its ability to inhibit the p-glycoprotein pump were studied on Caco-2 cells. The pharmacokinetic parameters were analyzed by oral administration of a single dose of 15 mg/kg in Wistar rats. Anti-osteoporotic effects were studied by measuring the calcium, phosphorous, and uterus weight of rats after one month of oral administration of 6 mg/kg/day of RH in ovariectomized rats. Igepal CO-890 micelles enhanced the RH solubility by about two-fold. The FT-IR and DSC studies indicated no interaction between the drug and the surfactant. XRD spectrum showed an amorphous state of RH in the micelles. The p-glycoprotein pump was inhibited by Igepal CO-890 in Caco-2 cells comparable to verapamil. Micelles increased the uterine weight and decreased the serum calcium and phosphorus significantly compared to the untreated drug. Oral bioavailability of RH increased about four-fold by nanomicelles.

Recent advances in oral delivery of drugs and bioactive natural products using solid lipid nanoparticles as the carriers

Chemical and enzymatic barriers in the gastrointestinal (GI) tract hamper the oral delivery of many labile drugs. The GI epithelium also contributes to poor permeability for numerous drugs. Drugs with poor aqueous solubility have difficulty dissolving in the GI tract, resulting in low bioavailability. Nanomedicine provides an opportunity to improve the delivery efficiency of orally administered drugs. Solid lipid nanoparticles (SLNs) are categorized as a new generation of lipid nanoparticles consisting of a complete solid lipid matrix. SLNs used for oral administration offer several benefits over conventional formulations, including increased solubility, enhanced stability, improved epithelium permeability and bioavailability, prolonged half-life, tissue targeting, and minimal side effects. The nontoxic excipients and sophisticated material engineering of SLNs tailor the controllable physicochemical properties of the nanoparticles for GI penetration via mucosal or lymphatic transport. In this review, we highlight the recent progress in the development of SLNs for disease treatment. Recent application of oral SLNs includes therapies for cancers, central nervous system-related disorders, cardiovascular-related diseases, infection, diabetes, and osteoporosis. In addition to drugs that may be active cargos in SLNs, some natural compounds with pharmacological activity are also suitable for SLN encapsulation to enhance oral bioavailability. In this article, we systematically introduce the concepts and amelioration mechanisms of the nanomedical techniques for drug- and natural compound-loaded SLNs.

Design, characterization and in vitro evaluation of novel amphiphilic block sunflower oil-based polyol nanocarrier as a potential delivery system: Raloxifene-hydrochloride as a model

Presently, modern pharmaceuticals, are almost exclusively derived from the arduous refining of petroleum whose supply is inherently unsustainable. In order to address this issue bio-based materials are increasingly being used for chemical synthesis, particularly in drug delivery systems. Biodegradable and biocompatible hyper-branched polyol (an alcohol containing three or more hydroxyl groups) was synthesized via a facile method through the ring-opening and thiol-ene click reactions at room temperature. Due to the bio-based content of the polyol backbone, the synthesized polyol had both excellent biodegradability and low cytotoxicity. Raloxifene hydrochloride, an oral selective estrogen receptor modulator, was used as a hydrophobic drug model to test the potential of polyol as a drug delivery system carrier. Polyol showed an amphiphilic character and could be prepared as a nanoparticle for the sustained delivery of raloxifene hydrochloride, a drug with poor bioavailability in aqueous solution. Raloxifene hydrochloride was readily encapsulated in the lipophilic core of polyol whose branched hydroxyls were on the external part of the prepared nanoparticles. The diameter of the nanoparticles was 94±0.43nm, their drug entrapment efficiency was 93±0.5% and they showed a sustained release profile (17±1.5% after 4weeks). The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay showed low toxicity towards human osteoblast MG-63 cells. Based on its good biodegradability and low cytotoxicity, polyol provides a bio-based source for the design new drug delivery systems.

Local anesthetic effects of bupivacaine loaded lipid-polymer hybrid nanoparticles: In vitro and in vivo evaluation

PURPOSE

There is a compelling need for prolonged local anesthetic that would be used for analgesia with a single administration. However, due to the low molecular weight of local anesthetics (LA) (lidocaine, bupivacaine, procaine, dibucaine, etc), they present fast systemic absorption.

METHODS

The aim of the present study was to develop and evaluate bupivacaine lipid-polymer hybrid nanoparticles (BVC LPNs), and compared with BVC loaded PLGA nanoparticles (BVC NPs). Their morphology, particle size, zeta potential and drug loading capacity were evaluated. In vitro release study, stability and cytotoxicity were studied. In vivo evaluation of anesthetic effects was performed on animal models.

RESULTS

A facile nanoprecipitation and self-assembly method was optimized to obtain BVC LPNs, composed of PLGA, lecithin and DSPE-PEG₂₀₀₀, of ∼175nm particle size. Compared to BVC NPs, BVC LPNs exhibited prolonged in vitro release in phosphate-buffered saline (pH=7.4). Further, BVC LPNs displayed enhanced in vitro stability in 10% FBS and lower cytotoxicity (the concentration of BVC ranging from 1.0μM to 20μM). In addition, BVC LPNs exhibited significantly prolonged analgesic duration.

CONCLUSION

These results demonstrate that the LPNs could function as promising drug delivery system for overcoming the drawbacks of poor stability and rapid drug leakage, and prolonging the anesthetic effect with slight toxicity.

Chitosan Nanolayered Cisplatin-Loaded Lipid Nanoparticles for Enhanced Anticancer Efficacy in Cervical Cancer

In this study, cisplatin (CDDP)-loaded chitosan-coated solid lipid nanoparticles (SLN) was successfully formulated to treat HeLa cervical carcinoma. The formulation nanoparticles were nanosized and exhibited a controlled release of drug in physiological conditions. The blank nanoparticles exhibited an excellent biocompatibility profile indicating its suitability for cancer targeting. The incorporation of CDDP in SLN remarkably increased the cancer cell death as evident from the MTT assay. Importantly, CDDP-loaded chitosan-coated SLN (CChSLN) significantly (P < 0.05) decreased the viability of cancer cells even at low concentration. The higher cytotoxicity potential of CChSLN was attributed to the higher cellular uptake as well as the sustained drug release manner in comparison with CSLN. Consistent with the cytotoxicity assay, CChSLN showed the lowest IC50 value of 0.6125 μg/ml while CSLN presented 1.156 μg/ml. CChSLN showed a significantly higher apoptosis in cancer cells compared to that of CSLN and CDDP, which is attributed to the better internalization of nanocarriers and controlled release of anticancer drugs in the intracellular environment. Our findings suggest that this new formulation could be a promising alternative for the treatment of cervical cancers. These findings are encouraging us to continue our research, with a more extended investigation of cellular response in real time and in animal models.

Osteotropic nanoscale drug delivery systems based on small molecule bone-targeting moieties

Bone-targeted drug delivery is an active research area because successful clinical applications of this technology can significantly advance the treatment of bone injuries and disorders. Molecules with bone-targeting potential have been actively investigated as promising moieties in targeted drug delivery systems. In general, bone-targeting molecules are characterized by their high affinity for bone and their predisposition to persist in bone tissue for prolonged periods, while maintaining low systemic concentrations. Proteins, such as monoclonal antibodies, have shown promise as bone-targeting molecules; however, they suffer from several limitations including large molecular size, high production cost, and undesirable immune responses. A viable alternative associated with significantly less side effects is the use of small molecule-based targeting moieties. This review provides a summary of recent findings regarding small molecule compounds with bone-targeting capacity, as well as nanoscale targeted drug delivery approaches employing these molecules.

Carvedilol nano lipid carriers: formulation, characterization and in-vivo evaluation

The purpose of this study was to develop Carvedilol nanostructured lipid carriers (CAR-NLCs) using stearic acid and oleic acid as lipid, and to estimate the potential as oral delivery system for poorly water soluble drug. The particle-size analysis revealed that all the developed formulations were within the nanometer range. The EE and loading were found to be between 69.45-88.56% and 9.58-12.56%, respectively. The CAR-NLCopt showed spherical morphology with smooth surface under transmission electron microscope (TEM). The crystallization of the drug in NLC was investigated by powder X-ray diffraction and differential scanning calorimetry (DSC) and revealed that the drug was in an amorphous state in the NLC matrix. The ex vivo gut permeation study showed many folds increment in the permeation of CAR-NLCs compared to Carvedilol suspension (CAR-S). The oral bioavailability study of CAR was carried out using Wistar rats and relative bioavailability of CAR-NLCopt was found to be 3.95 fold increased in comparison with CAR-S. In vivo antihypertensive study in Wistar rats showed significant reduction in mean systolic BP by CAR-NLCopt vis-à-vis CAR-S (p < 0.05) owing to the drug absorption through lymphatic pathways. In conclusion, the NLC formulation remarkably improved the oral bioavailability of CAR and demonstrated a promising perspective for oral delivery of poorly water-soluble drugs. The promising findings in this investigation suggest the practicability of these systems for the enhancement of bioavailability of CAR.

Development of a Graphene Oxide Nanocarrier for Dual-Drug Chemo-phototherapy to Overcome Drug Resistance in Cancer

Despite tremendous progress in chemotherapy, drug resistance remains a major challenge for anticancer treatment. The combinations of chemo-photothermal and chemo-chemo treatments have been reported to be potential solutions to overcome drug resistance. In this study, we developed a dual-in-dual synergistic therapy based on the use of dual anticancer drug-loaded graphene oxide (GO) stabilized with poloxamer 188 for generating heat and delivering drugs to kill cancer cells under near-infrared (NIR) laser irradiation. The nanocomparable system is stable and uniform in size, generating sufficient heat to induce cell death. Dual drugs (doxorubicin and irinotecan)-loaded GO (GO-DI) in combination with laser irradiation caused higher cytotoxicity than that caused by the administration of a free single drug as well as a combination of drugs and blank GO in various cancer cells, especially in MDA-MB-231 resistant breast cancer cells. Exposure to "hot" NIR and GO-DI activated the intrinsic apoptosis pathway, which was confirmed based on changes in the morphology of cell nuclei and overexpression of apoptosis-related proteins. On the basis of the results, the combined treatment showed a synergistic effect compared to the effect of chemotherapy or photothermal treatment alone, demonstrating higher therapeutic efficacy to overcome one of the most severe problem in anticancer therapy, that of intrinsic resistance to chemotherapeutics.

Development and Evaluation of Artesunate-Loaded Chitosan-Coated Lipid Nanocapsule as a Potential Drug Delivery System Against Breast Cancer

Artesunate (ART)--a well-known hydrophobic anti-malarial agent was incorporated in a polymer-lipid hybrid nanocolloidal system for anti-cancer therapeutic. The lipid negatively charged nanoemulsion was formulated by modified hot homogenization method then covered with positively charged chitosan via electrostatic interaction to obtain chitosan-coated lipid nanocapsule (ART-CLN). Physical properties of the system were characterized in terms of size, charge, morphology, drug loading capacity, and physical state. In addition, anti-cancer activities were confirmed by conducting MTT assay for ART and ART-CLN on different cancer cell lines. Obtained ART-CLN after coating chitosan revealed positive charge (13.2 ± 0.87 mV), small particle size (160.9 ± 3.5 nm), and spherical shape. High drug entrapment efficiency (95.49 ± 1.13%) and sustained release pattern were observed. Moreover, the good cellular uptake was recorded by flow cytometry as well as confocal image. Finally, ART-CLN exhibited stronger anti-cancer activity than free ART on breast cancer cell lines (MCF-7, MDA-MB-231). These results suggested that by loading ART into lipid core of polymer-lipid hybrid carrier, the activity and physical stability of ART can be significantly increased for cancer chemotherapy.

The challenges for cancer chemoprevention

The incidence of cancer is rising in parallel with an ageing populous thus increasing the strain on both treatment options and budgets for healthcare providers worldwide. New cancer therapies are being developed but at what cost? The new treatments are expensive and poor survival rates still exist for some cancers. What is needed now is to prevent or at least limit the disease occurring in the first place. This review evaluates the current situation and the progress in upcoming strategies as well as suggesting some areas for further research within the increasingly important field of cancer chemoprevention. The key principles of cancer chemoprevention are discussed and areas for improvement highlighted. Despite significant progress, chemoprevention has not been widely adopted. Cancer chemoprevention has many challenges to face but this only emphasises the size of the task. These hurdles include a lack of awareness of the benefits, a lack of interest and a lack of investment in taking prevention forward. Despite the huge potential importance of cancer prevention and clinical success stories such as the well-publicised HPV vaccine, the challenges remain significant. With cancer and its treatment being a global issue, the opportunities offered by chemoprevention must be re-evaluated and uptake of chemoprevention actively encouraged. If chemoprevention is to be adopted successfully, a holistic approach is required. This approach will involve multidisciplinary teams of healthcare providers and scientists with the big challenge particularly for medicinal chemists being to design and synthesise the ideal chemopreventative agent.

Tumor-targeting, pH-sensitive nanoparticles for docetaxel delivery to drug-resistant cancer cells

The attachment of polyethylene glycol (PEG) increases the circulation time of drug-containing nanoparticles; however, this also negatively affects cellular uptake. To overcome this problem, unique lipid polymer hybrid (LPH) nanoparticles were developed with a pH-responsive PEG layer that detached prior to cell uptake. Docetaxel (DTX) was incorporated into the lipid core of the nanoparticles, which was then shielded with the pH-responsive block co-polymer polyethylene glycol-b-polyaspartic acid (PEG-b-PAsp) using a modified emulsion method. The optimized LPH nanoparticles were ~200 nm and had a narrow size distribution. Drug release from DTX-loaded LPH (DTX-LPH) nanoparticles was pH-sensitive, which is beneficial for tumor targeting. More importantly, DTX-LPH nanoparticles were able to effectively induce apoptosis in cancer cells. The negative surface charge and PEG shell of vehicle remarkably enhanced the blood circulation and physiological activity of DTX-LPH nanoparticles compared with that of free DTX. The nanoparticles were also found to reduce the size of tumors in tumor-bearing xenograft mice. The in vivo anticancer effect of DTX-LPH nanoparticles was further confirmed by the elevated levels of caspase-3 and poly ADP ribose polymerase found in the tumors after treatment. Thus, the results suggest that this novel LPH system could be an effective new treatment for cancer.

Layer-by-layer assembly of liposomal nanoparticles with PEGylated polyelectrolytes enhances systemic delivery of multiple anticancer drugs

Layer-by-layer (LbL)-engineered nanoparticles (NPs) are a promising group of therapeutic carriers used in an increasing number of biomedical applications. The present study uses a controlled LbL process to create a multidrug-loaded nanoplatform capable of promoting blood circulation time, biodistribution profile and controlling drug release in the dynamic systemic environment. LbL assembly is achieved by sequential deposition of poly-l-lysine (PLL) and poly(ethylene glycol)-block-poly(l-aspartic acid) (PEG-b-PLD) on liposomal nanoparticles (LbL-LNPs). This generates spherical and stable multilayered NPs ∼240nm in size, enabling effective systemic administration. The numerous functional groups and compartments in the polyelectrolyte shell and core facilitate loading with doxorubicin and mitoxantrone. The nanoarchitecture effectively controls burst release, providing different release kinetics for each drug. LbL-LNPs are pH-sensitive, indicating that intracellular drug release can be increased by the acidic milieu of cancer cells. We further demonstrate that the LbL nanoarchitecture significantly reduces the elimination rates of both drugs tested and markedly extends their systemic circulation times, paving the way for efficacious tumor drug delivery. Because this delivery system accommodates multiple drugs, improves drug half-life and diminishes burst release, it provides an exciting platform with remarkable potential for combination therapeutics in cancer therapy.

Preparation and characterization of fenofibrate-loaded nanostructured lipid carriers for oral bioavailability enhancement

The aim of this study is to investigate the potential of nanostructured lipid carriers (NLCs) in improving the oral bioavailability of a lipid lowering agent, fenofibrate (FEN). FEN-loaded NLCs (FEN-NLCs) were prepared by hot homogenization followed by an ultrasonication method using Compritol 888 ATO as a solid lipid, Labrafil M 1944CS as a liquid lipid, and soya lecithin and Tween 80 as emulsifiers. NLCs were characterized in terms of particle size and zeta potential, surface morphology, encapsulation efficiency, and physical state properties. Bioavailability studies were carried out in rats by oral administration of FEN-NLC. NLCs exhibited a spherical shape with a small particle size (84.9 ± 4.9 nm). The drug entrapment efficiency was 99% with a loading capacity of 9.93 ± 0.01% (w/w). Biphasic drug release manner with a burst release initially, followed by prolonged release was depicted for in vitro drug release studies. After oral administration of the FEN-NLC, drug concentration in plasma and AUCt-∞ was fourfold higher, respectively, compared to the free FEN suspension. According to these results, FEN-NLC could be a potential delivery system for improvement of loading capacity and control of drug release, thus prolonging drug action time in the body and enhancing the bioavailability.

Insights on novel particulate self-assembled drug delivery beads based on partial inclusion complexes between triglycerides and cyclodextrins

Most of the newly designed drug molecules are lipophilic in nature and often encounter erratic absorption and low bioavailability after oral administration. Finding ways to enhance the absorption and bioavailability of these lipophilic drugs is one of the major challenges that face pharmaceutical industry nowadays. In view of that, the purpose of this review is to shed some light on a novel particulate self-assembling system named "beads" than can act as a safe carrier for delivering lipophilic drugs. The beads are prepared simply by mixing oils with cyclodextrin (CD) aqueous solution in mild conditions. A unique interaction between oil components and CD molecules occurs to form in situ surface-active complexes which are prerequisites for beads formation. This review mainly focuses on the fundamentals of beads preparation through reviewing present, yet scarce, literature. The key methods used for beads characterization are discussed in details. Also, the potential mechanisms by which beads increase the bioavailability of lipophilic drugs are illustrated. Finally, the related research areas that needs to be addressed in future for optimizing this promising delivery system are briefly outlined.

Enhancing the in vitro anti-cancer efficacy of artesunate by loading into poly-D,L-lactide-co-glycolide (PLGA) nanoparticles

Artesunate (ART)-a well-known anti-malarial agent is also known to have potential anti-proliferative activities but its instability, poor aqueous solubility, and lack of relevant studies have limited its application as an effective anti-cancer drug. To overcome these problems, ART was loaded in poly (lactic-co-glycolic) acid (PLGA) nanoparticles using oil/water emulsion evaporation method. PLGA nanoparticles with small particle size and high entrapment efficiency were obtained. The PLGA nanoparticles were optimized by evaluating the effects of several formulation parameters on physicochemical properties of nanoparticles. The in vitro cytotoxicity of blank PLGA, free ART, and ART-PLGA on 3 human cancer cell lines viz. A549, SCC-7, and MCF-7 was conducted using MTT assay. The particles showed nanometric size (~170 nm), large entrapment efficiency (up to 83.4%), and excellent stability (evaluated for 1 month) after lyophilization with 5% mannitol. ART was dispersed inside particle core allowing a sustained release up to 48 h. The in vitro cytotoxicity results demonstrated strong activity of ART against cancer cell lines. The ART-PLGA formulation significantly reduced cell viability than the free ART. The formulation of ART loaded PLGA nanoparticles supported a potential application of ART as an anticancer agent.

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.