Nanoemulsion loaded with lycobetaine-oleic acid ionic complex: physicochemical characteristics, in vitro, in vivo evaluation, and antitumor activity

Antiepileptic drug-loaded and multifunctional iron oxide@silica@gelatin nanoparticles for acid-triggered drug delivery

The current study developed an innovative design for the production of smart multifunctional core-double shell superparamagnetic nanoparticles (NPs) with a focus on the development of a pH-responsive drug delivery system tailored for the controlled release of Phenytoin, accompanied by real-time monitoring capabilities. In this regard, the ultra-small superparamagnetic iron oxide@silica NPs (IO@Si MNPs) were synthesized and then coated with a layer of gelatin containing Phenytoin as an antiepileptic drug. The precise saturation magnetization value for the resultant NPs was established at 26 emu g-1. The polymeric shell showed a pH-sensitive behavior with the capacity to regulate the release of encapsulated drug under neutral pH conditions, simultaneously, releasing more amount of the drug in a simulated tumorous-epileptic acidic condition. The NPs showed an average size of 41.04 nm, which is in the desired size range facilitating entry through the blood-brain barrier. The values of drug loading and encapsulation efficiency were determined to be 2.01 and 10.05%, respectively. Moreover, kinetic studies revealed a Fickian diffusion process of Phenytoin release, and diffusional exponent values based on the Korsmeyer-Peppas equation were achieved at pH 7.4 and pH 6.3. The synthesized NPs did not show any cytotoxicity. Consequently, this new design offers a faster release of PHT at the site of a tumor in response to a change in pH, which is essential to prevent epileptic attacks.

Applications and advancements of nanoparticle-based drug delivery in alleviating lung cancer and chronic obstructive pulmonary disease

Lung cancer (LC) and chronic obstructive pulmonary disease (COPD) are among the leading causes of mortality worldwide. Cigarette smoking is among the main aetiologic factors for both ailments. These diseases share common pathogenetic mechanisms including inflammation, oxidative stress, and tissue remodelling. Current therapeutic approaches are limited by low efficacy and adverse effects. Consequentially, LC has a 5-year survival of < 20%, while COPD is incurable, underlining the necessity for innovative treatment strategies. Two promising emerging classes of therapy against these diseases include plant-derived molecules (phytoceuticals) and nucleic acid-based therapies. The clinical application of both is limited by issues including poor solubility, poor permeability, and, in the case of nucleic acids, susceptibility to enzymatic degradation, large size, and electrostatic charge density. Nanoparticle-based advanced drug delivery systems are currently being explored as flexible systems allowing to overcome these limitations. In this review, an updated summary of the most recent studies using nanoparticle-based advanced drug delivery systems to improve the delivery of nucleic acids and phytoceuticals for the treatment of LC and COPD is provided. This review highlights the enormous relevance of these delivery systems as tools that are set to facilitate the clinical application of novel categories of therapeutics with poor pharmacokinetic properties.

Future Nanotechnology-Based Strategies for Improved Management of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) is a recalcitrant pathogen, which can cause gastric disorders. During the past decades, polypharmacy-based regimens, such as triple and quadruple therapies have been widely used against H. pylori. However, polyantibiotic therapies can disturb the host gastric/gut microbiota and lead to antibiotic resistance. Thus, simpler but more effective approaches should be developed. Here, some recent advances in nanostructured drug delivery systems to treat H. pylori infection are summarized. Also, for the first time, a drug release paradigm is proposed to prevent H. pylori antibiotic resistance along with an IVIVC model in order to connect the drug release profile with a reduction in bacterial colony counts. Then, local delivery systems including mucoadhesive, mucopenetrating, and cytoadhesive nanobiomaterials are discussed in the battle against H. pylori infection. Afterward, engineered delivery platforms including polymer-coated nanoemulsions and polymer-coated nanoliposomes are poposed. These bioinspired platforms can contain an antimicrobial agent enclosed within smart multifunctional nanoformulations. These bioplatforms can prevent the development of antibiotic resistance, as well as specifically killing H. pylori with no or only slight negative effects on the host gastrointestinal microbiota. Finally, the essential checkpoints that should be passed to confirm the potential effectiveness of anti-H. pylori nanosystems are discussed.

Rivastigmine-DHA ion-pair complex improved loading in hybrid nanoparticles for better amyloid inhibition and nose-to-brain targeting in Alzheimer's

Rivastigmine hydrogen tartrate (RIV-HT) is given orally for Alzheimer's disease. However, oral therapy shows low brain bioavailability, short half-life and gastrointestinal-mediated adverse effects. RIV-HT intranasal delivery can avoid these side effects, but its low brain bioavailability remains challenging. These issues could be solved with hybrid lipid nanoparticles with enough drug loading to enhance RIV-HT brain bioavailability while avoiding oral route side effects. The RIV-HT and docosahexaenoic acid (DHA) ion-pair complex (RIV:DHA) was prepared to improve drug loading into lipid-polymer hybrid (LPH) nanoparticles. Two types of LPH, i.e., cationic (RIV:DHA LPH(+ve)) and anionic LPH (RIV:DHA LPH(-ve)) were developed. The effect of LPH surface charge on in-vitro amyloid inhibition, in-vivo brain concentrations and nose-to-brain drug targeting efficiency were investigated. LPH nanoparticles showed concentration dependant amyloid inhibition. RIV:DHA LPH(+ve) demonstrated relatively enhanced Aβ1-42 peptide inhibition. The thermoresponsive gel embedded with LPH nanoparticles improved nasal drug retention. LPH nanoparticles gel significantly improved pharmacokinetic parameters compared to RIV-HT gel. RIV:DHA LPH(+ve) gel showed better brain concentrations than RIV:DHA LPH(-ve) gel. The histological examination of nasal mucosa treated with LPH nanoparticles gel showed that the delivery system was safe. In conclusion, the LPH nanoparticle gel was safe and efficient in improving the nose-to-brain targeting of RIV, which can potentially be utilized in managing Alzheimer's.

Lycorine transfersomes modified with cell-penetrating peptides for topical treatment of cutaneous squamous cell carcinoma

BACKGROUND

Topical anticancer drugs offer a potential therapeutic modality with high compliance for treating cutaneous squamous cell carcinoma (cSCC). However, the existing topical treatments for cSCC are associated with limited penetrating ability to achieve the desired outcome. Therefore, there remains an urgent requirement to develop drugs with efficient anticancer activity suitable for treating cSCC and to overcome the skin physiological barrier to improve the efficiency of drug delivery to the tumor.

RESULTS

We introduced lycorine (LR) into the topical treatment for cSCC and developed a cell-penetrating peptide (CPP)-modified cationic transfersome gel loaded with lycorine-oleic acid ionic complex (LR-OA) (LR@DTFs-CPP Gel) and investigated its topical therapeutic effects on cSCC. The anti-cSCC effects of LR and skin penetration of LR-OA transfersomes were confirmed. Simultaneously, cationic lipids and modification of R5H3 peptide of the transfersomes further enhanced the permeability of the skin and tumor as well as the effective delivery of LR to tumor cells.

CONCLUSIONS

Topical treatment of cSCC-xenografted nude mice with LR@DTFs-CPP Gel showed effective anticancer properties with high safety. This novel formulation provides novel insights into the treatment and pathogenesis of cSCC.

Selecting Counterions to Improve Ionized Hydrophilic Drug Encapsulation in Polymeric Nanoparticles

Hydrophobic ion pairing (HIP) can successfully increase the drug loading and control the release kinetics of ionizable hydrophilic drugs, addressing challenges that prevent these molecules from reaching the clinic. Nevertheless, polymeric nanoparticle (PNP) formulation development requires trial-and-error experimentation to meet the target product profile, which is laborious and costly. Herein, we design a preformulation framework (solid-state screening, computational approach, and solubility in PNP-forming emulsion) to understand counterion-drug-polymer interactions and accelerate the PNP formulation development for HIP systems. The HIP interactions between a small hydrophilic molecule, AZD2811, and counterions with different molecular structures were investigated. Cyclic counterions formed amorphous ion pairs with AZD2811; the 0.7 pamoic acid/1.0 AZD2811 complex had the highest glass transition temperature (T_g; 162 °C) and the greatest drug loading (22%) and remained as phase-separated amorphous nanosized domains inside the polymer matrix. Palmitic acid (linear counterion) showed negligible interactions with AZD2811 (crystalline-free drug/counterion forms), leading to a significantly lower drug loading despite having similar log P and pK_a with pamoic acid. Computational calculations illustrated that cyclic counterions interact more strongly with AZD2811 than linear counterions through dispersive interactions (offset π-π interactions). Solubility data indicated that the pamoic acid/AZD2811 complex has a lower organic phase solubility than AZD2811-free base; hence, it may be expected to precipitate more rapidly in the nanodroplets, thus increasing drug loading. Our work provides a generalizable preformulation framework, complementing traditional performance-indicating parameters, to identify optimal counterions rapidly and accelerate the development of hydrophilic drug PNP formulations while achieving high drug loading without laborious trial-and-error experimentation.

Signaling Pathway Inhibitors, miRNA, and Nanocarrier-Based Pharmacotherapeutics for the Treatment of Lung Cancer: A Review

Lung cancer is one of the most commonly diagnosed cancers and is responsible for a large number of deaths worldwide. The pathogenic mechanism of lung cancer is complex and multifactorial in origin. Thus, various signaling pathways as targets for therapy are being examined, and many new drugs are in the pipeline. However, both conventional and target-based drugs have been reported to present significant adverse effects, and both types of drugs can affect the clinical outcome in addition to patient quality of life. Recently, miRNA has been identified as a promising target for lung cancer treatment. Therefore, miRNA mimics, oncomiRs, or miRNA suppressors have been developed and studied for possible anticancer effects. However, these miRNAs also suffer from the limitations of low stability, biodegradation, thermal instability, and other issues. Thus, nanocarrier-based drug delivery for the chemotherapeutic drug delivery in addition to miRNA-based systems have been developed so that existing limitations can be resolved, and enhanced therapeutic outcomes can be achieved. Thus, this review discusses lung cancer's molecular mechanism, currently approved drugs, and their adverse effects. We also discuss miRNA biosynthesis and pathogenetic role, highlight pre-clinical and clinical evidence for use of miRNA in cancer therapy, and discussed limitations of this therapy. Furthermore, nanocarrier-based drug delivery systems to deliver chemotherapeutic drugs and miRNAs are described in detail. In brief, the present review describes the mechanism and up-to-date possible therapeutic approaches for lung cancer treatment and emphasizes future prospects to bring these novel approaches from bench to bedside.

Pathogen Receptor Membrane-Coating Facet Structures Boost Nanomaterial Immune Escape and Antibacterial Performance

Nanomaterials show great potential for the treatment of bacterial infections, but their effects remain limited by low antibacterial efficiency and immune clearance. Facet-dependent nanozymes coated with pathogen receptor membranes were fabricated, providing an approach for producing superphotothermal antibacterial nanomaterials with high biocompatibility and low immune clearance. (100)- and (112)-Faceted CuFeSe₂ presented excellent photothermal conversion efficiency (46%). However, the peroxidase-like activity of (100)-faceted CuFeSe₂ enhanced the decomposition of H₂O₂ to hydroxyl radicals (^•OH) and was markedly greater than that of (112)-faceted CuFeSe₂, with nearly 100% of Staphylococcus aureus being killed under near-infrared (NIR) irradiation. Importantly, bacteria-pretreated immune membranes (i.e., pathogen receptor membranes) coated with CuFeSe₂ exhibited superior S. aureus-binding ability, presented obvious immune-evading capability, and resulted in targeted delivery to infected sites. As a proof-of-principle demonstration, these findings hold promise for the use of pathogen receptor membrane-coated facet-dependent nanomaterials in clinical applications and the treatment of bacterial infections.

A novel irinotecan-lipiodol nanoemulsion for intravascular administration: pharmacokinetics and biodistribution in the normal and tumor bearing rat liver

Colorectal cancer is one of the most common cancers in the United States and treatment options are limited for patients who develop liver metastases. Several chemotherapeutic regimens have been used for transvascular liver-directed therapy in the treatment of colorectal liver metastases without clear evidence of superiority of one therapy over another. We describe the development of a novel nanoemulsion through combining irinotecan (IRI), a first line systemic agent used for the treatment of colon cancer, with lipiodol, an oily contrast medium derived from poppy seed oil, and evaluated its pharmacokinetic and biodistribution profile as a function of portal venous chemoembolization (PVCE) versus transarterial chemoembolization (TACE) delivery. The Tessari technique was used to create a stable emulsion (20 mg IRI mixed with 2 mL lipiodol) with resultant particle size ranging from 28.9 nm to 56.4 nm. Pharmacokinetic profile established through venous sampling in Buffalo rats demonstrate that the area under the curve (AUC_0−∞) of IRI was significantly less after PVCE with IRI-lipiodol as compared to IRI alone (131 vs. 316 µg*min/mL, p-value = .023), suggesting significantly higher amounts of IRI retention in the liver with the IRI-lipiodol nanoemulsion via first-pass extraction. Subseqent biodistribution studies in tumor-bearing WAG/Rjj rats revealed more IRI present in the tumor following TACE versus PVCE (29.19 ± 12.33 µg/g versus 3.42 ± 1.62; p-value = .0033) or IV (29.19 ± 12.33 µg/g versus 1.05 ± 0.47; p-value = .0035). The IRI-lipiodol nanoemulsion demonstrated an acceptable hepatotoxicity profile in all routes of administration. In conclusion, the IRI-lipiodol nanoemulsion via TACE showed promise and warrants further investigation as an option for the treatment of metastatic colorectal cancer.

Opportunities and challenges of fatty acid conjugated therapeutics

Instability, poor cellular uptake and unfavorable pharmacokinetics and biodistribution of many therapeutic molecules require modification in their physicochemical properties. The conjugation of these APIs with fatty acids has demonstrated an enhancement in their lipophilicity and stability. The improvement in the formulations that resulted from the conjugation of a drug with a fatty acid includes increased half-life, enhanced cellular uptake and retention, targeted tumor delivery, reduced chemoresistance in cancer, and improved blood-brain-barrier (BBB) penetration. In this review, various therapeutic molecules, including small molecules, peptides and oligonucleotides, that have been conjugated with fatty acid have been thoroughly discussed along with various conjugation strategies. The application of nano-system based delivery is gaining a lot of attention due to its ability to provide controlled drug release, targeting and reducing the extent of side effects. This review also covers various nano-carriers that have been utilized for the delivery of fatty acid drug conjugates. The enhanced lipophilicity of the drug-fatty acid conjugate has shown to enhance the affinity of the drug towards these carriers, thereby increasing the entrapment efficiency and formulation performance.

Enhanced antitumor efficacy of lapachol-loaded nanoemulsion in breast cancer tumor model

Lapachol (LAP) is a natural compound with various biological properties, including anticancer activity. However, its clinical application is limited due to the low aqueous solubility and potential adverse side effects. Nanoemulsions are drug delivery systems that can assist in the administration of hydrophobic drugs, increasing their bioavailability and protecting from degradation. Thus, this study aimed to prepare a LAP-loaded nanoemulsion (NE-LAP), and evaluate its antitumor activity. For this purpose, the nanoemulsion was prepared using a hot homogenization method and characterized morphologically by cryogenic transmission electron microscopy (cryo-TEM). Mean diameter, polydispersity index, and zeta potential was evaluated by DLS, encapsulation efficiency was measured by HPLC. Moreover, the short-term storage stability, the drug release and hemolysis in vitro was determined. Additionally, pharmacokinetic, toxicology and toxicity properties of99mTc-NE-LAP were evaluated in a breast cancer (4T1) tumor model. The cryo-TEM showed spherical globules, and the physicochemical characterization of NE-LAP showed a homogeneous stable nanoemulsion with a mean diameter of ∼170 nm, zeta potential of around -20 mV, and encapsulation greater than 85 %. In vitro studies validated that encapsulation did not impair the cytotoxicity activity of LAP. The nanoemulsion was successfully radiolabeled and 99mTc-NE-LAP showed prolonged blood circulation and tumor affinity was confirmed by tumor-to-muscle ratio. Moreover, NE-LAP showed higher antitumor activity than the free drug and the treatment did not result in any signs of toxicity. Therefore, these findings suggest that NE-LAP can be considered an effective strategy for cancer treatment.

Co-delivery of doxorubicin, docosahexaenoic acid, and α-tocopherol succinate by nanostructured lipid carriers has a synergistic effect to enhance antitumor activity and reduce toxicity

Doxorubicin (DOX) is widely used in cancer treatment, however, its use is often limited due to its side effects. To avoid these shortcomings, the encapsulation of DOX into nanocarriers has been suggested. Herein, we proposed a novel nanostructured lipid carrier (NLC) formulation loading DOX, docosahexaenoic acid (DHA), and α-tocopherol succinate (TS) for cancer treatment. DHA is an omega-3 fatty acid and TS is a vitamin E derivative. It has been proposed that these compounds can enhance the antitumor activity of chemotherapeutics. Thus, we hypothesized that the combination of DOX, DHA, and TS in NLC (NLC-DHA-DOX-TS) could increase antitumor efficacy and also reduce toxicity. NLC-DHA-DOX-TS was prepared using emulsification-ultrasound. DOX was incorporated after preparing the NLC, which prevented its degradation during manufacture. High DOX encapsulation efficiency was obtained due to the ion-pairing with TS. This ion-pairing increases lipophilicity of DOX and reduces its crystallinity, contributing to its encapsulation in the lipid matrix. Controlled DOX release from the NLC was observed in vitro, with increased drug release at the acidic environment. In vitro cell studies indicated that DOX, DHA, and TS have synergistic effects against 4T1 tumor cells. The in vivo study showed that NLC-DHA-DOX-TS exhibited the greatest antitumor efficacy by reducing tumor growth in 4T1 tumor-bearing mice. In addition, this formulation reduced mice mortality, prevented lung metastasis, and decreased DOX-induced toxicity to the heart and liver, which was demonstrated by hematologic, biochemical, and histologic analyses. These results indicate that NLC-DHA-DOX-TS may be a promising carrier for breast cancer treatment.

Oleic Acid Copolymer as A Novel Upconversion Nanomaterial to Make Doxorubicin-Loaded Nanomicelles with Dual Responsiveness to pH and NIR

Oleic acid (OA) as main component of plant oil is an important solvent but seldom used in the nanocarrier of anticancer drugs because of strong hydrophobicity and little drug release. In order to develop a new type of OA nanomaterial with dual responses to pH and near infrared light (NIR) to achieve the intelligent delivery of anticancer drugs. The novel OA copolymer (mPEG-PEI-(NBS, OA)) was synthesized by grafting OA and o-nitrobenzyl succinate (NBS) onto mPEGylated polyethyleneimine (mPEG-PEI) by amidation reaction. It was further conjugated with NaYF₄:Yb³⁺/Er³⁺ nanoparticles, and encapsulated doxorubicin (DOX) through self-assembly to make upconversion nanomicelles with dual response to pH and NIR. Drug release behavior of DOX, physicochemical characteristics of the nanomicelles were evaluated, along with its cytotoxic profile, as well as the degree of cellular uptake in A549 cells. The encapsulation efficiency and drug loading capacity of DOX in the nanomicelles were 73.84% ± 0.58% and 4.62% ± 0.28%, respectively, and the encapsulated DOX was quickly released in an acidic environment exposed to irradiation at 980 nm. The blank nanomicelles exhibited low cytotoxicity and excellent biocompatibility by MTT assay against A549 cells. The DOX-loaded nanomicelles showed remarkable cytotoxicity to A549 cells under NIR, and promoted the cellular uptake of DOX into the cytoplasm and nucleus of cancer cells. OA copolymer can effectively deliver DOX to cancer cells and achieve tumor targeting through a dual response to pH and NIR.

Nanomedicines in Diagnosis and Treatment of Cancer: An Update

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Nanomedicine has revolutionized the field of cancer detection and treatment by enabling the delivery of imaging agents and therapeutics into cancer cells. Cancer diagnostic and therapeutic agents can be either encapsulated or conjugated to nanosystems and accessed to the tumor environment through the passive targeting approach (EPR effect) of the designed nanomedicine. It may also actively target the tumor exploiting conjugation of targeting moiety (like antibody, peptides, vitamins, and hormones) to the surface of the nanoparticulate system. Different diagnostic agents (like contrast agents, radionuclide probes and fluorescent dyes) are conjugated with the multifunctional nanoparticulate system to achieve simultaneous cancer detection along with targeted therapy. Nowadays targeted drug delivery, as well as the early cancer diagnosis is a key research area where nanomedicine is playing a crucial role. This review encompasses the significant recent advancements in drug delivery as well as molecular imaging and diagnosis of cancer exploiting polymer-based, lipid-based and inorganic nanoparticulate systems.

Co-Delivery of Prednisolone and Curcumin in Human Serum Albumin Nanoparticles for Effective Treatment of Rheumatoid Arthritis

Background

Prednisolone (PD) is extremely effective for treating rheumatoid arthritis (RA). However, it distributes nonspecifically throughout the body and its use is associated with serious side effects, which promoted us to compound it into a phytomedicine for greater efficacy and safety.

Methods

We combined PD with curcumin (CU), an effective monomer from traditional Chinese medicine, and human serum albumin (HSA) in a nanoparticulate system (N-PD/CU) to compensate for the poor bioavailability of PD and CU. N-PD/CU was prepared by high-pressure homogenization, and its characteristics were evaluated in vitro. Next, we investigated its toxicity and mechanism of anti-inflammatory to macrophages. Finally, its pharmacokinetics, biodistribution and therapeutic efficacy were assessed in rats with adjuvant-induced arthritis (AIA).

Results

N-PD/CU showed a narrow size distribution around 150.4 ± 2.4 nm, a polydispersity index of 0.22 ± 0.02 and drug loading efficiency (DLE) of 88.75 ± 1.82% for PD and 85.79 ± 1.43% for CU. N-PD/CU showed sustained release of both drugs in vitro. N-PD/CU had no toxicity to macrophages in vitro on concentrations between 0.1 and 1.2 μmol/mL. In activated macrophages, N-PD decreased levels of pro-inflammatory cytokines, while N-CU increased levels of anti-inflammatory IL-10, and N-PD/CU exhibited best therapeutic effect in vitro, suggesting co-delivery of PD and CU may synergistically control the course of RA. In AIA rats, N-PD/CU accumulated in inflamed joints through the effect of extravasation through leaky vasculature and subsequent inflammatory cell-mediated sequestration (ELVIS effect) in inflammatory lesion and showed higher therapeutic efficacy than single-loaded nanoparticles, either free drug on its own, or a simple mixture of the two drugs.

Conclusion

This codelivery system based on HSA is a promising platform for combination chemotherapy in RA.

Alternative and Injectable Preformed Albumin-Bound Anticancer Drug Delivery System for Anticancer and Antimetastasis Treatment

Biomimetic design has been extensively investigated. The only FDA-approved biomimetic albumin-bound paclitaxel may not be beneficial to some treated patients due to rapid dissociation upon intravenous infusion and no substantial improvement in the drug's pharmacokinetics or biodistribution. Herein, we developed an alternative and injectable preformed albumin-bound anticancer drug delivery. We combined HSA, Kolliphor HS 15 (HS15), and pirarubicin (THP) via purely physical forces in a thin-film hydration method to obtain an albumin-bound complex of HSA-THP. The lack of any chemical reactions preserves HSA bioactivity, in contrast to the destroyed secondary structure within AN-THP (albumin nanoparticle of THP) for the harsh manipulation during preparation. In vitro, HSA-THP showed a significantly higher cellular uptake efficiency than THP, and the complex was more cytotoxic. In vivo, HSA-THP showed longer half-life than THP. It also exhibited greater tumor accumulation and tumor penetration via gp60- and SPARC-mediated biomimetic transport than THP and AN-THP. As a result, HSA-THP showed strong antitumor and antimetastasis efficacy, with relatively little toxicity. These results suggest the clinical potential of biomimetic tumor-targeted drug delivery.

Hydrophobic ion pairing: encapsulating small molecules, peptides, and proteins into nanocarriers

Hydrophobic ion pairing has emerged as a method to modulate the solubility of charged hydrophilic molecules ranging in class from small molecules to large enzymes. Charged hydrophilic molecules are ionically paired with oppositely-charged molecules that include hydrophobic moieties; the resulting uncharged complex is water-insoluble and will precipitate in aqueous media. Here we review one of the most prominent applications of hydrophobic ion pairing: efficient encapsulation of charged hydrophilic molecules into nano-scale delivery vehicles - nanoparticles or nanocarriers. Hydrophobic complexes are formed and then encapsulated using techniques developed for poorly-water-soluble therapeutics. With this approach, researchers have reported encapsulation efficiencies up to 100% and drug loadings up to 30%. This review covers the fundamentals of hydrophobic ion pairing, including nomenclature, drug eligibility for the technique, commonly-used counterions, and drug release of encapsulated ion paired complexes. We then focus on nanoformulation techniques used in concert with hydrophobic ion pairing and note strengths and weaknesses specific to each. The penultimate section bridges hydrophobic ion pairing with the related fields of polyelectrolyte coacervation and polyelectrolyte-surfactant complexation. We then discuss the state of the art and anticipated future challenges. The review ends with comprehensive tables of reported hydrophobic ion pairing and encapsulation from the literature.

Integration of phospholipid-drug complex into self-nanoemulsifying drug delivery system to facilitate oral delivery of paclitaxel

Self-nanoemulsifying drug delivery system (SNEDDS) has emerged as a promising platform to improve oral absorption of drugs with poor solubility and low permeability. However, large polarity molecules with insufficient lipid solubility, such as paclitaxel (PTX), would suffer from inferior formulation of SNEDDS due to poor compatibility. Herein, phospholipid-drug complex (PLDC) and SNEDDS were integrated into one system to facilitate oral delivery of PTX. First, PTX was formulated into PLDC in response to its inferior physicochemical properties. Then, the prepared PLDC was further formulated into SNEDDS by integrating these two drug delivery technologies into one system (PLDC-SNEDDS). After PLDC-SNEDDS dispersed in aqueous medium, nanoemulsion was formed immediately with an average particle size of ∼30 nm. Furthermore, the nanomulsion of PLDC-SNEDDS showed good colloidal stability in both HCl solution (0.1 mol/l, pH 1.0) and phosphate buffer solution (PBS, pH 6.8). In vivo, PTX-PLDC-SNEDDS showed distinct advantages in terms of oral absorption efficiency, with a 3.42-fold and 2.13-fold higher bioavailability than PTX-PLDC and PTX solution, respectively. Our results suggest that the integration of PLDC into SNEDDS could be utilized to facilitate the oral delivery of hydrophobic drugs with large polarity.

Novel skin penetrating berberine oleate complex capitalizing on hydrophobic ion pairing approach

Berberine hydrochloride (Brb) is a well-known herbal drug that holds a great promise in the recent years thanks to its various pharmacological actions. Currently, Brb is extensively researched as a natural surrogate with evidenced potentiality against numerous types of skin diseases including skin cancer. However, Brb's high aqueous solubility and limited permeability hinder its clinical topical application. In the current work, to enhance Brb's dermal availability, hydrophobic ion pairing approach was implemented combining the privileges of altering the solubility characteristics of Brb and the nanometric size that is usually gained during the ion pairing precipitation process. Sodium oleate (SO) was selected as the complexing agent due to its low toxicity and skin penetrating characteristics. Ion paired berberine oleate complex (Brb-OL) was prepared by simple precipitation technique. Brb-OL complex formation was confirmed by differential scanning calorimetry (DSC), infrared spectroscopy (IR), X-ray powder diffraction (XRD) and saturation solubility studies. It was found that Brb-OL complex formed at stoichiometric binding between oleate and Brb had an average particle size of 195.9 nm and zeta potential of -53.6 mV. The proposed Brb-OL showed 251-fold increase in saturation solubility in n-octanol which confirmed the augmented lipid solubility of the complex compared with free drug. Comparative in-vitro release study showed that Brb-OL complex had much slow and sustained release profile compared to that of free Brb. Furthermore, ex-vivo permeation study using rat skin revealed the enhanced skin permeation of ion-paired Brb-OL complex compared with free Brb. In-vivo study on healthy rats confirmed that topical application of hydrogels enriched with Brb-OL had superior skin penetration and deposition than free Brb as revealed by confocal microscope. Conclusively, ion pair formation between Brb and oleate lead to the formation of more lipophilic Brb-OL complex with nanometric particle size which is expected to be a major progressive step towards the development of a topical berberine formulation.

nRGD modified lycobetaine and octreotide combination delivery system to overcome multiple barriers and enhance anti-glioma efficacy

For glioma as one of the most common and lethal primary brain tumors, the presence of BBB, BBTB, vasculogenic mimicry (VM) channels and tumor-associated macrophages (TAMs) are key biological barriers. Here, a novel drug delivery system which could efficiently deliver drugs to glioma by overcoming multi-barriers and increase antitumor efficacy through multi-therapeutic mechanisms was well developed. In this study, a multi-target peptide nRGD was used to transport across the BBB, mediate tumor penetration and target TAMs. Lycobetaine (LBT) was adopted to kill glioma cells and octreotide (OCT) was co-delivered to inhibit VM channels and prevent angiogenesis. LBT-OCT liposomes (LPs) showed controlled release profile in vitro, increased uptake efficiency, improved inhibitory effect against glioma cells and VM formation, and enhanced BBB-crossing capability. The median survival time of glioma-bearing mice administered with LBT-OCT LPs-nRGD was significantly longer than LBT-OCT LPs (P<0.01). Besides, nRGD achieved a stronger inhibitory effect against tumor associated macrophages (TAMs) compared to LPs-iRGD treatment groups in vivo. Thus, LPs-nRGD represented a promising versatile delivery platform for combination drug therapy in glioma treatment.

Analysis of Lycobetaine in Rat Plasma by LC-ESI-MS/MS

In this study, a selective and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometric method was developed and validated for the determination of lycobetaine in rat plasma. Berberine was selected as the internal standard, and rat plasma samples were pretreated via protein precipitation and further separated on a diamonsil octadecyl-silylated silica column using 0.2% (v/v) aqueous formic acid and methanol as the mobile phase. Selected reaction monitoring was performed using the transitions m/z 266.1 → 208.1 and m/z 336.1 → 320.0 to determine the concentrations of lycobetaine and internal standard, respectively. The injection volume was 1 µL, and the calibration curve was linear (R2 = 0.9998), while the validated lower limit of quantification was 25 ng/mL. Precision varied from 3.4% to 9.9%, and accuracy varied from -2.6% to 8.7%. Lycobetaine remained stable under all relevant analytical conditions tested in the study. The method was successfully applied to determine the plasma concentration of lycobetaine in a pharmacokinetic study. After intravenous administration of 10 mg/kg and oral administration of 200 mg/kg lycobetaine in rats, the pharmacokinetic parameters were calculated and the oral bioavailability of lycobetaine was determined as 7.30% ± 1.44%.

Cell-penetrating self-nanoemulsifying drug delivery systems (SNEDDS) for oral gene delivery

OBJECTIVE

The aim of study was to investigate whether cell-penetrating peptides could amplify cellular uptake of plasmid DNA (pDNA) loaded self-nanoemulsifying drug delivery systems (SNEDDS) by mucosal epithelial cells, thereby enhancing transfection efficiency.

METHODS

HIV-1 Tat peptide-oleoyl conjugate (TAT-OL) was synthesized through amide bond formation between HIV-1 Tat-protein 49-57 (TAT) and oleoyl-chloride (OL). SNEDDS formulation contained 29.7% each of Cremophor EL, Capmul MCM and Crodamol, 9.9% propylene glycol and 1% TAT-OL. SNEDDS with OL instead of TAT-OL served as control.

RESULTS

Fluorescent-microscopy demonstrated 0.5% (m/v) nanoemulsions were suitable for subsequent studies. Mucus diffusion of nanoemulsion loaded with fluorescein diacetate (FDA) was 1.5-fold increased by incorporation of TAT-OL. Confocal microscopy confirmed that droplets of nanoemulsions were successfully internalized. Furthermore, quantitative analysis showed that addition of TAT-OL increases uptake of nanoemulsions by 2.3- and 2.6-folds after 2 and 4 hours of incubation, respectively. Cellular internalization pathways were found with substantial decrease in uptake in presence of indomethacin and chlorpromazine. Transfection efficiency investigated on HEK-293-cells was found to be 1.7- and 1.8-fold higher for SNEDDS loaded with TAT-OL compared to Lipofectin and control, respectively.

CONCLUSION

In comparison to prevailing lipid and polymer-based delivery systems, these novel cell-penetrating SNEDDS likely represent most effective, simplistic and expedite dosage form for mucosal gene delivery.

Optimization of ultrasound induced emulsification on the formulation of palm-olein based nanoemulsions for the incorporation of antioxidant β-D-glucan polysaccharides

Polysaccharides of β-D-glucan configuration have well-known antioxidant activity against reactive free radicals generated from the oxidation of metabolic processes. In this study, β-D-glucan-polysaccharides extracted from Ganoderma lucidum were incorporated in palm olein based nanoemulsions which act as carrier systems to enhance the delivery and bioactivity of these polysaccharides and could be potentially useful for skin care applications. Initially response surface statistical design (Central Composite Design--CCD) was subjected to optimize the formulation variables of oil-in-water (O/W) nanoemulsions induced by ultrasound. The optimal formulation variables as predicted by CCD resulted in considerably improving the physical characteristics of ultrasonically formulated nanoemulsions by minimizing their droplet size, polydispersity index and viscosity. Moreover, the β-D-glucan-loaded nanoemulsions exhibited good stability over 90 days under different storage conditions (4 °C and 25 °C). The studies using palm olein based β-D-glucan-loaded nanoemulsion generated using ultrasound confirm higher antioxidant activity as compared to free β-D-glucan.

Development, Optimization, and Characterization of PEGylated Nanoemulsion of Prostaglandin E1 for Long Circulation

Lipo-PGE1 is the most widely used formulation of PGE1 in clinic. However, PGE1 is easier to leak out from lipo-PGE1 and this will lead to the phlebophlogosis when intravenous injection. The stability of lipo-PGE1 in storage and in vivo is also discounted. The aim of this study is to develop a long-circulating prostaglandin E1-loaded nanoemulsion modified with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG) to improve the stability and pharmacokinetics profiles of lipo-PGE1. PEGylated PGE1 nanoemulsion was prepared using a dispersing-homogenized method. The stability of nanoemulsion in 1 month was investigated. Pharmacokinetic studies were employed to evaluate the in vivo profile of the optimized nanoemulsion. The optimized nanoemulsion PGE1-PEG2000(1%)-NE showed an oil droplet size <100 nm with a surface charge of -14 mV. Approximately, 97% of the PGE1 was encapsulated in the nanoemulsion. The particle size, zeta potential, and drug loading of PGE1-PEG2000(1%)-NE were stable in 1 month. After PGE1-PEG2000(1%)-NE was intravenously administered to rats, the area under curve (AUC) and half-life of PGE1 were, respectively, 1.47-fold and 5.98-fold higher than those of lipo-PGE1 (commercial formulation). PGE1-PEG2000(1%)-NE was an ideal formulation for prolonging the elimination time of PGE1. This novel parenteral colloidal delivery system of PGE1 has a promising potential in clinic use.

Drug delivery and drug targeting with parenteral lipid nanoemulsions - A review

Lipid nanosized emulsions or nanoemulsions (NE) are oil in water dispersions with an oil droplet size of about 200nm. This size of oil droplets dispersed in a continuous water phase is a prerequisite for the parenteral, namely intravenous administration. Many parenteral nutrition and drug emulsions on the market confirm the safe use of NE over years. Parenteral emulsions loaded with APIs (active pharmaceutical ingredients) are considered as drug delivery systems (DDS). DDS focuses on the regulation of the in vivo dynamics, such as absorption, distribution, metabolism, and extended bioavailability, thereby improving the effectiveness and the safety of the drugs. Using an emulsion as a DDS, or through the use of surface diversification of the dispersed oil droplets of emulsions, a targeted increase of the API concentration in some parts of the human body can be achieved. This review focuses on NE similar to the marketed once with no or only low amount of additional surfactants beside the emulsifier from a manufacturing point of view (technique, used raw materials).

Nanoparticles as drug carriers: current issues with in vitro testing

Incorporation of nanotechnology in the field of drug delivery has created exciting opportunities for the purposeful design of nanocarriers with potentials such as targeted delivery or controlled release of the incorporated cargo, improvement of bioavailability and reduction of therapeutic side-effects. Prior to in vivo administration, nanocarriers should undergo a set of in vitro evaluation procedures to ensure their stability, safety, conformity and ability to fulfill the desired mission. In this paper, current issues with in vitro evaluation techniques used for nanocarrier characterization (assessment of particle size, surface charge, drug release and toxicity) will be discussed. Furthermore, sufficiency of in vitro evaluation procedures for the prediction of in vivo scenarios and the necessary considerations to improve the correlation between the two settings will be debated.

Mechanism of enhanced oral absorption of morin by phospholipid complex based self-nanoemulsifying drug delivery system

Phospholipid complex (PLC) based self-nanoemulsifying drug delivery system (PLC-SNEDDS) has been developed for efficient delivery of drugs with poor solubility and low permeability. In the present study, a BCS class IV drug and a P-glycoprotein (P-gp) substrate, morin, was selected as the model drug to elucidate the oral absorption mechanism of PLC-SNEDDS. PLC-SNEDDS was superior to PLC in protecting morin from degradation by intestinal enzymes in vitro. In situ perfusion study showed increased intestinal permeability by PLC was duodenum-specific. In contrast, PLC-SNEDDS increased morin permeability in all intestinal segments and induced a change in the main absorption site of morin from colon to ileum. Moreover, ileum conducted the lymphatic transport of PLC-SNEDDS, which was proven by microscopic intestinal visualization of Nile red labeled PLC-SNEDDS and lymph fluids in vivo. Low cytotoxicity and increased Caco-2 cell uptake suggested a safe and efficient delivery of PLC-SNEDDS. The increased membrane fluidity and disrupted actin filaments were closely associated with the increased cell uptake of PLC-SNEDDS. PLC-SNEDDS could be internalized into enterocytes as an intact form in a cholesterol-dependent manner via clathrin-mediated endocytosis and macropinocytosis. The enhanced oral absorption of morin was attributed to the P-gp inhibition by Cremophor RH and the intact internalization of M-PLC-SNEDDS into Caco-2 cells bypassing P-gp recognition. Our findings thus provide new insights into the development of novel nanoemulsions for poorly absorbed drugs.

Computed tomography-guided screening of surfactant effect on blood circulation time of emulsions: application to the design of an emulsion formulation for paclitaxel

PURPOSE

In an effort to apply the imaging techniques currently used in disease diagnosis for monitoring the pharmacokinetics and biodisposition of particulate drug carriers, we sought to use computed tomography (CT) scanning methodology to investigate the impact of surfactant on the blood residence time of emulsions.

METHODS

We prepared the iodinated oil Lipiodol emulsions with different compositions of surfactants and investigated the impact of surfactant on the blood residence time of emulsions by CT scanning.

RESULTS

The blood circulation time of emulsions was prolonged by including Tween 80 or DSPE-PEG (polyethylene glycol 2000) in emulsions. Tween 80 was less effective than DSPE-PEG in terms of prolongation effect, but the blood circulating time of emulsions was prolonged in a Tween 80 content-dependent manner. As a proof-of-concept demonstration of the usefulness of CT-guided screening in the process of formulating drugs that need to be loaded in emulsions, paclitaxel was loaded in emulsions prepared with 87 or 65% Tween 80-containing surfactant mixtures. A pharmacokinetics study showed that paclitaxel loaded in 87% Tween 80 emulsions circulated longer in the bloodstream compared to those in 65% Tween 80 emulsions, as predicted by CT imaging.

CONCLUSIONS

CT-visible, Lipiodol emulsions enabled the simple evaluation of surfactant composition effects on the biodisposition of emulsions.