Therapeutic efficacy of lipid emulsions of docetaxel-linoleic acid conjugate in breast cancer

Improving cellular uptake and synergetic anti-tumor effects of magnolol and Brucea javanica oil through self-microemulsion

OBJECTIVE

Magnolol (MG) and Brucea javanica (L.) Merr. oil (BJO) possess synergetic anti-tumor effects, but have poor water solubility and stability, which results in low oral bioavailability.

SIGNIFICANCE

The MG loaded self-microemulsion drug delivery system (MG-SMDDS) with BJO as oil phase component was utilized to improve the cellular uptake and synergetic anti-tumor effects.

METHODS

Compatibility study and pseudoternary phase diagram (PTPD) were respectively employed to screen for the composition and proportion of oil phase in the formulation. Central composite design-effect surface method was applied to optimize proportion of each formulation condition. The droplet size, ζ-potential, colloid stability, encapsulation rate (ER) and in vitro dissolution rate of MG-SMDDS were evaluated. Furthermore, cellular uptake and cytotoxicity of the microemulsion on HepG2 cells were assessed.

RESULTS

The optimal composition of MG-SMDDS was: MG (9.09%), castor oil (7.40%), BJO (2.47%), Cremophor EL 35 (54.04%) and 1, 2-propanediol (27.01%). The MG-SMDDS exhibited satisfactory droplet size, ζ-potential, colloid stability and ER, as well as faster dissolution rate than free MG. More importantly, SMEDDS containing BJO could enhance the cellular uptake and cytotoxicity of free BJO and free MG on tumor cells.

CONCLUSIONS

The BJO self-microemulsion delivery technique can provide an idea for design of oral delivery vehicles based on BJO.

Current views on in vivo models for breast cancer research and related drug development

INTRODUCTION

Animal models play a crucial role in breast cancer research, in particular mice and rats, who develop mammary tumors that closely resemble their human counterparts. These models allow the study of mechanisms behind breast carcinogenesis, as well as the efficacy and safety of new, and potentially more effective and advantageous therapeutic approaches. Understanding the advantages and disadvantages of each model is crucial to select the most appropriate one for the research purpose.

AREA COVERED

This review provides a concise overview of the animal models available for breast cancer research, discussing the advantages and disadvantages of each one for searching new and more effective approaches to treatments for this type of cancer.

EXPERT OPINION

Rodent models provide valuable information on the genetic alterations of the disease, the tumor microenvironment, and allow the evaluation of the efficacy of chemotherapeutic agents. However, in vivo models have limitations, and one of them is the fact that they do not fully mimic human diseases. Choosing the most suitable model for the study purpose is crucial for the development of new therapeutic agents that provide better care for breast cancer patients.

Preparation and in vivo evaluation of an intravenous emulsion loaded with an aprepitant-phospholipid complex

In present, there was no detailed report on the formulation optimization and quality evaluation of aprepitant (APT) injectable lipid emulsion (APT-IE). The aim of the present investigation was to prepare and evaluate its properties of APT-IE loaded with an APT phospholipid complex (APT-PC) in vitro and in vivo. APT-PC was obtained by solvent evaporation with APT and phospholipids, then analyzed by X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry. Lipid emulsions are a new formulation that can reduce side effects and improve drug loading.APT-IE prepared by High-pressure homogenization and optimized by response surface methodology (RSM). The proportion of sodium oleate, poloxamer 188 and soybean oil were selected as variables for the optimization. The optimal formulation of ATP-IE had the following characteristics: particle size, 82.83 ± 1.89 nm; polydispersity index, 0.243 ± 0.008; zeta potential, -59.0 ± 2.54 mV; encapsulation efficiency, 98.84%±1.43%; drug loading, 7.08 ± 0.16 mg/mL; and osmotic pressure, 301 ± 2.15 mOsmol/kg. Transmission electron microscopy images indicated that the particle diameter of APT-IE was approximately 100 nm, with a morphology of spheroidal or spherical. APT-IE exhibited sufficient stability after storage at 4 ± 2 °C for more than 6 months. The results of the pharmacokinetic study demonstrated that APT-IE had the advantages of better safety, higher bioavailability, and obvious liver targeting than APT solution (APT-SL). The area under the curve (AUC) of APT-IE was 3-fold enhanced compared with APT-SL. The targeted enhancement multiple of APT-IE to liver tissue was greater than that of APT-SL. These results suggested that APT-IE has broad clinical application and industrial production potential.

Sialic acid-decorated liposomes enhance the anti-cancer efficacy of docetaxel in tumor-associated macrophages

Tumor-associated macrophages (TAMs) in the tumor microenvironment potentially enhance tumor growth and invasion through various mechanisms and are thus an essential factor in tumor immunity. The highly expressed siglec-1 receptors on the surfaces of TAMs are potential targets for cancer drug delivery systems. Sialic acid (SA) is a specific ligand for siglec-1. In this study, the sialic acid-polyethylene glycol conjugate (DSPE-PEG2000-SA) was synthesized to modify the surface of liposomes and target TAMs by interacting with the siglec-1 receptor. Three docetaxel (DTX)-loaded liposomes, conventional (DTX-CL), DSPE-PEG2000-coated (DTX-PL), and DSPE-PEG2000-SA-coated (DTX-SAPL) liposomes, were prepared, with a particle size of <100 nm, uniform polydispersity index (PDI) values, negative zeta potential, and % encapsulation efficiency (EE) exceeding 95 %. Liposomes showed high stability after 3 months of storage at 4 °C without significant changes in particle size, PDI, zeta potential, or % EE. DTX was released from liposomes according to the Weibull model, and DTX-SAPL exhibited more rapid drug release than other liposomes. In vitro studies demonstrated that DTX-SAPL liposome exhibited a higher uptake and cytotoxicity on RAW 264.7 cells (TAM model) and lower toxicity on NIH3T3 cells (normal cell model) than other formulations. The high cell uptake ability was demonstrated by the role of the SA-SA receptor. Biodistribution studies indicated a high tumor accumulation of surface-modified liposomal formulations, particularly SA-modified liposomes, showing high signal accumulation at the tumor periphery, where TAMs were highly concentrated. Ex vivo imaging showed a significantly higher accumulation of SA-modified liposomes in the tumor, kidney, and heart than conventional liposomes. In the anti-cancer efficacy study, DTX-SAPL liposomes showed effective inhibition of tumor growth and relatively low systemic toxicity, as evidenced by the tumor volume, tumor weight, body weight values, and histopathological analysis. Therefore, DSPE-PEG2000-SA-coated liposomes could be promising carriers for DTX delivery targeting TAMs in cancer therapy.

Emulsion Technology in Nuclear Medicine: Targeted Radionuclide Therapies, Radiosensitizers, and Imaging Agents

Radiopharmaceuticals serve as a major part of nuclear medicine contributing to both diagnosis and treatment of several diseases, especially cancers. Currently, most radiopharmaceuticals are based on small molecules with targeting ability. However, some concerns over their stability or non-specific interactions leading to off-target localization are among the major challenges that need to be overcome. Emulsion technology has great potential for the fabrication of carrier systems for radiopharmaceuticals. It can be used to create particles with different compositions, structures, sizes, and surface characteristics from a wide range of generally recognized as safe (GRAS) materials, which allows their functionality to be tuned for specific applications. In particular, it is possible to carry out surface modifications to introduce targeting and stealth properties, as well as to control the particle dimensions to manipulate diffusion and penetration properties. Moreover, emulsion preparation methods are usually simple, economic, robust, and scalable, which makes them suitable for medical applications. In this review, we highlight the potential of emulsion technology in nuclear medicine for developing targeted radionuclide therapies, for use as radiosensitizers, and for application in radiotracer delivery in gamma imaging techniques.

Tumor microenvironment stimuli-responsive lipid-drug conjugates for cancer treatment

Lipid drug conjugates (LDCs) have attracted considerable attention in the fields of drug delivery and pharmacology due to their ability to target specific cells, increase drug solubility, reduce toxicity, and improve therapeutic efficacy. These unique features make LDCs promising candidates for the treatment cancer, inflammation, and infectious diseases. In fact, by choosing specific linkers between the lipid and drug molecules, stimuli-responsive LDCs can be designed to target cancer cells based on the unique properties of the tumor microenvironment. Despite the fact that many reviews have described LDCs, few articles have focused on tumor microenvironmental stimuli-responsive LDCs for cancer treatment. Therefore, the key elements of these types of LDCs in cancer treatment will be outlined and discussed in this paper. Our paper goes into detail on the concepts and benefits of LDCs, the various types of tumor microenvironment stimuli-responsive LDCs (such as pH, redox, enzyme, or reactive oxygen species-responsive LDCs), and the current status of LDCs in clinical trials.

Nanoemulsion Composed of α-Tocopherol Succinate and Dequalinium Shows Mitochondria-Targeting and Anticancer Effects

Targeted drugs have been used to treat mitochondrial dysfunction-related diseases, including metabolic disorders and cancer; however, targeting and penetrating intracellular organelles remains a challenge. Dominant targeting approaches for therapeutic delivery are detailed in many nanoemulsion studies and show the tremendous potential of targeted delivery to inhibit cancer cell growth. Dequalinium (DQA) and α-tocopherol succinate (α-TOS) are good agents for targeting mitochondria. In this study, we aimed to develop a mitochondria-targeting emulsion, using DQA and α-TOS (DTOS), for cancer treatment. DTOS emulsions of 150-170 nm in diameter were formulated using homogenization. DQA and α-TOS were used as bifunctional agents (surfactants) to stabilize the nanoemulsion and anticancer drugs. Various molar ratios of DQA and α-TOS were tested to determine the optimal condition, and DTOS 5-5 was selected for further study. The DTOS emulsion showed improved stability, as evidenced by its ability to remain stable for three years at room temperature. This stability, combined with its effective targeting of mitochondria, led to inhibition of 71.5% of HeLa cells after 24 h. The DTOS emulsion effectively inhibited spheroid growth in the 3D model, as well as prevented the growth of HeLa cells grafted onto zebrafish larvae. These results highlight the DTOS emulsion's promising potential for mitochondria-targeting and cancer treatment.

Improving cellular uptake and bioavailability of periplocymarin-linoleic acid prodrug by combining PEGylated liposome

Periplocymarin (PPM), a cardiac glycoside isolated from Cortex periplocae, has a strong anti-tumor effect against various cancer cells. However, cardiotoxicity and rapid metabolism hinder its clinical applications. In this study, small molecule prodrug was integrated into PEGylated liposome to improve the efficiency of periplocymarin in vivo. The periplocymarin-linoleic acid (PL) prodrug was constructed by conjugating the linoleic acid with PPM via esterification, which was further facilitated to form PEGylated liposome (PL-Lip) through film dispersion. Compared with PL self-assembling nano-prodrug (PL-SNP), PL-Lip showed better colloid stability, sustained drug release kinetics, and enhanced cellular uptake by tumor cells. Notably, PL-Lip performed better than PPM and PL-SNP in terms of tumor distribution and pharmacokinetics, which include bioavailability and half-life. Altogether, the prodrug PEGylated liposome represents a good strategy and method for long-circulating and tumor-targeting delivery of periplocymarin with enhanced clinical application prospect.

The Fabrication of Docetaxel-Containing Emulsion for Drug Release Kinetics and Lipid Peroxidation

Docetaxel (DTX)-based formulation development is still confronted with significant challenges, due to its refractory solubility and side effects on normal tissues. Inspired by the application of the transdermal drug delivery model to topical treatment, we developed a biocompatible and slow-release DTX-containing emulsion via self-assembly prepared by a high-speed electric stirring method and optimized the formulation. The results of accelerated the emulsion stability experiment showed that the emulsion prepared at 10,000 rpm/min had a stability of 89.15 ± 2.05%. The ADME, skin irritation, skin toxicity and molecular interaction between DTX and excipients were predicted via Discovery Studio 2016 software. In addition, DTX addition in oil or water phases of the emulsion showed different release rates in vitro and ex vivo. The DTX release ex vivo of the DTX/O-containing emulsion and the DTX/W-containing emulsion were 45.07 ± 5.41% and 96.48 ± 4.54%, respectively. In vitro antioxidant assays and anti-lipid peroxidation models revealed the antioxidant potential of DTX. However, DTX-containing emulsions could maintain and even enhance the antioxidant effect, both scavenging free radicals in vitro and inhibiting the process of lipid peroxidation.

Taxanes prodrug-based nanomedicines for cancer therapy

Malignant tumor remains a huge threat to human health and chemotherapy still occupies an important place in clinical tumor treatment. As a kind of potent antimitotic agent, taxanes act as the first-line broad-spectrum cancer drug in clinical use. However, disadvantages such as prominent hydrophobicity, severe off-target toxicity or multidrug resistance lead to unsatisfactory therapeutic effects, which restricts its wider usage. The efficient delivery of taxanes is still quite a challenge despite the rapid developments in biomaterials and nanotechnology. Great progress has been made in prodrug-based nanomedicines (PNS) for cancer therapy due to their outstanding advantages such as high drug loading efficiency, low carrier induced immunogenicity, tumor stimuli-responsive drug release, combinational therapy and so on. Based on the numerous developments in this filed, this review summarized latest updates of taxanes prodrugs-based nanomedicines (TPNS), focusing on polymer-drug conjugate-based nanoformulations, small molecular prodrug-based self-assembled nanoparticles and prodrug-encapsulated nanosystems. In addition, the new trends of tumor stimuli-responsive TPNS were also discussed. Moreover, the future challenges of TPNS for clinical translation were highlighted. We here expect this review will inspire researchers to explore more practical taxanes prodrug-based nano-delivery systems for clinical use.

Paclitaxel derivative-based liposomal nanoplatform for potentiated chemo-immunotherapy

The combination of chemotherapy with the immune checkpoint blockade (ICB) therapy is bringing a tremendous hope in the treatment of malignant tumors. However, the treatment efficacy of the existing chemo-immunotherapy is not satisfactory due to the high cost and immunogenicity of ICB antibodies, low response rate to ICB, off-target toxicity of therapeutic agents, and low drug co-delivery efficacy. Therefore, a high-efficient nanosystem combining the delivery of chemotherapeutics with small molecule ICB inhibitors may be promising for an efficient cancer therapy. Herein, a novel reactive oxygen species (ROS)-activated liposome nanoplatform was constructed by the loading of a ROS-sensitive paclitaxel derivative (PSN) into liposomes to overcome the difficulties on delivering paclitaxel mostly represented by premature drug release and a low amount accumulated into the tumor. The innovative liposomal nanosystem was rationally designed by a remote loading of BMS-202 (a small molecule PD-1/PD-L1 inhibitor) and PSN into the liposomes for a ROS-sensitive paclitaxel release and sustained BMS-202 release. The co-loaded liposomes resulted in a high co-loading ability and improved pharmacokinetic properties. An orthotopic 4 T1 breast cancer model was used to evaluate the efficiency of our nanoplatform in vivo, resulting in a superior antitumor activity. The antitumor immunity was activated by paclitaxel-mediated immunogenic cell death, while BMS-202 continuously blocked PD-L1 which could be up-regulated by paclitaxel in tumors to increase the response to ICB and further recover the host immune surveillance. These results revealed that this dual-delivery liposome might provide a promising strategy for a high-efficient chemo-immunotherapy, exhibiting a great potential for clinical translation.

Docosahexaenoic acid (DHA) and linoleic acid (LA) modulate the expression of breast cancer involved miRNAs in MDA-MB-231 cell line

BACKGROUND AND AIMS

Docosahexaenoic acid (DHA) and linoleic acid (LA) have modulatory effects on breast cancer (BC) cell lines. We aimed to investigate the effects of DHA, LA alone, in combination, and in the presence of paclitaxel on the expression of five microRNAs involved in the pathology of BC in MDA-MB-231 cell line.

METHODS

MDA-MB-231 cells were treated with either DHA or LA or in combination in the presence/absence of paclitaxel (Taxol). Total RNA was extracted and cDNA synthesized from the cells before and after treatment. The expression levels of miR-30, miR-106b, miR-20, miR-126, and miR-194 were determined by quantitative real-time PCR (qPCR).

RESULTS

Treatment of MDA-MB-231 cells with DHA modulated the gene expression of miR-30 (increased by 7.74-fold (p < 0.0001), miR-194 (decreased by 11-fold (p < 0.0001)), miR-106b (increased by 2.64-fold (p = 0.0004), miR-126 (decreased by 50-fold (p < 0.0001)), and miR-20 (decreased by 4-fold (p < 0.0001)). Additionally, treatment of MDA-MB-231 cells with LA modulated the gene expression of miR-30 (increased by 2.38-fold (p = 0.0001)), miR-194 (decreased by 100-fold (p < 0.0001)), miR-106b (decreased by 10-fold (p < 0.0001)). The combined DHA/LA treatment of MDA-MB-231 cells showed regulatory effect on the expression of studied microRNAs in which decreased the expression of miR-30 (5.5-fold (p < 0.0001)), miR-194 (11-fold (p < 0.0001)), miR-20 (3.5-fold (p = 0.0006)), and increased the expression of miR-106b (9.78-fold (p < 0.0001)).

CONCLUSIONS

Modulation of the expression levels of BC-involved microRNAs could be one of the possible mechanisms of action through which DHA and LA may exert their biologic effects on MDA-MB-231 cell line.

Antitumor Activity of α-Linolenic Acid-Paclitaxel Conjugate Nanoparticles: In vitro and in vivo

Purpose

Small molecule modified antitumor drug conjugate nanoparticles have the advantages of high drug loading, simple synthesis and preparation, and better biocompatibility. Due to the large demand for exogenous α-linolenic acid (ALA) by tumor cells, we synthesized α-linolenic acid-paclitaxel conjugate (ALA-PTX) and prepared α-linolenic acid-paclitaxel conjugate nanoparticles (ALA-PTX NPs), in order to obtain better tumor cellular uptake and antitumor activity in vitro and in vivo.

Methods

We synthesized and characterized ALA-PTX, and then prepared and characterized ALA-PTX NPs. The cellular uptake, uptake pathways, intracellular behavior, in vitro and in vivo antitumor activity of ALA-PTX NPs were evaluated.

Results

The size of ALA-PTX NPs was approximately 110.7±1.7 nm. The drug loading was approximately 90% (w/w) with CrEL-free and organic solvent-free characteristics. The cellular uptake of ALA-PTX NPs was significantly higher than that of PTX injection by MCF-7, MCF-7/ADR and HepG2 cells. In these three cell lines, the cellular uptake of ALA-PTX NPs at 6h was approximately 1.5-2.6 times higher than that of PTX injection. ALA-PTX NPs were ingested through clathrin-mediated endocytosis, then transferred to lysosomes, and could dissolve in cells to play an antitumor activity. The in vitro and in vivo antitumor activity of ALA-PTX NPs was confirmed in MCF-7/ADR and HepG2 cell models and tumor-bearing nude mouse models.

Conclusion

ALA-PTX NPs developed in our study could provide a new method for the preparation of nano-delivery systems suitable for antitumor therapy that could increase tumor cellular uptake and enhance antitumor activity.

Nanoparticulation of Prodrug into Medicines for Cancer Therapy

This article provides a broad spectrum about the nanoprodrug fabrication advances co-driven by prodrug and nanotechnology development to potentiate cancer treatment. The nanoprodrug inherits the features of both prodrug concept and nanomedicine know-how, attempts to solve underexploited challenge in cancer treatment cooperatively. Prodrugs can release bioactive drugs on-demand at specific sites to reduce systemic toxicity, this is done by using the special properties of the tumor microenvironment, such as pH value, glutathione concentration, and specific overexpressed enzymes; or by using exogenous stimulation, such as light, heat, and ultrasound. The nanotechnology, manipulating the matter within nanoscale, has high relevance to certain biological conditions, and has been widely utilized in cancer therapy. Together, the marriage of prodrug strategy which shield the side effects of parent drug and nanotechnology with pinpoint delivery capability has conceived highly camouflaged Trojan horse to maneuver cancerous threats.

Direct comparison of two kinds of linoleic acid-docetaxel derivatives: in vitro cytotoxicity and in vivo antitumor activity

Rational designed lipid-drug derivatives provide a favorable approach to improve the druggability of highly hydrophobic prototypes. It has been regarded as common sense that good cytotoxicity is the guarantee of superior anticancer efficacy for candidate derivatives screening. However, does it apply to lipid-drug conjugate-based self-assembled nanoparticles? Here, we established the above two derivatives and a non-correlation between the cytotoxic activity in vitro and drug efficacy in vivo was found. The IC₅₀ of DSL NPs (DTX-S-LA nanoparticles) and DL NPs (DTX-LA nanoparticles) were 4.02 and 209.6 ng/mL (DTX equivalent concentration), respectively. However, DL NPs unexpectedly showed stronger tumor inhibition abilities than DSL NPs. To explain the non-positive correlation between cytotoxicity and anticancer efficacy, more experiments were carried out in depth. Remarkably, the drug release studies in blood and PK study both suggested that the DL NPs were more stable to remain the structural integrity in circulation, which resulted in more accumulation in tumor sites. As verified by the bio-distribution study, DL NPs performed a superior target effect than DSL NPs in tumors. Our data indicated that the biological fates of so-called smart bond inserted derivatives in vivo are complicated; thus, simple cytotoxicity is not enough for derivatives screening, and the comprehensive understanding of both in vitro and in vivo behaviors is essential.

Prospects and challenges of anticancer agents' delivery via chitosan-based drug carriers to combat breast cancer: a review

Breast cancer (BC) is considered as one the most prevalent cancers worldwide. Due to its high resistance to chemotherapy and high probability of metastasis, BC is one of the leading causes of cancer-related deaths. The controlled release of chemotherapy drugs to the precise site of the tumor tissue will increase the therapeutic efficacy and decrease side effects of systemic administration. Among various drug delivery systems, natural polymers-based drug carriers have gained significant attention for cancer therapy. Chitosan, a natural polymer obtained by de-acetylation of chitin, holds huge potential for drug delivery applications because chitosan is non-toxic, non-immunogenic, biocompatible, chemically modifiable, and can be processed to form various formulations. In the current review, we will discuss the prospects and challenges of chitosan-based drug delivery systems in treating BC.

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.

Exciting Potential of Nanoparticlized Lipidic System for Effective Treatment of Breast Cancer and Clinical Updates: A Translational Prospective

Breast cancer (BC) is a multifactorial disease and becoming a major health issue in women throughout the globe. BC is a malignant type of cancer which results from transcriptional changes in proteins and genes. Besides the availability of modern medicines and detection tools, BC has become a topmost deadly disease and its cure still remains challenging. Nanotechnology based approaches are being employed for the diagnosis and treatment of BC at clinical stages. Nanosystems have a significant role in the study of the interaction of malignant cells with their microenvironment through receptor-based targeted approach. Nowadays, lipid-based nanocarriers are being popularized in the domain of pharmaceutical and medical biology for cancer therapy. Lipidic nanoparticlized systems (LNPs) have proven to have high loading efficiency, less toxicity, improved therapeutic efficacy, enhanced bioavailability and stability of the bioactive compounds compared to traditional drug delivery systems. In the present context, several LNPs based formulations have been undertaken in various phases of clinical trials in different countries. This review highlights the importance of chemotherapeutics based lipidic nanocarriers and their anticipated use for the treatment of BC. Furthermore, the clinical trials and future prospective of LNPs have been widely elaborated.

Emerging insights on drug delivery by fatty acid mediated synthesis of lipophilic prodrugs as novel nanomedicines

Many drug molecules that are currently in the market suffer from short half-life, poor absorption, low specificity, rapid degradation, and resistance development. The design and development of lipophilic prodrugs can provide numerous benefits to overcome these challenges. Fatty acids (FAs), which are lipophilic biomolecules constituted of essential components of the living cells, carry out many necessary functions required for the development of efficient prodrugs. Chemical conjugation of FAs to drug molecules may change their pharmacodynamics/pharmacokinetics in vivo and even their toxicity profile. Well-designed FA-based prodrugs can also present other benefits, such as improved oral bioavailability, promoted tumor targeting efficiency, controlled drug release, and enhanced cellular penetration, leading to improved therapeutic efficacy. In this review, we discuss diverse drug molecules conjugated to various unsaturated FAs. Furthermore, various drug-FA conjugates loaded into various nanostructure delivery systems, including liposomes, solid lipid nanoparticles, emulsions, nano-assemblies, micelles, and polymeric nanoparticles, are reviewed. The present review aims to inspire readers to explore new avenues in prodrug design based on the various FAs with or without nanostructured delivery systems.

Effective management of acute postoperative pain using intravenous emulsions of novel ketorolac prodrugs: in vitro and in vivo evaluations

The aim was to prepare intravenous fat emulsions (IFEs) of ketorolac (KTL) ester prodrugs and to investigate the pharmacokinetics and pharmacodynamics of these formulations. Three prodrugs of KTL (KTL-IS, KTL-AX and KTL-BT) were synthesized as a means to increase the lipid solubility of KTL. All KTL prodrugs with higher Log P values presented increased tendency to partition into a blank IFE using extemporaneous addition method - the encapsulation efficiency of KTL-IS IFE and KTL-BT IFE was more than 97%. The particle sizes and zeta potentials of these two formulations were comparable to that of the blank IFE. PK studies in rabbits showed significant larger AUC0-8h (646.969 ± 154.326 mg/L•h-1 for KTL-IS IFE and 559.426 ± 103.057 mg/L•h-1 for KTL-BT IFE) than that of ketorolac tromethamine (KTL-T) injectable (286.968 ± 63.045 mg/L•h-1) and approximately 2-fold increases in the elimination t1/2 over KTL-T. In a rat postoperative pain model, the paw withdrawal thresholds and the paw withdrawal latency after I.V. KTL prodrug IFEs were significantly higher than that after I.V. KTL-T at 3~4 h. Effective controlling of acute postoperative pain in a longer duration can be achieved by using non-addictive ketorolac derivatives intraveneous emulsions.

Preparation, characterization and in vitro activity of a docetaxel-albumin conjugate

Docetaxel is one of the most effective anticancer drugs. However, the current formulation of docetaxel contains Tween 80 and ethanol as the solvent, which can cause severe side effects. Consequently, the development of new type of formulation of docetaxel with high efficiency and low side effects is a very important issue. In this study, we explored the covalent linking of docetaxel and albumin via one organic linker. 6-Maleimidocaproic acid was applied to link the C2' hydroxyl group of docetaxel with the cysteine-34 of albumin to obtain 1:1 docetaxel-albumin conjugate. The synthesized conjugate can control the release of docetaxel in the bovine serum. Furthermore, in vitro cell cytotoxicity experiments indicated that the docetaxel-albumin conjugate have high activities for human prostate cancer cell line PC3 and human breast cancer cell line MCF-7. The present study provides a valuable strategy for further development of a new type of docetaxel-albumin prodrug.