Exploring the vast potentials and probable limitations of novel and nanostructured implantable drug delivery systems for cancer treatment.

Conventional cancer chemotherapy regimens, albeit successful to some extent, suffer from some significant drawbacks, such as high-dose requirements, limited bioavailability, low therapeutic indices, emergence of multiple drug resistance, off-target distribution, and adverse effects. The main goal of developing implantable drug delivery systems (IDDS) is to address these challenges and maintain anti-cancer drugs directly at the intended sites of therapeutic action while minimizing inevitable side effects. IDDS possess numerous advantages over conventional drug delivery, including controlled drug release patterns, one-time drug administration, as well as loading and stabilizing poorly water-soluble chemotherapy drugs. Here, we summarized conventional and novel (three-dimensional (3D) printing and microfluidic) preparation techniques of different IDDS, including nanofibers, films, hydrogels, wafers, sponges, and osmotic pumps. These systems could be designed with high biocompatibility and biodegradability features using a wide variety of natural and synthetic polymers. We also reviewed the published data on these systems in cancer therapy with a particular focus on their release behavior. Various release profiles could be attained in IDDS, which enable predictable, adjustable, and sustained drug releases. Furthermore, multi-step or stimuli-responsive drug release could be obtained in these systems. The studies mentioned in this article have proven the effectiveness of IDDS for treating different cancer types with high prevalence, including breast cancer, and aggressive cancer types, such as glioblastoma and liver cancer. Additionally, the challenges in applying IDDS for efficacious cancer therapy and their potential future developments are also discussed. Considering the high potential of IDDS for further advancements, such as programmable release and degradation features, further clinical trials are needed to ensure their efficiency. The overall goal of this review is to expand our understanding of the behavior of commonly investigated IDDS and to identify the barriers that should be addressed in the pursuit of more efficient therapies for cancer. See also the graphical abstract(Fig. 1).

Biocompatible phospholipid-based mixed micelles for posaconazole ocular delivery: Development, characterization, and in - vitro antifungal activity.

Current study intended to prepare and evaluate phospholipid-based, mixed micelles (MMs) to improve the ocular delivery of posaconazole (POS), a broad-spectrum antifungal drug. For this, MMs based on egg phosphatidylcholine (EPC), as the main component, in combination with various bile salts (sodium cholate (NaC), sodium deoxycholate (NaDC), sodium taurocholate (NaTC)) or non-ionic surfactants (Pluronic® F-127, Pluronic® F-68, Tween 80, Labrasol® ALF, and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS)) were prepared. Particle size, polydispersity index, zeta potential and entrapment efficiency were evaluated to optimize the composition and preparation method of the MMs. Finally, morphology, stability, in vitro release pattern, and in vitro antifungal activity of the optimized formulation were investigated. Among the prepared MMs, vesicles composed of EPC: TPGS with a molar ratio of 70:30, prepared by the thin-film hydration method, showed more appropriate features. Among the prepared MMs, vesicles composed of EPC: TPGS with a molar ratio of 70:30 showed more appropriate features, including an entrapment efficiency (EE) greater than 80%, spherical shape morphology, an average particle size of about 58 nm, desirable stability over a month, slow-release without a noticeable initial burst, and a significantly higher in vitro antifungal activity in comparison with the drug suspension. Therefore, this formulation was selected as the optimal MMs and could be considered as a promising carrier for topical ocular delivery of POS.

Multivesicular liposomal depot system for sustained delivery of risperidone: development, characterization, and toxicity assessment.

OBJECTIVE: Considering the limitations of conventional risperidone (RSP) therapies, the present research characterizes the usefulness of multivesicular liposomes (MVLs) as an efficient controlled-release carrier for this widely used antipsychotic drug, to be employed for the treatment of schizophrenia. METHODS: A 23 full factorial design based on three independent variables was implemented to plan the experiments: the molar ratios of lipid to the drug, triolein to phospholipid, and cholesterol to phospholipid. The impacts of these parameters on the risperidone encapsulation efficiency and its release pattern within the first 24 and 48 h were investigated as dependent variables. Then, the optimized liposomal system was further in-depth analyzed in terms of size, morphological and structural features, release profile over 15 days, biocompatibility, and stability. RESULTS: Optimized formulation parameters gave rise to MVLs possessing a spherical morphology with a median diameter of about 8 µm, a relatively narrow size distribution (span value of 1.49), and an encapsulation efficiency of 57.6%. These carriers not only exhibited a sustained-release behavior in vitro, lasting until the end of the 15 days but also underwent a negligible change in their size and RSP incorporation over two months at refrigerator condition. Furthermore, in vitro cytotoxicity and hemolysis assessments revealed that the optimized MVL formulation is biocompatible. CONCLUSION: This study revealed the potential of MVLs as a promising system for the delivery of RSP and could open a new vista for the successful management of schizophrenia.

Tuning the Physicochemical Characteristics of Particle-Based Carriers for Intraperitoneal Local Chemotherapy.

Over the last few decades, intraperitoneal (IP) local drug delivery, providing high drug concentrations with prolonged retention in the peritoneal cavity, has opened a new horizon for the management of life-threatening peritoneal disorders, such as peritoneal carcinomatosis (PC). However, clinical translation of this strategy is hampered by several hurdles, namely premature clearance of small-sized molecules from the peritoneum, limited distribution within the peritoneal space and inadequate penetration into the target tissues. To address these challenges, incorporation of therapeutic agents into the particulate-based drug delivery systems has brought new hope in this direction. Nonetheless, as yet, there has been no formulation specifically approved for IP delivery. To gain this goal, it is crucial to have a detailed understanding of the correlation between the physicochemical characteristics of particle-based carriers and their biological fate and anticancer efficacy after IP administration. The main focus of this review, therefore, concerns the significance of these characteristics, namely composition, particle size, charge, coating and presence of targeting moieties in the design of carriers for successful IP delivery. Graphical Abstract Physicochemical characteristics of particle-based carriers influence their peritoneal residence time, biological fate and anticancer efficacy after intraperitoneal administration.

Green formulation of curcumin loaded lipid-based nanoparticles as a novel carrier for inhibition of post-angioplasty restenosis.

Restenosis is one of the major complications affecting outcomes of percutaneous coronary interventions. The aims of this study were to formulate curcumin (CUR) nanoparticles by using only lipidic ingredients in the absence of any organic solvent and to determine key formulation parameters using 2-level factorial design. CUR nanoparticles were prepared using triglyceride and egg phosphatidylcholine (EPC) by high-pressure homogenization (HPH) and fully characterized regarding drug loading, particle size, zeta potential, stability, drug release profile, conductivity, viscosity, refractive index, stability, morphology and FTIR analysis. The efficacy of CUR nanoparticles in inhibiting restenosis was investigated in a rat carotid artery model. Balloon-injured rats were randomly assigned to two control (saline and empty carrier) groups and CUR nanoparticle treated group. Arterial restenosis was assessed by histomorphometric, immunohistochemical and CT angiography analyses. Optimized CUR nanoparticles with almost 70% drug entrapment, an average particle size of 58 nm, PDI < 0.2, spherical nanostructures and sustained release profile were prepared. In morphometric analysis, neointimal area and neointima/media ratio significantly decreased in the animal group received CUR nanoparticles compared with control groups. Expression of Ki67 was markedly lower in the CUR nanoformulation group. CT angiograms confirmed patency of the artery in this group. These results suggest that the new strategy of intramural delivery of CUR lipid-based nanoparticles can be considered as a novel approach to prevent neointimal hyperplasia.

Green Formulation of Triglyceride/Phospholipid-Based Nanocarriers as a Novel Vehicle for Oral Coenzyme Q10 Delivery.

This study was aimed to develop a novel nanocarrier for coenzyme Q10 (CoQ10) by a green process that prevented the use of surfactants and organic solvents. Triglyceride/phospholipid-based nanocarriers were developed through high-pressure homogenization (an industrial feasible process), and a 25-1 fractional factorial design was adopted to assess the influences of formulation variables on the considered responses, including vesicle size, entrapment efficiency, loading capacity, and solubility of the vehicles in simulated gastrointestinal fluids. The optimized formulation was further in-depth characterized in terms of morphology, release behavior, biocompatibility (Caco-2 cell cytotoxicity and histological examination), thermal behavior, and Fourier transform infrared analysis. Optimal nanocarriers were found to have mean particle size of 75 nm, narrow particle distribution, and CoQ10 entrapment of 95%. The optimized formulation was stable upon incubation in simulated gastrointestinal fluids without considerable leakage of cargo, which was in agreement with their sustained release behavior. Microscopic observations also confirmed nanosized nature of the vesicles and revealed their spherical shape. Moreover, toxicity evaluations at the cellular and tissue levels revealed their nontoxic nature. In conclusion, triglyceride/phospholipid-based nanocarriers proved to be a green safe vehicle for delivery of CoQ10 with industrial-scale production capability and could provide a new horizon for delivery of hydrophobic nutraceuticals. PRACTICAL APPLICATION: Green nanostructure formulation approaches have recently gained tremendous attraction for their safe profile especially when it comes to supplements, which are generally recommended for daily use. However, their sufficient association with cargoes and industrial-scale production have remained considerable challenges. This study focuses on the development of lipid-based nanocarriers for CoQ10 by an industrial feasible process that prevents the use of any surfactants or organic solvents.

Tadalafil nanocomposites as a dry powder formulation for inhalation, a new strategy for pulmonary arterial hypertension treatment.

Tadalafil (a phosphodiesterase-5 inhibitor) is a choice for treatment of pulmonary arterial hypertension (PAH) that is known as an increase in mean pulmonary arterial pressure ≥25 mmHg at rest and ≥30 mmHg during exercise with reduced cardiac output. The aim of this study was to prepare inhalable tadalafil nanocomposites as a dry powder formulation by spray drying technique for increasing bioavailability and treatment efficacy, as well as decreasing systemic side effects. The D-optimal design was used for optimization of formulation parameters. Microparticle size, morphology, crystallinity, density, solubility, redispersion (%), and in-vitro inhalation performance of tadalafil nanocomposites were investigated as physicochemical characteristics. Pharmacokinetic parameters were also evaluated in plasma and lung tissue of Wistar rats after intratracheal insufflation and compared with a control group receiving an oral tadalafil marketed product (dose = 10 mg/kg). The suggested optimum formulation contained stable amorphous particles with almost rounded shape and corrugated surface that were completely redispersed in the lung simulated medium with the mass median geometric diameter of 3.2 µm, density of 1.4 g/cm3, fine particle fraction based on emitted dose (%) of 57.2 ±â€¯6.5%, and 13.7-fold enhancement in dissolution rate. In-vivo studies showed that the ratio of AUC0-24h lung/AUC0-24h plasma, achieved in the treated group after intratracheal insufflation, was significantly higher than the control group that means high local drug concentration and more efficacy. Besides, plasma data analysis indicated high value of MRT (2.3-fold) and tmax (3.7-fold) after intratracheal insufflation of tadalafil nanocomposites in comparison with the conventional oral route, indicating longer retention of tadalafil molecules in the lungs and their slower entry to the systemic blood circulation. In conclusion, it seems that inhalable tadalafil nanocomposites can be introduced as an alternative to oral tadalafil in the treatment of PAH.

Freeze-Dried K-Carrageenan/Chitosan Polyelectrolyte Complex-Based Insert: A Novel Intranasal Delivery System for Sumatriptan Succinate.

Intranasal route, ensuring suitable bioavailability of medicines under circumvention of the gastrointestinal degradation and hepatic first-pass elimination, has been a popular choice for drug delivery. Among nasal dosage forms, mucoadhesive solid inserts have been shown to resist mucociliary clearance and provide a prolonged nasal residence time. Hence, the purpose of this study was the preparation and characterization of nasal inserts composing of polyelectrolyte complexes (PECs) based on k-carrageenan (k-CA) and chitosan (CS) to boost therapeutic efficacy of sumatriptan succinate in the treatment of migraine headache. k-CA/CS PECs were developed in different molar ratios, subjected to lyophilization in small inserts in the presence of sumatriptan succinate, and finally investigated for water uptake ability, mucoadhesive potential, and drug release profile. The formation of PEC between the two polymers was affirmed by Fourier transform infrared spectroscopy (FTIR). Based on the results, it was revealed that the polyanion/polycation molar ratio plays a critical role in modulating the characteristics of the inserts, and among all the formulations, the one comprising k-CA/CS PEC with molar ratio of (4:1), (k-CA/CS (4:1)), demonstrated the highest water uptake ability and mucoadhesive potential and provided a more controlled release of sumatriptan succinate. This study illustrates the potential of the lyophilized inserts based on the k-CA/CS PECs, especially k-CA/CS (4:1), for efficient delivery of sumatriptan succinate via the nasal route of administration and suggests a potential therapeutic approach for the termination of migraine attacks.

Nanomedicine approaches for sirolimus delivery: a review of pharmaceutical properties and preclinical studies.

Sirolimus (rapamycin) is a mammalian target of rapamycin (mTOR) inhibitor with immunosuppressive, antiproliferative, antiangiogenic, antifungal, anti-restenosis and anti-inflammatory properties. However, its clinical application is often hampered by poor aqueous solubility, first-pass metabolism, transport by p-glycoprotein efflux pump, limited oral bioavailability and nonspecific distribution in off-target sites. Recently, various formulation strategies have emerged to overcome these limitations. Among these, pharmaceutical nanotechnology with numerous advantages has great potential for sirolimus delivery. Up to now, the only nanoparticle based FDA approved formulation in the market is Rapamune® tablet which is composed of drug nanocrystals. This review focuses on recent studies that have been investigated various nanostructured carriers such as liposomes, micelles, polymeric nanoparticles, nanocrystals, magnetic nanoparticles, albumin nanoparticles, solid dispersion nanoparticles and niosomes for sirolimus delivery (in organ transplantation, cancer, vascular restenosis, etc.).

Utilization of chitosan-caged liposomes to push the boundaries of therapeutic delivery.

Liposomes are self-assembled bilayer vesicles which have attracted a great deal of interest as potential carriers for a wide range of therapeutic agents. They have significantly decreased toxicity of drugs while improving or at least maintaining their efficacy. However, their further development has been hampered by their considerable instabilities and, in some cases, providing comparable efficacy to conventional products. Decoration of liposomal nanocarriers with chitosan (CS) and its derivatives has recently gained importance to overcome this obstacle. CS, a cationic polysaccharide, has prompted the continuous impetus for the advent of efficient drug delivery systems owing to its unique characteristics. CS decoration of liposomes confers high mucoadhesion capacity, enhanced carrier permeability, and sterically stabilized properties. The number of examples having been explained within the present review through different administration routes and for various applications clearly heralds the promise of CS caged liposomes for the pharmaceutical market.