Recent advances in intravenous delivery of poorly water-soluble compounds

A novel lipophenol quercetin derivative to prevent macular degeneration: Intravenous and oral formulations for preclinical pharmacological evaluation

Drugs with properties against oxidative and carbonyl stresses are potential candidates to prevent dry age-related macular degeneration (Dry-AMD) and inherited Stargardt disease (STGD1). Previous studies have demonstrated the capacity of a new lipophenol drug: 3-O-DHA-7-O-isopropyl-quercetin (Q-IP-DHA) to protect ARPE19 and primary rat RPE cells respectively from A2E toxicity and under oxidative and carbonyl stress conditions. In this study, first, a new methodology has been developed to access gram scale of Q-IP-DHA. After classification of the lipophenol as BCS Class IV according to physico-chemical and biopharmaceutical properties, an intravenous formulation with micelles (M) and an oral formulation using lipid nanocapsules (LNC) were developed. M were formed with Kolliphor® HS 15 and saline solution 0.9 % (mean size of 16 nm, drug loading of 95 %). The oral formulation was optimized and successfully allowed the formation of LNC (25 nm, 96 %). The evaluation of the therapeutic potency of Q-IP-DHA was performed after IV administration of micelles loaded with Q-IP-DHA (M-Q-IP-DHA) at 30 mg/kg and after oral administration of LNC loaded with Q-IP-DHA (LNC-Q-IP-DHA) at 100 mg/kg in mice. Results demonstrated photoreceptor protection after induction of retinal degeneration by acute light stress making Q-IP-DHA a promising preventive candidate against dry-AMD and STGD1.

Efficient Drug Loading Method for Poorly Water-Soluble Drug into Bicelles through Passive Diffusion

The bicelle, a type of solid lipid nanoparticle, comprises phospholipids with varying alkyl chain lengths and possesses the ability to solubilize poorly water-soluble drugs. Bicelle preparation is complicated and time-consuming because conventional drug-loading methods in bicelles require multiple rounds of thermal cycling or co-grinding with drugs and lipids. In this study, we proposed a simple drug-loading method for bicelles that utilizes passive diffusion. Drug-unloaded bicelles were placed inside a dialysis device and incubated in a saturated solution of ketoconazole (KTZ), which is a model drug. KTZ was successfully loaded into bare bicelles over time with morphological changes, and the final encapsulated concentration was dependent on the lipid concentration of the bicelles. When polyethylene glycol (PEG) chains of two different lengths (PEG2K and 5K) were incorporated into bicelles, PEG2k and PEG5k bicelles mitigated the morphological changes and improved the encapsulation rate. This mitigation of morphological changes enhanced the encapsulated drug concentration. Specifically, PEG5k bicelles, which exhibited the greatest prevention of morphological changes, had a lower encapsulated concentration after 24 h than that of PEG2k bicelles, indicating that PEGylation with a longer PEG chain length improved the loading capacity but decreased the encapsulation rate owing to the presence of a hydration layer of PEG. Thus, PEG with a certain length is more suitable for passive loading. Moreover, loading factors, such as temperature and vehicles used in the encapsulation process, affected the encapsulation rate of the drug. Taken together, the passive loading method offers high throughput with minimal resources, making it a potentially valuable approach during early drug development phases.

Exploring the Influence of Spacers in EDTA-β-Cyclodextrin Dendrimers: Physicochemical Properties and In Vitro Biological Behavior

The synthesis of a new family of ethylenediaminetetraacetic acid (EDTA) core dimers and G0 dendrimers end-capped with two and four β-cyclodextrin (βCD) moieties was performed by click-chemistry conjugation, varying the spacers attached to the core. The structure analyses were achieved in DMSO-d6 and the self-inclusion process was studied in D2O by 1H-NMR spectroscopy for all platforms. It was demonstrated that the interaction with adamantane carboxylic acid (AdCOOH) results in a guest-induced shift of the self-inclusion effect, demonstrating the full host ability of the βCD units in these new platforms without any influence of the spacer. The results of the quantitative size and water solubility measurements demonstrated the equivalence between the novel EDTA-βCD platforms and the classical PAMAM-βCD dendrimer. Finally, we determined the toxicity for all EDTA-βCD platforms in four different cell lines: two human breast cancer cells (MCF-7 and MDA-MB-231), human cervical adenocarcinoma cancer cells (HeLa), and human lung adenocarcinoma cells (SK-LU-1). The new EDTA-βCD carriers did not present any cytotoxicity in the tested cell lines, which showed that these new classes of platforms are promising candidates for drug delivery.

The Development of Magnolol-Loaded Intravenous Emulsion with Low Hepatotoxic Potential

Intestinal failure-associated liver disease (IFALD) is a severe liver injury occurring due to factors related to intestinal failure and parenteral nutrition administration. Different approaches are studied to reduce the risk or ameliorate the course of IFALD, including providing omega-3 fatty acids instead of soybean oil-based lipid emulsion or administering active compounds that exert a hepatoprotective effect. This study aimed to develop, optimize, and characterize magnolol-loaded intravenous lipid emulsion for parenteral nutrition. The preformulation studies allowed for chosen oils mixture of the highest capacity of magnolol solubilization. Then, magnolol-loaded SMOFlipid was developed using the passive incorporation method. The Box-Behnken design and response surface methodology were used to optimize the entrapment efficiency. The optimal formulation was subjected to short-term stress tests, and its effect on normal human liver cells and erythrocytes was determined using the MTT and hemolysis tests, respectively. The optimized magnolol-loaded SMOFlipid was characterized by the mean droplet diameter of 327.6 ± 2.9 nm with a polydispersity index of 0.12 ± 0.02 and zeta potential of -32.8 ± 1.2 mV. The entrapment efficiency of magnolol was above 98%, and pH and osmolality were sufficient for intravenous administration. The magnolol-loaded SMOFlipid samples showed a significantly lower toxic effect than bare SMOFlipid in the same concentration on THLE-2 cells, and revealed an acceptable hemolytic effect of 8.3%. The developed formulation was characterized by satisfactory stability. The in vitro studies showed the reduced cytotoxic effect of MAG-SMOF applied in high concentrations compared to bare SMOFlipid and the non-hemolytic effect on human blood cells. The magnolol-loaded SMOFlipid is promising for further development of hepatoprotective lipid emulsion for parenteral nutrition.

COSMO Models for the Pharmaceutical Development of Parenteral Drug Formulations

The aqueous solubility of active pharmaceutical ingredients is one of the most important features to be considered during the development of parenteral formulations in the pharmaceutical industry. Computational modelling has become in the last years an integral part of pharmaceutical development. In this context, ab initio computational models, such as COnductor-like Screening MOdel (COSMO), have been proposed as promising tools for the prediction of results without the effective use of resources. Nevertheless, despite the clear evaluation of computational resources, some authors had not achieved satisfying results and new calculations and algorithms have been proposed over the years to improve the outcomes. In the development and production of aqueous parenteral formulations, the solubility of Active Pharmaceutical Ingredients (APIs) in an aqueous and biocompatible vehicle is a decisive step. This work aims to study the hypothesis that COSMO models could be useful in the development of new parenteral formulations, mainly aqueous ones.

In-vitro modeling of intravenous drug precipitation by the optical spatial precipitation analyzer (OSPREY)

Intravenous (IV) administration of poorly water-soluble small molecule therapeutics can lead to precipitation during mixing with blood. This can limit characterization of pharmacological and safety endpoints in preclinical models. Most often, tests of kinetic and thermodynamic solubility are used to optimize the formulation for solubility prior to infusion in animals, but these do not capture the dynamic precipitation processes that take place during in-vivo administration. To better capture the fluid dynamic processes that occur during IV administration, we developed the Optical Spatial PREcipitation analYzer (OSPREY) as a method to quantify the amount and size of compound precipitates in whole blood using a flow-through system that mimics IV administration. Here, we describe the OSPREY device and its underlying imaging processing methods. We then validate the ability to accurately segment particles according to their size using monodisperse suspensions of microspheres (diameter 50 to 425 µm). Next, we use a tool compound, ABT-737, to study the effects of compound concentration, vessel flow rate, compound infusion rate and vessel diameter on precipitation. Finally, we use the physiological diameter and flow rate of rat femoral vein and dog saphenous vein to demonstrate the potential of OSPREY to model in-vivo precipitation in a controlled, dynamic in-vitro assay.

Honokiol-Loaded Nanoemulsion for Glioblastoma Treatment: Statistical Optimization, Physicochemical Characterization, and an In Vitro Toxicity Assay

BACKGROUND

Glioblastoma (GBM) is an extremely invasive and heterogenous malignant brain tumor. Despite advances in current anticancer therapy, treatment options for glioblastoma remain limited, and tumor recurrence is inevitable. Therefore, alternative therapies or new active compounds that can be used as adjuvant therapy are needed. This study aimed to develop, optimize, and characterize honokiol-loaded nanoemulsions intended for intravenous administration in glioblastoma therapy.

METHODS

Honokiol-loaded nanoemulsion was developed by incorporating honokiol into Lipofundin MCT/LCT 20% using a horizontal shaker. The Box-Behnken design, coupled with response surface methodology, was used to optimize the incorporation process. The effect of the developed formulation on glioblastoma cell viability was determined using the MTT test. Long-term and short-term stress tests were performed to evaluate the effect of honokiol on the stability of the oil-in-water system and the effect of different stress factors on the stability of honokiol, respectively. Its physicochemical properties, such as MDD, PDI, ZP, OSM, pH, and loading efficiency (LE%), were determined.

RESULTS

The optimized honokiol-loaded nanoemulsion was characterized by an MDD of 201.4 (0.7) nm with a PDI of 0.07 (0.02) and a ZP of -28.5 (0.9) mV. The LE% of honokiol was above 95%, and pH and OSM were sufficient for intravenous administration. The developed formulation was characterized by good stability and a satisfactory toxicity effect of the glioblastoma cell lines.

CONCLUSIONS

The honokiol-loaded nanoemulsion is a promising pharmaceutical formulation for further development in the adjuvant therapy of glioblastoma.

Molecular Dynamics Simulation of Drug Solubilization Behavior in Surfactant and Cosolvent Injections

Surfactants and cosolvents are often combined to solubilize insoluble drugs in commercially available intravenous formulations to achieve better solubilization. In this study, six marketed parenteral formulations with surfactants and cosolvents were investigated on the aggregation processes of micelles, the structural characterization of micelles, and the properties of solvent using molecular dynamics simulations. The addition of cosolvents resulted in better hydration of the core and palisade regions of micelles and an increase in both radius of gyration (Rg) and the solvent accessible surface area (SASA), causing a rise in critical micelle concentration (CMC), which hindered the phase separation of micelles. At the same time, the presence of cosolvents disrupted the hydrogen bonding structure of water in solution, increasing the solubility of insoluble medicines. Therefore, the solubilization mechanism of the cosolvent and surfactant mixtures was successfully analyzed by molecular dynamics simulation, which will benefit future formulation development for drug delivery.

Critical Points in the Methodology of Preparing Copper (II) Histidinate Injections and their Quality Assessment Applying Color Measurement

Copper (II) histidinate injection solution, applied in Menkes disease treatment, is characterized by low stability due to sensitivity to oxidation. The aim of this article was to determine the critical points of the injection preparation procedure, taking into account selection of appropriate packaging, determining the solution pH or application of an excess of L-histidine. In order to assess the stability of the Cu(His)2 complex, the spectrophotometric method (VIS: 400-800 nm), and the colorimetric method using a reflectance colorimeter were applied. The color changes observed using the CIELAB color system made it possible to determine: the differences in the observed color (ΔΕ) and the color chroma (C*) and hue (h°). It was found that the following parameters: λmax and ΔE enable fast and objective assessment of copper (II) histidinate injection solution quality. The advantage of the colorimetric method is the non-invasiveness of the analysis which is performed through the packaging material (transparent vial). The developed methodology of preparing Cu(His)2 injections in hospitals or community pharmacies guarantees their stability for at least 6 months, provided that the solution is stored at lower temperatures (2-8°C or 4°C).

Cyclodextrin-based delivery systems in parenteral formulations: a critical update review

Parenteral formulations are indispensable in clinical practice and often are the only option to administer drugs that cannot be administrated through other routes, such as proteins and certain anticancer drugs - which are indispensable to treat some of the most prevailing chronic diseases worldwide (like diabetes and cancer). Additionally, parenteral formulations play a relevant role in emergency care since they are the only ones that provide an immediate action of the drug after its administration. However, the development of parenteral formulations is a complex task owing to the specific quality and safety requirements set for these preparations and the intrinsic properties of the drugs. Amongst all the strategies that can be useful in the development of parenteral formulations, the formation of water-soluble host-guest inclusion complexes with cyclodextrins (CDs) has proven to be one of the most advantageous. CDs are multifunctional pharmaceutical excipients able to form water-soluble host-guest inclusion complexes with a wide variety of molecules, particularly drugs, and thus improve their apparent water-solubility, chemical stability, and bioavailability, to make them suitable for parenteral administration. Besides, CDs can be employed as building blocks of more complex injectable drug delivery systems with enhanced characteristics, such as nanoparticles and supramolecular hydrogels, that has been found particularly beneficial for the delivery of anticancer drugs. However, only a few CDs are considered safe when parenterally administered, and some of these types are already approved to be used in parenteral dosage forms. Therefore, the application of CDs in the development of parenteral formulations has been a more common practice in the last few years, due to their significant worldwide acceptance by the health authorities, promoting the development of safer and more efficient injectable drug delivery systems.

Transformation of Amphiphilic Antiviral Drugs into New Dimensional Nanovesicles Structures

Improved techniques were applied to formulate drugs into dimensional nanostructures, doped "nanovesicles". These nanovesicles are solely composed of self-assembled amphiphilic antiviral agents used for the treatment of viral infections caused by flaviviruses, such as Zika virus. Studies were done to evaluate the effectiveness of the syntheses, formation, and performance under different experimental conditions, and behavior of the drug nanovesicles in vitro and in vivo. These studies demonstrated that assembling the hydrophobic antiviral drug molecules into nanodrugs is a successful technique for the delivery of the therapeutic agents, otherwise difficult to be supplied. Our studies confirmed that this nanodrug preserved and, in many cases, enhanced the embedded cellular activity of the parental free drug molecules, both in vitro and in vivo. This proposed formulation is highly important as it addresses the issue of insolubility and low bioavailabiity of a wide range of highly potent pharmaceutical drugs-not limited to a specific class of antiviral drugs-that are of high demand for the treatment of medical conditions and emerging pathogens.

Recent advancements of nanoparticles application in cancer and neurodegenerative disorders: At a glance

Nanoscale engineering is one of the innovative approaches to heal multitudes of ailments, such as varieties of malignancies, neurological problems, and infectious illnesses. Therapeutics for neurodegenerative diseases (NDs) may be modified in aspect because of their ability to stimulate physiological response while limiting negative consequences by interfacing and activating possible targets. Nanomaterials have been extensively studied and employed for cancerous therapeutic strategies since nanomaterials potentially play a significant role in medical transportation. When compared to conventional drug delivery, nanocarriers drug delivery offers various benefits, such as excellent reliability, bioactivity, improved penetration and retention impact, as well as precise targeting and administering. Upregulation of drug efflux transporters, dysfunctional apoptotic mechanisms, and a hypoxic atmosphere are all elements that lead to cancer treatment sensitivity in humans. It has been possible to target these pathways using nanoparticles and increase the effectiveness of multidrug resistance treatments. As innovative strategies of tumor chemoresistance are uncovered, nanomaterials are being developed to target specific pathways of tumor resilience. Scientists have recently begun investigating the function of nanoparticles in immunotherapy, a field that is becoming increasingly useful in the care of malignancies. Nanoscale therapeutics have been explored in this scientific literature and represent the most current approaches to neurodegenerative illnesses and cancer therapy. In addition, current findings and various biomedical nanomaterials' future promise for tissue regeneration, prospective medication design, and the synthesis of novel delivery approaches have been emphasized.

Supercritical fluid (SCF)-assisted fabrication of carrier-free drugs: An eco-friendly welcome to active pharmaceutical ingredients (APIs)

Despite the success in developing various pharmaceutical formulations, most of the active pharmaceutical ingredients (APIs)/drugs, according to the Biopharmaceutics Classification System (BCS), often suffer from various intrinsic limitations of solubility and permeability, substantially hindering their bioavailability in vivo. Regardless of the fact that the availability of different particle fabrication approaches (top-down and bottom-up) towards pharmaceutical manufacturing, the supercritical fluid (SCF) technology has emerged as one of the highly effective substitutes due to the environmentally benign nature and processing convenience, as well as the economically promising character of SCFs. The exceptional features of SCFs have endowed the fabrication of various APIs either solely or in combination with the compatible supramolecular species towards achieving improved drug delivery. Operating such APIs in high-pressure conditions often results in arbitrary-sized particulate forms, ranging from micron-sized to sub-micron/nano-sized particles. Comparatively, these SCF-processed particles offer enhanced tailorable physicochemical and morphological properties (size, shape, and surface), as well as improved performance efficacy (bioavailability and therapy) over the unprocessed APIs. Although the "carrier-based" delivery is practical among diverse delivery systems, the direct fabrication of APIs into suitable particulate forms, referred to as "carrier-free" delivery, has increased attention towards improving the bioavailability and conveying a high payload of the APIs. This review gives a comprehensive emphasis on the SCF-assisted fabrication of diverse APIs towards exploring their great potential in drug delivery. Initially, we discuss various challenges of drug delivery and particle fabrication approaches. Further, different supercritical carbon dioxide (SC-CO₂)-based fabrication approaches depending on the character of SCFs are explicitly described, highlighting their advantages and suitability in processing diverse APIs. Then, we provide detailed insights on various processing factors affecting the properties and morphology of SCF-processed APIs and their pharmaceutical applications, emphasizing their performance efficacy when administered through multiple routes of administration. Finally, we summarize this compilation with exciting perspectives based on the lessons learned so far and moving forward in terms of challenges and opportunities in the scale-up and clinical translation of these drugs using this innovative technology.

Sub-50 nm ultra-small organic drug nanosuspension prepared by cavi-precipitation and its brain targeting potential

The purpose of this study was to show whether it is possible to prepare sub 100 nm or preferably sub-50 nm drug nanosuspension (NS) of suitable quality for intravenous administration. Furthermore, we have studied how the brain targeting potential of such small size organic NS differs from relatively bigger size NS. Two combination technologies (cavi-precipitation, H96) and a standard high-pressure homogenization (HPH) technology were used to prepare drug NS of different sizes. The cavi-precipitation process generated the smallest AmB NS, i.e., 27 nm compared to 79 nm by H96 technology and 252 nm by standard HPH technology. Dialysis of the nanosuspension in the original dispersion media was found to be the most efficient solvent removal method without negatively affecting particle size. The removal of organic solvent was found to drastically improve the stability of the formulations. The protein adsorption pattern shows that the small size NS particles obtained by the cavi-precipitation process have the potential to circulate longer in the bloodstream and have the potential to be taken up by the blood-brain barrier. The cavi-precipitation process generated ultrafine NS particles, which fulfilled the quality requirements for intravenous administration and offer a potential solution for brain targeting.

Improving the Solubility and Oral Bioavailability of a Novel Aromatic Aldehyde Antisickling Agent (PP10) for the Treatment of Sickle Cell Disease

BACKGROUND

Aromatic aldehydes, with their ability to increase the oxygen affinity of sickle hemoglobin, have become important therapeutic agents for sickle cell disease (SCD). One such compound, voxelotor, was recently approved for SCD treatment. Methyl 6-((2-formyl-3-hydroxyphenoxy)methyl) picolinate (PP10) is another promising aromatic aldehyde, recently reported by our group. Like voxelotor, PP10 exhibits O2-dependent antisickling activity, but, unlike voxelotor, PP10 shows unique O2-independent antisickling effect. PP10, however, has limited solubility. This study therefore aimed to develop oral and parenteral formulations to improve PP10 solubility and bioavailability.

METHODS

Oral drug tablets with 2-hydroxypropyl beta cyclodextrin (HP-β-CD), polyvinylpyrrolidone, or Eudragit L100-55 PP10-binary system, and an intravenous (IV) formulation with d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) or HP-β-CD, were developed. The pharmacokinetic behavior of the formulations was studied in Sprague-Dawley rats. PP10, a methylester, and its acid metabolite were also studied in vitro with sickle whole blood to determine their effect on Hb modification, Hb oxygen affinity, and sickle red blood cell inhibition.

RESULTS

Aqueous solubility of PP10 was enhanced ~5 times with the HP-β-CD binary system, while the TPGS aqueous micelle formulation was superior, with a drug concentration of 0.502 ± 0.01 mg/mL and a particle size of 26 ± 3 nm. The oral tablets showed relative and absolute bioavailabilities of 173.4% and 106.34%, respectively. The acid form of PP10 appeared to dominate in vivo, although both PP10 forms demonstrated pharmacologic effect.

CONCLUSION

Oral and IV formulations of PP10 were successfully developed using HP-β-CD binary system and TPGS aqueous micelles, respectively, resulting in significantly improved solubility and bioavailability.

Clinically translatable formulation strategies for systemic administration of nerve-specific probes

Nerves are extremely difficult to identify and are often accidently damaged during surgery, leaving patients with lasting pain and numbness. Herein, a novel near-infrared (NIR) nerve-specific fluorophore, LGW01-08, was utilized for enhanced nerve identification using fluorescence guided surgery (FGS), formulated using clinical translatable strategies. Formulated LGW01-08 was examined for toxicology, pharmacokinetics (PK), and pharmacodynamics (PD) parameters in preparation for future clinical translation. Optimal LGW01-08 imaging doses were identified in each formulation resulting in a 10x difference between the toxicity to imaging dose window. Laparoscopic swine surgery completed using the da Vinci surgical robot (Intuitive Surgical) demonstrated the efficacy of formulated LGW01-08 for enhanced nerve identification. NIR fluorescence imaging enabled clear identification of nerves buried beneath ~3 mm of tissue that were unidentifiable by white light imaging. These studies provide a strong basis for future clinical translation of NIR nerve-specific fluorophores for utility during FGS to improve patient outcomes.

Can the cavi-precipitation process be exploited to generate smaller size drug nanocrystal?

OBJECTIVE

Cavi-precipitation has the potential to generate drug nanocrystals very efficiently. Achieving smaller than 100 nm particle size for organic drug substances still remained a challenge. The objective of this study was to demonstrate if cavi-precipitation technology can be used to generate smaller than 100 nm drug nanocrystal particle.

SIGNIFICANCE

This study demonstrates that cavi-precipitation process can be used to generate drug nanocrystals of the model compound resveratrol (RVT) consists of crystallites of 30-50 nm size.

METHOD

RVT was dissolved in different organic solvents to prepare the solvent phase (S-phase). Several stabilizers were tested for the organic phase. A combination of SDS and PVP was used stabilizer system in the aqueous anti-solvent phase (AS-phase). The S-phase was added to the AS-phase inside the Emulsiflex C5 homogenizer. Nanosuspension was characterized by laser diffractometry (LD), photon correlation spectroscopy (PCS) and scanning electron microscopy (SEM). The solid state of the suspended particles was investigated by powder X-ray diffractometry (PXRD) and differential scanning calorimetry (DSC).

RESULTS

It was found that DMSO, alone or in combination with acetone in the S-Phase generated the smallest size RVT nanocrystals. The optimum solvent (S) antisolvent (AS) ratio (S:AS) was found to be 3.6:56.4 (v:v). Span 20 was identified as the best stabilizer for the organic phase at a ratio (w:w) of 1:3 (Span 20:RVT). The particles precipitated from different solvents were predominantly crystalline.

CONCLUSIONS

The best sample had a mean particle size (LD) of 167 nm [d(0.5)] which was composed of smaller crystallites having 30-50 nm size (SEM).

Innovations in Thermal Processing: Hot-Melt Extrusion and KinetiSol® Dispersing

Thermal processing has gained much interest in the pharmaceutical industry, particularly for the enhancement of solubility, bioavailability, and dissolution of active pharmaceutical ingredients (APIs) with poor aqueous solubility. Formulation scientists have developed various techniques which may include physical and chemical modifications to achieve solubility enhancement. One of the most commonly used methods for solubility enhancement is through the use of amorphous solid dispersions (ASDs). Examples of commercialized ASDs include Kaletra®, Kalydeco®, and Onmel®. Various technologies produce ASDs; some of the approaches, such as spray-drying, solvent evaporation, and lyophilization, involve the use of solvents, whereas thermal approaches often do not require solvents. Processes that do not require solvents are usually preferred, as some solvents may induce toxicity due to residual solvents and are often considered to be damaging to the environment. The purpose of this review is to provide an update on recent innovations reported for using hot-melt extrusion and KinetiSol® Dispersing technologies to formulate poorly water-soluble APIs in amorphous solid dispersions. We will address development challenges for poorly water-soluble APIs and how these two processes meet these challenges.

Formulation aspects of intravenous nanosuspensions

Intravenous (IV) route is preferred for rapid onset of action, avoiding first pass metabolism and achieving site specific delivery. Development of IV formulations for poorly water soluble drugs poses significant challenges. Formulation approaches like salt formation, co-solvents, surfactants and inclusion complexation using cyclodextrins are used for solubilisation. However, these approaches are not applicable universally and have limitations in extent of solubilisation, hypersensitivity, toxicity and application to only specific type of molecules. IV nanosuspension have been attracting attention as a viable strategy for development of IV formulations of poorly water-soluble drugs. Nanosuspension consists of nanocrystals of poorly water soluble drug suspended in aqueous media and stabilized using minimal concentration of stabilizers. Recent years have witnessed their potential in formulations for toxicological studies and clinical trials. However various challenges are associated with the translational development of IV nanosuspensions. Therefore, the objective of the current review is to provide a holistic view of formulation development and desired properties of IV nanosuspensions. It will also focus on advancements in characterization tools, manufacturing techniques and post-production processing. Challenges associated with translational development and regulatory aspects of IV nanosuspension will be addressed. Additionally, their role in preclinical evaluation and special applications like targeting will also be discussed with the help of case studies. The applications of IV nanosuspensions shall expand as their applications move from preclinical phase to commercialization.

Temperature Effect on the Adsorption and Volumetric Properties of Aqueous Solutions of Kolliphor®ELP

Density, viscosity and surface tension of Kolliphor^® ELP, the nonionic surfactant aqueous solutions were measured at temperature T = 293–318 K and at 5K interval. Steady-state fluorescence measurements have been also made using pyrene as a probe. On the basis of the obtained results, a number of thermodynamic, thermo-acoustic and anharmonic parameters of the studied surfactant have been evaluated and interpreted in terms of structural effects and solute–solvent interactions. The results suggest that the molecules of studied surfactant at concentrations higher than the critical micelle concentration act as structure makers of the water structure.

Expanding the Application and Formulation Space of Amorphous Solid Dispersions with KinetiSol®: a Review

Due to the high number of poorly soluble drugs in the development pipeline, novel processes for delivery of these challenging molecules are increasingly in demand. One such emerging method is KinetiSol, which utilizes high shear to produce amorphous solid dispersions. The process has been shown to be amenable to difficult to process active pharmaceutical ingredients with high melting points, poor organic solubility, or sensitivity to heat degradation. Additionally, the process enables classes of polymers not conventionally processable due to their high molecular weight and/or poor organic solubility. Beyond these advantages, the KinetiSol process shows promise with other applications, such as the production of amorphous mucoadhesive dispersions for delivery of compounds that would also benefit from permeability enhancement.

Solubility of Hydrophobic Compounds in Aqueous Solution Using Combinations of Self-assembling Peptide and Amino Acid

Self-assembling peptides (SAPs) are promising vehicles for the delivery of hydrophobic therapeutics for clinical applications; their amphipathic properties allow them to dissolve hydrophobic compounds in the aqueous environment of the human body. However, self-assembling peptide solutions have poor blood compatibility (e.g., low osmolarity), hindering their clinical application through intravenous administrations. We have recently developed a generalized platform for hydrophobic drug delivery, which combines SAPs with amino acid solutions (SAP-AA) to enhance drug solubility and increase formulation osmolarity to reach the requirements for clinical uses. This formulation strategy was thoroughly tested in the context of three structurally different hydrophobic compounds - PP2, rottlerin, and curcumin - in order to demonstrate its versatility. Furthermore, we examined effects of changing formulation components by analyzing 6 different SAPs, 20 naturally existing amino acids at low and high concentrations, and two different co-solvents dimethyl sulfoxide (DMSO) and ethanol. Our strategy proved to be effective in optimizing components for a given hydrophobic drug, and therapeutic function of the formulated inhibitor, PP2, was observed both in vitro and in vivo. This manuscript outlines our generalized formulation method using SAP-AA combinations for hydrophobic compounds, and analysis of solubility as a first step towards potential use of these formulations in more functional studies. We include representative solubility results for formulation of the hydrophobic compound, curcumin, and discuss how our methodology serves as a platform for future biological studies and disease models.

An Ilomastat-CD Eye Drop Formulation to Treat Ocular Scarring

Purpose

The purpose of this study was to develop a topical matrix metalloproteinase inhibitor preparation for antiscarring therapy.

Methods

The broad spectrum matrix metalloproteinase inhibitor ilomastat was formulated using 2-hydroxypropyl-β-cyclodextrin in aqueous solution. In vitro activity of ilomastat-cyclodextrin (ilomastat-CD) was examined using fibroblasts seeded in collagen. Permeation of ilomastat-CD eye drop through pig eye conjunctiva was confirmed using Franz diffusion cells. Ilomastat-CD eye drop was applied to rabbit eyes in vivo, and the distribution of ilomastat in ocular tissues and fluids was determined by liquid chromatography-mass spectroscopy.

Results

The aqueous solubility of ilomastat-CD was ∼1000 μg/mL in water and 1400 μg/mL in PBS (pH 7.4), which is greater than ilomastat alone (140 and 160 μg/mL in water and PBS, respectively). The in vitro activity of ilomastat-CD to inhibit collagen contraction in the presence of human Tenon fibroblast cells was unchanged compared to uncomplexed ilomastat. Topically administered ilomastat-CD in vivo to rabbit eyes resulted in a therapeutic concentration of ilomastat being present in the sclera and conjunctiva and within the aqueous humor.

Conclusions

Ilomastat-CD has the potential to be formulated as an eye drop for use as an antifibrotic, which may have implications for the prevention of scarring in many settings, for example glaucoma filtration surgery.

Nanosizing techniques for improving bioavailability of drugs

The poor solubility of significant number of Active Pharmaceutical Ingredients (APIs) has become a major challenge in the drug development process. Drugs with poor solubility are difficult to formulate by conventional methods and often show poor bioavailability. In the last decade, attention has been focused on developing nanocrystals for poorly water soluble drugs using nanosizing techniques. Nanosizing is a pharmaceutical process that changes the size of a drug to the sub-micron range in an attempt to increase its surface area and consequently its dissolution rate and bioavailability. The effectiveness of nanocrystal drugs is evidenced by the fact that six FDA approved nanocrystal drugs are already on the market. The bioavailabilities of these preparations have been significantly improved compared to their conventional dosage forms. There are two main approaches for preparation of drug nanocrystals; these are the top-down and bottom-up techniques. Top-down techniques have been successfully used in both lab scale and commercial scale manufacture. Bottom-up approaches have not yet been used at a commercial level, however, these techniques have been found to produce narrow sized distribution nanocrystals using simple methods. Bottom-up techniques have been also used in combination with top-down processes to produce drug nanoparticles. The main aim of this review article is to discuss the various methods for nanosizing drugs to improve their bioavailabilities.

If Euhydric and Isotonic Do Not Work, What Are Acceptable pH and Osmolality for Parenteral Drug Dosage Forms?

Parenteral products should aim toward being isotonic and euhydric (physiological pH). Yet, due to other considerations, this goal is often not reasonable or doable. There are no clear allowable ranges related to pH and osmolality, and thus, the objective of this review was to provide a better understanding of acceptable formulation pH, buffer strength, and osmolality taking into account the administration route (i.e., intramuscular, intravenous, subcutaneous) and administration technique (i.e., bolus, push, infusion). This evaluation was based on 3 different approaches: conventional, experimental, and parametric. The conventional way of defining formulation limits was based on standard pH and osmolality ranges. Experimental determination of titratable acidity or in vitro hemolysis testing provided additional drug product information. Finally, the parametric approach was based on the calculation of theoretical values such as (1) the maximal volume of injection which cannot shift the blood's pH or its molarity out of the physiological range and (b) a dilution ratio at the injection site and by verifying that threshold values are not exceeded. The combination of all 3 approaches can support the definition of acceptable pH, buffer strength, and osmolality of formulations and thus may reduce the risk of failure during preclinical and clinical development.

A Novel Sterol Isolated from a Plant Used by Mayan Traditional Healers Is Effective in Treatment of Visceral Leishmaniasis Caused by Leishmania donovani

Visceral leishmaniasis (VL), caused by the protozoan parasite Leishmania donovani, is a global health problem affecting millions of people worldwide. Treatment of VL largely depends on therapeutic drugs such as pentavalent antimonials, amphotericin B, and others, which have major drawbacks due to drug resistance, toxicity, and high cost. In this study, for the first time, we have successfully demonstrated the synthesis and antileishmanial activity of the novel sterol pentalinonsterol (PEN), which occurs naturally in the root of a Mexican medicinal plant, Pentalinon andrieuxii. In the experimental BALB/c mouse model of VL induced by infection with L. donovani, intravenous treatment with liposome-encapsulated PEN (2.5 mg/kg) led to a significant reduction in parasite burden in the liver and spleen. Furthermore, infected mice treated with liposomal PEN showed a strong host-protective TH1 immune response characterized by IFN-γ production and formation of matured hepatic granulomas. These results indicate that PEN could be developed as a novel drug against VL.

Drug Delivery Approaches in Addressing Clinical Pharmacology-Related Issues: Opportunities and Challenges

Various drug delivery approaches can be used to maximize therapeutic efficacy and minimize side effects, by impacting absorption, distribution, metabolism, and elimination (ADME) of a drug compound. For those drugs with poor water solubility or low permeability, techniques such as amorphous solid dispersion, liposomes, and complexations have been used to improve their oral bioavailability. Modified release (MR) formulations have been widely used to improve patient compliance, as well as to reduce side effects, especially for those drugs with short half-lives or narrow therapeutic windows. More than ten drugs using sterile long-acting release (LAR) formulations with clear clinical benefit have been successfully marketed. Furthermore, drug delivery systems have been used in delaying drug clearance processes. Additionally, modifying the in vivo drug distribution using targeted delivery systems has significantly improved oncology treatments. All the drug delivery approaches have their advantages and limitations. For both brand and generic drugs, the achievement of consistent quality and therapeutic performance using drug delivery systems can also pose serious challenges in developing a drug for the market, which requires close collaboration among industry, academia, and regulatory agencies. With the advent of personalized medicines, there will be great opportunities and challenges in utilizing drug delivery systems to provide better products and services for patients.

From nanospheres to micelles: simple control of PCL-g-PEG copolymers’ amphiphilicity through thiol–yne photografting

A unique combination of polyester post-polymerization modification and photoradical thiol–yne addition is reported for the synthesis of amphiphilic degradable graft copolymers with controlled compositions, used to prepare micelles or nanospheres.

Strategies to address low drug solubility in discovery and development

Drugs with low water solubility are predisposed to low and variable oral bioavailability and, therefore, to variability in clinical response. Despite significant efforts to "design in" acceptable developability properties (including aqueous solubility) during lead optimization, approximately 40% of currently marketed compounds and most current drug development candidates remain poorly water-soluble. The fact that so many drug candidates of this type are advanced into development and clinical assessment is testament to an increasingly sophisticated understanding of the approaches that can be taken to promote apparent solubility in the gastrointestinal tract and to support drug exposure after oral administration. Here we provide a detailed commentary on the major challenges to the progression of a poorly water-soluble lead or development candidate and review the approaches and strategies that can be taken to facilitate compound progression. In particular, we address the fundamental principles that underpin the use of strategies, including pH adjustment and salt-form selection, polymorphs, cocrystals, cosolvents, surfactants, cyclodextrins, particle size reduction, amorphous solid dispersions, and lipid-based formulations. In each case, the theoretical basis for utility is described along with a detailed review of recent advances in the field. The article provides an integrated and contemporary discussion of current approaches to solubility and dissolution enhancement but has been deliberately structured as a series of stand-alone sections to allow also directed access to a specific technology (e.g., solid dispersions, lipid-based formulations, or salt forms) where required.

Antitumor efficacy of a novel CLA-PTX microemulsion against brain tumors: in vitro and in vivo findings

BACKGROUND

Considering the observations that linoleic acid conjugated with paclitaxel (CLA-PTX) possesses antitumor activity against brain tumors, is able to cross the blood-brain barrier, but has poor water solubility, the purpose of this study was to prepare a novel CLA-PTX microemulsion and evaluate its activity against brain tumors in vitro and in vivo.

METHODS

The in vitro cytotoxicity of a CLA-PTX microemulsion was investigated in C6 glioma cells. The in vivo antitumor activity of the CLA-PTX microemulsion was evaluated in tumor-bearing nude mice and rats. The pharmacokinetics of the CLA-PTX microemulsion were investigated in rats, and its safety was also evaluated in mice.

RESULTS

The average droplet size of the CLA-PTX microemulsion was approximately 176.3 ± 0.8 nm and the polydispersity index was 0.294 ± 0.024. In vitro cytotoxicity results showed that the IC(50) of the CLA-PTX microemulsion was 1.61 ± 0.83 μM for a C6 glioma cell line, which was similar to that of free paclitaxel and CLA-PTX solution (P > 0.05). The antitumor activity of the CLA-PTX microemulsion against brain tumors was confirmed in our in vivo C6 glioma tumor-bearing nude mice as well as in a rat model. In contrast, Taxol(®) had almost no significant antitumor effect in C6 glioma tumor-bearing rats, but could markedly inhibit growth of C6 tumors in C6 glioma tumor-bearing nude mice. The pharmacokinetic results indicated that CLA-PTX in solution has a much longer circulation time and produces higher drug plasma concentrations compared with the CLA-PTX microemulsion. The results of the acute toxicity study showed that the LD(50) of CLA-PTX solution was 103.9 mg/kg. In contrast, the CLA-PTX microemulsion was well tolerated in mice when administered at doses up to 200 mg/kg.

CONCLUSION

CLA-PTX microemulsion is a novel formulation with significant antitumor efficacy in the treatment of brain tumors, and is safer than CLA-PTX solution.

Drug nanocrystals in the commercial pharmaceutical development process

Nanosizing is one of the most important drug delivery platform approaches for the commercial development of poorly soluble drug molecules. The research efforts of many industrial and academic groups have resulted in various particle size reduction techniques. From an industrial point of view, the two most advanced top-down processes used at the commercial scale are wet ball milling and high pressure homogenization. Initial issues such as abrasion, long milling times and other downstream-processing challenges have been solved. With the better understanding of the biopharmaceutical aspects of poorly water-soluble drugs, the in vivo success rate for drug nanocrystals has become more apparent. The clinical effectiveness of nanocrystals is proven by the fact that there are currently six FDA approved nanocrystal products on the market. Alternative approaches such as bottom-up processes or combination technologies have also gained considerable interest. Due to the versatility of nanosizing technology at the milligram scale up to production scale, nanosuspensions are currently used at all stages of commercial drug development, Today, all major pharmaceutical companies have realized the potential of drug nanocrystals and included this universal formulation approach into their decision trees.

Nanoaggregates of biodegradable amphiphilic random polycations for delivering water-insoluble drugs

Cationic amphiphilic random copolyesters were obtained by copolymerization of 5-Z-amino-δ-valerolactone and ε-caprolactone. The amino content of the final copolymers was controlled by the polymerization feed ratio and was in the range 10 to 100%. Copolymers solubility and aggregation behavior was assessed by conductometric and zeta potential analyses. A critical aggregation concentration of ca. 0.05% (w/v) was found for all water-soluble copolymers that formed nanoaggregates. Two populations were found to be present in equilibrium with hydrodynamic diameters in the range of 30-50 and 100-250 nm. The capacity to use the amphiphilic and cationic character of the nanoaggregates to encapsulate highly hydrophobic compounds was further investigated. Finally, copolymers hemo- and cytocompatibility were evaluated by hemagglutination, hemolysis, and cells proliferation tests. The results showed that the proposed cationic amphiphilic random copolyesters are biocompatible.

Surfactant-assisted controlled release of hydrophobic drugs using anionic surfactant templated mesoporous silica nanoparticles

A series of mesoporous silica nanoparticles (MSNs) were synthesized using the co-structure directing method. A non-cytotoxic anionic surfactant, undec-1-en-11-yltetra(ethylene glycol) phosphate monoester surfactant (PMES), was used as a structure directing agent (SDA) together with aminopropyltrimethoxysilane that functioned as a co-structure directing agent (CSDA). The morphology and mesoporous structure of these materials were tuned by changing the molar ratio of CSDA and SDA. These mesoporous nanomaterials containing PMES inside the pores showed excellent biocompatibility in vitro. The cellular internalization and endosome escape of PMES-MSNs in cervical cancer cells (HeLa) was demonstrated by flow cytometry and confocal microscopy, respectively. The PMES-MSNs were used as drug delivery carriers for resveratrol, a low water solubility drug, by taking advantage of the hydrophobic environment created by the PMES micelle inside the pores. This surfactant-assisted delivery strategy was tested under physiological conditions showing an increase of the drug loading compared to the material without surfactant and steady release of resveratrol. Finally, the therapeutic properties of resveratrol-loaded PMES-MSNs were evaluated in vitro using HeLa and Chinese hamster ovarian cells. We envision that this surfactant-assisted drug delivery method using MSNs as nanovehicles would lead to a new generation of carrier materials for intracellular delivery of a variety of hydrophobic therapeutic agents.

Formation, characterization, and fate of inhaled drug nanoparticles

Nanoparticles bring many benefits to pulmonary drug delivery applications, especially for systemic delivery and drugs with poor solubility. They have recently been explored in pressurized metered dose inhaler, nebulizer, and dry powder inhaler applications, mostly in polymeric forms. This article presents a review of processes that have been used to generate pure (non polymeric) drug nanoparticles, methods for characterizing the particles/formulations, their in-vitro and in-vivo performances, and the fate of inhaled nanoparticles.