71 research outputs found
Summary Report of PQRI Workshop on Nanomaterial in Drug Products: Current Experience and Management of Potential Risks
At the Product Quality Research Institute (PQRI) Workshop held last January 14-15, 2014, participants from academia, industry, and governmental agencies involved in the development and regulation of nanomedicines discussed the current state of characterization, formulation development, manufacturing, and nonclinical safety evaluation of nanomaterial-containing drug products for human use. The workshop discussions identified areas where additional understanding of material attributes, absorption, biodistribution, cellular and tissue uptake, and disposition of nanosized particles would continue to inform their safe use in drug products. Analytical techniques and methods used for in vitro characterization and stability testing of formulations containing nanomaterials were discussed, along with their advantages and limitations. Areas where additional regulatory guidance and material characterization standards would help in the development and approval of nanomedicines were explored. Representatives from the US Food and Drug Administration (USFDA), Health Canada, and European Medicines Agency (EMA) presented information about the diversity of nanomaterials in approved and newly developed drug products. USFDA, Health Canada, and EMA regulators discussed the applicability of current regulatory policies in presentations and open discussion. Information contained in several of the recent EMA reflection papers was discussed in detail, along with their scope and intent to enhance scientific understanding about disposition, efficacy, and safety of nanomaterials introduced in vivo and regulatory requirements for testing and market authorization. Opportunities for interaction with regulatory agencies during the lifecycle of nanomedicines were also addressed at the meeting. This is a summary of the workshop presentations and discussions, including considerations for future regulatory guidance on drug products containing nanomaterials
Controlling and Predicting Nanoparticle Formation by Block Copolymer Directed Rapid Precipitations
Nanoparticles
have shown promise in several biomedical applications,
including drug delivery and medical imaging; however, quantitative
prediction of nanoparticle formation processes that scale from laboratory
to commercial production has been lacking. Flash NanoPrecipitation
(FNP) is a scalable technique to form highly loaded, block copolymer
protected nanoparticles. Here, the FNP process is shown to strictly
obey diffusion-limited aggregation assembly kinetics, and the parameters
that control the nanoparticle size and the polymer brush density on
the nanoparticle surface are shown. The particle size, ranging from
40 to 200 nm, is insensitive to the molecular weight and chemical
composition of the hydrophobic encapsulated material, which is shown
to be a consequence of the diffusion-limited growth kinetics. In a
simple model derived from these kinetics, a single constant describes
the 46 unique nanoparticle formulations produced here. The polymer
brush densities on the nanoparticle surface are weakly dependent on
the process parameters and are among the densest reported in the literature.
Though modest differences in brush densities are observed, there is
no measurable difference in the amount of protein adsorbed within
this range. This work highlights the material-independent and universal
nature of the Flash NanoPrecipitation process, allowing for the rapid
translation of formulations to different stabilizing polymers and
therapeutic loads
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Polymer Directed Self-Assembly of pH-Responsive Antioxidant Nanoparticles
We have developed pH-responsive, multifunctional nanoparticles based on encapsulation of an antioxidant, tannic acid (TA), using flash nanoprecipitation, a polymer directed self-assembly method. Formation of insoluble coordination complexes of tannic acid and iron during mixing drives nanoparticle assembly. Tuning the core material to polymer ratio, the size of the nanoparticles can be readily tuned between 50 and 265 nm. The resulting nanoparticle is pH-responsive, i.e., stable at pH 7.4 and soluble under acidic conditions due to the nature of the coordination complex. Further, the coordination complex can be coprecipitated with other hydrophobic materials such as therapeutics or imaging agents. For example, coprecipitation with a hydrophobic fluorescent dye creates fluorescent nanoparticles. In vitro, the nanoparticles have low cytotoxicity and show antioxidant activity. Therefore, these particles may facilitate intracellular delivery of antioxidants
Formulation of pH-Responsive Methacrylate-Based Polyelectrolyte-Stabilized Nanoparticles for Applications in Drug Delivery
pH-responsive polyelectrolytes, including
methacrylate-based
anionic
copolymers (MACs), are widely used as enteric coatings and matrices
in oral drug delivery. Despite their widespread use in these macroscopic
applications, the molecular understanding of their use as stabilizers
for nanoparticles (NPs) is lacking. Here, we investigate how MACs
can be used to create NPs for therapeutic drug delivery and the role
of MAC molecular properties on the assembly of NPs via flash nanoprecipitation.
The NP size is tuned from 59 to 454 nm by changing the degree of neutralization,
ionic strength, total mass concentration, and the core-to-MAC ratio.
The NP size is determined by the volume of hydrophilic domains on
the surface relative to the volume of hydrophobic domains in the core.
We calculate the dimensions of the hydrophobic NP core relative to
the thickness of the polyelectrolyte layer over a range of ionizations.
Importantly, the results are shown to apply to both high-molecular-weight
polymers as core materials and small-molecule drugs. The pH responsiveness
of MAC-stabilized NPs is also demonstrated. Future development of
polyelectrolyte copolymer-stabilized nanomedicines will benefit from
the guiding principles established in this study
Hydrophobic Ion Pairing of Peptide Antibiotics for Processing into Controlled Release Nanocarrier Formulations
Nanoprecipitation
of active pharmaceutical ingredients (APIs) to
form nanocarriers (NCs) is an attractive method of producing formulations
with improved stability and biological efficacies. However, nanoprecipitation
techniques have not been demonstrated for highly soluble peptide therapeutics.
We here present a model and technique to encapsulate highly water-soluble
biologic APIs by manipulating API salt forms. APIs are ion paired
with hydrophobic counterions to produce new API salts that exhibit
altered solubilities suitable for nanoprecipitation processing. The
governing rules of ion pair identity and processing conditions required
for successful encapsulation are experimentally determined and assessed
with theoretical models. Successful NC formation for the antibiotic
polymyxin B requires hydrophobicity of the ion pair acid to be greater
than logP = 2 for strong acids and greater than logP = 8 for weak
acids. Oleic acid with a logP = 8, and p<i>K</i><sub>a</sub> = 5, appears to be a prime candidate as an ion pair agent since
it is biocompatible and forms excellent ion pair complexes. NC formation
from preformed, organic soluble ion pairs is compared to in situ ion
pairs where NCs are made in a single precipitation step. NC properties,
such as stability and release rates, can be tuned by varying ion pair
molecular structure and ion pair-to-API molar ratios. For polymyxin
B, NCs â 100â200 nm in size, displaying API release
rates over 3 days, were produced. This work demonstrates a new approach
that enables the formation of nanoparticles from previously intractable
compounds
Real-Time and Multiplexed Photoacoustic Imaging of Internally Normalized Mixed-Targeted Nanoparticles
Photoacoustic
(PA) imaging is a developing diagnostic technique
where multiple species can be simultaneously imaged with high spatial
resolution in 3D if the absorbance spectrum of each species is distinct
and separable. However, multiplexed PA imaging has been greatly limited
by the availability of spectrally separable contrast agents that can
be used in vivo. Toward this end, we present the formation and application
of a series of poly ethylene glycol (PEG)-coated nanoparticles (NPs)
with unique separable absorbance profiles suitable for simultaneous
multiplexed imaging. As a proof-of-concept, we demonstrate this form
of mixed-sample multiplexed imaging, using cRGD peptide surface-modified
NPs with nonmodified NPs in a murine subcutaneous Lewis lung carcinoma
tumor model. The simultaneous imaging of nonmodified NPs provides
an âinternal standardâ, to deconvolute the contributions
of active-ligand and passive-NP targeting effects. Particles with
25% surface cRGD modification display 52 ± 22 fold higher liver
to tumor ratio accumulation levels, while the same set of particles
display only 9.8 ± 4 fold accumulation levels when internally
normalized. The pharmacokinetic profiles of targeted and nontargeted
NPs can be simultaneously tracked in real-time to study how biodistribtions
of particles are affected by ligand modification. The internal normalization
of control particles greatly enhances the precision and decreases
the number of animals needed in studies of nanoparticle targeting.
These new dyes are an enabling technology for PA imaging of NP fate
and targeting. This is the first demonstration of real-time multiplexed
PA imaging of mixed-targeted samples in vivo
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Polymer Directed Self-Assembly of pH-Responsive Antioxidant Nanoparticles
We have developed pH-responsive,
multifunctional nanoparticles
based on encapsulation of an antioxidant, tannic acid (TA), using
flash nanoprecipitation, a polymer directed self-assembly method.
Formation of insoluble coordination complexes of tannic acid and iron
during mixing drives nanoparticle assembly. Tuning the core material
to polymer ratio, the size of the nanoparticles can be readily tuned
between 50 and 265 nm. The resulting nanoparticle is pH-responsive,
i.e., stable at pH 7.4 and soluble under acidic conditions due to
the nature of the coordination complex. Further, the coordination
complex can be coprecipitated with other hydrophobic materials such
as therapeutics or imaging agents. For example, coprecipitation with
a hydrophobic fluorescent dye creates fluorescent nanoparticles. <i>In vitro</i>, the nanoparticles have low cytotoxicity and show
antioxidant activity. Therefore, these particles may facilitate intracellular
delivery of antioxidants
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Spray drying OZ439 nanoparticles to form stable, water-dispersible powders for oral malaria therapy
Abstract Background OZ439 is a new chemical entity which is active against drug-resistant malaria and shows potential as a single-dose cure. However, development of an oral formulation with desired exposure has proved problematic, as OZ439 is poorly soluble (BCS Class II drug). In order to be feasible for low and middle income countries (LMICs), any process to create or formulate such a therapeutic must be inexpensive at scale, and the resulting formulation must survive without refrigeration even in hot, humid climates. We here demonstrate the scalability and stability of a nanoparticle (NP) formulation of OZ439. Previously, we applied a combination of hydrophobic ion pairing and Flash NanoPrecipitation (FNP) to formulate OZ439 NPs 150 nm in diameter using the inexpensive stabilizer hydroxypropyl methylcellulose acetate succinate (HPMCAS). Lyophilization was used to process the NPs into a dry form, and the powderâs in vitro solubilization was over tenfold higher than unprocessed OZ439. Methods In this study, we optimize our previous formulation using a large-scale multi-inlet vortex mixer (MIVM). Spray drying is a more scalable and less expensive operation than lyophilization and is, therefore, optimized to produce dry powders. The spray dried powders are then subjected to a series of accelerated aging stability trials at high temperature and humidity conditions. Results The spray dried OZ439 powderâs dissolution kinetics are superior to those of lyophilized NPs. The powderâs OZ439 solubilization profile remains constant after 1 month in uncapped vials in an oven at 50 °C and 75% RH, and for 6 months in capped vials at 40 °C and 75% RH. In fasted-state intestinal fluid, spray dried NPs achieved 80â85% OZ439 dissolution, to a concentration of 430 ”g/mL, within 3 h. In fed-state intestinal fluid, 95â100% OZ439 dissolution is achieved within 1 h, to a concentration of 535 ”g/mL. X-ray powder diffraction and differential scanning calorimetry profiles similarly remain constant over these periods. Conclusions The combined nanofabrication and drying process described herein, which utilizes two continuous unit operations that can be operated at scale, is an important step toward an industrially-relevant method of formulating the antimalarial OZ439 into a single-dose oral form with good stability against humidity and temperature
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