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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5443_Библиотеки_им_академика_М_И_Перельмана
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7.5.1 Database selection
Database selection in VS of mucoadhesive polymers is an important consideration as
it influences the quality of candidates we can evaluate and the accuracy of predictions
regarding the polymer’s ability to adhere to mucosal surfaces or interact with specific
molecular targets [55]. Here are some factors to consider when selecting databases for
VS of mucoadhesive polymers:
1. Chemical structure databases:
– Begin by choosing databases that contain chemical structures of mucoadhe-
sive polymers or polymer-like compounds. These databases should provide
3D coordinates and structural information needed for molecular modeling
and docking [56].
2. Commercial databases:
– Explore commercially available databases that may contain a wide variety of
polymers or compounds with potential mucoadhesive properties. Examples in-
clude chemical supplier databases and proprietary chemical collections.
3. Public databases:
– Utilize publicly accessible databases that offer informatio n on polymers, in-
cluding their structures, properties, and characteristics. These databases may
include PubChem, ChemSpider, or other chemical databases [57].
4. Polymers and materials databases:
– Seek databases specifically focused on polymers and materials. Some materi-
als science databases provide information on polymer structures, properties,
and applications.
5. Mucosal targets or receptors databases:
– If our research involves the interaction of mucoadhesive polymers with spe-
cific mucosal targets or receptors, consider databases containing structural
information about these targets. This information is essential for molecular
docking studies [58].
6. In-house libraries:
– If available, use in-house libraries of mucoadhesive polymers or compounds.
These libraries may include polymers synthesized or collected as part of our
research efforts and can be tailored to our specific needs.
7. Biological databases:
– In cases where mucoadhesive polymers are designed to interact with mucosal
tissues, consider accessin g biological databases for information on mucosal
tissue structures, mucins, or other relevant biological molecules.
8. Specialized polymer databases:
– Look for specialized polymer databases that focus on mucoadhesive poly-
mers, hydrogels, or materials designed for biomedical applications. These da-
tabases may provide unique insights and structures.
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9. Chemical property filters:
– Apply chemical property filters or criteria to narrow down the database en-
tries to those that are most relevant to our research. Filters may include prop-
erties like molecular weight, chemical composition, or functional groups.
10. Diversity and representation:
– Ensure that the selected database represents a diverse range of mucoadhe-
sive polymers, including different polymer types, structures, and adhesive
mechanisms. A diverse database increases the chances of identifying novel
candidates.
11. Experimental validation data:
– Consider databases that include experimental validation data for mucoadhe-
sive properties, such as adhesive strength, mucoadhesion time, or tissue in-
teraction studies. This can help in selecting candidates with known adhesive
properties.
12. Update and quality assurance:
– Check the update frequency and quality assurance p rocesses of t he data-
bases. Timely updates ensure access to the latest data, while quality assur-
ance reduces the risk of inaccurate or low-quality information.
13. Cost and licensing:
– Assess the cost and licensing terms associated with the chosen databases. Be
aware of any subscription fees, licensing agreements, or usage restrictions.
The choice of the database should align with our specific research goals, whether it in-
volves screening polymers for mucosal adhesion, designing new mucoadhesive materi-
als, or investigating interactions with mucosal targets. Combining multiple databases
and applying rigorous filtering and validation processes can enhance the success of our
VS efforts.
7.5.2 Target selection
Target selection in the VS of mucoadhesive polymers involves identifying the specific
biological or physiological target to which these polymers will adhere or interact. Mu-
coadhesive polymers are used in various pharmaceutical and biomedical applications,
and the choice of target is critical for achieving the desired therapeutic or functional
outcome. Here are some considerations and strategies for target selection in VS of mu-
coadhesive polymers:
1. Mucosal tissues: Mucoadhesive polymers are designed to adhere to mucosal sur-
faces in the body, such as the gastrointestinal tract, nasal mucosa, ocular surface,
or vaginal mucosa [59]. The first step is to determine the specific mucosal tissue
we want the polymer to adhere to.
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2. Disease or condition: Consider the disease or medical condition that we are tar-
geting. Different diseases may require mucoadhesive polymers with specific prop-
erties or adhesive capabilities. For example, mucoadhesive polymers used to
deliver drugs to the gastrointestinal tract may have different requirements than
those used for ocular drug delivery.
3. Biological receptors: Identify the biological receptors or targets on mucosal surfa-
ces that are relevant to our application. These receptors may include mucins, cell
surface proteins, glycoproteins, or other molecules present in mucosal epithelial
cells. Understanding the interactions between mucoadhesive polymers and these
receptors is essential.
4. Functional goals: Define the functional goals of the mucoad hesive polymer. Are
we aiming to enhance drug delivery, prolong drug release, improve tissue adhe-
sion, or achieve another specific objective? The choice of target should align with
these goals.
5. Local versus systemic del ivery: Determine whether the polymer’stargetisin-
tended for local drug delivery or systemic absorption through mucosal surfaces
[60]. The properties and mechanisms of mucoadhesion may differ for these two
scenarios.
6. Biocompatibility and safety: Ensure that the chosen target is biologically relevant
and safe for interaction with mucoadhesive polymers. Toxic or harmful interac-
tions should be avoided.
7. Specificity: Depending on our application, we may need mucoadhesive polymers
that exhibit high specificity for a particular target [60]. This can help minimize
off-target effects and improve therapeutic efficacy.
8. In vitro and in vivo models: If possible, validate the target selection using in vitro
and in vivo models. This can help assess the effectiveness of the mucoadhesive
polymers in interacting with the chosen target under physiological conditions.
9. Previous research: Review existing literature and research related to mucoadhe-
sive polymers in our target area. Understanding the current state of knowledge
can guide our target selection and help us build on existing research.
10. Computational modeling: Consider using computational modeling and molecular
docking techniques to predict the interactions between mucoadhesive polymers
and potential targets. This can help identify promising candidates for further ex-
perimental validation.
11. Iterative approach: Target selection may involve an iterative process of hypothe-
sis generation, computational screening, experimental validation, and refinement
of the target, based on results [61].
Overall, target selection in the VS of mucoadhesive polymers requires a deep under-
standing of the specific application, mucosal environment, and biological interactions
involved. It often involves a multidisciplinary approach that combines knowledge of
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polymer chemistry, pharmacology, and physiology to achieve the desired therapeutic
or functional outcome.
7.5.3 Molecular modeling and docking
Molecular modeling and docking play a crucial role in the VS of mucoadhesive poly-
mers as they help predict and understand the interactions between these polymers
and their target mucosal surfaces or receptors [59]. Here is how molecular modeling
and docking are applied in this context:
1. Structure modeling of mucoadhesive polymers:
– Begin by constructing 3D structural models of the mucoadhesive polymers
we intend to study [62]. This can be done using molecular modeling software
and may involve the use of force field parameters and QM calculations to de-
termine the polymer’s conformation and properties.
2. Target identification and modeling:
– Identify the specific mucosal receptors, proteins, or mucins that the mucoad-
hesive polymer is expected to interact with. Collect or construct 3D structural
models of these targets. Experimental data and availab le crystal structures
can be valuable sources of information.
3. Molecular docking:
– Employ molecular docking soft ware or tools to predict the binding interac-
tions between the mucoadhesive polymer and the mucosal target [62]. Dock-
ing algorithms will explore various orientations and conformations of the
polymer to determine the energetically favorable binding modes.
– Consider use of flexible docking, which allows both the polymer and the tar-
get to be flexible during the docking process. This is particularly relevant
when studying flexible polymers and dynamic mucosal surfaces [63].
– Analyze docking scores and binding energies to rank potential binding
modes and assess the strength of interactions. Lower energy values typically
indicate more favorable binding.
4. Visualization and analysis:
– Visualize the docking results using molecular visualization software. This will
help us understand the binding modes and the spatial arrangement of inter-
acting residues or regions [64].
– Analyze the interactions between the mucoadhesive polymer and the muco-
sal target. Look for key molecular interactions, such as hydrogen bonds, elec-
trostatic interactions, van der Waals forces, and hydrophobic contacts.
5. Validation and refinement:
– Validate the predicted binding modes and interactions through experimental
studies. Techniq ues like surface plasmon resonance (SPR), isothermal titra-
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tion calorimetry (ITC), or fluorescence assays can be used to confirm binding
affinities and kinetics [60].
– If necessary, refine the polymer structure or targ et model, based on experi-
mental findings or further computational simulations, to improve the accu-
racy of predictions.
6. Computational screening:
– If we are working with a library of mucoadhesive polymers, perform VS by
docking multiple polymers against the mucosal target. This can help identify
potential lead polymers with strong binding affinities.
7. Optimization and design:
– Based on the insights gained from molecular docking and experimental vali-
dation, optimize the mucoadhesive polymer’s structure or design new po ly-
mer variants with enhanced mucoadhesive properties and interactions with
the mucosal surface [63].
8. Data integration and decision-making:
– Combine the results of molecular modeling, docking, and experimental data
to make informed decisions regarding the selection of mucoadhesive poly-
mers for further development in drug delivery or other applications.
Molecular modeling and docking techniques provide valuable insights into the molec-
ular-level interactions between mucoadhesive polymers and mucosal targets. These
insights can guide the design and optimization of mucoadhesive polymer-based for-
mulations for improved drug delivery, tissue adhesion, or other therapeutic or func-
tional purposes.
7.5.4 Scoring and ranking
Scoring and ranking in VS of mucoadhesive polymers are essential steps for identify-
ing the most promising polymer candidates that are likely to have strong interactions
with mucosal surfaces or receptors. Scoring and ranking methods help prioritize and
select the mucoad hesive polymers with the best potential for further experimental
validation [65]. Here is how scoring and ranking are typically conducted:
1. Scoring functions:
– Choose appropriate scoring functions or algorithms that can quantify the in-
teraction energy or binding affinity between the mucoadhesive polymer and
the mucosal target. Scoring functions are designed to estimate the stability of
the complex formed by the polymer and the target.
2. Energy calculation:
– Use molecular modeling software to calculate the energy of interaction be-
tween the mucoadhesive polymer and the mucosal target. This energy calcu-
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lation is based on the force fields, parameters, and potential energy functions
defined in the modeling software [65].
3. Docking scores:
– For each mucoadhesive polymer-receptor complex generated during molecu-
lar docking simulations, compute a docking score or binding energy. This
score represents the strength of the interaction between the polymer and the
target. Lower scores typically indicate more favorable binding.
4. Scoring components:
– Scoring functions often consist of various components, including van der
Waals interactions, elec trostatic interactions, hydrogen bonding, and solva-
tion effects. These components contribute to the overall binding energy and
are typically combined to generate a single docking score [66].
5. Empirical versus physics-based scoring:
– Decide whether to use empirical scoring functions (e.g., scoring functions de-
rived from experimental data) or physics-based scoring functions (e.g., force
field-based calculations). Empirical scoring functions are often faster but may
be less accurate, while physics-based scoring can provide more detailed
insights.
6. Ranking:
– Rank the mucoadhesive polymers based on their docking scores or bind ing
energies. The polymer with the lowest (most negative) energy is typically
ranked highest as it is predicted to have the strongest interaction with the
mucosal target.
7. Thresholds and cutoffs:
– Define cutoff values or thresholds for docking scores to filter out less promis-
ing polymer candidates [62]. Polymers with docking scores below a certain
threshold may be considered potential hits for further investigation.
8. Visual inspection:
– Visualize the docking poses and interactions between the mucoadhesive poly-
mers and the mucosal target. Visual inspection can help identify specific mo-
lecular interactions (e.g., hydrogen bonds and hydrophobic contacts) that
contribute to the binding energy and ranking.
9. Validation and refinement:
– Validate the top-ranked mucoadhesive polymers experimentally using techni-
ques such as SPR or ITC. Experimental validation helps confirm the accuracy
of the scoring and ranking results.
– Refine the scoring and ranking criteria, if needed, based on experimental
data and insights gained from the validation process.
10. Iterative screening: If necessary, conduct iterative VS by refining the polymer
structures or parameters and re-running the docking simulations. This iterative
process can improve the accuracy of scoring and ranking [66].
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Scoring and ranking are iterative processes that combine computational predictions
with experimental validation to identify mucoadhesive polymers with the highest po-
tential for successful interaction with the mucosal surfaces or receptors. The use of
reliable scoring functions and careful analysis of docking results are essential for the
success of VS in mucoadhesive polymer research.
7.5.5 Filtering and optimization
Filtering and optimiz ation are important steps in the VS of mucoadhesive polymers,
allowing us to focus on the most promising candidates while optimizing their proper-
ties for effective mucosal adhesion. Here is how these processes work:
7.5.5.1 Filtering
1. Chemical property filters:
– Apply filters to the mucoadhesive polymer candidates based on relevant
chemical properties. Filters can include criteria such as molecular weight, lip-
ophilicity, hydrogen bond donors and acceptors, and charge distribution [67].
These filters ensure that the selected polymers meet certain drug-likeness
and physicochemical properties.
2. Biocompatibility and toxicity:
– Filter out mucoadhesive polymers that may have toxic effects or undesirable
biocompatibility. Use predictive models or available toxicity databases to
screen for potential safety concerns.
3. Solubility:
– Assess the solubility of mucoadhesive polymers in relevant physiological flu-
ids. Polymer s that are too insoluble may not effectively adhere to mucosal
surfaces or dissolve for drug release.
4. Drug delivery requirements:
– If the mucoadhesive polymers are intended for drug delivery, consider filter-
ing based on drug delivery requirements such as controlled release, bioavail-
ability enhancement, or specific release profiles.
5. Target tissue compatibility:
– Ensure that the selected polymers are compatible with the target mucosal tis-
sue. Compatibility can include considerations like pH sensitivity, mucoadhe-
sion strength, and tissue-specific properties.
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7.5.5.2 Optimization
1. Chemical modification:
– Based on screening results, consider chemical modifications to optimize the
mucoadhesive polymer’s properties. This can involve altering functional
groups, molecular weight, or polymer structure to enhance adhesion or other
desired characteristics [68].
2. Conjugation and coating:
– Explore the use of conjugation techniques to attach specific ligands or target-
ing moieties to the mucoadhesive polymer. These modifications can improve
target specificity or enhance adhesion.
3. Surface modification:
– Modify the surface properties of mucoadhesive polymer particles or films to
optimize their adhesive properties [65]. Surface modifications can involve
changing hydrophilicity/hydrophobicity, charge, or roughness.
4. Hydrogel formulation:
– Develop hydrogel formulations using mucoadhesive polymers to optimize
their release properties and adhesion. Hydrogels can provide sustained drug
release and improve tissue contact.
5. Cross-linking and polymer blending:
– Experiment with cross-linking techniques or blend mucoadhesive polymers
with other materials to achieve the desired mechanical properties, release ki-
netics, and mucoadhesive strength.
6. In silico modeling:
– Use computational modeling to simulate the behavior of mucoadhesive poly-
mers under different conditions, such as pH changes or mucosal environ-
ments. This can guide optimization efforts [68].
7. Experimental validation:
– Validate the optimized mucoadhesive polymers experimentally through
in vitro and, eventually, in vivo studies. These experiments will confirm the
improved properties and functionality of the optimized polymers.
8. Iterative optimization:
– Optimization may involve an iterative process where we fine-tune the poly-
mer properties based on the results of experimental testing and computa-
tional modeling.
Filtering and optimization ensure that mucoadhesive polymer candidates are not
only selected based on theoretical predictions but are also tailored to meet the specific
requirements of the intended application. This iterative approach increases the likeli-
hood of identifying successful mucoadhesive polymer formulations for mucosal drug
delivery or other therapeutic purposes.
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7.5.6 Experimental validation
Experimental validation is a crucial step in the VS of mucoadhesive polymers. It helps
confirm the predictions made during the computational phase and provides empirical
evidence of a polymer’s ability to adhere to mucosal surfaces or interact with specific
targets [69]. Here are some common experimental validation techniques used in mu-
coadhesive polymer research:
1. SPR:
– SPR is a powerful technique for studying biomolecular interactions, including
the binding of mucoadhesiv e polymers to mucosal surfaces or receptors. It
measures changes in refractive index near a sensor surface as molecules
bind, allowing the determination of binding kinetics and affinities.
2. ITC:
– ITC measures the heat released or absorbed during a binding event. It can be
used to determine the binding thermodynamics, such as enthalpy (ΔH)and
equilibrium binding constants (K
d
), providing insights into the binding inter-
actions between polymers and mucosal targets [69].
3. Contact angle measurements:
– Contact angle measurements assess the wettability of surfaces by measuring
the angle formed between aliquiddropletandthesurface.Mucoadhesive
polymers are expected to have lower contact angles on mucosal surfaces due
to enhanced wetting and adhesion [68].
4. Rheological studies:
– Rheological tests assess the viscoelastic properties of mucoadhesive polymer
formulations. These tests can provide insights into the mechanical strength
and adhesive properties of hydrogel-based mucoadhesive systems.
5. Tensile strength and adhesive strength tests:
– Mechanical testing, including tensile strength and adhesive strength tests,
evaluates the physical properties of mucoadhesive polymers. It assesses their
ability to withstand forces and maintain adhesion to mucosal tissues.
6. Mucoadhesion studies:
– Conduct in vitro and ex vivo mucoadhesion studies using model mucosal sur-
faces or tissues. These studies assess the ability of mucoadhesive polymers to
adhere to mucosal surfaces under physiological conditions. Techniques like
tensile detachment, rotating cylinder, or texture analysis can be employed.
7. Fluorescence and confocal microscopy:
– Visualize the interaction of fluorescently labeled mucoadhesive polymers
with mucosal surfaces or receptors using microscopy techniques. This pro-
vides spatial information on the distribution and localization of the poly-
mers [70].
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8. Release studies:
– If mucoadhesive polymers are used for drug delivery, perform release studies
to determine the release kinetics of drug-loaded polymers. This helps assess
the controlled drug-release properties of the polymers.
9. In vivo studies:
– Ultimately, in vivo studies in animal models can provide valuable insights
into the mucoadhesive properties and safety of polymers. These studies can
include assessments of tissue adhesion, pharmacokinetics, and biodistribu -
tion [71].
10. Cytotoxicity and biocompatibility assays:
– Evaluate the cytotoxicity and biocompatibility of mucoadhesive polymers
using cell culture models. Assess cell viability, inflammation, and tissue
compatibility.
11. Histological analysis:
– Histological analysis of tissues can provide information on the interaction be-
tween mucoadhesive polymers and mucosal surfaces at the microscopic
level.
12. Inflammatory response assessment:
– Measure markers of inflammation or immune response, such as cytokines, in
response to the presence of mucoadhesive polymers, to ensure they do not
induce adverse reactions [71].
13. Clinical trials (if applicable):
– In some cases, clinical trials may be conducted to assess the safety and effi-
cacy of mucoadhesive polymer-based formulations in humans.
Experimental validation ensures that the mucoadhesive polymers selected, based on
computational screening, perform as expected in real-world scenarios. The combina-
tion of computational predictions and experimental data allows researchers to opti-
mize mucoadhesive polymers for various applications, including drug delivery, tissue
adhesion, and biomedical devices [72, 73].
VS offers several advantages in drug discovery and materials science [74–76]:
– Cost-efficiency: It can significantly reduce the time and cost associated with tra-
ditional high-throughput screening of compounds in the laboratory.
– High throughput: VS can analyze thousands to millions of compounds quickly.
– Hit identification: It can identify potential lead compounds or materials for fur-
ther development.
– Rational drug design: It allows researchers to design molecules with specific
properties by understanding the molecular interactions between compounds and
their targets.
However, VS also has limitations, such as the accuracy of the computational models
and the need for experimental validation. It is most effective when combined with
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