Coarse-Grained Simulations of Release of Drugs Housed in Flexible Nanogels: New Insights into Kinetic Parameters

Quesada‐Pérez, Manuel; Pérez-Mas, Luis; Carrizo-Tejero, David; Maroto-Centeno, José Alberto; Ramos-Tejada, María del Mar

doi:10.3390/polym14214760

Cited by 6 publications

(3 citation statements)

References 54 publications

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“…paid attention to the pH-regulated nanogels to seek for the effect of ionic strength on the swelling behavior. Manuel et al aimed at the drug delivery by nanogels, simulation results proved the feasibility. Jiang et al focused on membrane antifouling via the molecular dynamics (MD) simulation.…”

Section: Introductionmentioning

confidence: 99%

Zwitterion-Modified Nanogel Responding to Temperature and Ionic Strength: A Dissipative Particle Dynamics Simulation

Miao,

Qin,

Zhou

et al. 2023

Langmuir

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The self-assembly and stimuli-responsive properties of nanogel poly(n-isopropylacrylamide) (p(NIPAm)) and zwitterion-modified nanogel poly(n-isopropylacrylamide-co-sulfobetainemethacrylate) (p(NIPAm-co-SBMA)) were explored by dissipative particle dynamics simulations. Simulation results reveal that for both types of nanogel, it is beneficial to form spherical nanogels at polymer concentrations of 5–10%. When the chain length (L) elongates from 10 to 40, the sizes of the nanogels enlarge. As for the p(NIPAm) nanogel, it shows thermoresponsiveness; when it switches to the hydrophilic state, the nanogel swells, and vice versa. The zwitterion-modified nanogel p(NIPAm-co-SBMA) possesses thermoresponsiveness and ionic strength responsiveness concurrently. At 293 K, both hydrophilic p(NIPAm) and superhydrophilic polysulfobetaine methacrylate (pSBMA) could appear on the outer surface of the nanogel; however, at 318 K, superhydrophilic pSBMA is on the outer surface to cover the hydrophobic p(NIPAm) core. As the temperature rises, the nanogel shrinks and remains antifouling all through. The salt-responsive property can be reflected by the nanogel size; the volumes of the nanogels in saline systems are larger than those in salt-free systems as the ionic condition inhibits the shrinkage of the zwitterionic pSBMA. This work exhibits the temperature-responsive and salt-responsive behavior of zwitterion-modified-pNIPAm nanogels at the molecular level and provides guidance in antifouling nanogel design.

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Section: Introductionmentioning

confidence: 99%

Zwitterion-Modified Nanogel Responding to Temperature and Ionic Strength: A Dissipative Particle Dynamics Simulation

Miao,

Qin,

Zhou

et al. 2023

Langmuir

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“…Theoretical models and numerical investigations can provide insights into the dependence of the release characteristics on different parameters of the system, thus facilitating the design of delivery devices that exhibit the desired release rates [ 9 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. As regards conjugated polymer–drug formulations, Pitt and Schindler have discussed various properties of the release kinetics obtained through an analytical solution of the reaction–diffusion equation in a one-dimensional setting, which is appropriate for slab geometries [ 38 ].…”

Section: Introductionmentioning

confidence: 99%

Interplay between Diffusion and Bond Cleavage Reaction for Determining Release in Polymer–Drug Conjugates

Kalosakas

2023

Materials

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In conjugated polymeric drug delivery systems, both the covalent bond degradation rate and the diffusion of the freely moving drug particles affect the release profile of the formulation. Using Monte Carlo simulations in spherical matrices, the release kinetics resulting from the competition between the reaction and diffusion processes is discussed. For different values of the relative bond cleavage rate, varied over four orders of magnitude, the evolution of (i) the number of bonded drug molecules, (ii) the fraction of the freely moved detached drug within the polymer matrix, and (iii) the resulting fractional release of the drug is presented. The characteristic release time scale is found to increase by several orders of magnitude as the cleavage reaction rate constant decreases. The two extreme rate-limiting cases where either the diffusion or the reaction dominates the release are clearly distinguishable. The crossover between the diffusion-controlled and reaction-controlled regimes is also examined and a simple analytical formula is presented that can describe the full dependence of the release time on the bond cleavage rate constant. This simple relation is provided simply by the sum of the characteristic time for purely diffusional release and the bond cleavage decay time, which equals the inverse of the reaction rate constant.

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“…Depending on the physical mechanism that dominates the release process in a particular case, various analytical methods or numerical simulations have been proposed in order to investigate the release characteristics. Therefore, different models have been developed which describe situations ranging from pure diffusion [8][9][10][11][12][13][14][15][16][17] to reaction-diffusion systems [18][19][20][21][22][23][24], to hydrogel swelling [25][26][27], or to kinetically limited release [28,29].…”

Section: Introductionmentioning

confidence: 99%

Exact Analytical Relations for the Average Release Time in Diffusional Drug Release

Kalosakas

2023

Processes

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Although analytical solutions for the problem of diffusion-controlled drug release from uniform formulations of simple geometries, like slabs, spheres, or cylinders, are well known, corresponding exact expressions for the average release times are not widely used. However, such exact analytical formulae are very simple and useful. When the drug is initially distributed homogeneously within the matrix, the average time of release from a sphere of radius R is tav=(1/15)R2/D and from a slab of thickness L is tav=(1/12)L2/D, where D is the corresponding drug diffusion coefficient. Regarding cylindrical tablets of height H and radius R, simple analytical expressions are obtained in the two opposite limits of either very long (H≫R) or very short (H≪R) cylinders. In the former case, of practically radial release, the average release time is tav=(1/8)R2/D, while in the latter case the same result as that of a slab with thickness H is recovered, tav=(1/12)H2/D, as expected. These simple and exact relations are useful not only for an estimate of the average release time from a drug carrier device when diffusion is the dominant mechanism of drug delivery, but also for the experimental determination of the drug diffusion coefficient in a release system of interest through the measured release profile, given the mean squared size of the formulation.

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Coarse-Grained Simulations of Release of Drugs Housed in Flexible Nanogels: New Insights into Kinetic Parameters

Cited by 6 publications

References 54 publications

Zwitterion-Modified Nanogel Responding to Temperature and Ionic Strength: A Dissipative Particle Dynamics Simulation

Zwitterion-Modified Nanogel Responding to Temperature and Ionic Strength: A Dissipative Particle Dynamics Simulation

Interplay between Diffusion and Bond Cleavage Reaction for Determining Release in Polymer–Drug Conjugates

Exact Analytical Relations for the Average Release Time in Diffusional Drug Release

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