The effect of polymer length on the in vitro characteristics of a drug loaded and targeted silica nanoparticles (original) (raw)
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IOP Conference Series: Materials Science and Engineering, 2018
One of the problems in the use of nanoparticles (NPs) as carriers in drug delivery systems is their agglomeration which mainly appears due to their high surface energy. This results in formation of NPs with different sizes leading to differences in their distribution and bioavailability. The surface coating of NPs with certain compounds can be used to prevent or minimize this problem. In this study, the effect of cyclodextrin (CD) on the agglomeration state and hence on the in vitro characteristics of drug loaded and targeted silica NPs was investigated. A sample of NPs was loaded with anticancer agents, then modified with a long polymer, carboxymethyl-β-cyclodextrin (CM-β-CD) and folic acid (FA), respectively. Another sample was modified similarly but without CD. The surface modification was characterized using fourier transform infrared spectroscopy (FT-IR). The polydispersity (PD) was measured using dynamic light scattering (DLS) and was found to be smaller for CD modified NPs. The results of the in vitro drug release showed that the release rate from both samples exhibited similar pattern for the first 5 hours, however the rate was faster from CD modified NPs after 24 hours. The in vitro cell viability assay confirmed that CD modified NPs were about 30% more toxic to HeLa cells. These findings suggest that CD has a clear effect in minimizing the agglomeration of such modified silica NPs, accelerating their drug release rate and enhancing their targeting effect.
Jordan Journal of Pharmaceutical Sciences, 2022
Silica nanoparticles (SNs) possess unique properties making them ideal carriers for many agents. Both the size and the surface chemistry are important features that impact the in vitro characteristics of their loaded agents. In this study, different surface functionalization of SNs with a particle size of 200 nm (propyl thiol, propyl carboxylic acid, and propyl amine) and two different sizes of propyl amine SNs (200 and less than 100 nm) were investigated. The nanoparticles (NPs) parameters were characterized using Dynamic Light Scattering (DLS) and their Encapsulation Efficiency (EE) and Loading Capacity (LC) with quercetin were measured using UV Spectrophotometer. Quercetin cumulative release was studied in phosphate buffer saline (PBS) (pH 7.4, 37°C) and its in vitro cytotoxicity toward HeLa cells was evaluated using an MTT assay. Our results showed that the mean particle size of all samples increased after drug loading and the polydispersity (PD) values were all within the acceptable range (0.2-0.5). All SNs exhibited negative values of zeta potential with the highest value for propylcarboxylated NPs. The EE and LC percentages of quercetin in SNs depend on the type of surface functional group where the aminated SNs showed higher percentages compared to the other groups. A direct relation was observed between the drug release rate and the cytotoxicity where the highest and smallest values were exhibited by thiolated and aminated SNs, respectively. Surface modifications have thus a more pronounced effect on the in vitro properties of our studied SNs compared to the size.
Microporous Structure and Drug Release Kinetics of Polymeric Nanoparticles
Langmuir, 2008
The aim of the present study was to characterize pegylated nanoparticles (NPs) for their microporosity and study the effect of microporosity on drug release kinetics. Blank and drug-loaded NPs were prepared from three different pegylated polymers, namely, poly(ethylene glycol)1%-graft-poly(D,L)-lactide, poly(ethylene glycol)5%-graft-poly(D,L)-lactide, and the multiblock copolymer (poly(D,L)-lactide-block-poly(ethylene glycol)-block-poly(D,L)-lactide)n. These NPs were characterized for their microporosity using nitrogen adsorption isotherms. NPs of the multiblock copolymer showed the least microporosity and Brunauer-Emmett-Teller (BET) surface area, and that of PEG1%-g-PLA showed the maximum. Based on these results, the structural organization of poly(D,L)-lactide (PLA) and poly(ethylene glycol) (PEG) chains inside the NPs was proposed and was validated with differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS) surface analysis. An in vitro drug release study revealed that PEG1%-g-PLA NPs exhibited slower release despite their higher surface area and microporosity. This was attributed to the presence of increased microporosity forming tortuous internal structures, thereby hindering drug diffusion from the matrix. Thus, it was concluded that the microporous structure of NPs, which is affected by the molecular architecture of polymers, determines the release rate of the encapsulated drug.
Innovative pharmaceutical development based on unique properties of nanoscale delivery formulation
Nanoscale, 2013
The advent of nanotechnology has reignited interest in the field of pharmaceutical science for the development of nanomedicine. Nanomedicinal formulations are nanometer-sized carrier materials designed for increasing the drug tissue bioavailability, thereby improving the treatment of systemically applied chemotherapeutic drugs. Nanomedicine is a new approach to deliver the pharmaceuticals through different routes of administration with safer and more effective therapies compared to conventional methods. To date, various kinds of nanomaterials have been developed over the years to make delivery systems more effective for the treatment of various diseases. Even though nanomaterials have significant advantages due to their unique nanoscale properties, there are still significant challenges in the improvement and development of nanoformulations with composites and other materials. Here in this review, we highlight the nanomedicinal formulations aiming to improve the balance between the efficacy and the toxicity of therapeutic interventions through different routes of administration and how to design nanomedicine for safer and more effective ways to improve the treatment quality. We also emphasize the environmental and health prospects of nanomaterials for human health care.
Infuence of Microstructure in Drug Release Behavior of Silica Nanocapsules
Journal of Drug Delivery, 2013
Meso-and nanoporous structures are adequate matrices for controlled drug delivery systems, due to their large surface areas and to their bioactive and biocompatibility properties. Mesoporous materials of type SBA-15, synthesized under different pH conditions, and zeolite beta were studied in order to compare the different intrinsic morphological characteristics as pore size, pore connectivity, and pore geometry on the drug loading and release process. These materials were characterized by X-ray diffraction, nitrogen adsorption, scanning and transmission electron microscopy, and calorimetric measurements. Ibuprofen (IBU) was chosen as a model drug for the formulation of controlled-release dosage forms; it was impregnated into these two types of materials by a soaking procedure during different periods. Drug loading and release studies were followed by UV-Vis spectrophotometry. All nano-and mesostructured materials showed a similar loading behavior. It was found that the pore size and Al content strongly influenced the release process. These results suggest that the framework structure and architecture affect the drug adsorption and release properties of these materials. Both materials offer a good potential for a controlled delivery system of ibuprofen.
Advanced Powder Technology, 2013
Nature has developed an elegant biologically based self-assembling synthetic route to produce silica biomaterials with complex 3-dimensional (3-d) porous structures, offering great potential to replace synthetic mesoporous materials as suitable drug carriers for the development of cost-effective drug delivery systems. This work presents the application of a diatomaceous earth (DE), naturally available silica, originated from fossilized phytoplankton as a potential substitute for synthetic materials used for drug delivery applications. The aim of this study is to explore the influence of particle size, morphology and surface modifications of diatom silica microparticles on their drug release properties. Raw diatomaceous earth (DE) material was purified and classified to obtain high purity DE silica porous particles with different size and shapes. Comparative scanning electron microscope and particle characterization confirmed their particle size including irregularly shaped silica particles (size 0.1-1 µm, classified as "fine"), mixed fractions (size 1-10µm, classified as "mixed") and pure unbroken DE structures (size 10-15 µm, classified as "entire"). Surface modification of isolated DE with silanes and phosphonic acids were done using standard silanisation and phosphonation process. Water insoluble (indomethacin) and water soluble (gentamicin sulphate) drugs were loaded to study the release performances of modified DE particles. In-vitro drug release studies were performed over 1-4 weeks, to examine the impact of the particle size and hydrophilic/hydrophobic functional groups. Drug release studies showed a biphasic pattern, comprising of an initial burst release for 6 h, followed by zero order sustained release over 1-4 weeks. This study demonstrates the potential of silica DE particles as a natural carrier for water soluble and insoluble drugs with release controlled by their morphological and interfacial properties.
Tuning drug loading and release properties of diatom silica microparticles by surface modifications
International Journal of Pharmaceutics, 2013
Diatomaceous earth (DE), or diatomite silica microparticles originated from fossilized diatoms are a potential substitute for its silica-based synthetic counterparts to address limitations in conventional drug delivery. This study presents the impact of engineered surface chemistry of DE microparticles on their drug loading and release properties. Surface modifications with four silanes, including 3-aminopropyltriethoxy silane (APTES), methoxy-poly-(ethylene-glycol)-silane (mPEG-silane), 7-octadecyltrichlorosilane (OTS), 3-(glycidyloxypropyl)trimethoxysilane (GPTMS) and two phosphonic acids, namely 2-carboxyethyl-phosphonic acid (2 CEPA) and 16-phosphono-hexadecanoic acid (16 PHA) were explored in order to tune drug loading and release characteristics of water insoluble (indomethacin) and water soluble drugs (gentamicin). Successful grafting of these functional groups with different interfacial properties was confirmed using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Thermogravimetric analysis (TGA) was applied to determine the amount of loaded drugs and UV-spectrophotometry to analyse in vitro drug release from modified DE microparticles. Differences in drug release time (13-26 days) and loading capacity (14-24%) were observed depending on functional groups on the surface of DE microparticles. It was found that hydrophilic surfaces, due to the presence of polar carboxyl, amine or hydrolyzed epoxy group, favor extended release of indomethacin, while the hydrophobic DE surface modified by organic hydrocarbons gives a better sustained release profile for gentamicin. This work demonstrates that by changing surface functionalities on DE microparticles, it is possible to tune their drug loading and release characteristics for both hydrophobic and hydrophilic drugs and therefore achieve optimal drug delivery performance.
Journal of colloid and interface science, 2018
Nanoparticles are normally classified as "hard", mainly consisting of metal or metal oxide cores, or "soft", including polymer-based, liposomes and biomimetic nanoparticles. Soft nanoparticles have been studied in depth for drug formulation and therapeutic delivery applications, albeit hard nanoparticles may offer easier synthesis, smaller size and more effective tumor penetration. Among them, silica nanoparticles maintain excellent biocompatibility and biodegradability and can be finely adjusted in size and shape, easily produced in a large scale and functionalized or loaded with active molecules. To help filling the gap of a poor clinical translation of hard nanoparticles, we have designed and developed three different nonporous silica nanocarriers loading the chemotherapeutic doxorubicin within the core matrix, on the surface or both inside and outside, respectively. A comparative study was performed on drug loading and drug release, silica matrix degradation ...