Methacrylic Acid Copolymer Research Articles

Angiogenic Biomaterials to Promote Tissue Vascularization and Integration

AbstractRobert Langer’s work with Judah Folkman brought angiogenesis into the spotlight and herein we focus on an offshoot of this work – biomaterial‐driven therapeutic angiogenesis. Angiogenic biomaterials are expected to improve vascularization and integration in tissue engineering, wound healing and medical device applications. This review focuses on therapeutic methacrylic acid copolymers, highlighting some new approaches to use these materials. Such copolymers require no biological components (drugs or cells) to promote in vivo vascularization; they are therapeutic polymers.

Development of a solid‐phase microextraction fiber coated with poly(methacrylic acid‐ethylene glycol dimethacrylate) and its application for the determination of chlorophenols in water coupled with GC

A solid-phase microextraction (SPME) fiber coated with poly(methacrylic acid-ethylene glycol dimethacrylate) coupled to GC with a micro electron-capture detector was developed for the determination of four chlorphenols in water samples for the first time. A novel and simple method for the preparation of this novel SPME fiber was proposed by copolymerization of methacrylic acid and ethylene glycol dimethacrylate in an appropriate solvent using a glass capillary as a "mold". The factors affecting the polymerization were optimized in detail. Furthermore, the extraction performance of the poly(methacrylic acid-ethylene glycol dimethacrylate) fiber was evaluated. Moreover, experimental headspace-SPME parameters, such as extraction temperature, extraction time, salt concentration, stirring speed, and pH, were optimized by orthogonal array experimental designs. Under the optimized conditions, the target analytes were linear in the range of 0.2-50 ng/mL, and the correlation coefficients were all greater than 0.99. RSD was less than 8.9%, and the detection limits were in the range of 0.1-10 ng/L. Four cholorphenols were detected from tap and lake water samples using the proposed method, with the recoveries of spiked natural water samples were ranged from 91.8 to 110.8, and 90.6 to 111.4% for tap and lake water samples, respectively.

<b>The importance of coating standardization in gastro-resistant capsules produced in magistral pharmacy</b> - doi: 10.4025/actascihealthsci.v35i2.14581

Gastro-resistant capsules are often used for several purposes, such as protection of unstable drugs in acid medium to the action of gastric fluids or protection of the gastric mucosa to irritants drugs. The aim of this study was to verify the variation of preparations of capsules coating with cellulose acetate phthalate and methacrylic acid copolymer, without drug addition, in 7-10% coating concentrations, prepared manually with four or five immersions in tested coating solution. Results were analyzed considering the formulation’s disintegration test. Within the context of formulations under analysis, it was observed that the capsules coated with cellulose acetate phthalate 10% complied with the pharmacopeia’s disintegration specifications. However, capsules coated with methacrylic acid copolymer did not show accordance with the pharmacopeia’s specifications. The results emphasize the need for the standardization of coating methodology.

Long-time crystallization kinetics in zinc-neutralized ethylene–methacrylic acid ionomers

The classic paper by Flory [1] regarding the crystallization of random copolymers presents a theory where fractional crystallization depends only on molar substitution level if the comonomer cannot be incorporated into the crystal structure of the crystallizable comonomer. A rather large number of indirect experiments on ethylene copolymers since that publication nearly 60 years ago are consistent with this hypothesis; for example the crystallinity content in ethylene copolymers depends to a first approximation only on the level of molar substitution and not the identity of the comonomer. Ethylene–methacrylic acid copolymer ionomers offer a unique opportunity to test this hypothesis directly, since it is possible to vary crystallization kinetics simply by varying the neutralization cation or neutralization level, without changing the comonomer content or its distribution along the polymer backbone. After annealing times as long as 6 months, it was found that the constraints caused by the phase-separating ionic groups lead to significantly lower crystallinity levels versus the case where such constraints were not present. Although disproving Flory's theory in this particular case, the result was not surprising since Flory's original paper certainly did not consider the case where the other monomer can phase separate. One surprising result of this study was that the rates of formation of secondary crystals relative to the crystallization amount at infinite time was independent of neutralization level for the phase-separated ionomers; in other words the Avrami constants n and K were independent of neutralization level for the secondary crystals.

Effect of the backbone-chain structure of acrylimide-forming copolymers on the maximum degree of their thermal imidization

The effect of the backbone-chain structure of acrylonitrile and methacrylic acid copolymers of various compositions on the maximum degree of intramolecular imidization has been studied. An estimating method for calculating this value on the basis of 13C NMR spectroscopy data on the sequences of comonomers units in the initial copolymers is proposed. Poly-2-cyanoacrylic acid, in which the carboxylic acid and nitrile groups are located at the same carbon atom, has been used as a reference “ideally regular” polymer. The actual maximum degree of the intramolecular imidization of copolymers after thermolysis was ascertained by means of IR Fourier spectroscopy with the use of Lorentz approximations for deconvolution of absorption peaks in the spectra.

Properties of aspirin modified enteric polymer prepared by hot-melt mixing

Melt mixing in batch equipment or continuous extruders is a technique that recently gained the attention of the pharmaceutical industry. The present work has employed hot-melt mixing to prepare a modified enteric matrix, as a delayed-release dosage form. Different concentrations of aspirin (ASP) ranging from 10 to -30% (w/w) were melt-mixed with a plasticized methacrylic acid copolymer, Eudragit(®) L100-55 in a batch mixer for 5 min at 100 °C which is above the plasticized polymer's glass transition temperature and below the ASP's melting point. The samples were cooled down to room temperature and compressed to thin discs. Processing ASP with Eudragit(®) L100-55 did not promote hydrolysis of ASP. X-ray diffraction spectra obtained at room temperature revealed that aspirin was present in a crystalline state. However, at elevated temperatures the dissolved aspirin displayed a plasticizing effect by reducing the glass transition temperature (Tg) and lowering the viscosity of the polymer in proportion to its increasing concentration. The addition of ASP altered to some extent the rheological behavior of the polymer from rubbery to viscous. However, the amount of ASP loading had no significant impact on the dissolution profiles. The samples met USP delayed-release requirements and the API release mechanism was shown to be diffusion dominant.

Enhanced loading of doxorubicin into polymeric micelles by a combination of ionic bonding and hydrophobic effect, and the pH-sensitive and ligand-mediated delivery of loaded drug

Folate-conjugated micelles were fabricated from amphiphilic diblock copolymers with poly(ethylene glycol) as the hydrophilic block and a random copolymer of n-butyl methacrylate and methacrylic acid as the hydrophobic block. Doxorubicin (DOX), a model drug that contains an amine group and hydrophobic moiety, was loaded with a high loading capacity into micelles by a combination of ionic bonding and hydrophobic effect. The combined interactions imparted a pH-sensitive delivery property to the system. The release rate of loaded DOX was slow at pH 7.4 (i.e., mimicking the plasma environment) but increased significantly at acidic pH (i.e., mimicking endosome/lysosome conditions). Acid-triggered drug release resulted from the carboxylate protonation of poly(methacrylic acid), which dissociated the ionic bonding between the micelles and DOX. Cellular uptake by folate receptor-overexpressing HeLa cells of the DOX-loaded folate-conjugated micelles was higher than that of micelles without folate conjugation. Thus, the DOX-loaded folate-conjugated micelles displayed higher cytotoxicity to HeLa cells.

Chromium-assisted immobilization of N-isopropylacrylamide-based methacrylic acid copolymers on collagen and leather surfaces: thermo-responsive behaviour

In the present paper, we report the non-covalent immobilization of pH and temperature responsive poly(N-isopropylacrylamide)-co-methacrylic acid on a protein collagen (type I) and a leather surface. The polymer has N-isopropylacrylamide (NIPAM) functionality that is responsible for the thermo-responsive characteristics and carboxylic acid/carboxylate functionality that facilitates the pH-responsive behaviour. We were able to tune the clouding behaviour of the polymer in water from 15 to 40 °C by changing the pH from 4.5 to 5.7. The binding of the polymer to a native collagen protein (type I) or leather is facilitated by the carboxylate groups that form coordination complexes with chromium(III). The polymer was successfully used in the retanning and coating of leather. The polymer-coated leather as well as the polymer-grafted collagen clearly show thermo-responsive characteristics.

Biodegradation of starch–graft–polystyrene and starch–graft–poly(methacrylic acid) copolymers in model river water

In this paper the biodegradation study of grafted copolymers of polystyrene (PS) and corn starch and poly(methacrylic acid) and corn starch in model river water is described. These copolymers were obtained in the presence of different amine activators. The synthesized copolymers and products of degradation were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Biodegradation was monitored by mass decrease and number of microorganisms by Koch?s method. Biodegradation of both copolymers advanced with time, poly(methacrylic acid)-graft-starch copolymers completely degraded after 21 day, and polystyrene-graft-starch partially degraded (45.78-93.09 % of total mass) after 27 days. Differences in the degree of biodegradation are consequences of different structure of the samples, and there is a significant negative correlation between the share of polystyrene in copolymer and degree of biodegradation. The grafting degree of PS necessary to prevent biodegradation was 54 %. Based on experimental evidence, mechanisms of both biodegradation processes are proposed, and influence of degree of starch and synthetic component of copolymers on degradation were established.

RETRACTED ARTICLE: Synthesis, characterization and in vitro studies of doxorubicin-loaded magnetic nanoparticles grafted to smart copolymers on A549 lung cancer cell line

BackgroundThe aim of present study was to develop the novel methods for chemical and physical modification of superparamagnetic iron oxide nanoparticles (SPIONs) with polymers via covalent bonding entrapment. These modified SPIONs were used for encapsulation of anticancer drug doxorubicin.MethodAt first approach silane–grafted magnetic nanoparticles was prepared and used as a template for polymerization of the N-isopropylacrylamide (NIPAAm) and methacrylic acid (MAA) via radical polymerization. This temperature/pH-sensitive copolymer was used for preparation of DOX–loaded magnetic nanocomposites. At second approach Vinyltriethoxysilane-grafted magnetic nanoparticles were used as a template to polymerize PNIPAAm-MAA in 1, 4 dioxan and methylene-bis-acrylamide (BIS) was used as a cross-linking agent. Chemical composition and magnetic properties of Dox–loaded magnetic hydrogel nanocomposites were analyzed by FT-IR, XRD, and VSM.ResultsThe results demonstrate the feasibility of drug encapsulation of the magnetic nanoparticles with NIPAAm–MAA copolymer via covalent bonding. The key factors for the successful prepardtion of magnetic nanocomposites were the structure of copolymer (linear or cross-linked), concentration of copolymer and concentration of drug. The influence of pH and temperature on the release profile of doxorubicin was examined. The in vitro cytotoxicity test (MTT assay) of both magnetic DOx–loaded nanoparticles was examined. The in vitro tests showed that these systems are no toxicity and are biocompatible.ConclusionIC50 of DOx–loaded Fe3O4 nanoparticles on A549 lung cancer cell line showed that systems could be useful in treatment of lung cancer.

Ionic nanocomposite networks in poly(styrene‐co‐methacrylic acid) copolymers with calcium carbonate

AbstractTo create reversible supramolecular ionic networks, ionic cross‐links were formed from acid pendant functions in poly(styrene‐co‐methacrylic acid) copolymers by the addition of calcium carbonate. The random dispersion of acid functions in the polystyrene chain is ensured by NMR analysis. The partial reaction of the calcium carbonate with the carboxylic acids is highlighted by a limewater test. The influence of methacrylic acid and calcium‐carbonate contents on the formation of an ionic network has been studied through solubility tests. Two main effects were obtained: the exfoliation of the unreacted calcium carbonate characterized by TEM is due to ionic interactions at the surface of nanometric particles that form the first level of organization of the calcium carbonate. Another part of the calcium carbonate reacts with carboxylic acid and is detached from particles to form clusters as shown by x‐ray analysis. Finally, by analyzing the dynamic rheological spectrum, the conclusion that the strength of the ionic bonds arises with the calcium content is made. The interest of such an approach with a wide range of observed phenomena in the material is a one‐batch process to make thermoreversible nanocomposite networks. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Novel hybrid fluoro-carboxylated copolymers deposited by initiated chemical vapor deposition as protonic membranes

Copolymers of 1H, 1H, 2H, 2H,-perfluorodecyl acrylate and methacrylic acid are synthesized by initiated chemical vapor deposition (iCVD) to serve as proton exchange membranes for potential application in miniaturized fuel cells. The copolymerization of hydrophobic and hydrophilic monomers is difficult by conventional liquid-phase technique. We demonstrate that the use of iCVD is very promising for the synthesis of these membranes. Changing the monomer feed ratio we have a systematical control over the copolymer composition. The calculation of the copolymer ratios shows a moderate alternate composition of the copolymer which is advantageous to obtain highly conductive (acid functionalities) and stable (hydrophobic functionalities) membrane in the operating conditions of the fuel cells. The copolymers show a high degree of chain mobility when passing from dry to hydrated state as demonstrated by XPS analysis and by the high water contact angle hysteresis measured (>30°). An ionic conductivity of 70 mS/cm is obtained in conditions of highest percentage of hydrophobic functionalities. This conductivity value is comparable with the ionic conductivity of commercial Nafion®.

Well-Defined Cholesterol Polymers with pH-Controlled Membrane Switching Activity

Cholesterol has been used as an effective component of therapeutic delivery systems because of its ability to cross cellular membranes. Considering this, well-defined copolymers of methacrylic acid and cholesteryl methacrylate, poly(methacrylic acid-co-cholesteryl methacrylate) P(MAA-co-CMA), were generated as potential delivery system components for pH-controlled intracellular delivery of therapeutics. Statistical copolymers with varying cholesterol contents (2, 4, and 8 mol %) were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Dynamic light scattering (DLS) analysis showed that the hydrodynamic diameters of the copolymers in aqueous solutions ranged from 5 ± 0.3 to 7 ± 0.4 nm for the copolymers having 2 and 4 mol % CMA and 8 ± 1.1 to 13 ± 1.9 nm for the copolymer having 8 mol % CMA with increasing pH (pH 4.5-7.4). Atomic force microscopy (AFM) analysis revealed that the copolymer having 8 mol % CMA formed supramolecular assemblies while the copolymers having 2 and 4 mol % CMA existed as unimers in aqueous solution. The pH-responsive behavior of the copolymers was investigated via UV-visible spectroscopy revealing phase transitions at pH 3.9 for 2 mol % CMA, pH 4.7 for 4 mol % CMA, and pH 5.4 for 8 mol % CMA. Lipid bilayers and liposomes as models for cellular membranes were generated to probe their interactions with the synthesized copolymers. The interactions were determined in a pH-dependent manner (at pH 5.0 and 7.4) using surface plasmon resonance (SPR) spectroscopy and liposome leakage assay. Both the SPR analyses and liposome leakage assays indicated that the copolymer containing 2 mol % CMA displayed the greatest polymer-lipid interactions at pH 5.0, presenting the highest binding ability to the lipid bilayer surfaces, and also demonstrating the highest membrane destabilization activity. CellTiter-Blue assay showed that the copolymers did not affect the cell viability up to 30 μM over a period of 72 h.

Poly(ɛ-caprolactone), Eudragit® RS 100 and poly(ɛ-caprolactone)/Eudragit® RS 100 blend submicron particles for the sustained release of the antiretroviral efavirenz

The design of simple and scalable drug delivery systems to target the central nervous system (CNS) could represent a breakthrough in the addressment of the HIV-associated neuropathogenesis. The intranasal (i.n.) route represents a minimally invasive strategy to surpass the blood–brain barrier, though it demands the use of appropriate nanocarriers bearing high drug payloads and displaying sufficiently long residence time. The present work explored the development of submicron particles made of poly(ɛ-caprolactone) (PCL), Eudragit® RS 100 (RS a copolymer of ethylacrylate, methylmethacrylate and methacrylic acid esterified with quaternary ammonium groups) and their blends, loaded with the first-choice antiretroviral efavirenz (EFV) as an approach to fine tune the particle size and the release kinetics. Particles displaying hydrodynamic diameters between 90 and 530nm were obtained by two methods: nanoprecipitation and emulsion/solvent diffusion/evaporation. In general, the former resulted in smaller particles and narrower size distributions. The encapsulation efficiency was greater than 94%, the drug weight content approximately 10% and the yield in the 72.5–90.0% range. The highly positive surface (>+30mV) rendered the suspensions physically stable for more than one month. In vitro release assays indicated that the incorporation of the poly(methacrylate) into the composition reduced the burst effect and slowed the release rate down with respect to pure poly(ɛ-caprolactone) particles. The analysis of the release profile indicated that, in all cases, the kinetics adjusted well to the Higuchi model with Radj2 values >0.9779. These findings suggested that the release was mainly controlled by diffusion. In addition, when data were analyzed by the Korsmeyer–Peppas model, n values were in the 0.520–0.587 range, indicating that the drug release was accomplished by the combination of two phenomena: diffusion and polymer chain relaxation. Based on ATR/FT-IR analysis that investigated drug/polymer matrix interactions, the potential role of the hydrophobic interactions of CF groups of EFV with carbonyl groups in the backbone of PCL and poly(methacrylate) could be ruled out. The developed EFV-loaded particles appear as a useful platform to investigate the intranasal administration to increase the bioavailability in the CNS.

Synthesis and properties of water‐soluble azlactone copolymers

AbstractPreparation and study of a series of copolymers incorporating 2‐vinyl‐4,4‐dimethylazlactone (VDMA) is reported. The reactivity ratios for photo‐initiated free radical copolymerization of VDMA with methacrylic acid (MAA), acrylic acid (AA), acrylamide (AAm), dimethylacrylamide (DMAA), hydroxyethyl methacrylate (HEMA), methoxy poly(ethylene glycol) methacrylate (MPEG300MA), and 2‐methacryloyloxyethyl phosphorylcholine (MPC), were determined by fitting comonomer conversion data obtained by in situ 1H NMR to a terminal copolymerization equation. Semi‐batch photo‐copolymerizations were then used to synthesize the corresponding VDMA copolymers with constant composition. Their solubility and dissolution behavior, as well as their hydrolysis half‐lives under physiological conditions, were determined. P(VDMA‐co‐MAA) copolymers with 52 to 93 mol % VDMA showed decreasing initial solubility and increasing hydrolysis half‐lives with increasing VDMA content. VDMA copolymers with nonionic monomers AAm and DMAA were water soluble only at VDMA contents of 41 and 22 mol % or less, respectively, and showed longer hydrolysis half‐lives than comparable MAA copolymers. VDMA copolymers with HEMA and MPEG300MA were found to crosslink during storage, so their hydrolysis half‐lives were not determined. VDMA copolymers with 18% zwitterionic MPC showed a much longer half‐life and superior initial solubility compared to analogous p(VDMA‐co‐MAA), identifying this copolymer as a promising candidate for macromolecular crosslinkers in, for example, aqueous layer‐by‐layer co‐depositions with polyamines. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Non-chromatographic mercury speciation and determination in wine by new core–shell ion-imprinted sorbents

In this study new Hg(II) core–shell imprinted sorbents (Hg(II)-IIPs) were prepared and tested for speciation and determination of Hg in wine. The silica gel, chemically modified with 3-(trimethoxysilyl)propyl methacrylate (TSPM) was used as supporting material. The Hg(II)-imprinted polymer layer was grafted by copolymerization of methacrylic acid and trimethylolpropane trimethacrylate in the presence of Hg(II) complexes with two different chelating agents: 1-pyrrolidinedithiocarboxylic acid (P(PDC-Hg)/SiG) and 1-(2-thiazolylazo)-2-naphthol (P(TAN-Hg)/SiG). High selectivity and fast kinetics of processes of sorption and desorption for Hg(II) were found by using P(PDC-Hg)/SiG. Recovery experiments performed for selective determination of inorganic mercury in wines showed that the interfering organic matrix did not influence the extraction efficiency. Column solid phase extraction scheme was developed for the determination and speciation of Hg in wines. The limit of detection (LOD) achieved for inorganic mercury determination in wine samples is 0.02μgL1 (3σ), measured by CV AAS. The relative standard deviation varied in the range 6–11% at 0.05–2μgL1 Hg levels. The sorbents showed high mechanical and chemical stability and extraction efficiency has not changed after more than 50 sorption/desorption cycles.

Application of a voltammetric method for investigation the formation mechanisms of silver nanoparticles in multicomponent solutions

A voltammetric method has been tested for the investigation of the kinetics of formation of silver nanoparticles in two systems: (a) silver(I) triflourineacetate, methylcellosolve, butyl acetate, toluene and methyl methacrylate with methacrylic acid copolymer; and (b) silver nitrate, sodium citrate, poly-N-vinyl-2-pirrolydone, sodium borohydride. It could be established for the first system that the formation rate of metal nanoparticles from silver triflourineacetate solutions depends on the dielectric constant and complexing ability of the solvent. The formation of silver particles proceeds faster in methylcellosolve than in other solvents. The butyl acetate addition to the solution contributes to the complex stability of methylcellosolve with silver triflourineacetate and decelerates the formation process of particles. It could be shown that nitrogen purging of solutions containing poly-N-vinyl-2-pirrolydone affects the silver-ion concentration in the first stage of synthesis and accelerates the formation process of nanoparticles for the second system. The spherical silver nanoparticles which are formed at the first stage of the synthesis are destroyed after starting the UV–irradiation. Then new silver nanoparticles (triangular prisms) are formed.

Development and comparative evaluation of in vitro, in vivo properties of novel controlled release compositions of paroxetine hydrochloride hemihydrate as against Geomatrix™ platform technology

The objective of this study is to develop, in vitro and in vivo evaluation of novel approaches for controlled release of paroxetine hydrochloride hemihydrate (PHH) in comparison to patented formulation PAXIL CR® tablets of GlaxoSmithKline (Geomatrix™ technology). In one of the approaches, hydrophilic core matrix tablets containing 85% of the dose were prepared and further coated with methacrylic acid copolymer to delay the release. An immediate release coating of 15% was given as top coat. The tablets were further optionally coated using ethyl cellulose. In the second approach, hydrophobic matrix core tablets containing metharylic acid copolymer were prepared. In the third approach, PHH was granulated with enteric polymer and further hydrophobic matrix core tablets were prepared. The effect of polymer concentration, level of enteric coating on drug release was evaluated by in vitro dissolution study by varying dissolution apparatus and the rotation speeds. It was found that increase in concentration of high viscosity hydroxypropylmethylcellulose (HPMC) resulted in reduction of the release rate. The drug release was observed to be dependent on the level of enteric coating and ethyl cellulose coating, being slower at increased coating. The release mechanism of PHH followed zero-order shifting to dissolution dependent by the increase of HPMC content. The formulation was stable without change in drug release rate. In vivo study in human volunteers confirmed the similarity between test and innovator formulations. In conclusion, HPMC-based matrix tablets, which were further coated using methacrylic acid copolymer, were found to be suitable for the formulation of single layer-controlled release PHH.

Effect of Polacrilin Potassium as Disintegrant on Bioavailability of Diclofenac Potassium in Tablets : a Technical Note

Polacrilin potassium is an ion exchange resin used in oral pharmaceutical formulations as a tablet disintegrant. It is a weakly acidic cation exchange resin. Chemically, it is a partial potassium salt of a copolymer of methacrylic acid with divinyl benzene. It ionizes to an anionic polymer chain and potassium cations. It was hypothesized that polacrilin potassium may be able to improve the permeability of anionic drugs according to the Donnan membrane phenomenon. The effect of polacrilin potassium on the permeability of diclofenac potassium, used as a model anionic drug, was tested in vitro using diffusion cells and in vivo by monitoring serum levels in rats. The amount of drug permeated across a dialysis membrane in vitro was significantly more in the presence of polacrilin potassium. Significant improvement was found in the extent of drug absorption in vivo. It could be concluded that polacrilin potassium may be used as a high-functionality excipient for improving the bioavailability of anionic drugs having poor gastrointestinal permeability.

Preparação de nanopartículas poliméricas a partir da polimerização de monômeros: parte I

Nanopartículas poliméricas produzidas a partir de polímeros sintéticos, como copolímeros do ácido metacrílico, ésteres acrílicos ou metacrílicos, têm sido amplamente utilizadas na área farmacêutica para encapsulação de princípios ativos. Essas nanopartículas apresentam as vantagens de proteção, liberação controlada, melhor biodisponibilidade e menor toxicidade, proporcionando maior conforto aos pacientes e adesão ao tratamento. A produção das nanopartículas (nanocápsulas e nanosferas) por polimerização de monômeros é revisada e descrita neste artigo, evidenciando os parâmetros tecnológicos que interferem nas características físico-químicas das nanopartículas, como a solubilidade do princípio ativo, o volume e pH do meio de polimerização, a massa molar e concentração do monômero e a natureza e concentração do tensoativo.