Stability of Aqueous α-Al2O3 Suspensions with Poly(methacrylic acid) Polyelectrolyte

Stability of aqueous α-Al2O3 suspensions with Na+ salt of poly(methacrylic acid) (PMAA-Na) polyelectrolyte was studied as a function of pH. At a given pH, the transition from the flocculated to the dispersed state corresponded to the adsorption saturation limit of the powders by the PMAA. As the pH was decreased, the adsorption saturation limit increased until insolubility and charge neutralization of the PMAA was approached. The critical amount of PMAA required to achieve stability is outlined in a stability map.[1]


New polymeric architectures with (meth)acrylic acid segments

This review summarizes recent advances in the design and synthesis of novel complex polymers with (meth)acrylic acid segments using various living and controlled polymerization techniques. As polymeric architectures, we will focus on block copolymers, branched polymers, Janus micelles, and polymer brushes. Characteristic solution behavior and morphologies derived from their amphiphilic properties and three-dimensional architectures will be introduced briefly.[2]


Preparation of chitosan nanoparticles using methacrylic acid

In this work the preparation of chitosan nanoparticle was investigated using methacrylic acid in different conditions and studied by particle size analyzer, zeta-potential, Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM). The particle size was dependent on the chitosan concentration used during the preparation method. Nanoparticles with sizes as small as 60 nm were achieved, that can be extremely important for several applications. The nanoparticles solution was also pH-sensitive, due to swelling and aggregation of the nanoparticles. The nanoparticles obtained presented a very homogeneous morphology showing a quite uniform particles size distribution and a rather spherical shape.[3]


Preparation and Characterization of Methacrylic Acid-based Molecularly Imprinted Polymer as a New Adsorbent for Recognition of 1,4-dihydroxybenzene

This article presents the first example of sequentially reported template removal procedure in molecularly imprinted polymers (MIPs) using UV-spectrophotometer. Polymerization was achieved in a glass tube containing 1,4-dihydroxybenzene (DHB) template molecule, methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), azobisisobutyronitrile (AIBN). The polymer matrix obtained was ground and the template molecule was removed from polymer particles by leaching with methanol/acetic acid, which leaves cavities in the polymer material. The polymer material both prior to and after leaching was characterized by Fourier transform infrared spectroscopy, Scanning electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller model. The rate of template removal from the synthesized MIPs was studied at ten different times: 15, 30, 45, 60, 75, 90, 105, 120, 135, and 150 min. The percentage leached from the template increased sharply within 60 min, and over 90% of the template was removed within 75 min. The recovery of DHB achieved in aqueous solution, using the MIP sorbent, was found to range from 47.45 to 86.56%, while that of non-imprinted polymer (NIP) sorbent was found to range from 7.73 to 83.10%. The elastic retractive force between the polymer and solvent was found to be higher in chloroform than water and methanol. The study shows that MAA is a suitable matrix for the formation of binding sites for water soluble template molecules through molecular imprinting.[4]


Formulation and Evaluation of Sustained Release Matrix Tablets of Metformin Hydrochloride Using pH Dependent and pH Independent Methacrylate Polymers

Metformin hydrochloride is recommended globally as first line therapy due to its favorable profile on morbidity and mortality associated with type-2 diabetes mellitus. However, limitations of multiple dosing and risk of triggering gastrointestinal symptoms make its dose optimization difficult. Extended-release metformin matrix tablets were prepared by direct compression of drug and different pH-dependent (Eudragit L-100 and S-100) and pH-independent (Eudragit RLPO and RSPO) polymer combinations. The influence of varying the polymer/polymer (w/w) ratio was evaluated. Among the different examined polymer blends, matrix tablets based on S-100/RLPO and S-100/RSPO mixtures gave the more sustained release pattern. The excipients used in this study did not alter physicochemical properties of the drug, as tested by Fourier transform Infrared Spectroscopy and the thermal analysis using differential scanning calorimetry. All the batches were evaluated for thickness, weight variation, hardness, and drug content uniformity. The in vitro drug dissolution study was carried out using USP 22 apparatus II, paddle method and the release mechanisms were explored. Mean dissolution time is used to characterize drug release rate from a dosage form and indicates the drug release retarding efficiency of polymer. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism ranges from diffusion controlled to anomalous type. Fitting the data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release.[5]
Reference

[1] CESARANO III, J.O.S.E.P.H., Aksay, I.A. and Bleier, A., 1988. Stability of aqueous α‐Al2O3 suspensions with poly (methacrylic acid) polyelectrolyte. Journal of the American Ceramic Society, 71(4), pp.250-255.

[2] Mori, H. and Müller, A.H., 2003. New polymeric architectures with (meth) acrylic acid segments. Progress in Polymer Science, 28(10), pp.1403-1439.

[3] de Moura, M.R., Aouada, F.A. and Mattoso, L.H., 2008. Preparation of chitosan nanoparticles using methacrylic acid. Journal of colloid and interface science, 321(2), pp.477-483.

[4] Awokoya, K.N., Oninla, V.O., Adeleke, I.T. and Babalola, J.O., 2018. Preparation and Characterization of Methacrylic Acid-based Molecularly Imprinted Polymer as a New Adsorbent for Recognition of 1, 4-dihydroxybenzene. International Research Journal of Pure and Applied Chemistry, pp.1-11.

[5] Wadher, K.J., Kakde, R.B. and Umekar, M.J., 2011. Formulation and evaluation of sustained release matrix tablets of metformin hydrochloride using pH dependent and pH independent methacrylate polymers. Journal of Pharmaceutical Research International, pp.29-45.