The paper discusses the enzymatic behaviour of a series of copolymers composed of alginate grafted with poly(ε-caprolactone) (PCL) of various lengths and degrees of substitution. The study is focused on viscosity measurements and pyrene probe fluorescence with or without two enzymes: alginate lyase, which breaks the alginate backbone; and esterase, which breaks PCL pendent groups. Alginate lyase is inactive at pH = 3.8 and degrades quickly all copolymers at pH = 6.3. The degradation is not complete and is slowed down by the presence of PCL. Esterase degrades only copolymers with long pendent PCL groups. It has no effect on copolymers when PCL has a length of 530 g mol −1 . These systems are good candidates for controlled release of drugs using an enzymatic method.

Hydrochlorothiazide (HCTZ), which was developed and introduced in the late 1950s, is still one of the most frequently employed drugs in antihypertensive treatments. Its poor aqueous solubility is one of the reasons for its limited bioavailability after oral administration. The present paper provides details of the preparation of HCTZ-loaded microspheres by the solvent evaporation technique. A total of seven formulations were prepared using ethyl cellulose, poly(?-caprolactone) (PCL), ?-cyclodextrin (?-CD) and synthesized poly-(methyl methacrylate) (PMMA) of different molecular weights in different drug-to-carrier ratios in order to investigate their effect on the encapsulation efficiency and drug release kinetics. The prepared formulations were characterized by Fourier transform-infrared (FTIR) spectroscopy, powder X-ray diffractometry, differential scanning calorimetry, yield, drug loading, optical microscopy, surface morphology by scanning electron microscopy (SEM), and in vitro release studies in simulated gastrointestinal tract fluid. The loading efficiency was found in the range from 18?0.34 to 39?0.95 %. The microspheres were spherical, and the mean Sauter diameter (d32) of the obtained microparticles ranged from 26?0.16 to 107?0.58 ?m. The presence of the drug and polymer carriers in the microparticles was confirmed by FTIR spectroscopy and XRD analysis. In vitro dissolution studies showed that the release rate was largely affected by the characteristics of the microparticles, namely the particle size and the nature of the matrix. The release data are best fitted to the Higuchi model with high correlation coefficients (r?).

Water-soluble polymer, cationic poly(N-[3-hexyldimethyl-aminopropyl]methacrylamide bromide) (PHDAPMAA), is synthesized by radical polymerization and studied in terms of its solubility, viscosity, surface tension and conductivity. Viscometry and surface tension measurements confirmed that intramolecular hydrophobic microdomains were formed by the pendent alkyl chains. Conductivity of cationic polymer in aqueous solution was determined. Variation of conductivity versus concentration in investigated system exhibits a typical polyelectrolyte behaviour.

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Introduction:The present paper provides details of preparation of hardcapsules based on microspheres containing 2-aminothiazole as an antithyroidian agent and synthesized poly(butylsuccinate) (PBS) or ethylcellulose(EC10) as biodegradable matrices as well as the study of the drug delivery. Methods: A disintegration tests of these gelatinous capsules were done. The biodegradable synthesized polyester was characterized by infrared spectroscopy, nuclear magnetic resonance (mono and bidimentional H1NMR, 13CNMR) and by Differential Scanning Calorimetry (DSC). A viscosimetric study has been done in order to evaluate viscosimetric PBS's weight wich was calculated from Mark-Houwink equation. The microencapsulation of 2-aminothiazole was done using solvent evaporation technique. Results: Microspheres were spherical and the effects of varying emulsifiers and blades number on microspheres encapsulation efficiency were evaluated. A kinetic studies of releases of 2-aminothiazole in gastric pH were done in order to evaluate the best late effect and then the best formulation.