The aim of this paper is theophylline (THP) inclusion into xanthan-chitosan polyionic complex (Xa-CS) and the study of its in vitro and in vivo kinetic release. Xa-CS hydrogel was obtained by ionic complexation between two oppositely charged polysaccharides. THP was loaded into the Xa-CS matrix by diffusion of the drug solution. The obtained samples were characterized by FTIR spectroscopy, SEM microscopy and study of the swelling behavior. THP in vitro release experiments were carried out in conditions mimicking the gastrointestinal environment. The chosen drug dose for in vivo study was 15 mg THP/Kg body weight of THP powder or an equivalent dose in complex form. THP serum concentrations were determined by an HPLC assay. The THP peak serum concentration (C(max)) was 7.18 microg/ml for free THP and AUC(0-48) was 25.76 microg h/ml, while in the case of Xa-CS-THP, C(max) was of 5.72 microg/ml and AUC(0-48) = 45.72 microg h/ml. The in vivo study regarding the behaviour of the obtained formulation, showed an increase bioavailability of THP compared to the raw drug, suggesting the possible application of the complex Xa-CS as an oral controlled drug delivery system in the management of chronic pulmonary obstructive disease.

Chitosan, a natural polycationic polysaccharide, was coupled with two polyanionic polymers: Na-alginate and carboxymethylcellulose (CMC) and with tannic acid (TA) obtaining three species of self-assembled complexes: chitosan/alginate/TA (sample 1), chitosan/TA (sample 2) and chitosan/CMC/TA (sample 3). The microparticle formation was achieved by dropwise addition of one solution into other by using a coaxial airflow sprayer. These systems were characterized with regard to particle size distribution, thermal stability, tannic acid entrapment efficiency. Sample 2 showed quite a different behavior compared to the other two samples; the particle diameter is located in the nanometric region, the quantity of incorporated tannic acid is higher than in the other two samples and the material shows better thermal stability. The release of tannic acid from these complexes was studied in water (pH = 5.89), phosphates buffer (pH = 7.04) and acetate buffer (pH = 4.11). These studies revealed two distinct periods in tannic acid delivery process: an initial period, varying between 4 and 10 h, characterized by a high release rate with a delivered tannic acid amount of approximately 80% of the incorporated polyphenol and a second period, which starts after 20 to 30 h of delivery and it ends after approximately 120 h, when the release process takes place with low and constant rate and the kinetic curve is linear--characteristic for a zero order kinetic.

No abstract

Mixed-interpenetrated polymeric networks based on sodium alginate (ALG) and poly(N-isopropylacryl amide) (PNI-PAAm) covalently cross-linked with N,N'-methylenebisacrylamide are studied for their biocompatibility, nontoxicity, and biodegradability aiming their application in drug delivery. The presence of drug-polymeric matrix interactions and the distribution of the drug in the polymeric network for theophylline-loaded ALG/PNIPAAm hydrogels are also investigated by spectroscopic and microscopic methods. The quantitative evaluation of theophylline loaded hydrogels performed by NIR-CI technique shows a better drug entrapment and a higher homogeneity of the samples with increased alginate content. The thermal behavior of the hydrogels is significantly modified by theophylline presence. The application of the ALG/PNIPAAm hydrogels as carriers for sustained drug release formulations was assessed by the theophylline release tests performed both by in vitro and in vivo studies. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40733.

No abstract