EXPERIMENTAL STUDY OF THE EFFECT OF MINERAL WATERS ON THE GASTRIC MUCOSA OF WISTAR RATS.

Acid-related diseases (ARD) are the most common among digestive diseases. The main goals of therapy of ARD are to reduce the influence of aggression factors (production of HCl, pepsin) and increase the protective properties of the mucous membrane of the upper digestive tract. Also currently in medicine, one of the therapeutic and preventive methods is the use of chloride-hydrocarbonate sodium boron mineral waters. In this study, we compared the efficacy of table mineral waters in the therapy of induced gastropathy in Wistar rats. The study of the effect of mineral waters on the gastric mucosa of Wistar rats has provided valuable information that can be applied in medical practice for the treatment and prevention of various diseases of the gastrointestinal tract in humans. Careful analysis of the data obtained has shown that certain types of mineral waters can significantly reduce inflammatory processes and promote regeneration of the gastric mucosa, which makes them a useful addition to traditional treatment methods such as pharmacotherapy.

Nanoparticles formed from PNIPAM-g-PEO copolymers in the presence of indomethacin.

Biocompatible double-hydrophilic PNIPAM-g-PEO copolymers containing 0.3-3.2 mol% PEO grafts were synthesized and utilized to prepare indomethacin (IMC)-loaded core-shell nanoparticles by dialysis and nanoprecipitation methods. IMC loading was conducted at room temperature using the organic solvents ethanol and DMF, which induced phase separation in the copolymers aqueous solutions due to the cononsolvency of PNIPAM. In ethanol-water solutions, the cononsolvency-induced phase separation of the copolymers promoted effective drug incorporation into the formed micellar structures. In DMF-water system, the formation of the nanoparticles did not correspond to the cononsolvent region of PNIPAM-g-PEO. In this case, hydrophobic interactions between PNIPAM and IMC allowed the copolymer self-association and drug loading. Irrespective of the solvents or preparation methods applied, the drug loading content (DLC) depended on the drug-to-copolymer feed weight ratio. DLC was relatively low at the 0.5:1 ratio but it significantly increased at the ratios of 0.75:1 and 1:1 (DLC approximately 90%). The particle size was strongly affected by the different mechanisms of nanoparticles formation. The nanoprecipitation from ethanol produced significantly smaller particles (<150 nm) with narrow size distribution than the dialysis from DMF. The velocity of indomethacin release from the nanoparticles was influenced by the amount of encapsulated drug, the process being faster at lower DLC.

Influence of hydrogel structure on the processes of water penetration and drug release from mixed hydroxypropylmethyl cellulose/thermally pregelatinized waxy maize starch hydrophilic matrices.

The kinetics of water penetration and molsidomine release from both hydroxypropylmethyl cellulose (HPMC) and mixed HPMC/thermally pregelatinized waxy maize starch (SDWMT) hydrophilic matrices has been examined in 0.1 mol x dm(-3) HCl (pH 1.0) and 0.06 mol x dm(-3) Na3PO4/HCl buffer (pH 6.8). The rheological oscillatory test parameters of their gel layers obtained by swelling of the matrices in the two aqueous media have been observed. The kinetic swelling properties of mixed HPMC/SDWMT hydrogels (i.e. degree and velocity of both water penetration and swelling, transport mechanism which controls solvent sorption) directly influence the drug release behaviour and the structural features of the formed gel layer. Both diffusion processes are diffusion-controlled ones, their mechanisms being influenced insignificantly by the relaxation properties of the hydrated macromolecules. It has been established by means of comparative viscoelastic analysis, that mixed HPMC/SDWMT hydrogels demonstrate the typical behaviour of 'filled' composite systems having poor adhesion between the surface of the elastic SDWMT 'filler' and the continuous HPMC phase. Due to the inter-phase relations between the swollen starch granules and the linear cellulose derivative as well as to the specific structure of amylopectin molecule, the pregelatinized waxy maize starch shows a stronger influence on the velocities of both water penetration and drug release from mixed HPMC/SDWMT matrices.

Water uptake and relaxation processes in mixed unlimited swelling hydrogels.

The rheological oscillatory test parameters have been observed for highly concentrated hydroxypropylmethyl cellulose (HPMC), carboxymethylcellulose-sodium (NaCMC) and mixed HPMC/NaCMC hydrogels obtained by swelling of matrix tablets in 0.1 mol cm(-3) HCl and pH 6.8 phosphate buffer. The mechanical spectra of the gels have been analysed using theoretical models, i.e. a generalised Maxwell model and an adapted Maxwell model, both based on Ferry and Williams approximations. The relaxation time spectra as well as the parameters characteristic of linear viscoelastic behaviour have been calculated: zero shear viscosity (eta(0)), plateau moduli (G(N)(0), G(0)' and G(0)"), zero-relaxation time (tau(0)) and mean relaxation time (θ). The mechanical spectra of mixed HPMC/NaCMC hydrogels differ considerably from those of the pure ones, the type of the spectrum depending on the two polymers' ratios. In both media, the rheological models applied define the HPMC gels as homogeneous entangled networks, and those of NaCMC and mixed HPMC/NaCMC as heterogeneous physical gels. The relationship between the kinetic constants of water penetration and the mean relaxation times suggests that the molecular relaxation controls the water uptake velocity. With all the systems tested irrespective of pH of the aqueous phase, an inversely proportional dependence between the viscosity and the water penetration velocity has been noted. Since the degree of hydration is one of the factors determining the degree and velocity of drug release from the hydrogel matrices, the relation between the kinetic parameters of water penetration and the viscosity is a characteristic indicator for the gel structure, the degree of swelling and the drug release rate.

Multiple endobronchial chondromatous hamartoma in a child.

The multiple endobronchial chondromatous hamartoma is a very rare tumour. The authors report a case of a 5-year-old girl treated by pneumonectomy.