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Biomedical subjects

R Zelko

Publications and source records attributed to R Zelko.

4 recordsLinked to original sources

Application of sucrose fatty acid esters in transdermal therapeutic systems.

Transdermal therapeutic systems (TTSs) were studied applying different sucrose fatty acid esters (SEs) as drug delivery agents. Matrix and membrane controlled TTSs were prepared and compared. Membrane was made from a methacrylic polymer (Eudragit NE) of pH independent permeability which can achieve diffusion controlled drug liberation. Model drug was a water soluble beta-blocker, metoprolol, which has short biological half-life, so applying it in a TTS, the duration of its action could be prolonged. Sucrose fatty acid esters of different fatty acid chain lengths and consequently different hydrophilic-lipophilic balance (HLB) values were studied considering their effect on the metoprolol release from TTSs. Different mathematical models were applied for the evaluation of the release process. The results of the in vitro studies indicated that SEs of shorter fatty acid chain length and higher HLB value increased the amount of released drug about 10 times. SEs could be promising agents in transdermal therapeutic systems to control the drug release and cutaneous absorption.

Administration, Cutaneous↗

Kinetic study of zinc sulphate release from lipophilic matrices prepared for the therapy of Wilson's disease.

The rate and extent of drug release from the most controlled release wax matrices are influenced by the drug loading/embedding excipient ratio of the systems. In the present study hydrophobic wax - zinc sulphate matrices with different drug loadings were prepared for the therapy of Wilson's disease. The drug release was tested by the paddle method of USP and the dissolution data were analysed. Both the dissolution rate and kinetic profile can be controlled by alteration in the quantity of embedding material. Matrices of 75% zinc sulphate loadings showed steady state diffusion-controlled matrix release with good correlation in vitro. Good absorption of zinc sulphate from the gastrointestinal tract was proven by significant elevation of serum zinc level in patients with Wilson's disease.

Absorption↗

[Usage modeling test in aerosols formulations].

Authors emphasize the importance of "usage-modelling" test concerning the uniformity of doses in the case of aerosol formulations, containing propellants or supplied with atomising devices. Weight measurement was carried out to identify the uniformity of doses per actuation keeping non-use periods in the case of water-based solutions with different density and suspension containing HFC propellants. It can be concluded that uniformity of doses--applying non-use periods during the testing time--significantly depends on the composition, the density of the formulation and the spraying mechanism of the atomising device.

Aerosols↗