The use of kinetic N-order model in description of active substance release from various drug forms. Part 1. Premises and mathematical analysis of the N-order model.

The paper presents the premises and equations which are the basis of the mathematical n-order model, which contrarily to standard models based on the laws of chemical kinetics, i.e. 0-order and 1-order kinetics, enables categorization of the investigated process taking into account two parameters: the rate at which it occurs, and actual order, which it is distinguished by. Standard models, which assume in advance the kinetic order of the described processes, may be used with satisfactory accuracy to analyze only a low percentage of performed experiments. However, as shown in practice, the order of many physico-chemical processes, including those which are most interesting for us, active substance release from the drug form, may assume intermediate values, what is manifested as various types of "smooth non-linearities" in the obtained release profiles, which cannot be explained on the basis of assumed standard theories. N-order model may be numbered among the group of physical mathematical models based on the premises of chemical kinetics, possessing the analytical structure of internally non-linear function. It is characterized by two parameters: release rate constant K and order coefficient N.

The use of kinetic N-order model in description of active substance release from various drug forms. Part 2. Analysis of paracetamol and sodium diclofenac release from methylcellulose.

The first part of the monograph presented the premises and equations which are the basis for the proposed mathematical n-order model. This non-linear physical model obeying the laws of chemical kinetics was used to describe the processes of active substance release from drug form. The possibilities of its application in the mathematical description and detailed analysis of the kinetics of paracetamol and sodium diclofenac release from various viscosity gels based on methylcellulose were investigated. Moreover, the effect of temperature on the release profiles of the above-mentioned active substances from investigated formulations was analyzed. On the basis of a series of performed experiments and detailed comparative statistical analysis of the estimators of two parameters characterizing n-order model: release rate constant K and order coefficient of the release process N, it was demonstrated that the active substance release rate from formulations with uncontrolled release is correlated with actual order of the process. Also, the proposed n-order model was compared with models obeying the laws of chemical kinetics: 0-order model, 1-order model and with diffusion Higuchi "square root of time" model, and the comparison demonstrated superiority of the n-order model over standard models. A non-linear statistical analysis was performed by means of computer software Statistica Pl. v. 7.1 manufactured by StatSoft Polska and Mathematica v. 5.0 manufactured by Wolfram Research.

The effect of hydrophilic base on pharmaceutical availability of prednisolone complexed with beta-cyclodextrin.

Studies on the effect of hydrophilic gel composition on pharmaceutical availability of prednisolone complexed with beta-cyklodextrin at P:beta-CD ratios 1:1 and 1:2 revealed that the half-release times were shortened and differentiated depending on the substances added hydrogel to propylene glycol, dimethylacetamide and polysorbate 20 in comparison to preparations containing non-complexed active substance.

[Acute, hemorrhagic, overgrowing vaginal inflammation caused by Streptococcus agalacitae--case study]. / Ostre krwotoczne zarastajace zapalenie pochwy wywolane Streptococcus agalactiae - opis przypadku.

The aim of this study was to discuss a case of an acute, hemorrhagic, overgrowing vaginal inflammation caused by Streptococcus agalacitae. Intravaginal globules based on methylcellulose and gelatin, containing a lactic acid and chitosan complex in mole relation 1:1 to 4:1 and, in succesion, an addition of hydrophilisating substances like: PEG-200, propylene-1,2 glycol or glycerol, were applied in the treatment process. The technology was invented in Fac. of pharmacy. Dep. of Pharmaceutical Technology, Wroclaw Medical Univ, Poland (recipe patent-protected).

[Some interactions of natural and synthetic anionic polymers with biologically active substances]. / Wybrane interakcje naturalnych i syntetycznych polimerów anionowych z substancjami leczniczymi.

Anionic polymers are nowadays extensively used in drug form technology, especially in drug delivery and drug targeting. Development of proper drug and macromolecular excipient composition allows controlled drug delivery in the term of the drug concentration in blood or other tissues, and in the term of the action-time. Between anionic polymers most frequently carbopols, eudragits, alginates and pectins are used. Application of anionic polymers in drug form technology is an up to date problem. According to new synthesis methods and new anionic polymers, new drug delivery systems would be researched. Most selective and safe devices should be developed, concerning biodegradation aspects.

Effect of some ethoxylated sorbitan alkanoate on hydrocortisone release from methylcellulose gels.

The process of hydrocortisone release from the nonionic polymer--methylcellulose hydrogels with the addition of 1% and 3% ethoxylated sorbitan alkanoate: polysorbate 20 or polysorbate 80, in the presence of 1,2-propylene glycol or PEG 200 has two stages. In the first stage the release rates are higher in comparison with the second stage. Concerning the hydrogel as a two-compartment system with micellas of polysorbates, the release rates of the first stage are in the range 4.27 x 10(-4)-6.23 x 10(-4) h-1 and in the second stage are in the range 8.29 x 10(-6)-1.16 x 10(-5) h-1 what can be affected by HLB of mentioned polysorbates.