Estimation of genetic parameters for hip dysplasia in Czech Labrador Retrievers.

The objective of this study was to estimate the genetic parameters, genetic trends and breeding values using linear model (LM) and threshold model (TM) for the development of hip dysplasia (HD) in Labrador Retrievers in the Czech Republic (n = 3151). The right and left hip joints were evaluated separately using the Fédération Cynologique Internationale scoring system. Four linear and four TMs were tested for the correct estimation of genetic parameters. All the tested models utilized fixed effects of sex, assessor, year of birth, regression of age at evaluation, random direct genetic effects and the effect of the animals' permanent environments. The models differed in the inclusion of the following effects: fixed effects of regression of inbreeding coefficient, random maternal effect and random effect of the maternal permanent environment. Compared to the TM, the LM provided lower coefficients of direct (0.25-0.29 versus 0.26-0.35) and maternal heritability (0.01-0.02 versus 0.03-0.05), repeatability (0.76-0.77 versus 0.78-0.83) and of the correlation between direct and maternal effects (-0.55 to -0.21 versus -0.80 to -0.27). In the tested models, no statistical significance was found for fixed regression of inbreeding coefficients or for the random effect of the permanent maternal environment. In spite of the similarity of the LM and TM results, the TM is recommended as the more suitable model for estimating genetic parameters and subsequent breeding values for HD in Labrador Retrievers in the Czech Republic.

[Effect of humectants on pharmaceutical availability and rheological properties of cetirizine-containing hydrogels]. / Vplyv humektantov na farmaceutickú dostupnost a reologické vlastnosti hydrogélov s cetirizínom.

The paper is concerned with the formulation of the antihistamine cetirizine into hydrogels. The cellulose derivatives hydroxyethylcellulose (HEC) and methylcellulose (MC) were employed to prepare hydrogels. As auxiliary substances from the group of humectants are indispensable components of hydrogels, the paper examines their effect (glycerol--GL, propylene glycol--PG, and sorbitol--SO) on the rheological properties and pharmaceutical availability of cetirizine in its formulation into hyrogel. The obtained results show that from the viewpoint of dermal administration for cetirizine at this stage of research hydrogels of the following composition are optimal: 3% HEC + 15% GL and 2.5% MC + 10% SO.

[Effect of humectants on pharmaceutical availability and rheological properties of loratadine-containing hydrogels]. / Vplyv humektantov na farmaceutickú dostupnost a reologické vlastnosti hydrogélov s loratadínom.

The paper examines the formulation of the antihistamine loratadine into hydrogels, the polymers under evaluation being Carbopol 980 and Vivastar P 5000. As other pharmaceutical auxiliary substances from the group of humectants are an indispensable component of hydrogels, the paper evaluates their influence (glycerol--GL, propylene glycol--PG, and sorbitol--SO) on the structural viscosity and pH of hydrogels as well as pharmaceutical availability of loratadine. On the basis of the results of the study it can be concluded that from the viewpoint of dermal administration of loratadine the hydrogels of the following composition are optimal: 0.5% Carbopol 980 + 5% SO and 1.5% Vivastar P 5000 + 5% PG.

[Pre-formulation studies of the H1-antihistamine loratadine for a topical dosage form]. / Predformulacné stúdie H1--antihistaminika loratadínu do topickej liekovej formy.

The paper focuses on the formulation of the antihistamine loratadine for hydrogels. In the first stage of this study, the evaluated polymer for the preparation of hydrogels was Carbopol 980 of concentrations of 0.5, 0.8, and 1.0%. The paper aimed to determine the optimal concentration of Carbopol 980 in hydrogel formulation on the basis of the evaluation of the rheological properties and biological availability of loratadine from prepared hydrogels. The results of the study show 0.5% hydrogel of Carbopol 980 to be optimal for loratadine from the standpoint of topical administration.

[Preformulation studies of potential drug XIX M: partition coefficient]. / Predformulacné stúdie potenciálneho lieciva XIX M--rozdel'ovací koeficient.

The factors which markedly influence availability of the drug from the dosage form include also auxiliary substances, which are an inevitable component in the formulation of the drug. In the selection of auxiliary substances for a newly formulated drug, it is necessary to know that the drug is never a simple mixture of mutually independent ingredients, but a dynamic system in which various physical and chemical processes take place. The present paper aims to study the effect of auxiliary substances from the group of humectants with graded concentrations and the effect of the preservative on the partition coefficient of potential drug XIX M. Partition coefficient (P') was estimated in the system n-octanol/aqueous solution with graded concentrations of polyols. In these estimations, n-octanol simulated the horny layer, and the aqueous solution the base of the topical preparation. The auxiliary substances employed were polyols - glycerol, propylene glycol, and sorbitol in 5, 10, 15, and 20% concentrations and an antimicrobially effective solution of Ajatin (Solution benzododecinii bromati) in two concentrations of 0.01 and 0.1 wt %. It follows from the obtained results that the values of partition coefficient of potential drug XIX M are greatly influenced by auxiliary substances. The value of this parameter, and therefore also biological availability, depend not only on the sort of the polyol used and its concentration, but also on the concentration of the preservative employed, in this case Ajatin.

[Examination of the stability of hydrogen peroxide solutions]. / Sledovanie stability roztokov peroxidu vodíka.

Reliable stabilization of the pharmaceutical preparation and the active ingredient remains one of the most important problems of world pharmacy because pharmaceutical preparations are not systems which are stable without limitation. The patient must receive a quality drug and that is why the question of stability is paid grest attention to not only in research and development, industrial manufacture, but also in distribution. The measure of stability is the expiration period. Diluted solution of hydrogen peroxide (3% solution) still belongs to the most widely used and at the same time the most easily accessible disinfectants. In practice it is common both in Slovakia and abroad. It is used in several concentrations. One of its most important disadvantages is its limited stability, which markedly decreases its expiration period. The present paper investigates the stability of hydrogen peroxide solutions of routinely used concentrations (3%, 6%, and 10%) without and with a stabilizing additive (phenacetin) prepared in the pharmacy and stored under different conditions for the period of their expected usability. The content of hydrogen peroxide was assayed by the pharmacopoeial method in 7-day time intervals. All concentrations of 3%, 6%, and 10% hydrogen peroxide were found to fulfil the conditions for stability in the period of time under study. Their concentration did not fall below the limit od 90% of the content of the active ingredient, and storage under decreased temperature proved to be more suitable. Storage of hydrogen peroxide in the light is inadmissible. When the conditions of storage are observed, the required therapeutic effect of hydrogen peroxide solution can be expected for the period of three months.

[A study of the stability of dioxopromethazine in aqueous solutions and ophthalmic instillation]. / Stúdium stability dioxoprometazínu vo vodných roztokoch a v ocnej instilácii metódou HPLC.

Dioxopromethazine began to be used in therapy as a modern antihistamine agent in the 1970s. A dioxopromethazine-containing ophthalmic instillation and a gel were employed until the end of the 1990s. The paper deals with the examination of the stability of the drug dioxopromethazine in aqueous solutions and the ophthalmic instillation Promefrin stored under different conditions. High-performance liquid chromatography with spectrophotometrical and electrochemical detection and HPLC connected on-line with mass spectrometry were employed for analysis. Dioxopromethazine in aqueous solutions and in ophthalmic instillations stored in direct sunlight was found not to be stable. However, the cover of the ophthalmic instillation, a brown-glass prescription bottle, and observation of storing conditions sufficiently protect the active ingredient from decomposition processes.