Robust Control of Repeated Drug Administration with Variable Doses Based on Uncertain Mathematical Model.

The aim of this paper was to design a repeated drug administration strategy to reach and maintain the requested drug concentration in the body. Conservative designs require an exact knowledge of pharmacokinetic parameters, which is considered an unrealistic demand. The problem is usually resolved using the trial-and-error open-loop approach; yet, this can be considered insufficient due to the parametric uncertainties as the dosing strategy may induce an undesired behavior of the drug concentrations.

Using a State-Bounding Observer to Predict the Guaranteed Limits of Drug Amounts in Rats after Oral Administration Based on an Uncertain Pharmacokinetic Model.

In the first part of this paper, the problem of using an uncertain pharmacokinetic model is resolved to determine drug concentrations in rats after the oral administration of drug suspensions with and without added tenside. To this end, a generalized pharmacokinetic model determining the guaranteed limits of drug concentrations was designed. Based on this, the design of the so-called state-bounding observer is described in the second part.

In-Vivo Analysis and Model-Based Prediction of Tensides' Influence on Drug Absorption.

Depending on their concentrations the surface-active substances, tensides (surfactants) can positively or negatively influence the drug absorption, which is widely used in the design of the dosage forms with controlled release. A problem is that the (in-vivo) rate of absorption cannot be directly measured and for that reason, it is frequently substituted by evaluation of the (in-vitro) dissolution. On other hand, a suitably designed pharmacokinetic model can directly predict virtually all pharmacokinetic quantities including both the rate of absorption and fraction of the dose reaching the blood circulation.

Effect of Molecular Composition of Head Group and Temperature on Micellar Properties of Ionic Surfactants with C12 Alkyl Chain.

The paper analyses influences of the temperature and hydrophilic groups on micellar properties of ionic surfactants with 12-carbonic hydrophobic chains. The aim is to assess the impact of hydrophilic groups and temperature on thermodynamic parameters and micellization. This knowledge is indispensable for the formulation of new dosage forms.

Association, Distribution, Liberation, and Rheological Balances of Alkyldimethylbenzylammonium Chlorides (C12-C16).

It is known that cationic surfactants have an antimicrobial effect and act as enhancers. This paper studies three cationic surfactants from the group of alkyldimethylbenzylammonium chlorides (dodecyl-, tetradecyl-, and hexadecyl). Interest is focused on the association of the surfactants with respect to temperature, partition balances and their influence on drug release, rheological properties, and the pH of hydrogels.

Simultaneous formulation of terbinafine and salvia monoterpenes into chitosan hydrogel with testing biological activity of corresponding dialysates against C. albicans yeast.

This work was aimed at a progressive formulation of drugs into chitosan hydrogels. It was taken into consideration that a therapeutic effect of the drugs could be enhanced by a combination of natural compounds with chemical (synthetic) drugs. In this work, sage essential oil (SEO) bicyclic monoterpenes with antiflogistic, antiseptic, and antimycotic properties were combined with terbinafine (TB) having a strong antimycotic activity.

[Influence of excipients on caffeine permeation from gels].

Unlabelled: The subject of this paper is a study of the influence of excipients on caffeine permeation from dermal semisolids drugs. Due to its advantageous properties, caffeine can be successfully used in dermal hydrogels. The choice of excipients from the group of humectants and cationic surfactants also plays an important role.

[Formulation of benzethonium chloride into gels].

This study is focused on the preparation of gels with antimicrobial effects. A quaternary ammonium salt, benzethonium chloride, in a concentration of 0.01-0.

Formulation of sage essential oil (Salvia officinalis, L.) monoterpenes into chitosan hydrogels and permeation study with GC-MS analysis.

This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples.

[Influence of quaternary ammonium salt on liberation of drug with antiseptic effect].

The paper evaluates the influence of three surfactants (carbetopendecinium halogenides) on the liberation of the drug chlorhexidine dihydrochloride (CHX) in 0.1% (w/w) from the dosage form-gel and also the flow properties of gels. The following tensides were evaluated: carbetopendecinium bromide (SB), carbetopendecinium chloride (SC), and carbetopendecinium iodide (SI).

[Influence of temperature and concentration of a surfactant on pharmaceutical availability].

This study aimed to analyze the influence of surfactant concentration and temperature on drug liberation from hydrogels and their flow properties. The surfactant benzethonium chloride (BZCl) was used in concentrations of 0.01, 0.

[Evaluation of liberation of caffeine from dermal semisolids drugs].

The paper deals with formulation of caffeine into dermal semisolid dosage forms - hydrogels. Caffeine was chosen as a model drug because its properties can be successfully used just in hydrogels. Protective and tranquilization effects can be used in the preparations for sunbathing, and its lipolytic and regenerative effect can be used for the treatment of androgenic alopecia or cellular bioprotection.

[Study of local anaesthetics - part 200 choice of the optimal type of chitosan for the formulation of local anaesthetics of the carbamate type into hydrogels].

The aim of this examination was a study of hydrogels on the base of various types of the natural polymer chitosan with an assay of local anaesthetics of the carbamate type. The concentration of the gel-creating compound in hydrogels was 2.5%.

[Formulation of salvia-containing gels].

The trend during the past years is to prefer natural drugs to synthetically prepared medicines. Due to its important antiphlogistic, antiseptic and antihidrotic effects, Salvia officinalis L. has a wide use in medicine, pharmacy and cosmetics in various dosage forms.

[Studies of local anaesthetics - part 197. Effect of xylitol on pharmaceutical availability of lidocaine and flow properties of hydrogels].

Unlabelled: The paper examines the formulation of hydrogel on the base of a synthetic polymer containing a local anaesthetic and a mass-produced drug in the form of a solution with an antiphlogistic effect. It aimed to prepare a hydrogel of a suitable composition with suitable flow properties and drug release, the active ingredient being lidocaine hydrochloride. Besides the role of a synthetic polymer which ensures that the active ingredient remains at the affected site, an important role in the formulation is played by the presence of an artificial sweetener, which to a great extent as a taste correcting agent of the unpleasant taste of the active ingredient influences the compliance of many patients.

Study of local anaesthetics--Part 196 formulation of the local anaesthetic heptacaine into hydrogel on the basis of chitosan.

The study aimed to formulate the local anaesthetic heptacaine into hydrogels on the basis of chitosan. The gel-creating compounds used included natural polymers --three different types of chitosan, namely those of a medium molecular weight, from the shells of shrimp, and from the bumblebees species Bombus terrestris. The prepared hydrogels were evaluated on the basis of their rheological properties and drug liberation.

[Influence of membranes on alaptide permeation from hydrogels].

The paper evaluates the liberation of alaptide from gels through various types of permeable membranes. The gels were prepared on the basis of three different polymers (3% chitosan; 2.5% hydroxypropyl cellulose; 3% hydroxyethyl cellulose) in different concentrations with additions of humectants (5 %; 15% propylene glycol and 10% glycerol) and the preserving agent, 0.

[Study of local anaesthetics--Part 194. Evaluation of carbopol hydrogels with lidocaine].

The objective of this article is to describe the formulation and evaluation of dermal semisolid drugs--carbopol hydrogels containing the solution of Bukofit, zinc chloride and the local anaesthetic lidocaine. The hydrogels were evaluated after 2, 7, 14 and 28 days after their preparation and stored at the temperature of 5 degrees C +/- 0.2 degrees C.

Alternative and generalized approach to in vitro-in vivo correlation.

Evaluation of in vitro-in vivo correlation (IVIVC) plays important role in securing therapeutic effect if a dosage form undergoes technological modifications. Similarity (closeness) of dissolution profiles of the original and modified dosage forms has been traditionally considered to be sufficient for similar in vivo responses. This may be true if the IVIVC model (dependence between the dissolution and corresponding absorption profiles) is given by a linear straight line with the unit slope.

Evaluation of aqueous preparations from herbal drugs.

The paper presents results obtained within analysis of aqueous preparations obtained from the herbal drugs, (APHD) which are available in pharmacy as mass produced drugs. In particular, the following drugs were analyzed: CYNAROFIT, L'ALIAFIT, Tinctura belladonnae, Tinctura gentianae, Tinctura chinae a Tinctura valerianae made by Calendula, j.s.