Should stimulation site be tailored in the individual heart failure patient?

Right ventricular pacing at various sites and shortened atrioventricular (AV) delay has failed to demonstrate a convincing short-term and long-term improvement of left ventricular function. Left-ventricular-based stimulation offers a new therapeutic option for patients with symptomatic congestive heart failure and conduction disturbances, especially of left bundle-branch block configuration. Left ventricular mechanical improvement seems mainly dependent on the pacing site, in addition to optimizing the AV delay.

[Extraction and determination of prednisolone in drugs and excipients in ointments and creams and the uniformity of distribution in prednisolone ointment].

For the purpose of measuring the contents of prednisolone in low concentrated ointments and creams an instruction was elaborated that includes several steps of extraction, in the resulting solution of which the assay of the steroid by Blue Tetrazolium reaction will be done. The procedure permits the determination of prednisolone in presence of most of usual ingredients of ointment bases except wool alcohols. Also no influence is given by some remedies combined with prednisolone for topical application except coal tar solution.

[Contributions to the liberation of drugs from suspension ointments. Part 19: Studies on the interactions of hydroxyquinoline (salts) with ointment components (author's transl)].

On studying the interactions of hydroxyquinoline and its watersoluble salts with substances commonly used to ointment preparation, the authors stated a large agreement between the decreases in release rate and the quotients of binding determined by equilibrium dialysis. Sodium carboxymethyl cellulose, zinc oxide, and talc react with these drugs to form bindings of some strength the impair the release of the drugs, whereas hydroxyethylcellulose and Aerosil behave indifferently.

[On the different release kinetics of water-soluble and lipid-soluble forms of hydroxyquinoline in oleogel ointment bases (author's transl)].

Studies using the model according to Horsch and Kögel showed that the release kinetics of the suspended water-soluble (but not lipid-soluble) drugs hydroxyquinoline sulphate and hydroxy-quinoline sulphate--potassium sulphate from oleogels is of a zero order. Differences in drug dispersity do not affect the release rates. Oleogels containing the lipid-soluble hydroxyquinoline base yielded undersaturated solution ointments, the release kinetics of which can be stated by a semilogarithmic relationship.

[Contributions to the liberation of drugs from suspension ointments. Part 13: The effects of physiochemical factors on the liberation of prednisolone from oleogels (author's transl)].

The liberation rates of oleogels containing 0.25% of prednisolone can be stated by the following equation: q=f(square root of t). The regression equations may be used to calculate the liberation rate constants from which the apparent diffusion coefficients are obtainable.

[Contributions to the liberation of drugs from suspension ointments. Part 12: On the suitability of some synthetic hydrophobic membranes for liberation studies (author's transl)].

The release rates determined for various salicylic acid and prednisolone ointments on using different membranes in the in vitro model according to Horsch and Kögel [20] were compared with one another in regard to possible membrane-specific differences in liberation kinetics and in validity. The results obtained with salicylic acid ointments by the lipophil collodion-lipid membranes and silicone membranes developed by Fürst and coworkers [14] were comparable with those yielded by the hydrophilic cellulose membrane: release rates of comparable order of magnitude; same order of ranking of the bases used; plots of the cumulated percentages of release against the root of time providing no evidence of differences in kinetics. In contrast, the permeability of a further hydrophobic membranes (silicone, polyester) was markedly lower.