Water-soluble copolymers based on poly[N-(2-hydroxypropyl)methacrylamide] and bearing in their side chains a chromogenic substrate for chymotrypsin were prepared by direct copolymerization or polymeranalogous reaction. The substrate was L-phenylalanine-4-nitroanilide linked by its amino group to the terminal carboxylic group of the side chain. The cleavage of the substrate thus bonded, was expressed by means of the Michaelis constant, the maximum velocity, and the percentage of substrate unit accesible to the enzyme. The effect of length and chemical structure of the side chain was investigated in the first place. It was found that the chain must be longer than 6 atoms; longer chains are generally more favourable for this cleavage. The E-aminocaproyl group provides a chain that is most favourable for the cleavage, whereas chains with several glycyl units, though longer, are less favourable. Polymers with higher content of the substrate units undergo cleavage more readily. ZUSAMMENFASSUNG: Durch direkte Copolymerisation oder durch polymeranaloge Reaktion wurden auf der Basis von Poly[N-(2-hydroxypropyl)methacrylamid] wasserlosliche Copolymere hergestellt, die in Seitenketten farbige Substratgruppen fur Chymotrypsin tragen. Substrat war L-Phenylalanin-p-nitroanilid, das uber seine Aminogruppe an die endstandige Carboxylgruppe der Seitenkette gebunden war. Die Spaltbarkeit des so gebundenen Substrates wurde durch die Michaelis-Konstante, durch die maximale Geschwindigkeit und durch den Prozentsatz an Substrateinheiten ausgedruckt, der fur das Enzym zuganglich ist. Hauptsachlich wurde der Effekt der Lange und der chemischen Struktur der Seitenkette untersucht. Es wurde gefunden, daB sie langer als 6 Atome sein mu& daB allgemein *I The scope of these results was presented on 4th Bratislava International Conference on Modified Polymers, Preparation and Properties. Preprints of Short Commun. J P-15, 1975, and the principle is the object of PV 2958-74 from April 25, 1974 (CSSR). die Spaltung durch langere Ketten begiinstigt wird. Die E-Aminocapryl-Gruppe als Seitenkette ist fur die Spaltung am gunstigsten, wahrend Seitenketten mit einigen Glycyl-Gruppen obwohl langer weniger giinstig sind. Polymere mit einem hoheren Gehalt an Substrateinheiten sind besser spaltbar.

The elimination and retention of a new, fully synthetic plasma prosthesis of Czechoslovak origin under the working name of Duxon (poly[N-(2-hydroxypropyl)methacrylamide]) was investigated in experiments on rabbits by using a 14C-labeled polymer. Results published earlier on elimination have been confirmed and extended. Retention was examined after repeated application. The effect of molecular weight prevailed both in elimination and in retention. Polymers of lower molecular weights, which possess a good therapeutical effect, are not permanently deposited in the organism.

A number of general reviews have already been published on this topic and so the authors will present information on their approach and some results obtained. Polymers for medical uses are a traditional field at the Institute of Macromolecular Chemistry. However, crosslinked hydrophilic polymers ‐ so called hydrogels ‐ were the prevailing object in the past. Either as soft highly swollen materials for prothesis ‐ like soft contact lenses ‐ or heavily crosslinked macroporous beads designed as special sorbents or carriers of biologically active groups. Only a few years ago a research programme on soluble polymers was focussed mainly on general problems. The overall view about the main directions of the authors research is schematically presented on Fig. 1. It also shows the two types of polymers the authors are using in their experiments. The first one poly[N(2‐hydroxypropyl)methacrylamide]3a was chosen from the set of N‐substituted acryl‐and methacrylamides4 because of simple preparation and purification of the monomer. The other is a polyamide (polypeptide) described by Neri et al. in 1973.5 It is more hydrophilic and provides a good possibility to prepare a whole set of derivatives from a common polymeric intermediate ‐ polysuccinimide.

Eine Synthese für an der α‐Methylgruppe mit Tritium markierten Äthylen/Propylen‐Co‐polymeren wurde ausgearbeitet. Deren Aktivität ist für die Messung der pyrolytischen Spaltprodukte in einem Durchfluß‐Zählrohr ausreichend. Die Sequenzlängenverteilung der mit löslichen Ziegler‐Natta‐Katalysatoren hergestellten Copolymeren wurde aus der Kinetik berechnet. Über Untersuchungen der thermischen Spaltungsmechanismen in solchen Copolymeren und die Pyrolyse zur Bestimmung der Sequenzlängenverteilung wird in Kürze berichtet.

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