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Complexes formed by the interaction of histone H1 and the immunomodulator Pyran co-polymer, were evaluated using nephelometric titration. At a constant concentration of histone (10 microgram/ml), maximum turbidity was obtained at a Pyran concentration of 2 microgram/ml. Titration of H1 by Pyran was found to be sensitive to ionic strength. Concentration of Na+ greater than 200 mM or Mg+2 greater than 3 mM apparently blocked Pyran . H1 complex formation.

The release of 3-methylpyrazole from monolithic polymer films into aqueous media has been studied. The diffusion of the active agent decreased with increasing of the content of acetate groups in reacetylated poly(vinyl alcohols) and with increasing of the ester lengths in copolymers of maleic esters, respectively. The release rate of active ingredient is dependent on the hydrophilicity of the polymer films. Contrary to the glass transition temperature the hydrophilicity of polymers expressed the interaction between polymer chains and water in a direct way. The hydrophilicity of copolymers of maleic esters correlated with the turbidimetric point, which can be determined by acidimetric titrations. The influences of interactions between polymers and the active agents on their diffusion in the polymers were also discussed.

Acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) and cholinesterase (acylcholine acylhydrolase, EC 3.1.1.8), respectively, were covalently attached to a cross-linked copolymerisate of maleinic anhydride and butanediol-divinylether. Based on the coupling procedure reported by Brümmer et al. (Brummer, W., Hennrich, N., Klockow, M., Lang, H. and Orth, H.D. (1972) Eur. J. Biochem. 2k, 129--135), a simple method is described which requires only 24 h for completion and provides a sufficient yield. Although a polyanionic carrier was used the Km and k2 values as well as the substrate and pH optima of the bound acetylcholinesterase and bound cholinesterase did not differ considerably from the corresponding values of the free enzymes. Bound acetylcholinesterase and to some extent also bound cholinesterase did not lose any enzymatic activity after storage in saline at 4 degrees C for 140 days.

This study describes the principle of a simple rapid method for encapsulating hydrochlorothiazide in butyl half-ester of polyvinyl methyl ether-maleic anhydride copolymer to produce a controlled release dosage form. Unplasticized microcapsules and microcapsules plasticized with Tween 80 and castor oil were prepared. Particle size distribution, flow properties and drug content of microcapsules suggested the suitability of the method for encapsulating a wide variety of materials. The in-vitro release rate was studied as a function of core: coat ratio, type and concentration of plasticizer. Various release mechanisms were considered but no single mechanism can explain all the data completely.