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P Rambourg

Publications and source records attributed to P Rambourg.

6 recordsLinked to original sources
PubMed1982

Microencapsulation III: Preparation of invertase microcapsules.

Invertase was incorporated into polyamide microcapsules. The following parameters were studied: pH of the aqueous phase during interfacial polymerization; duration of the polymerization; surfactant concentration; stirring rate; improvements in the isolation procedure; effect of lyophilization. The inactivation of the encapsulated enzyme by pepsin was shown to be related to the acidic incubation medium and prompted incorporation of protective proteins in the microcapsules. This process allowed relative protection of the enzyme. In a second set of experiments, an emulsification-reticulation method was developed, which encapsulated invertase in a cross-linked protein. Various proteins and bifunctional acylating agents were tested. Microcapsules of immobilized invertase were prepared through cross-linking of the enzyme protein itself.

Capsules↗
PubMed1982

Microencapsulation IV: Cross-linked hemoglobin microcapsules.

Hemoglobin microcapsules were prepared through cross-linking of hemoglobin itself with various acyldichlorides. Variations in the reticulation conditions were preformed in order to ameliorate the oxygen dissociation curve, the mean diameter, and the possibility for the microcapsules to be lyophilized. With terephthaloylchloride, as the cross-linking agent, incorporation of inositol hexaphosphate and glucose, followed by stabilization through glutaraldehyde and using high stirring speed, allowed preparation of stable hemoglobin microcapsules, 5 micrometers in diameter, which suffered rapid lysis by proteases. They were able to ensure oxygen transfer: the dissociation curve was sigmoidal with a p50 = 13 mm Hg. They retained these properties after lyophilization followed by rehydration.

Capsules↗
PubMed1982

[Lyophilization protection of hemoglobin by N-acetyltryptophan].

Measurements of methemoglobin content, different oxyphoric powers, oxygen affinity were made on freeze-dryed hemoglobin without protector and in presence of N-acetyl tryptophan and/or alpha-D glucose. These measurements revealed that, at low concentrations, N-acetyl tryptophan offers a better protection than glucose. Moreover, this acetylated amino-acid decreases the oxygen affinity of hemoglobin (Po(2)50 increased). The two protectors do not seem to compete, but present complementary effects.

Biological Transport↗