caa a22 4500 477127592 CHVBK 20180405111654.0 cr unu---uuuuu 170330e19970401xx s 000 0 eng 10.1023/A:1012111116002 doi (NATIONALLICENCE)springer-10.1023/A:1012111116002 Development of a Statistical Model for the Formation of Poly [Acryloyl Hydroxyethyl Starch] Microspheres [Elektronische Daten] [L. Huang, R. Mehta, P. DeLuca] Purpose. To develop a mathematical model for predicting the molecular weight between crosslinks, Mc, of poly[Acryloyl Hydroxyethyl Starch] (Ac-HES) microspheres system and to identify and evaluate the key microsphere preparation parameters which affect the Mc of the formed microsphere structure based on the developed model. Methods. Link probability generating functions (LPGFs) based on the classical branching theory were used to derive a model for the calculation of Mc for the Ac-HES system. Based on the developed model, simulation was made to study the effects of the microsphere preparation variables on Mc of the formed microspheres. The process variables were the degree of derivatization (DD) of the Ac-HES, the molar ratio (MR) of the Ac-HES to acrylamide monomer, the fractional conversion of the unsaturation (α), the initiator efficiency (f), the molar concentration of initiator (I), the fraction of intramolecular cyclization (c), and the total weight of the reactable monomer and polymer (s). Results. A model to describe the crosslinking reaction of Ac-HES system and predict Mc was developed. Simulation based on the model showed that Mc decreased as α increased and reached a limiting value before total conversion. At constant α, Mc initially decreased with MR to a minimum and then increased with MR; while Mc decreased monotonically with DD. I and c affected Mc only at very low α and changes in s and f had no effect on Mc. Conclusions. Simulation based on the model suggested that the most important microsphere preparation parameters influencing Mc of the Ac-HES system are the number of functional groups on the Ac-HES (DD) and the stoichiometry (MR) of the crosslinking reaction. Plenum Publishing Corporation, 1997 poly(Acryloyl Hydroxyethyl Starch) microspheres nationallicence molecular weight between crosslinks (Mc) nationallicence degree of derivatization (DD) nationallicence molar ratio (MR) nationallicence link probability generating function (LPGF) nationallicence Huang L. 202, Her-Ping St., East District, Taichung City 401, Taiwan, R.O.C aut Mehta R. ISIS Pharmaceuticals, 2292 Faraday Ave., 92008, Carlsbad, California aut DeLuca P. College of Pharmacy, University of Kentucky, 907 Rose Street, 40536-0082, Lexington, Kentucky aut Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/4(1997-04-01), 469-474 0724-8741 14:4<469 1997 14 11095 https://doi.org/10.1023/A:1012111116002 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1012111116002 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Huang L. 202, Her-Ping St., East District, Taichung City 401, Taiwan, R.O.C aut NATIONALLICENCE 700 1- Mehta R. ISIS Pharmaceuticals, 2292 Faraday Ave., 92008, Carlsbad, California aut NATIONALLICENCE 700 1- DeLuca P. College of Pharmacy, University of Kentucky, 907 Rose Street, 40536-0082, Lexington, Kentucky aut NATIONALLICENCE 773 0- Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/4(1997-04-01), 469-474 0724-8741 14:4<469 1997 14 11095 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer