AbstractsBiology & Animal Science

Oral Controlled-Release Solid Dosage Forms, Use of Novel Polymer and Unconventional Polymer Blends

by Rebaz Ali

Institution: Freie Universität Berlin
Department: FB Biologie, Chemie, Pharmazie
Degree: PhD
Year: 2015
Record ID: 1098220
Full text PDF: http://edocs.fu-berlin.de/diss/receive/FUDISS_thesis_000000098975


Use of unconventional polymer blends of Kollicoat® SR 30 D and Eudragit® RL 30 D: Among the dissolution test conditions, hydrodynamic properties (agitation rate) and mechanical destructive force are important factors, which affect the dissolution behavior of the dosage form. In hydrogel-type tablets, in vivo drug release was much faster than that expected from in vitro dissolution tests due to the peristalsis of the gastrointestinal tract. Moreover, because single-unit reservoir tablets required a strong/flexible and permeable polymer, there are few publications in this respect, due to lack of polymer with these properties. The main objective of this part was to use polymer blends of Kollicoat® SR 30 D and Eudragit® RL 30 D as coating materials to increase the mechanical robustness of HPMC matrix tablets and to prepare single-unit reservoir tablets. The effect of polymer blend ratio, curing conditions, coating level, drug content, drug solubility, ionic strength, pH, agitation rate, type of excipient and storage conditions on drug release were evaluated. For coated HPMC matrix tablets, HPMC and film coat can control the drug release, which could easily be adjusted by varying the polymer blend ratio, which also affected the mechanical properties of the films. Flexibility increases as Kollicoat® SR 30 D increases and Young’s modulus increases as Eudragit® RL 30 D increases. At 8% w/w coating level, a force of 3.2 N was required to rupture the swollen tablet after 16 h in the release medium. The coated tablets were robust; coating level (6% to 10%, w/w) and agitation rate (50 rpm to 150 rpm) had no influence on the drug release. A water-insoluble model drug was not released; however, release of water-soluble drugs increased as the drug content increased and decreased as HPMC content increased. Curing at 40 °C/ 75% RH was required for polymer coalescence as it made the film more flexible. However, for single-unit reservoir tablets, drug release significantly decreased when tablets were cured at 40 °C/ 75% RH for 24 h. Drug release was accelerated by increased Eudragit® RL content, buffer species (phosphate ≥ acetate ˃ chloride ion), drug solubility (diprophylline ˃ metoprolol ≥ theophylline), type of the excipient (MCC ˃ lactose) and increased drug content (50% to 80%, w/w). Ionic strength (0 M to 0.4 M), increased agitation rate of the dissolution medium (50 rpm to 150 rpm), and coating level (6% to 10%, w/w) showed no effect on drug release. In vitro release studies showed that the reservoir tablets were strong enough to withstand gastric destructive force. Use of cellulose acetate butyrate (CAB-553-0.4) as a novel polymer in controlled-release drug delivery: Advances in polymer science have led to the development of several novel drug-delivery systems. Cellulose acetate is an example that is used for preparation of osmotic tablet; however, toxic solvents and flammability hazard are the greatest disadvantages of the process. Hence, alternative polymers with sufficient strength, permeability, and solubility in a…