Enhanced film-forming properties for ethyl cellulose and starch acetate using n-alkenyl succinic anhydrides as novel plasticizers

• Published in: European journal of pharmaceutical sciences Vol. 19; no. 5; pp. 363 - 371
• Main Authors: Tarvainen, Maarit, Sutinen, Riitta, Peltonen, Soili, Mikkonen, Hannu, Maunus, Jaana, Vähä-Heikkilä, Kalle, Lehto, Vesa-Pekka, Paronen, Petteri
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 01.08.2003; Elsevier
• Subjects: Algorithms; Biological and medical sciences; Calorimetry, Differential Scanning; Cellulose - analogs & derivatives; Cellulose - chemistry; Chemical Phenomena; Chemistry, Physical; Citrates; Crystallization; Dicarboxylic Acids; Ethyl cellulose; General pharmacology; Medical sciences; n-Alkenyl succinic anhydride; Permeability; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Plasticizer; Plasticizers - chemistry; Solvents; Starch - analogs & derivatives; Starch - chemistry; Starch acetate; Succinic Anhydrides - chemistry; Tensile Strength; Water; Starch acetate; n-Alkenyl succinic anhydride; DSC, differential scanning calorimetry; Film; OSA, 2-octenyl succinic anhydride; P, permeability coefficient; WVTR, water vapor transmission rate; TEC, triethyl citrate; Ethyl cellulose; n-ASA, n-alkenyl succinic anhydride; Plasticizer; EC, ethyl cellulose; DSA, 2-dodecen-1-ylsuccinic anhydride; T g, glass transition temperature; SA, starch acetate; DBS, dibutyl sebacate; MFT, minimum film formation temperature; Pharmaceutical technology; Mechanical properties; Cellulose(ethyl); Organic anhydride; Permeability; Water vapor; Glass transition temperature; Succinic acid; Coating; Starch derivative
• ISSN: 0928-0987; 1879-0720
• DOI: 10.1016/S0928-0987(03)00137-4

Purpose: The aim of this study was to investigate the ability of n-alkenyl succinic anhydrides ( n-ASAs) to improve the film-forming characteristics of a novel coating polymer, potato starch acetate degree of substitution 2.8 (SA). n-ASAs were also applied to improve the otherwise brittle properties of ethyl cellulose (EC) aqueous dispersion (Aquacoat ®) and EC solvent-based films. Methods: The effectiveness of two n-ASAs, 2-octenyl succinic anhydride (OSA) and 2-dodecen-1-ylsuccinic anhydride were evaluated as plasticizers. Mechanical properties, both water vapor and drug permeabilities, and glass transition temperatures of the cast free films were measured. Triethyl citrate and dibutyl sebacate were used as reference plasticizers. Results: The long hydrocarbon chain of n-ASA, with its accessible carbonyl groups, enabled a strong plasticization effect on the tested polymers. Due to the excellent mechanical properties (i.e., a tough film structure with considerable flexibility) and low permeability of the plasticized films, n-ASAs, and especially OSA proved to be an ideal plasticizer particularly for EC based coatings. Also, the EC aqueous dispersion plasticized with n-ASAs resulted in a markedly enhanced coalescence of the colloidal polymer particles, even at low drying temperatures. Conclusions: In applications where a coating with high flexibility is required, n-ASAs can be used as plasticizers at moderately high concentrations (up to 60–70%, w/w) without losing the high tensile strength, excellent toughness and low permeability of EC and SA films.