Preparation and evaluation of medicinal carbon oral films

Medicinal carbon (MC) films, which can be taken more easily than other dosage forms, were prepared using sodium carboxymethyl cellulose (CMC), hydroxypropylmethyl cellulose (HPMC) and alginic acid sodium (ALG) as film base materials. Brilliant blue FCF (BB) was used as a model drug. The films containing MC had sufficient strength and disintegration time, but their ability to adsorb BB was clearly inhibited compared to that of MC in powder form. When ALG was used as the film base, the BB adsorption capacity of MC film was approximately 50% of that of MC powder. In an attempt to improve this adsorption ability, two saccharides, sorbitol (SOR) and maltitol (MT), were separately added to MC at a mixing ratio of 1 : 1 by weight. When ALG was the film base, MC films containing SOR or MT showed rapid adsorption profiles and had greatly increased capacities for BB adsorption compared with films containing MC alone. SOR was superior to MT as an additive, though both gave MC-containing films a BB adsorption capacity almost equal to that of MC powder after 24 h, and physical mixtures tended to have better BB adsorption capacities than pre-treatment mixture. In addition, both SOR and MT tended to increase vertical strength of films, but neither additive in either type of mixture had a clear effect on disintegration time. When CMC or HPMC was used as the film base, on the other hand, the addition of SOR or MT caused hardly any improvement in adsorption ability. The above results demonstrate that ALG is useful as a film base material for the preparation of MC films, and that MC films with sufficient strength and adsorption capacities equal to those of MC powders can be produced using a physical mixture of MC and SOR on an ALG base.