Selective laser sintering (SLS) 3D printing of medicines
Selective laser sintering (SLS) 3-dimensional printing is currently used for industrial manufacturing of plastic, metallic and ceramic objects. To date there have been no reports on the use of SLS to fabricate oral drug loaded products; therefore, the aim of this work was to explore the suitability of SLS printing for manufacturing medicines. Two thermoplastic pharmaceutical grade polymers, Kollicoat IR (75% polyvinyl alcohol and 25% polyethylene glycol copolymer) and Eudragit L100-55 (50% methacrylic acid and 50% ethyl acrylate copolymer), with immediate and modified release characteristics respectively, were selected to investigate the versatility of a SLS printer. Each polymer was investigated with three different drug loadings of paracetamol (acetaminophen) (5, 20 and 35%). To aid the sintering process, 3% Candurin® gold sheen was added to each of the powdered formulations. In total, six solid formulations were successfully printed; the printlets (3D printed tablets) were robust, and no evidence of drug degradation was observed. In biorelevant bicarbonate dissolution media, the Kollicoat formulations showed pH-independent release characteristics, with the release rate dependent on the drug content. In the case of the Eudragit formulations, these showed pH-dependent, modified-release profiles independent of drug loading, with complete release being achieved over 12 h. In conclusion, this work has demonstrated that SLS is a versatile and practical 3D printing technology which can be applied to the pharmaceutical field, thus widening the armamentarium of 3D printing technologies available for the manufacture of modern medicines.