3D printing is a method of rapid prototyping and manufacturing in which materials are deposited onto one another in layers to produce a three-dimensional object. Although 3D printing was developed in the 1980s and the technology has found widespread industrial applications for production from automotive parts to machine tools, its application in pharmaceutical area is still limited. However, the potential of 3D printing in the pharmaceutical industry is now being recognized. The ability of 3D printing to produce medications to exact specifications tailored to the needs of individual patients has indicated the possibility of developing personalized medicines. The technology allows dosage forms to be precisely printed in various shapes, sizes and textures that are difficult to produce using traditional techniques. However, there are various challenges associated with the proper application of 3D printing in the pharmaceutical sector which should be overcome to exploit the scope of this technology. In this review, an overview is provided on the various 3D printing technologies used in fabrication of complex dosage forms along with their feasibility and limitations.

Buccal drug delivery is a suitable alternative to invasive routes of drug administration. The buccal administration of insulin for the management of diabetes has received substantial attention worldwide. The main aim of this study was to develop and characterize elastic liposomes and assess their permeability across porcine buccal tissues. Sodium-cholate-incorporated elastic liposomes (SC-EL) and sodium-glycodeoxycholate-incorporated elastic liposomes (SGDC-EL) were prepared using the thin-film hydration method. The prepared liposomes were characterized and their ex vivo permeability attributes were investigated. The distribution of the SC-EL and SGDC-EL across porcine buccal tissues was evaluated using confocal laser scanning microscopy (CLSM). The SGDC-EL were the most superior nanocarriers since they significantly enhanced the permeation of insulin across porcine buccal tissues, displaying a 4.33-fold increase in the permeability coefficient compared with the insulin solution. Compared with the SC-EL, the SGDC-EL were better at facilitating insulin permeability, with a 3.70-fold increase in the permeability coefficient across porcine buccal tissue. These findings were further corroborated based on bioimaging analysis using CLSM. SGDC-ELs showed the greatest fluorescence intensity in buccal tissues, as evidenced by the greater shift of fluorescence intensity toward the inner buccal tissue over time. The fluorescence intensity ranked as follows: SGDC-EL > SC-EL > FITC–insulin solution. Conclusively, this study highlighted the potential nanocarriers for enhancing the buccal permeability of insulin.