RESUMEN
A three-dimensional (3D) printing is a robotically controlled state-of-the-art technology that is promising for all branches of engineering with a meritorious emphasis to biomedical engineering. The purpose of 3D printing (3DP) is to create exact superstructures without any framework in a brief period with high reproducibility to create intricate and complex patient-tailored structures for organ regeneration, drug delivery, imaging processes, designing personalized dose-specific tablets, developing 3D models of organs to plan surgery and to understand the pathology of disease, manufacturing cost-effective surgical tools, and fabricating implants and organ substitute devices for prolonging the lives of patients, etc. The formulation of bioinks and programmed G codes help to obtain precise 3D structures, which determines the stability and functioning of the 3D-printed structures. Three-dimensional printing for medical applications is ambitious and challenging but made possible with the culmination of research expertise from various fields. Exploring and expanding 3DP for biomedical and clinical applications can be life-saving solutions. The 3D printers are cost-effective and eco-friendly, as they do not release any toxic pollutants or waste materials that pollute the environment. The sampling requirements and processing parameters are amenable, which further eases the production. This review highlights the role of 3D printers in the health care sector, focusing on their roles in tablet development, imaging techniques, disease model development, and tissue regeneration.
RESUMEN
The present study assessed the effect of retention on ex vivo skin and in vivo scalp penetration of radiolabeled minoxidil formulations (5% w/v). Minoxidil was radiolabeled with technetium (99mTc) with an efficiency of 99.1% using 0.2% stannous chloride as reducing agent at pH 6 and incubation temperature of 40 °C. Three different 99mTc-minoxidil formulations were prepared using aqueous ethanolic solution as vehicle. Formulation A contains 99mTc-minoxidil dissolved in vehicle, formulation B contains 10% propylene glycol (PG) and formulation C contains 10% hydroxypropyl cellulose (HPC), in addition. Results showed that addition of HPC resulted in enhanced viscosity (400 mPa.s) and significantly higher ex vivo retention (p < 0.05) and permeation (0.75±0.12%, 8 h). PG does not improve the permeation and the results (0.44±0.05%, 8 h) were not significantly different from vehicle alone (0.40±0.05%, 8 h). The results of the in vivo human scalp studies corroborated with the ex vivo results and addition of hydroxypropyl cellulose (HPH) showed significantly higher (p < 0.05) scalp retention. Post 8 h application, scalp penetration in group treated with formulation C was nearly 2.8-fold and 2.2-fold higher than those treated with formulation A and B, respectively. Further, absence of minoxidil in systemic circulation during study duration indicates safety. In conclusion, our results showed that increasing contact time of minoxidil with scalp by modifying viscosity results in reduced frequency of application and improved efficacy.