Prediction of drug permeation through microneedled skin by machine learning.

Stratum corneum is the outermost layer of the skin preventing external substances from entering human body. Microneedles (MNs) are sharp protrusions of a few hundred microns in length, which can penetrate the stratum corneum to facilitate drug permeation through skin. To determine the amount of drug delivered through skin, in vitro drug permeation testing is commonly used, but the testing is costly and time-consuming. To address this issue, machine learning methods were employed to predict drug permeation through the skin, circumventing the need of conducting skin permeation experiments. By comparing the experimental data and simulated results, it was found extreme gradient boosting (XGBoost) was the best among the four simulation methods. It was also found that drug loading, permeation time, and MN surface area were critical parameters in the models. In conclusion, machine learning is useful to predict drug permeation profiles for MN-facilitated transdermal drug delivery.

Recent progress in three-dimensionally-printed dosage forms from a pharmacist perspective.

OBJECTIVE: Additive manufacturing (AM), commonly known as 3D printing (3DP), has opened new frontiers in pharmaceutical applications. This review is aimed to summarise the recent development of 3D-printed dosage forms, from a pharmacists' perspective. METHODS: Keywords including additive manufacturing, 3D printing and drug delivery were used for literature search in PubMed, Excerpta Medica Database (EMBASE) and Web of Science, to identify articles published in the year 2020. RESULTS: For each 3DP study, the active pharmaceutical ingredients, 3D printers and materials used for the printing were tabulated and discussed. 3DP has found its applications in various dosage forms for oral delivery, transdermal delivery, rectal delivery, vaginal delivery, implant and bone scaffolding. Several topics were discussed in detail, namely patient-specific dosing, customisable drug administration, multidrug approach, varying drug release, compounding pharmacy, regulatory progress and future perspectives. AM is expected to become a common tool in compounding pharmacies to make polypills and personalised medications. CONCLUSION: 3DP is an enabling tool to fabricate dosage forms with intricate structure designs, tailored dosing, drug combinations and controlled release, all of which lend it to be highly conducive to personalisation, thereby revolutionising the future of pharmacy practice.

Micro and nanoneedles for drug delivery and biosensing.

Delivering therapeutics in a painless manner is one of the many objectives for the treatment of clinical conditions. Micro and nanoneedles are small-scale devices that can help overcome the resistance encountered during drug diffusion by creating conduits of small dimensions through biomembranes. Microneedles for drug delivery applications were manually produced until the 1990s and after this the high precision technology from the semiconductor industry was adopted for their production [ 1 ]. Over  the  last decade or so, microneedles for transdermal applications have been widely studied. Currently, microneedle patches, mainly based on hyaluronates, are available over the counter for cosmetic applications. On the other hand, nanoneedles are used in atomic force microscopy, which has been explored for drug delivery and biosensing over the last two decades [ 2 , 3 ]. Micro and nanoneedle-based biosensing also poses potential for environment-responsive drug delivery. In this article, the current research, clinical studies and future perspectives of micro and nanoneedle-based systems are discussed for drug delivery and biosensing applications.