Nanoparticles for drug delivery: Insight into in vitro and in vivo drug release from nanomedicines

Nanotechnology enables the achievement of the desired outcomes of nano-formulations, and the mode of drug delivery from the nanoparticles can significantly impact the efficacy of the embedded drug. This article reviews the various types of nanoparticles, methods of evaluating the drug release, in vitro-in vivo correlation, and regulatory challenges associated with nano-formulations. Nanoparticles have been classified into organic, inorganic, and hybrid nanoparticles. Several techniques, such as separated flow, continuous flow, and dialysis methods, have been utilized to assess nano-formulations' in vitro release. In vivo drug release evaluations in biological systems have also been demonstrated. Such evaluations often involve experimental models for the distribution of the nanoparticles, hematology, clearance, histopathology, and serum chemistry. Protein binding, enzymatic degradation, lipid absorption, carbohydrate absorption, and attachment to nucleic acid are some factors shown to affect drug release. In vitro-in-vivo correlation (IVIVC) involves the analysis of the drug release results and mathematical correlations. Factors such as the physicochemical properties of the nanoformulations, the subject’s physiological properties, and the formulation’s biopharmaceutical properties relative to the subject usually affect the correlation. Unlike previous reviews, this article uniquely combines mechanistic insights, production methods, stimuli-responsive systems, and regulatory considerations into a single reference, thereby offering a practical and translational perspective for researchers and formulators. This review also identifies current gaps in IVIVC standardization and highlights opportunities for advancing nanoformulation safety and efficacy. • Nanodrug delivery systems remain pivotal in the management and treatment of chronic diseases. • Evaluation of the in vitro and in vivo drug release from nanomedicines is one of the most important analyses to be carried out as the efficacy, safety and dosage of the nanomedicine to be administered relies on it. • Certain analytical tools and experimental models may be utilized to evaluate these parameters. • Correlation of the invitro and invivo drug release from nanomedicines still remains a challenge due to their complexities and inadequate regulatory guidelines. This is a call on research experts, regulatory and government agencies to put forth these guidelines concerning IVIVC for nanomedicines. • The continual use of nanomedicines would require a deeper exploration of their safety concerns and implications.