Performance Parameters and Characterizations of Nanocrystals: A Brief Review

Abstract

Poor bioavailability of drugs associated with their poor solubility limits the clinical effectiveness of almost 40% of the newly discovered drug moieties. Low solubility, coupled with a high log p value, high melting point and high dose necessitates exploration of alternative formulation strategies for such drugs. One such novel approach is formulation of the drugs as “Nanocrystals”. Nanocrystals are primarily comprised of drug and surfactants/stabilizers and are manufactured by “top-down” or “bottom-up” methods. Nanocrystals aid the clinical efficacy of drugs by various means such as enhancement of bioavailability, lowering of dose requirement, and facilitating sustained release of the drug. This effect is dependent on the various characteristics of nanocrystals (particle size, saturation solubility, dissolution velocity), which have an impact on the improved performance of the nanocrystals. Various sophisticated techniques have been developed to evaluate these characteristics. This article describes in detail the various characterization techniques along with a brief review of the significance of the various parameters on the performance of nanocrystals.

A Comparative Study of the Effect of Different Stabilizers on the Critical Quality Attributes of Self-Assembling Nano Co-Crystals

“…The lower melting temperature and peak broadening for the nano co-crystal is likely due to particle size reduction and is in agreement with the principles of the Van't Hoff equation [52][53][54]. In addition, slight peak broadening can be attributed to a loss crystallinity and partial formation of amorphous material during the formation of nanosuspensions [55,56].…”

Bioavailability Enhancement of Poorly Water-Soluble Drugs via Nanocomposites: Formulation–Processing Aspects and Challenges

“…Nanosuspension characterization methods have been discussed in several review papers [ 23 , 28 , 94 ]. In this section, we briefly review various characterization methods for the characterization of the nanocomposites.…”

“…Kesisoglou et al [ 28 ] described the principles of nanosizing, production, and characterization of nanoformulations, and in vivo impact of these formulations. Chogale et al [ 94 ] mainly described characterization techniques for various characteristics of nanocrystals (particle size, saturation solubility, dissolution velocity), which have an impact on the improved performance of nanocrystals. Peltonen and Hirvonen [ 95 ] presented the most important properties of nanocrystalline drug compounds, with multiple examples of the development and characterization of nanocrystalline drug formulations and a focus on the role of higher saturation solubility.…”

“…The organization of this review paper closely follows the sequence of preparation steps in Figure 1 . Section 2 presents a short review of various approaches used for the preparation of drug nanosuspensions; the characterization of nanosuspensions is not discussed at length, as several review papers cover this topic in detail; readers are referred to these review papers and the references cited therein [ 23 , 55 , 94 ]. Section 3 presents a comprehensive review of various drying methods, methods for characterizing the drug-laden nanocomposites including the newly developed redispersion test methods, and formulation aspects such as functionalities of dispersants and their impact on redispersion/drug dissolution.…”

Montelukast Nanocrystals for Transdermal Delivery with Improved Chemical Stability

“…In formulating drug nanosuspension, the types of dispersants and the interactions with the drug nanocrystals highly influence the colloidal stability in the vehicle [21]. Thus, different stabilizers, including hydrophilic polymers and surfactants were screened to formulate MTK nanosuspension based on the aspects of crystal size, homogeneity, and dispersibility.…”