Journal of Drug
Nanopartcles for Improved Delivery of Poorly Soluble Drugs
Vijaykumar Nekkant
*
and Javier Rueda
Department of Pharmacy, Western University of Health Sciences, Pomona, CA, USA
www.verizonaonlinepublishing.com
J. Drug 1(1). Page | 18
*Corresponding author: Vijaykumar Nekkant, Ph.D. College of Pharmacy, Western University of Health Sciences, 309 E. Second Street,
Pomona, CA 91766, USA; Tel: (909) 469-6476; Fax: (909) 469-5600; Email: vnekkant@westernu.edu
Artcle Type: Review, Submission Date: 05 February 2016, Accepted Date: 07 March 2016, Published Date: 20 April 2016.
Citaton: Vijaykumar Nekkant and Javier Rueda (2016) Nanopartcles for Improved Delivery of Poorly Soluble Drugs. J. Drug 1(1): 18-27.
Copyright: © 2016 Vijaykumar Nekkant and Javier Rueda. This is an open-access artcle distributed under the terms of the Creatve
Commons Atributon License, which permits unrestricted use, distributon, and reproducton in any medium, provided the original
author and source are credited.
Vol: 1, Issue: 1
Abstract
Nanoparticle based drug products are of growing interest in
the feld of pharmaceutics. Enhancing saturation solubility
and dissolution velocity by preparing drug nanoparticles
correlates with faster absorption rates. Te faster absorption
rates can correlate into better bioavailability, reduction in fed
and fast efects and inter-subject variability with improved
therapeutic response. Drug nanoparticles have shown potential
applications in developing several oral and parenteral dosage
forms with improved therapeutics. Suitable formulations for
the commonly used routes of administration can be identifed
employing nanoparticle technology. Drug nanoparticles provide
the discovery scientist an alternate avenue for screening and
identifying a superior drug delivery system. For toxicologist, the
approach provides a means for dose escalation with minimum
amount of drug substance. In the recent years, formulating
poorly water-soluble compounds using a nanoparticulate
approach has evolved from a conception to a realization whose
versatility and applicability are being vastly recognized. In the
present review, industrially relevant production technologies are
critically reviewed. Te nanoparticle characterization techniques
and potential challenges involved in the development of drug
nanoparticles were discussed in detail.
Introducton
With the advent of new technologies in drug discovery,
combinatorial chemistry, and computer aided drug design,
there was an exponential increase in the development of new
chemical entities with good therapeutic potential. However
because of the complex chemistry, nearly 40% of the drug
candidates in the development pipeline and about 60% of new
drugs produced by chemical synthesis are associated with poor
aqueous solubility resulting in low and variable bioavailability
[1,2]. Te poor solubility of drug may result in sub-optimal
dosing and concomitantly poor therapeutic response. Parenteral
administration of poorly soluble drugs as microsuspensions (e.g.
i.m. or i.p.) ofen fails to achieve required drug concentration
levels due to limited volume of solute at the site of injection. Tey
are instances wherein the solubilizing agents used to improve the
solubility of drug have resulted in allergic and toxic reactions.
For example, Cremphor EL used as solubilizing agent in Taxol
®
formulation have shown some adverse efects such as allergic
shock [3].
Te commonly used approach to overcome poor aqueous
solubility is by preparation of salts that had limited success. From
a formulation stand point, a crystalline salt is preferred foreseeing
the potential physical and chemical stability issues associated
with an amorphous form of drug substance. Identifcation of
a crystalline salt with adequate aqueous solubility requires
screening of various counter-ions and crystallization conditions
and at times isolation of a crystalline material itself is a tough
task. In some instances the salt formed may be highly hygroscopic
posing formulation challenges during drug product development
[1].
An alternate approach is to identify analogs or prodrugs with
enhanced solubility. Tis approach was not successful since the
chemically modifed drug molecule is ofen abandoned in its
early phase of development or the drug product is launched with
suboptimal properties including poor bioavailability, fed and
fast variability, lack of optimal dosing, presence of excipients at
high concentrations that pose limitations with respect to dose
escalation, and ultimately, poor therapeutic outcome. Generally,
chemical modifcation methods are expensive compared to
manipulation of drug with formulation strategies because once the
chemical structure is modifed, the associated pharmacological
activity may not be same and it is expensive to re-demonstrate
the efcacy and safety of the chemically altered drug. Terefore,
screening of suitable formulation technology for improving
the therapeutic performance of drug is a preferred approach to
develop a viable product for poorly soluble drug [4].
At present, they are limited formulation approaches available
to address the problems associated with drug’s poor aqueous
solubility and bioavailability. Te most commonly used
approaches are incorporation of drug into complexing agents
(cyclodextrins), using lipid carriers (liposomes, self-emulsifying
systems), micronization, and solid dispersions of the drug
in water-soluble carriers, etc. However the success of these
techniques is mostly dependent on specifc properties of drug
molecule therefore, have limited scope for general application.
For example, ability to ionization, solubility in oils, lipids,
molecular size, structure and shape to ft into the hydrophobic
cavities, etc. Liposomes have demonstrated reasonable success in
formulating poorly soluble drugs however because of the poor
stability issues and expensive product costs, these approaches are
not suitable for all the drugs, particularly of those which are not