SAFETY PHARMACOLOGY AND ITS IMPORTANCE(RENAL SAFETY PHARMACOLOGY)

1. Submitted By-: Jai Bhim
M Pharm (Pharmacology)
Department of pharmaceutical
Science
SAFETY PHARMACOCOLOGY AND ITS
IMPORTANCE
Babasaheb Bhimrao Ambedkar A Central University
Lucknow (226025)

2. Safety pharmacology (SP) is an essential part of the drug development process that aims to
identify and predict adverse effects prior to clinical trials.
SP studies are described in the International Conference on Harmonisation (ICH) S7A and S7B
guidelines.
 The core battery and supplemental SP studies evaluate effects of a new chemical entity (NCE)
at both anticipated therapeutic and supra-therapeutic exposures on major organ systems,
including cardiovascular, central nervous, respiratory, renal and gastrointestinal. This review
outlines the current practices and emerging concepts in SP studies including frontloading, parallel
assess ment of core battery studies, use of non-standard species, biomarkers, and combining
toxicology and SP as assessments. Integration of the newer approaches to routine SP studies may
significantly enhance the scope of SP by refining and providing mechanistic insight to potential
adverse effects associated with test compounds.
INTRODUCTION

3. The core battery SP studies, performed according to good laboratory practice (GLP)
standards as per the ICH guidelines, involves the investigation of the major vital organ
systems including :-
 Cardiovascular system (CVS)
 Central nervous system (CNS)
 Respiratory system
 supplemental studies investigating including :-
Renal System
 Gastrointestinal system

4. Objective of safety
Pharmacology
According to ICH S7A:-
1- To identify undesirablre pharmacodynamic properties of a substances.
2- To evaluate adverse pharmacodynmic and pathophysiological effect of a substance .
3- To investigate the mechanism of action of a adversse pharmacodynamic effect .

5. SAFETY REASON FOR DRUG
WITHDRAAWAL
USA withdrawal (95 medicine) Percentage
Cardiac toxicity
Incl. Arrythmias
19
12
Neuropsychiatric effect/abuse
liability/dependency
12
Hepatic toxicity 9
Bone marrow toxicity 7
Allergies reaction 6

6. Renal system
The kidney is a complex excretory organ playing a crucial role in various
physiological processes such as fluid and electrolyte balance, control of blood
pressure, removal of waste products, and drug disposition. Drug-induced kidney
injury (DIKI) remains a significant cause of candidate drug attrition during drug
development.

7. Methods to Assess Drug Effects on Renal Function
In vivo mammalian models
In vivo non mammalian models
In vitro models
In silico models

8. In vivo mammalian model
Rats, dogs, monkeys, and (mini-)pigs are the most common species used to assess
both excretory function and hemodynamic function of the kidneys. Renal function
assessment is mainly based on the analysis of urine and/or plasma samples and is
ideally conducted in conscious, freely moving animals, to better mimic physiological
conditions. Urine collection for quantitative analysis requires either urinary
bladder catheterization (feasible in large animals only) or use of metabolism cages
(in rodents mainly but also sometimes used for dogs and NHP) allowing urine
volume determination and collection of fractions over defined periods of time (e.g.,
0–8 h, 8–24 h, etc.).

9. Glomerular Function
The GFR can be estimated by clearance measurements of endogenous or exogenous
small molecules (urea, creatinine, 2-MPT, inulin, cystatin C, iohexol, or iodixanol).
An ideal marker of GFR should be primarily excreted by the kidneys, freely filtered
by the glomerulus, and neither secreted nor reabsorbed by the tubule. It should also
be supplied to the plasma at a constant rate and exhibit no or minimal protein
Binding. FITC-sinistrin (fluorescein isothiocyanate 1-sinistrin; active pharmaceutical ingredient
of the commercially available GFR marker in conscious animals. This allows the measurement
of the clearance of FITC-sinistrin from the plasma in real time without the need for any blood
sampling and thus is a means of measuring GFR with a much lower burden on the
individual animal.

10. Tubular Function
If plasma markers provide relevant information about the level of renal perfusion and
functional mass, the analysis of urine allows the identification of the functional status of
particular nephron segments. In general toxicology studies, routine urinalysis usually
includes visual assessment of urine (color, clarity), volume, specific gravity or osmolality,
pH, quantitative or semiquantitative protein, and glucose content. Dipstick test strips as used
in human medicine also include the determination of other parameters, such as ketones,
bilirubin,urobilinogen, hemoglobin, etc. For example, glucosuria in the absence of increased
plasma glucose indicates a functional defect of the proximal tubule.

11. Hemodynamic Function
Renal blood flow (RBF) can be measured either directly or indirectly. Direct
measurement requires the placement of a flow probe around the renal artery,
which is technically difficult in rats due to their small size. Therefore, renal
hemodynamic studies are rather conducted in large animal species such as dogs,
(mini-)pigs, and nonhuman primates, due to the easy surgical accessibility of kidneys and
vessels. RBF assessment is usually coupled with systemic blood
pressure monitoring, using a pressure catheter placed into an artery (e.g., femoral).
These probes can be exteriorized via a connector or a vascular access port. Telemetry
avoids exteriorization of these probes and therefore induces less risk of
infections or postoperative complications. It also allows the animals to be kept
over long periods of time, and thus, they can be reused across successive studies.
Another hemodynamic endpoint is the renal vascular resistance (RVR), calculated
as the ratio between RBF and mean arterial pressure (MAP). RVR can be increased
in case of renal dysfunction or in case of systemic hypertension.

12. In Vivo Non-mammalian Models
The zebrafish (Danio rerio) larva has gained increasing interest over the last decade
as an alternative to mammalian in vivo models (Redfern et al. 2008). The zebrafish
kidney is genetically and morphologically close to that of mammals, except that the
pronephros of larvae consists only of a fused glomerulus with one nephron on each
side. While previous investigations of renal function were limited to morphological
studies, new techniques have emerged more recently, which allow functional
investigations, such as renal clearance and cardiovascular flow. Assessments were
based on measurements of FITC-inulin intensity in the caudal artery and excreted

13. In Vitro Models
Renal slice technology has been extensively exploited for pharmacology and
safety assessments. This technique involves the removal of longitudinal sections of
kidney tissue using a precise-cut microtome. Dog, rat, and rabbit kidneys are the
most frequently used, but renal slices of human origin have started to be used more
recently. Over other in vitro cellular models, renal slices offer the advantage to keep
the architecture and cell heterogeneity of the whole organ, as well as surrounding
interstitial and vascular elements. They are functionally able to transport ions, to
maintain sodium and potassium balance, and to exhibit cell–cell interactions. They
can be used for short-term (up to a few hours) or long-term (up to 48 h) incubation
with test drugs. The primary endpoints of renal slices are metabolic function or
morphologic analysis, which can be coupled with gene expression and biomarker
Analysis.

14. In Silico Models
The SAPHIR project (a Systems Approach for PHysiological Integration of Renal, cardiac,
and respiratory functions), initiated in 2008 under the 6th European Framework Program,
provides a prototype core model of human physiology targeting the short- and long-term
regulation of blood pressure, body fluids, and homeostasis of the major solutes . It also
includes the main regulatory sensors (baro- and chemoreceptors) and nervous (autonomic
control)and hormonal regulators (antidiuretic hormone, aldosterone, and angiotensin).

15. Biomarkers of Kidney Injury
Qualified Biomarkers
KIM-1 is a type I cell membrane glycoprotein which contains, in its extracellular
portion, a six-cysteine immunoglobulin-like domain, two N-glycosylation sites, and
a T/SP-rich domain characteristic of mucin-like O-glycosylated proteins. KIM-1 confers on
epithelial cells the ability to recognize and phagocytose dead cells that are present in the
postischemic kidney and contribute to the obstruction of the tubule lumen that characterizes
acute kidney injury.
The secreted isoform of clusterin (CLU) is a 76–80-kDa glycosylated protein
with extensive posttranslational modifications, such as glycosylation, cleavages,
and dimerization. In the context of kidney injury, CLU has been suggested to play
an antiapoptotic role and to be involved in cell protection, lipid recycling, cell
aggregation, and cell attachment.

16. TFF3, TFF1, and TFF2 are small peptide hormones secreted by mucus producing
cells, and by epithelial cells of multiple tissues, in mammals. By inhibiting apoptosis and
promoting survival and migration of epithelial cells into lesion.
β2-Microglobulin is a 12-kDa polypeptide chain that is constantly synthesized throughout
the body.
CysC is a non-glycosylated low-molecular-weight protein of 13 kDa continuously
produced by all nucleated cells. CysC is directly filtered from blood in the glomerulus, and
its serum levels are an ideal estimator of the glomerular filtration rate.
Albumin is a major serum protein and is often the most abundant protein found in urine
during renal injury.

17. Novel Exploratory Biomarkers
miR181a and miR34a, may be indicative of proximal and distal tubular injury.
Current and Future Industry Practices with Respect
to Renal Safety Pharmacology
As stated previously, the ICH S7A recommendations state that the preclinical
investigation of renal effects under the remit of safety pharmacology is
supplementary and should only be performed when renal safety issues are
suspected on a “cause for concern” basis (Anon. 2001). Therefore, assessment of
renal function might not be performed by all companies.

18. Importance Of pharmacology
1- Hazard prediction.
2-Hazard identification.
3-Risk assessment.
4-Risk management and mitigation.
Scope of Safety pharmacology
1-New chemical entities.
2-Biotechnology derived product
3-Marketed pharmaceuticals when appropriate.

20. Reference:-
MichaelK.Pugsley;”Principle of safety pharmacology”, Springer Heidelberg New
York Dordrecht London,volume 229,pp 329-345.