A Computational Analysis to Study the Application of Lipid Nanotechnology in the Field of Drug Delivery to Treat Liver Diseases

 

Karthick J.¹, Praveen Kumar P.K.²

¹Final Year, Department of Biotechnology, Sri Venkateswara College of Engineering, Sriperumbudur

²Assistant Professor, Department of Biotechnology, Sri Venkateswara College of Engineering, Sriperumbudur

 

ABSTRACT:

The Present Study is to analyse the targeted delivery of Ursodiol, a drug used in the treatment of Primary Sclerosing Cholangitis (PSC) using Lipid Bilayer Nano-Particles or Solid Lipid Nano Particles(SLNPs) which is taken for in-silico binding studies with various 4 different liver receptors.  3 Solid Lipid Nano Particles are chosen and Binding Efficiency of the Drug with Solid Lipid Nano Particles are Studied Using DFT Analysis and FEM Analysis. It was seen that the complete drug binding is seen in Small Unilamellar Vessicle (SUV). Chosen Liver Receptors with Ursodiol of the SUV are checked for binding studies using AutoDock 4. The Study revealed that Liver X Receptor α has a greater efficiency in binding with the Solid Lipid Nano Particles.

 

 

INTRODUCTION:

Nano-Biotechnology is a combination of Nanotechnology or Nano sciences and Biotechnology and it is the recently emerged field that deals with the Nano scale Biological compounds, their structures and their predominant involvement in the living system. The important objectives are applying nano tools to relevant medical/biological problems and refining these applications and developing new tools for the medical and biological fields. Nano Imaging of biomolecules and biological membranes, cantilever array sensors’ usage in nanophotonics for manipulating molecular processes in living cells dominate the field. Using microorganisms in synthesizing functional nanoparticles has been of great interest. As with nanotechnology and biotechnology, it too has many potential ethical issues associated with it.

 

Primary Sclerosing Cholangities is a disease of bile ducts causing inflammation and subsequent obstruction of bile ducts both at intrahepatic and extrahepatic level and the cause may be due to autoimmunity. More than 80% of those with PSC have ulcerative colitis. Commonly diagnosed by endoscopic retrograde cholangiopancreatography, early detection and proper medication can cure the disease. The definitive treatment is liver transplantation but an alternative treatment is by chemotherapy, but only under certain circumstances.

 

Ursodiol, also called as Ursodeoxycholic acid and abbreviated as UDCA, is a Primary Bile Acid, stored in gall bladder and are metabolized to Secondary Bile Acid by Intestinal Bacteria. The Structure of Ursodiol is as shown in the Figure 1. Ursodiol, a drug is used for the treatment of Primary Sclerosing Cholangities. They are currently synthesized commercially and are available as Actigall, Ursosan, Ursofalk, BILIVER, Egyurso, Urso, Urso Forte, Deursil and Coric, Udiliv, Ursocol etc. They function by inhibiting apoptosis and reduce cholesterol levels and dissolves Gall stones. They are predominately used in treating common Liver Disorders and it is the common drug for almost all Primary Liver Cirrhosis. 

 

 

Solid Lipid Nano Particles (SLNPs) are spherical in shape with size 10-1000 nm and they are new Pharmaceutical Formulations or Pharmaceutical Drug Delivery Systems. As shown in Table 1, direct administration of Ursodiol might have serious symptoms in Humans, hence using SLNPs as delivery vehicles might be a correct alternative. The advantages in using SLNPs are much more than in Table 2, it is evident that future holds a good hand in SLNP research, which is evident from Figure 2.

 

MATERIALS AND METHODS:

Databases Used are

NCBI – National Centre for Biotechnological Information

RCSB – Research Collaboratory for Structural Bioinformatics.

EMBL – European Molecular Biology Laboratory.

 

Softwares used are

QUANTUM ESPRESSO: is a software suite for ab initio electronic-structure calculations and materials modeling distributed for free (under the GNU General Public License), based on Density Functional Theory for Research in Electronic Structure, Simulation, and Optimization.

 

CMISS: is a Continuum Mechanics, Image analysis, Signal processing and System Identification which is a mathematical modelling environment and 3D visualization tool that allows the application of finite element analysis, boundary element and collocation techniques to a variety of complex bioengineering problems

 

AutoDock: is a suite of automated docking tools. It is designed to predict how small molecules, such as substrates or drug candidates, bind to a receptor of known 3D structure.

 

Methodology Adopted:

In order to analyse the efficiency in Targeted delivery of drugs, the following methodology is followed.

a.       Drug-Structural Analysis:

The Structure of Synthetic Ursodiol varies a lot which depends on the synthesis method and raw materials used. For this study, the structure is obtained from ChemSpider with the ID No. 29131 (Figure 1). This is the basic structure without any R-groups added.

 

b.      Binding of Drug and SLNPs:

In order to deliver the drug efficiently, the drug should be properly bind to SLNPs and it should be inside the ball of Liposome (SLNP). About 6 different Liposomes namely Small Unilamellar Vesicle (SUV), Large Unliamellar Vesicle (LUV), Cochleate Vesicle(CV), Reverse Micelles, Micelles, Multi Lamellar Vesicle (MLV). The 3D visualization of the Drug-SLNP binding for all the 6 SLNPs are done using CMISS (as shown in Figure 3, 4, 5, 6, 7, 8 and 9) and the results are summarized using QUANTUM ESPRESSO (Table 3).

 

c.       Selection of Liver Receptors:

As there are chances for the liposomes to bind to various receptors of the liver, it was formulated to consider many liver receptors for the study. Hence around 10 different liver receptors are chosen and their significance are studied (Table 4).

d.      Docking Studies of Liver Receptor and SLNPs:

Then Docking studies were performed using AutoDock (Figure10) and the Binding Energy Scores in terms of Kcal/mol and Inhibition Constant value as K_i² were tabulated (Table 5). Then the results are summarized.

 

RESULTS:

Initial Drug-SLNP Binding study using CMISS and QUANTUM ESPRESSO show that Small Unilamellar Vessicle (SUV) have the higher Binding Capability (79.36%) and Multiple Lamellar Vessicle (MLV) has the least Binding Efficiency (32.43%).

 

Secondly, the Docking studies using AutoDock show that Docking of SUV with receptor in terms of Binding Energy scores is that Liver X Receptor α (LXR α) and Liver X Receptor β (LXR β) binding values are High and they are comparable and the Lyso Phosphatidic Acid Receptors (LPAr) has low binding scores.

 

Figure 1: Structure of Ursodiol or UDSA.

 

Figure 2: Increase in Number of Papers in Solid Lipid Nanoparticles Research. (S.Mukherjee et al.)

 

Figure 3: Binding of Drug to a SLNP. Greater the Drug size exposed, Lower the binding

 

Figure 4: MLV

Figure 5: Mcs  

 

Figure 6 and 7 :( RMcs and CV)   

 

Figure 8:(LUV)     

 

 

Figure 9:(SUV)

D74 and E202 – Terminal Ends of the Liposomes called as Lipid Chains made of Phosphotidylcholine.

 

Table 1: Side Effects of Ursodiol Usage

S.No	Side Effects of Ursodiol Usage
1.	Loss of Appetite and prolonged weight Loss.
2.	Promotes Colon Carcinogenesis, when come in contact with other bile acids like chenodeoxycholic and lithocholic acids, producing Pro-Carcinogenic Bile Acids.
3.	At inert conditions, Intestinal Bacteria degrades Ursodiol to Azoxymethane, a carcinogenic and Neurotoxic compound.
4.	Unclear Specificity of the drug, thereby leading to multiple organ Binding, thereby leaving the disease, untreated.
5.	LD50 dosage is 7.5g/kg rats and 5g/kg in mice for 7-10 days.

 

Table 2: Advantages of Solid Lipid Nano Particles (SLNPs)

S.No	Advantages of Lipid Bilayers or Liposomes or SLNPs
1.	Dissolves all Stability Issues with Pharmaceuticals
2.	Sterlizable, Improved Stability and easy to Scale-Up
3.	Avoids Organic Solvents as they are Water Based
4.	Targeted and Controlled Release of the Drug
5.	Feasible, Biodegradable and Biocompatable
6.	More Affordable than polymeric or surfactant carriers.

 

Table 3: Results of Compatibility Analysis of Drug and Liposome using QUANTUM ESPRESSO.

S.No	Name of the Liposome or SLNPs	% Compatibility
1.	Small Unilamellar Vesicle(SUV)	79.36
2.	Large Unliamellar Vesicle(LUV)	69.17
3.	Cochleate Vesicle(CV)	51.43
4.	R. Micelles	50.44
5.	Micelles	43.42
6.	Multi Lamellar Vesicle(MLV)	32.43

 

S.No	Name of the Receptor	Abbreviation	Significance
1.	Liver X Receptors α	LXR α	Important in Metabolism of Cholesterol
2.	Liver X Receptors β.	LXR β	Metabolic homeostasis of Glucose and Fatty Acids
3.	Low Density Lipoprotein receptor.	LDLr	A mosaic Protein involved in endocytosis of Cholesterol-Rich LDL
4	Sterol Regulatory Element-Binding Protein	SREBP	Trancription factors binding to the Sterol
5.	SREBP Cleavage Binding Protein.	SREBP-2/SCAP	Sterol Regulatory Binding Protein of Cholesterol Depleted Cells.
6.	Thyroid Hormone Receptor-Like Receptors	THRLr	Key role in Innate immunity System
7.	Lyso Phosphatidic Acid Receptors	EDG or LPA	Act Like GPCRs, Involved in cell growth and Proliferation
8.	Hepatocyte Specific CB1 (CannoBinoid) Receptors	HSCBr	Maintenance of Lipid and fatty acid Profile
9.	Toll-Like Receptors	TLRs	Important in Thyroid hormone Binding. Involved in maintaining Blood Flow
10.	Asialo Glyco Protein Binding Receptor	ASGPr	Significant Glycoprotein Binding Receptors

 

 

 

S.NO	Name of the Receptor	Binding Energy (Kcal/Mol))	Inhibition Constant Ki2
1.	LXR α	-6.65	18
2.	LXR β	-6.6	21
3.	LDLr	-6.0	38
4.	SREBP	-6.0	59
5.	SREBP-2/SCAP	-5.5	66
6.	THRLr	-4.3	74
7.	EDG or LPA	-3.9	89
8.	HSCBr	-2.1	93
9.	TLRs	-1.4	103
10.	ASGPr	-0.8	174

 

CONCLUSIONS:

Hence this study gave us In-Depth Knowledge about the Binding of the drug for Liver cirrhosis, Ursodiol with various Liposomes and further the docking studies of SUV with that of Various Liver Receptors.

 

REFERENCES:

1.       Essmann U, Perera L and Berkowitz M.L. The Origin of the Hydration Interaction of  Lipid Bilayers from Md Simulation of Dipalmitoyl phosphatidyl choline Membranes in Gel and Liquid-Crystalline Phases, Langmuir. 11: 1995; 4519–4531.

2.       Damodaran KV, Merz K.M and Gaber BP. Structure and Dynamics of the Dilauroyl phosphatidyl ethanolamine Lipid Bilayer. Biochemistry. 3: 1992; 7656–7664.

3.       Yang SC, Lu LF, Cai Y, Zhu JB, Liang BW and Yang CZ. Body distribution in mice of intravenously injected camptothecin solid lipid nanoparticles and targeting effect on brain. Journal of Control Release. 59: 1999; 299-307.

4.       Brenner DW, Sherendova OA and Areshkin A: Quantum Based Analytic Interatomic Forces and Materials Simulations. Reviews in Computational Chemistry. 213-245.

5.       Car R and Parrinello M. Unified Approach for Molecular Dynamics and Density Functional Theory. Physics Review Letters. 55; 1985: 2471-2474.

6.       Klimeck G, Oyafuso F, Boykin TB , Bowen CR and Allmen P V. Development of a Nanoelectronic 3-D (NEMO-3D) Simulator for Multimillion Atom Simulations and its Applications to Alloy Quantum Dots, CMES-Computer Modeling in Engineering and Sciences. 3(5); 2002: 601-642.

7.       Rudolph C, Schillinger U, Ortiz A, Tabatt K, Plank C and Muller RH, et al. Application of novel Solid lipid nanoparticles (SLN)- gene vector formulations based on a diametric HIV-1 VAT – peptide in vitro and in vivo. Pharmaceutic Research. 21(9); 2004: 1662-1669.

8.       Hayes ME, Drummond DC and Kirpotin DB. Self-assembling nucleic acid-lipid nanoparticles suitable for targeted gene delivery. Gene Therapy. 13; 2006: 646-651.

9.       Pedersen N, Hansen S, Heydenreich AV, Kristensen HG and Poulsen HS. Solid lipid nanoparticle can effectively bind DNA, streptavidin and biotinylated ligands. European Journal of Pharmacy and Biopharmaceutical. 62; 2006: 155-162.

10.     Mei Z and Wu Q. Triptolide loaded solid lipid nanoparticle hydrogel for topical application. Drug Development in Indian Pharmacy. 31; 2005: 161-168.

11.     Wilson EK. Computational nanotechnology - Modeling and theory are becoming vital to designing and improving nanodevices. Chemical Engineering News. 81; 2003: 27–29.

12.     Barnard AS. How can AB initio simulations address risks in nanotech? Natural Nanotechnology. 4; 2009: 332-335.

13.     Jenning V, Gysler A, Schafer-Korting M and Gohla SH. Vitamin A loaded solid lipid nanoparticles for topical use: occlusive properties and drug targeting to the upper skin. European Journal of Pharmacy and Biopharmaceutical. 49; 2000: 211-218.

14.     Mukherjee.S, Ray.S and Thakur. R.S Solid Lipid Nanoparticles: A Modern Formulation Approach in Drug Delivery System. Indian Journal of Pharmaceutical Sciences. 3; 2011: 323-354.

 

 

Received on 24.08.2013                             Accepted on 01.09.2013        

©A&V Publications all right reserved