Novel Molecular Target Discovery

Novel Molecular Target Discovery

Introduction

Target oriented drug delivery systems are the areas of the major interest in the modern pharmaceutical research. The Selective drug delivery to the target tissues increases the therapeutic efficacy of the drug and reduces its undesirable effect to non-target tissues. The main goal of a site specific drug delivery system is not only to increase the selectivity and drug therapeutic index, but also to reduce the toxicity of the drug.

 Rheumatoid arthritis (RA) is a chronic, inflammatory condition of unknown eitiology that affects about 1% of general population and is the most common cause of chronic inflammatory synovitis .Although spontaneous remission can occur, it often progresses to chronic state associated with significant functional disability (Geletka and Clair, 2003). A number of drugs are used in the treatment of RA over the past 10 -20 years. An ideal therapy in RA should ameliorate disease, prevent the development of extra-articular  complications such as vasculitis, serositis and lung fibrosis and prevent premature death .

Definition of novel drug :

A novel drug delivery system is a system that offers multiple drug delivery solutions such as:

·        Oral Drug Delivery Systems and Materials

·        Parenteral and Implant Drug Delivery Systems

·        Pulmonary and Nasal Drug Delivery

·        Trans mucosal Drug Delivery

·        Transdermal and Topical Drug Delivery

·        Delivery of Proteins and Peptides

·        Drug Delivery Pipelines

·        Drug Delivery Deals

Drug discovery:

In the fields of medicine, biotechnology and pharmacology, drug discovery is the process by which new candidate medications are discovered.

Historically, drugs were discovered through identifying the active ingredient from traditional remedies or by serendipitous discovery. Later chemical libraries of synthetic small molecules, natural products or extracts were screened in intact cells or whole organisms to identify substances that have a desirable therapeutic effect in a process known as classical pharmacology. Since sequencing of the human genome which allowed rapid cloning and synthesis of large quantities of purified proteins, it has become common practice to use high throughput screening of large compounds libraries against isolated biological targets which are hypothesized to be disease modifying in a process known as reverse pharmacology. Hits from these screens are then tested in cells and then in animals for efficacy. Even more recently, scientists have been able to understand the shape of biological molecules at the atomic level, and to use that knowledge to design (see drug design) drug candidates.

Modern drug discovery involves the identification of screening hits, medicinal chemistry and optimization of those hits to increase the affinity, selectivity (to reduce the potential of side effects), efficacy/potency, metabolic stability (to increase the half-life), and oral bioavailability. Once a compound that fulfills all of these requirements has been identified, it will begin the process of drug development prior to clinical trials. One or more of these steps may, but not necessarily, involve computer-aided drug design.

Despite advances in technology and understanding of biological systems, drug discovery is still a lengthy, "expensive, difficult, and inefficient process" with low rate of new therapeutic discovery.

Advantage of Novel Drug Delivery System :

1)  Improved patient compliance resulting from the reduction in the frequency of  doses required to maintain the desired

therapeutic response.

2)  Targeting of the drug molecule towards the tissue (or) organ reduces the toxicity to the normal tissues.

3)  Pulsatile and pH dependent systems release the drug whenever the body demands.

4)  Biocompatibility.

5)  Economic and better savings are claimed from better disease management achieved with this system.

Disadvantage of novel drug delivery system:

Through there are number of advantages in NDDS system, there are a few factors that limit its usage.

1.  Variable physiological factors such as gastrointestinal pH, enzyme activities, gastric and intestinal transit rates. The food and severity of patient’s disease often influences drug bioavailability from conventional dosage forms and may interfere with the precision of control release and absorption of drug from such system.

2.  The products which tend to remain intact may get lodged at some sites. If this occurs, slow release of the drug from the dosage form may produce a high localized concentration of drug causing local irritation.

3.  The drugs having biological half-life of 1 hr. or less are difficult to be formulated as sustained release formulations. The high rate of elimination of such drugs from the body needs an extremely large maintenance dose which provides 8-12 hrs of continuous therapy.

4.  These products normally contain a large amount of drug. There is a possibility of unsafe over dosage, if the product is improperly made and the total drug contained therein is released at one time or over too short time interval.