Drug discovery is so incredibly complex and so poorly understood that synthesising two actives into a singe, dual active is unlikely to work.  A lot of this has to do with the promiscuity of the receptors and also the symmetry of the two receptors as similar receptors are likely have similar function.

This duality approach begs the question.  Why is this attractive?  First, you would have a dual acting drug that may be administered at lower doses.  This is particularly attractive for chemotherapy where treatments are likely to have high toxicity.  The next question is one of synergism.  Is there another advantage to administering one drug instead of two?  There may be, but probably not.  More than likely you will be diminishing the efficacy of  both bioactive moieties as the key no longer fits the lock as well.    

The only exception to this rule are psychoactives.  Studies show a desired effect and then those tasked with drug discovery make a hypothesis on the MOA.  Hence, you have drugs that inhibit serotonin reuptake but some secondary action with norepinephrine receptors.  There may be some level of reconstitued biochemistry in vitro, but It's my suspicion that these MOA's are merely postulated.  After all, the FDA only requires you show saftey and efficacy, MOA is not required.

So to sum up, you can try to create such a drug, but I would be very surprised if it worked.

-Best

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.

Generally you combine two biological targets only if they have some synergistic effect. E.g. target two parts of the cancer cell cycle. However, diabetes and cancer is pretty far off...

- "Can two structure merges or attached to make new drug with effect of both molecule"

It is a very big question.

First of all, one molecule can have both antidiabetic and anticancer activities (and even more). For example, it is possible on the condition that the target or targets, which are affected by this molecule, have important role for both deseases development. It is very superficial explanation, though. But you can find a lot of studies dedicated to this problem. Searching for the data on metformin is a good starting point.

About merging distinct molecules together. The Simplier way to achieve multiple effects is mixing two or more compounds in one pill. But, as far as I know chemical merging may be beneficial in some cases, you can check this for more info:

http://pubs.acs.org/doi/abs/10.1021/ar7000843

- "Or simple method to determine this.Can be check with any software for particular disease or suggest easiest ,reliable and easily available method for the same."

You can try some docking and/or molecular dynamics tools. Since you have two active molecules and you connect them together typically through a linker, you need to be sure that your dual action drug retain the possibility to fit the initial binding pockets.

Hope this helps

I agree with all the comment above.

Designing a chimeric drug from distinct entities in order to obtain a pleiotropic desirable pharmacological profile is a formidable challenge. Few attempts have been described in research publications as stated above. See also

Proc Natl Acad Sci U S A. 2014 Sep 9;111(36):E3825-30. doi: 10.1073/pnas.1410315111. Epub 2014 Aug 25.

Design of donecopride, a dual serotonin subtype 4 receptor agonist/acetylcholinesterase inhibitor with potential interest for Alzheimer's disease treatment.

Beside the problem of designing the right molecular chimera, all the issues of distribution at the desired sites with the correct concentration for each target have to be adressed. I am not aware of any specific software to do this routinely.

you can try using pharmacophore modelling approach.One of the approach is Ligand-Based pharmacophore modelling which is you will be using establish drug molecule as example diabetic drug and created the pharmacophore model of the established drug and try overlapping and align the organic molecules with the drug. 

There are several ways or software for activity prediction for drug like molecules, some are weak not totally reliable, but still can be used for prediction such as Lipiniski's rule (rule of five), please read about it it may help

Thanks for ur suggestions.

PASS software predict biological activity from structure (not 100% reliable but quite good.)