PB designs are usually used as a screening design. This means you test a large number of variables at 2 levels each and see which ones show promise. Once you have this information, you can use a response surface to see what effect each remaining variable has on the response. PB designs all you to see linear effects and interactions. BBD allow you to see quadratic effects too. 

If you are looking at formulations, you might want to look into Mixture Designs. If you want to test more than 3 dose levels, you might want to look into Optimal Factorial Designs. They allow you to create a design that is specific to your system and test as many different dose levels as you want. 

Dear,

I would suggest these two articles for improving your understanding of DOE in formulations.

Crit Rev Ther Drug Carrier Syst. 2005;22(1):27-105.

Optimizing drug delivery systems using systematic "design of experiments." Part I: fundamental aspects.

Singh B1, Kumar R, Ahuja N.

Crit Rev Ther Drug Carrier Syst. 2005;22(3):215-94.

Optimizing drug delivery systems using systematic "design of experiments." Part II: retrospect and prospects.

Singh B1, Dahiya M, Saharan V, Ahuja N.

Dear Chetan Shinde   

In my last work, I employed L9 design for 4 factors & 3 levels & 3 responses with doing final confirmation optimum test, via Taguchi method. I explain about it, step by step in my article. You can see my article in below link.

I hope my article, would help you in your research filed.

Good Luck

http://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1092893?journalCode=tdwt20

Taguchi optimization method with explanation about ANOVA  with title "Clove oil nanoemulsion as an effective antibacterial agent: Taguchi optimization.” is available via the link below!

Article Clove oil nanoemulsion as an effective antibacterial agent: ...