Walgreens Boots Alliance Inc.'s mega acquisition to the tune of $70 billion would be one that is right from the textbook of Stefano Pessina.

While the reasons behind the company's informal talks with private equity firms, including KKR & Co, remain unclear as the drugstore chain's chief executive and largest shareholder, Pessina was undoubtedly at the center.

Without the support of the Italian billionaire who owns 16 percent of the group, any deal would be impossible.

Pessina has been developing his drug manufacturing and sales empire by swashbuckling transactions for more than 40 years. He was patient and added piece by piece to the group.

But he was opportunistic as well. He may have spotted his chance to extract the group from the public markets with shares in Walgreens down by about 24 percent over the past year.

He's actually been here before. Pessina merged with Boots in 2006 with his company Alliance UniChem. A year ago, in a $16 billion transaction, Europe's biggest buyout at the moment, he took the combined company private - to KKR.

It would dwarf Alliance boots to acquire Walgreens. A variety of financial partners and substantial debt financing will probably be needed.

The debt of Walgreens is already quite humongous. Net debt at the end of the current financial year will be about 1.8 times Ebitda, according to Bloomberg analyst estimates.

Cash is created by the retail business. Even so, maybe this isn't the perfect time to get ready. The buyout of Alliance Boots saddled the group with about $12 billion in debt, just as the financial crisis hit the global economy.

With concerns about escalating the US recession, there is a risk that history will repeat itself. What's more, over the past decade, the shopping landscape has changed significantly.

Amazon.com is much more robust than in 2007 and seems to threaten the pharmaceutical industry. Furthermore, in the US, Walgreens is battling other competitors including Ulta Beauty Inc. and Watson Corporation, which operates the Superdrug in Britain.

The private enterprise would need to shell out more cash to be able to keep up, as well as pay its outstanding loan obligations.

Walgreens also has a large number of stores that may need to be pruned. While closing shops away from the glare of public markets may be easier, terminating leases is costly.

Pessina - and more importantly any backers of private equity - will eventually need an exit if the purchase succeeds. He was able to convince Walgreens last time to buy Alliance shoes.

There is now no other clear candidate. The team might focus on the public market, but it would be necessary to convince prospective investors that this time around the investment case is unique. To create his ultimate goal: a truly global pharmaceutical distribution and retail group, the company may want to link up with an Asian operator.