BANGKOK, Nov 26 (Reuters) - Thailand"s state-owned oil firm PTT (PTT.BK) is set to expand further into pharmaceuticals as part of a consortium acquiring a unit of drugmaker Alvogen, the parent of Taiwan"s Lotus Pharmaceutical (1795.TW), PTT said on Friday. A consortium of PTT and Icelandic investment fund Aztiq have agreed a $475 million purchase of Alvogen Emerging Markets Holdings Ltd, which holds a 57.48% stake in Lotus, according to Refinitiv Eikon.The Alvogen unit also owns Adalvo, a business-to-business pharmaceutical firm based in Malta. PTT said it will have a 37% indirect shareholding in Lotus - which makes drugs to treat cancer, cardiovascular disease and mental diseases - when the deal closes in the first quarter of 2022 and 60% of Adalvo.In April, PTT bought 6.6% of Lotus for $50 million. The move is part of the oil and gas firm"s strategy to diversify its business away from fossil fuels. It has previously announced plans in electric vehicle production and the expansion of its coffee shop franchise, Café Amazon, in Asia. Aztiq is led by Robert Wessman, who is also chairman of Lotus Pharmaceutical and Alvogen.