The Nifty Pharma sub-index scaled a fresh record high in an otherwise weak market on Wednesday, as investors continued to shift towards defensive sectors amid rising uncertainty.

Among the top gainers, shares of Zydus Lifesciences Ltd, Mankind Pharma Ltd and Aurobindo Pharma Ltd were last seen climbing between 1 per cent and 6 per cent during the session.

Other pharma stocks, including Wockhardt Ltd, Gland Pharma Ltd, Sun Pharmaceutical Industries Ltd, Cipla Ltd, Laurus Labs Ltd, Lupin Ltd, Divi's Laboratories Ltd, Abbott India Ltd, IPCA Laboratories Ltd, Alkem Laboratories Ltd and Glenmark Pharmaceuticals Ltd, also traded higher.

"Pharma is one sector that has been performing well for quite some time. Over the past one month, we have witnessed strong buying interest in the sector. Most of these companies have reported reasonably well quarterly numbers. Export is one part which is completely benefiting. Depreciating rupee against the dollar is an advantageous position for pharma as well as for industries involved in export-oriented business," said Gaurav Sharma of Globe Capital.

Echoing similar views, Kranthi Bathini, Equity Strategist at WealthMills Securities, attributed the ongoing rally to the depreciating rupee. "One can buy pharma and healthcare stocks for medium- to longer-term horizon," he added.

Market expert Ajay Bagga also stated that the pharma sector remains an evergreen story amid a falling rupee.

India's export-focused pharmaceutical sector has emerged as a bright spot, as the weakening rupee has enhanced the appeal of dollar-linked revenues and supported margin expansion.

The sector is also witnessing support from rising global demand for generic weight-loss drugs.

Meanwhile, the Indian rupee slipped to a fresh record low of 96.88 against the US dollar.

Separately, shares of Zydus Lifesciences surged after the company reported its March quarter earnings. The drugmaker posted a consolidated net profit of Rs 1,272.5 crore for the fourth quarter, up 8.7 per cent year-on-year (YoY). Revenue from operations rose 16.2 per cent YoY to Rs 7,587 crore from Rs 6,528 crore in the corresponding period last year.

Zydus Lifesciences also announced a share buyback worth up to Rs 1,100 crore.