Some pharmaceutical companies in South Korea chalked up strong sales in the first nine months of this year on the back of their moneymaking subsidiaries, industry sources said Friday.

Consolidated sales of Kwangdong Pharmaceutical Co. are expected to exceed the 1 trillion-won mark this year for the first time in its history, bolstered by the rapid growth of its maintenance, repair and overhaul (MRO) unit Korea e-Platform.

Kwangdong Pharmaceutical's consolidated top line reached 791.2 billion won ($681 million) in the January-September period, for which revenue of Korea e-Platform accounted for 36 percent. The drugmaker's separate sales reached 481.6 billion won during the three-quarter period.

"Korea e-Platform, which Kwangdong Pharmaceutical acquired last year, contributes greatly to the drugmaker's overall sales," an industry watcher said. "On a separate basis, its revenue is unlikely to surpass the 1 trillion-won level."

Kwangdong Pharmaceutical is not alone. Chong Kun Dang Holdings Corp. has benefited greatly from the stellar performance of its drug substance producer Kyongbo Pharmaceutical.

Chong Kun Dang Holdings posted 239.5 billion won in consolidated revenue during the nine-month period, with 142.9 billion won coming from Kyongbo Pharmaceutical.

In contrast, Dong-A Socio Holdings Co. saw its sales decrease considerably as profitable active pharmaceutical ingredient subsidiary ST Pharm Co. was excluded from its consolidated financial statements following its listing on the tech-heavy secondary stock market in June this year.

Last year, ST Pharm took up approximately 20 percent of Dong-A Socio Holdings' sales. After the exclusion, sales of Dong-A Socio Holdings fell 8.5 percent on-year to 136.3 billion won in the July-September period of this year.

ST Pharm's sales came to 54 billion won in the third quarter of this year, up 18 percent from a year earlier, with its cumulative revenue of 154.6 billion won for the first three quarters already topping the full-year sales for 2015. (Yonhap)