The country of Aparantaka has been identified as the northwestern part of the Indian subcontinent, and comprises Northern Gujarat, Kathiawar, Kachch, and Sindh, the area where Greek communities were probably concentrated.
Dharmarashita is said to have preached the Aggikkhandopama Sutra, so that 37,000 people were converted in Aparantaka and that thousands of men and women entered the Order ("pabbajja"): In another Pali reference, a Buddhist monk from Sri Lanka named Punabbasukutumbikaputta Tissa Thera is said to have been to India in order to study with "the Yonaka Dhammarakkhita", whereupon he attained the "patisambhida" (analytical knowledge).
According to the Milinda Panha (I 32-35), the monk Nagasena, before his encounter with Menander, was once a student of Dharmaraksita and learnt Buddhism and reached enlightenment as an Arhat under his guidance in Pataliputra.
But at the end of that time the venerable Dhammarakkhita addressed him, and said: "Nâgasena, as a herdsman tends the cows, but others enjoy their produce, so thou too carriest in thy head the whole three baskets of the Buddha's word, and still art not yet a partaker of the fruit of Samanaship."
(Milinda Panha, I, 35)This event took place roughly a hundred years after the missionary efforts of Ashoka, and it would suggest that Dharmaraksita was a young man under Ashoka, became a respected elder settled in the Ashokan capital of Pataliputra, and then trained a young Nagasena in the Tripiṭaka and towards enlightenment, before Nagasena himself met Menander at a venerable age.