After reviewing the available information, I found that there is no exact date available for the submission of Ruxolitinib by Apotex in the USA. However, I can provide some context regarding the drug's approval process and submission.

Ruxolitinib, under the trade name Jakavi, is a medication used to treat myelofibrosis and polycythemia vera, two rare blood disorders. The drug was initially developed by Incyte Corporation and approved by the FDA in November 2011 [1]. Apotex, a Canadian-based pharmaceutical company, later sought approval for a generic version of Ruxolitinib.

Apotex submitted an Abbreviated New Drug Application (ANDA) for Ruxolitinib to the FDA [2]. The ANDA process is designed to allow generic drug manufacturers to apply for approval of a generic version of an already-approved drug [1]. However, the exact date of Apotex's ANDA submission for Ruxolitinib is not publicly available on the FDA's website or through the other provided sources.

In summary, while there is no specific date available for Apotex's submission of Ruxolitinib in the USA, the company did submit an ANDA for the drug. For the most accurate and up-to-date information on Apotex's ANDA submission, it would be best to contact the FDA directly or visit the FDA's website [1].

Sources:
[1] <https://www.fda.gov/drugs/abbreviated-new-drug-application-anda/patent-certifications-and-suitability-petitions>
[2] <https://www.fda.gov/drugs/abbreviated-new-drug-application-anda/list-abbreviated-new-drug-application-andas-received-fda-review-and-approved-fda>
[3] <https://www.drugpatentwatch.com/p/tradename/RUXOLITINIB>
[4] <https://www.canada.ca/en/health-canada/services/drug-health-product-review-approval/submissions-under-review/new-drug-submissions-under-review.html>