WASHINGTON – In trying to identify the culprit for the drug shortage crisis facing the nation, the Department of Health & Human Services (HHS) had only to look to the marketplace. But finding a solution isn't as easy.Patent expirations, a rush to generic drugs, manufacturing capacity limitations, pricing issues and expanding use of oncology drugs have combined to create a record number of shortages in off-patent sterile injectables, according to a new report from the Office of the Assistant Secretary for Planning and Evaluation at HHS.