How is the drug ceftriaxone being transport to the cns by iv? thanks

Transport is unclear: The transport of drugs into the CNS after IV administration is very complex and not fully understood. The blood brain barrier, which has a protective function, is difficult to cross. So the answer to the question is unknown. A good discussion of this subject can be found in clinical microbiology reviews, october 2010 vol23., no.4 pg 858-883.

Blood brain barrier: Ceftriaxone is very useful in infection of brain and spinal fluid because it is able to cross the blood brain barrier, which is a major lack of many other antibiotics. Giving antibiotics IV is quicker and more efficient than oral or intramuscular routes but Ceftriaxone will get to the brain regardless of route of administration.