For degradation, in a non-reversible reaction, PLP is catabolized to 4-pyridoxic acid, which is excreted in urine. Synthesis
Biosynthesis
Two pathways for PLP are currently known: one requires deoxyxylulose 5-phosphate (DXP), while the other does not, hence they are known as DXP-dependent and DXP-independent. These pathways have been studied extensively in Escherichia coli and Bacillus subtilis, respectively. Despite the disparity in the starting compounds and the different number of steps required, the two pathways possess many commonalities. The DXP-dependent pathway:

Commercial synthesis
The starting material is either the amino acid alanine, or propionic acid converted into alanine via halogenation and amination. Then, the procedure accomplishes the conversion of the amino acid into pyridoxine through the formation of an oxazole intermediate followed by a Diels–Alder reaction, with the entire process referred to as the "oxazole method". The product used in dietary supplements and food fortification is pyridoxine hydrochloride, the chemically stable hydrochloride salt of pyridoxine. Pyridoxine is converted in the liver into the metabolically active coenzyme form pyridoxal 5-phosphate. At present, while the industry mainly utilizes the oxazole method, there is research exploring means of using less toxic and dangerous reagents in the process. Fermentative bacterial biosynthesis methods are also being explored, but are not yet scaled up for commercial production. Functions
PLP is involved in many aspects of macronutrient metabolism, neurotransmitter synthesis, histamine synthesis, hemoglobin synthesis and function, and gene expression. PLP generally serves as a coenzyme (cofactor) for many reactions including decarboxylation, transamination, racemization, elimination, replacement, and beta-group interconversion.
Stereochemistry
Midodrine contains a stereocenter and consists of two enantiomers, making it a racemate; i.e., a 1:1 mixture of (R)- and (S)-forms:

Synthesis
Acylation of 1,4-dimethoxybenzene with chloroacetyl chloride gives the chloroketone 2. The halogen is then converted to the amine 3 by any set of standard schemes, and the ketone reduced to an alcohol with borohydride (4). Acylation of the amino group in this last intermediate with chloroacetyl chloride affords the amide 5. The halogen is then displaced with azide and the resulting product 6 reduced catalytically to the glycinamide, midodrine (7). References
External links
 Media related to Midodrine at Wikimedia Commons

"Midodrine". Drug Information Portal. U.S. National Library of Medicine.