Ritalinic acid is an inactive, major metabolite of methylphenidate, a schedule II drug in the United States commonly used as a psychostimulant drugs methylphenidate and ethylphenidate. The elimination half-life of methylphenidate is relatively short (approximately 2 hours); therefore it is also available in extended release (ER) forms. The main metabolite is ritalinic acid, and the methylphenidate metabolites are mostly excreted in urine.

Lobeline,(+)- is unnatural enantiomer of Lobeline. Lobeline is the main active alkaloid constituent of Lobelia inflata, a plant sometimes called “Indian tobacco” because it was initially used by Indians of North America as a tobacco substitute. The crude extract is toxic but has been widely recommended for treatment of respiratory illnesses such as asthma, bronchitis, pneumonia, and whooping cough.