Molecular structure of Acrivastine (CAS NO.87848-99-5) is:

Product Name: Acrivastine
CAS Registry Number: 87848-99-5
IUPAC Name: (E)-3-[6-[(E)-1-(4-methylphenyl)-3-pyrrolidin-1-ylprop-1-enyl]pyridin-2-yl]prop-2-enoic acid
Molecular Weight: 348.43816 [g/mol]
Molecular Formula: C₂₂H₂₄N₂O₂
XLogP3: 1.6
H-Bond Donor: 1
H-Bond Acceptor: 4 
Surface Tension: 52.2 dyne/cm
Density: 1.17 g/cm³
Flash Point: 289.5 °C
Enthalpy of Vaporization: 88 kJ/mol
Boiling Point: 555.1 °C at 760 mmHg
Vapour Pressure: 3.72E-13 mmHg at 25°C
Classification Code: Antihistaminic ;Histamine Agents ;Histamine Antagonists ;Histamine H1 Antagonists, Non-Sedating ;Histamine H1 antagonists ;Neurotransmitter Agents

 Acrivastine (CAS NO.87848-99-5) is used for the treatment of allergies and hay fever. It is a second-generation H1-receptor antagonist antihistamine and works by blocking H1 histamine receptors.It is sold under the brand name Benadryl Allergy Relief in the U.K. by Pfizer. It is the active ingredient in the Semprex brand. Semprex-D is also acrivastine based, but contains a decongestant, pseudoephedrine.

 Acrivastine , its cas register number is 87848-99-5. It also can be called Semprex-D ; (E)-6-((E)-3-(1-Pyrrolidinyl)-1-p-tolylpropenyl)-2-pyridineacrylic acid ; (E)-6-((E)-3-(1-Pyrrolidinyl-1-p-tolylpropenyl)-2-pyridinacrylsaeure ; 2-Propenoic acid, 3-(6-(1-(4-methylphenyl)-3-(1-pyrrolidinyl)-1-propenyl)-2-pyridinyl)-, (E,E)- ; Acrivastin ; Acrivastina ; Acrivastinum ; Semprex .