Pharmacotherapy for the management of achalasia: Current status, challenges and future directions

Table 1 Properties of commercially available botulinum toxin drugs

	Botox®	Dysport®	Xeomin®	NeuroBloc® Myobloc®
Manufacturer	Allergan Inc. Irvine, CA, United States	Ipsen Pharma Boulogne-Billancourt, France	Merz Pharmaceuticals Frankfurt/M, Germany	United States WorldMeds Louisville, KY, United States
Pharmaceutical preparation	Powder	Powder	Powder	Ready-to-use solution 5000 MU-E/mL
Storage conditions	Below 8 °C	Below 8 °C	Below 25 °C	Below 8 °C
Shelf life	36 mo	24 mo	36 mo	24 mo
Botulinum toxin type	A	A	A	B
Clostridium botulinum strain	Hall A	Ipsen strain	Hall A	Bean B
SNARE target	SNAP25	SNAP25	SNAP25	VAMP
Purification process	Precipitation and chromatography	Precipitation and chromatography	Precipitation and chromatography	Precipitation and chromatography
pH-value of the reconstituted preparation	7.4	7.4	7.4	5.6
Stabilisation	Vacuum drying	Freeze-drying (lyophilisate)	Vacuum drying	pH-reduction
Excipients	Human serum albumin 500 μg/100 MU-vial; NaCl 900 μg/100 MU-vial buffer system	Human serum albumin 125 μg/500 MU-vial; Lactose 2500 μg/100 MU-vial buffer system	Human serum albumin 1000 μg/100 MU-vial; Sucrose 4.7 mg/100 MU-vial buffer system	Human serum albumin 500 μg/mL; Disodium succinate 0.01 mol/L; Sodium chloride 0.1 mol/L; H2O; Hydrochloric acid
Biological activity	50/100 MU-A/vial	500 MU-I/vial	50/100 MU-M/vial	1.0/2.5/10.0 kMU-E/vial
Biological activity in relation to Botox®	1	1:2-1:3	1	1:40
Specific biological activity	60 MU-EV/ngBNT	100 MU-EV/ngBNT	167 MU-EV/ngBNT	5 MU-EV/ngBNT

SNARE: Soluble NSF-attachment protein receptor; NSF: N-ethylmaleimide-sensitive fusion protein; SNAP-25: Synaptosomal-associated protein of 25 kD; BNT: Botulinum neurotoxin; MU-A: Mouse unit in the Allergan mouse lethality assay; MU-E: Mouse unit in the Solstice mouse lethality assay; MU-I: Mouse unit in the Ipsen mouse lethality assay; MU-M: Mouse unit in the Merz mouse lethality assay; MU-EV: Equivalence mouse unit. 1 MU-EV = 1 MU-A = 1 MU-M = 3 MU-I = 40 MU-E. Adapted with permission from Dressler[11].