Development of novel vasodilator ointments using pharmacoscintigraphy followed by preliminary field use for treating mild cold injuries

Mild cold injuries, caused by local vasoconstriction, result in avoidable pain, discomfort and loss of efficiency in a huge number of subjects exposed to sub-zero temperature. The problem is aggravated in soldiers who have to face significant to extremely low effective environmental temperature due to operational reasons. The purpose of this work was to develop new vasodilator ointments for local effect only, and to objectively prove their efficacy (zero-phase clinical trial) before attempting field trials. Methods: Nuclear medicine scintigraphy was standardized to obtain qualitative & quantitative information about microcirculation of the hands and feat. 15 ointment formulations were prepared in-house using appropriate quantities of routine therapeutic agents known to possess vasodilator action on the microcirculation. Controlled pharmascintigraphy was done in 90 volunteers (6 for each formulation) to quantify the improvement in microcirculation following single application of drug ointment. Five best ointments were chosen for further studies. Two of these then entered a small field efficacy trial (n=50 subjects) in an appropriate cohort with cold injuries. Results & conclusion: 30–150% increase in local microcirculation was achieved with a single application of these two ointment forms in all 6 subjects undergoing pharmacoscintigraphy, along with a subjective feeling of warmth at the site of local application. Increase in microcirculation of underlying musculature was also proved, confirming deep penetration of the therapeutic agent. Ongoing field trial has given encouraging results suggesting utility of the novel ointments in mild cold injuries (Grade 1–2) in field conditions.