9.1. TOLERANCE AND  LOCAL ANESTHETIC EFFECTS OF INCREASING INTRADERMAL DOSES OF IQB-9302.HCl

Placebo (0.9% saline) and increasing concentrations of IQB-9302.HCl (0.1% - 0.25% - 0.50% - 0.75% and 1.0%) were injected in volumes of 0.2 ml subcutaneously to 12 male healthy volunteers.
Doses were injected under double blind conditions and at random so as each volunteers received the following doses:
 

Local anesthesia was evaluated by determination of pain by pin prick method 1 cm apart from the injection site and of sensitivity to touch at intervals after inyection. Spread of anesthesia was obtained by evaluation of sensitivity to pain  and to touch at different distances from the site of injection.  Local and systemic tolerance were evaluated by visual inspection of injection sites and by standard techniques (BP, ECG, blood analysis,  biochemistry, etc). 

RESULTS

No local or systemic side effects were reported and tolerance was excellent in all volunteers at all tested doses.  Most of volunteers exhibited some palor surrounding injected area, thus suggesting a vasoconstrictor  effect.

In the range 0.1% to 0.75% IQB-9302 exhibited lineal dose-response relationships in the duration of anesthesia that was found to be very prolonged (figure 1 and 2). Concentrations of 1% had similar or smaller effects than those of 0.75% but this maybe explained by the vasoconstrictor effect shown at high doses.
Spreading of anesthezided area was dose-dependent in the range 0.1 to 0.75%. Further increases in concentrations did not increased the size of anesthesized are.
 

9.2.- DOUBLE-BLIND COMPARISON OF INCREASING INTRADERMAL DOSES IQB-9302 AND BUPIVACAINE GIVEN TO HEALTHY VOLUNTEERS

Twelve healthy volunteers received under randomized double-blind conditions intradermal doses of  0.1 ml of IQB-9302, Bupivacaine or placebo according to the following scheme:
 

The administration schedule has the following characteristics, which were designed to ensure a maximum safety and evaluability of the anaesthetic effect:

• the injection sites were distal first, proximal last. >
• in the first two periods, the injections of the test and reference medications was be performed in different arms (spatial separation), and was separated by at least 8 hours; this allowed to link the causal relationship of any adverse events to the test or reference medication.
• in the first two periods, each subject received each dose level twice (once per arm)
• placebo was administered in each study period, allowing an intra-subject validation of the placebo effect over time.

RESULTS

No local or systemic side effects were reported and tolerance was excellent in all volunteers at all tested doses.

Duration of anaesthesia

All concentrations of IQB-9302 induced a very long-lasting effect as shown in the figure. Dose-related effects were more evident with IQB-9302 and local anaesthesia ranged between 105 ±  16 min and 129 ± 15 min. Dose-related effects were less evident for bupivacaine and local anaesthetic effects ranged between 37 ± 7 min and 43 ± 8 min

In the third period, when 0.1 ml of IQB-9302 0.25% were compared with bupivacaine 0.75%, anaesthetic effects shown by IQB-9302 were also longer than those induced by bupivacaine.

Capillary Blood flow:

Capillary blood flow was measured in subjects treated with bupivacaine 0.75% and IQB-9302 0.25% (because of the double-blind design). Results, depicted in the figure show a moderate increase of blood flow after bupivacaine and a mderate decrease of blood flow after IQB-9302. Differences betwwen Bupivacaine and IQB-9302 were statistically significant after 15 and 60 min. Placebo did not modify this parameter
 
 

9.3.- DOUBLE BLIND COMPARISON OF IQB-9302 AND BUPIVACAINE  IN THE  BLOCK OF CUBITAL NERVE IN HEALTHY VOLUNTEERS

IQB-9302 and bupivacaine were administered by infiltration near the cubital nerve at concentrations of 0.25% and 0.50% in two separate sessions with one week washout.  In the first day, 3 ml of the low concentration of each anesthetic was injected under double-blind conditions into each arm of 12 healthy volunteers. The following parameteres were evaluated:

• Onset of sensory blockade (pinprick method, three tests in the anesthesized area)
• Onset of motor block (capacity of volunteer to joint the thumb and the little finger
• Duration of sensory and motor blocks
• Skin temperature of the anesthesized area
• Side effects (including HR, BP and EGC)

Safety was evaluated comparing hematological, biochemical and urinanalysis before entering into the trial and one week after the last session.

RESULTS (DRAFT)

Low concentrations (0.25%)

Complete sensory block was achieved in 11 of 12 volunteers after IQB-9302 and
in 10 of 12 volunteers after bupivacaine. Onset of anaesthesia was shorter after IQB-9302 but differences were not statistically significant.

Motor block was achieved in 7 volunteers under IQB-9302 and in 5 volunteers after bupivacaine. Onset of motor block was shorter after bupivacaine (38 min ± 6 min) than after IQB-9302 (47 min ± 7 min), but due to the high interindividual variability the difference did not reach statistical significance.

Duration of sensory and motor blocks of IQB-9302 and bupivacaine are shown in figure 6.
Sensory and motor blocks run in parallel after IQB-9302 being 460 ± 60 min and 485 ± 72 min, respectively. Bupivacaine exhibited longer duration of motor block (482 ± 85 min) in comparison with the sensory block (350 ± 90 min). 

Figures 7 and  8 show the comparative time-courses of full sensory and motor blocks. Full sensory anesthesia was reached in 11 volunteers after 50 min and maintained for more than 100 min after IQB-9302. Conversely, only 10 volunteers obtained full anesthesia after bupivacaine after 140 min and for only 5 min. Motor block was parallel to sensory block for both drugs showing a shift to the right in the time axis.

Recovery from anesthesia, as shown by the slope of the right branch of the curve, was somewhat shorter for sensory block after IQB-9302.

Increases of skin temperature revealing the block of autonomic system was observed after IQB-9302 and bupivacaine. A trend to a large increase of temperature was observed after IQB-9302, thus confirming a most potent effect

No side effects were observed in the first section of the trial.

High concentrations (0.50%)

Eleven healthy volunteers participated in the second part of the study (one volunteer dropped out because paresthesia of several days of duration after the first part)

Sensory block was achieved in 11/11 subjects treated with IQB-9302 and in 11/11 subjects treated with bupivacaine. Motor block was also achieved in all participating subjects.

Onset of sensory anaesthesia was 18.1 min for IQB-9302 treated volunteers and 12,7 min for bupivacaine-treated subjects.

Motor blockade was obtained after 49,1 min in IQB-9302-treated subjects y after 30,3 min in bupivacaine-treated subjects.

Duration of sensory block was 549 min for IQB-9302 (extreme values = 735 min/440 min) and  715 min for bupivacaine (extreme vaules = 1098 min/365 min).

Duration of motor block was of 500 min for IQB-9302 (extreme values =  732min/210 min) and 662,3 min for bupivacaine (extreme values =  1030 min/150 min).

Hand temperature was initially similar for both drugs. From minute 30 and  thereafter, temperature of the hand of IQB-9302 treated subjects was 2ºC lesser than that of bupivacaine treated subjects.