**5. Conclusion**

166 Rheumatoid Arthritis – Treatment

and F1 generations (gestation, litter and lactation) as well as the litter of the F1 and F2 generations (number of offspring per litter, size, weight, growth, development and advancement until the age of 8 weeks) were followed. At the end of the study, *post mortem* analysis was performed on the tissue and reproductive organs of young male and female

Comparing to controls, Enkorten did not cause any changes in the first phase of testing. In the second phase of the study, no gestation appeared in the experimental group from the F1 generation, whereas in the remaining four groups the reproduction process was completely in accordance with the control. The number of offspring per litter ranged from 8 to 12. The size and weight of youth as well as gender contribution were fully in compliance with the control group. The development, growth, advancement of youth and lactation were progressing normally. Development was monitored until the age of 8 weeks of life, after which histopathological analysis of tissues and reproductive organs was performed. *Post mortem* analyses did not reveal significant changes in any of the young animals. No signs of

Based on the observed results, it can be concluded that Enkorten did not significantly affect the process of reproduction in rats. Enkorten did not cause any teratogenic changes.

The investigation of the effect of Enkorten on skin was conducted using the mouse ear model (according to: Hypersensitivity Test Methods: NTP-National Toxicology Program -

Adult BALB/c male and female mice, divided into groups of 6 animals (the Institute's own breeding colony) were receiving Enkorten in 2HD (α-MSH 0.028 mg/kg + met-enkephalin 0.143 mg/kg) per day, by i.p. route, during 4 days. As an irritant, croton oil (3%, in acetone) was applied topically, in a volume of 25 μL, once, at the fifth day of the first Enkorten application. By applying the dose of Enkorten in such conditions, the irritation/inflammation process on the mouse skin caused by croton oil was inhibited by 35% compared to the control group that received the physiological solution. Enkorten action

The doubled human therapeutic dose of Enkorten, applied topically to skin in a volume of 25 μL, 6 hours prior to the irritant application (3% croton oil in acetone, in the volume of 25 μL, topically), led to the inhibition of the irritation/inflammation processes by 57% to 60%,

It can be concluded that Enkorten administered preventively, in a dose equivalent to the doubled human therapeutic dose, by i.p. route, during 4 days, reduced the irritation/inflammation processes for about 35%. Compared to the control, this drug, applied once, topically, reduced irritation/inflammation processes caused on the mouse

The aim of this study was to assign the range of values of α-MSH and met-enkephalin plasma concentrations before and after the Enkorten application and to determine pharmacokinetic parameters of the test preparation (Cmax, Tmax, AUC, T½). Cmax (Maximum

teratogenicity were documented in the two generations of young rats.

Histopathological reports were completely normal.

Good Science and Good Decisions - NIEHS, USA, 2002).

was slightly more pronounced in males during the first 24 hours.

compared to both male and female control mice.

skin by 60%.

**4. Pharmacokinetic study** 

**3.6 Investigation of the effect on skin** 

rats from the F2 generation.

Enkorten is an immunomodulatory preparation containing two components, α-melanocyte stimulating hormone (α-MSH) and methionine-enkefalin (met-enkephalin). α-MSH and met-enkephalin are endogenous substances of the neuropeptide group. They participate in the homeostatic processes, maintaining the biochemical link between the brain, neuroendocrine system and the immune system. The mechanism of action of both peptides directly reclines on both mechanisms of immune response development. The effect also includes analgesia, antipyretic and anti-inflammatory activities.

Pharmacodynamics of the combination shown in the studies imply great therapeutic possibilities. The presumed indication range of Enkorten encompasses diseases with inflammatory processes as the primary pathophysiological aspect (asthma, inflammatory bowel disease, rheumatoid arthritis, multiple sclerosis).

Preclinical findings indicate that the tested combination was nontoxic and well tolerated in doses applied by i.v., s.c., i.m., and i.p. routes, and therefore have the potential for safe future use as a medicine.
