A study on toxicity, local irritative effect of and allergic response to a novel intranasal medication containing N-phenylacetyl-L-prolylglycine ethyl ester

Abstract

Development of novel medications for delivery of active ingredients with systemic absorption and high bioavailability is an actual challenge for modern pharmaceutical and medical science. Nowadays, the number of diseases of the central nervous system is continuously growing. These conditions lead to impairment of mnestic and intellectual brain functions, to a decrease in mental alertness and memory in particular, which results in deterioration in the quality of life, sometimes in disability and patients’ partial or complete dependence on other people.

The existing variety of nootropics does not fully respond to modern criteria of clinical science and practice due to insufficient effectiveness and neuroavailability. Recently, scientists have drawn attention to the potential of intranasal administration for delivery of active ingredients with systemic effect to human blood flow. Intranasal administration for delivery of active ingredients will enhance neuroavailability and, thus, a therapeutic effect of drugs.

At the Departments of Medicines Technology, Pharmacology and Medical Formulation of ZSMU, a composition of the novel medication containing N-phenylacetyl-L-prolylglycine ethyl ester for intranasal delivery was developed as the result of complex physical and chemical, microbiological and biopharmaceutical experiments. The medication contains 1 % of N-phenylacetyl-L-prolylglycine ethyl ester, 5 % of Glycerin and Poltava Bischofite (standardized solution prepared at the Department of Medicines Technology of ZSMU), Sodium carboxymethyl cellulose solution and Tween 80 (1 %). Given the above, the urgent task is to study some safety parameters of the developed dosage form.

The aim of the research is to study some toxicological parameters, local irritative effect of and allergic response to an effective dose of created medication containing N-phenylacetyl-L-prolylglycine ethyl ester for intranasal delivery.

Materials and methods. The created medications for intranasal delivery were used as materials for each test. These medications contained N-phenylacetyl-L-prolylglycine ethyl ester (Noopept) 1 %, Glycerin and standardized Poltava Bischofite (5 % each), Sodium carboxymethyl cellulose solution, and Tween 80 (1 %). N-phenylacetyl-L-prolylglycine ethyl ester (CAS №157115-85-0, obtained from Shijiazhuang Prosperity Import and Export Co., Ltd., China. Purity: ≥98 %), Poltava Bischofite (standardized solution prepared at the Department of Medicines Technology of ZSMU), Polysorbate 80 (obtained from Limited liability company “Synbias”, Kyiv), Sodium carboxymethyl cellulose (obtained from Limited liability company “Synbias”, Kyiv), Glycerin (obtained from Limited liability company “Synbias”, Kyiv), Benzalkonium chloride (obtained from Limited liability company “Istok-Plus”, Zaporizhzhia). A study of acute toxicity, allergic response and irritating effect on skin, and cutaneous anaphylaxis reaction was conducted on white rats. Local irritative effect (Conjunctival allergen provocation test, CAPT) of created medication containing N-phenylacetyl-L-prolylglycine ethyl ester for intranasal delivery was determined on guinea pigs in accordance with recommendations of the State Pharmacological Center of the Ministry of Health of Ukraine and other recommendations.

Results were statistically processed by means of the standard statistical package of the licensed program Statistica for Windows 13 (StatSoft Inc., № JPZ804I382130ARCN10-J). For all analysis types the P-value <0.05 (95 %) was considered statistically significant.

Results. One-time intranasal delivery of the maximum allowable volume of the medication under research (0.4 ml) to the rats weighing 100 g in a dose of 40 mg/kg did not result in death of any of 6 animals of the experimental group overnight.

In the course of studying potential local irritative effect of the intranasal gel containing N-phenylacetyl-L-prolylglycine ethyl ester, two experimental animals out of 10 developed a slight reddening of the conjunctiva immediately after the administration. No changes in mucous membrane of the eyes were observed in other eight experimental animals. Daily application of the studied medication for intranasal delivery (0.5 g) to a shaved area of the lateral surface of the animals’ bodies (4 × 4 cm) during 5 days, and consequent one-time application of the intranasal gel containing N-phenylacetyl-L-prolylglycine ethyl ester (0.3 g), did not result in anaphylactic shock development. No visible reactions were detected in the experimental animals after 20 more skin applications of the intranasal gel containing N-phenylacetyl-L-prolylglycine ethyl ester during 4 weeks (5 times per week). The skin area exposed to application in animals of the control and experimental groups looked the same.

Conclusions. Complex studies of some toxicological parameters (such as mortality, dynamics of body weight change, local irritative effect and allergic response to the effective dose of a novel medication containing N-phenylacetyl-L-prolylglycine ethyl ester for intranasal delivery) have been performed. Summarizing obtained results, it can be confirmed that the medication under study does not cause any local irritative effect and allergic response and does not demonstrate general toxic effects in case of its intranasal delivery. Thus, further research of the novel medication containing N-phenylacetyl-L-prolylglycine ethyl ester for intranasal administration has a potential perspective.