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Evaluation of the antidiarrheal activity of the leaf extract of Parquetina nigrescens and formulation into oral suspensions

Authors Kola-Mustapha AT, Ghazali YO, Ayotunde HT, Atunwa SA, Usman SO

Received 4 May 2019

Accepted for publication 17 June 2019

Published 17 July 2019 Volume 2019:11 Pages 65—72


Checked for plagiarism Yes

Review by Single-blind

Peer reviewer comments 2

Editor who approved publication: Professor Bal Lokeshwar

Video abstract presented by Yusuf Oluwagbenga Ghazali.

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Adeola Tawakalitu Kola-Mustapha,1 Yusuf Oluwagbenga Ghazali,1 Hameedat Taiye Ayotunde,1 Soliu Abiola Atunwa,2 Sukurat Olasumbo Usman3

1Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, University of Ilorin, Ilorin, Nigeria; 2Department of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of Ilorin, Ilorin, Nigeria; 3Department of Pharmacognosy and Drug Development, Faculty of Pharmaceutical Sciences, University of Ilorin, Ilorin, Nigeria

Purpose: Parquetina nigrescens (Pn) extract was evaluated for safety and antidiarrheal activity, formulated into stable suspensions, and characterized.
Methods: Acute toxicity of the extract based on Organization for Economic Cooperation and Development-423 guidelines was performed. The antidiarrheal effects of the extract on castor oil-induced diarrhea in four groups of Wistar rats were determined. The first and second groups received 5 and 200 mg/kg body weight (bw) of the extract, while the third and fourth groups received normal saline (5 mg/kg bw) and loperamide (5 mg/kg bw) as negative and positive controls, respectively. Pn extract was used at 1.25% w/v to formulate structured vehicle (carboxylmethylcellulose, polyvinylpyrrolidone and tragacanth) suspensions. The suspensions were tested for pharmacological activity and characterized.
Results: Acute toxicity gave a lethal dose 50 (LD50) that is greater than 300 and less than 2,000 mg/kg bw. A reduction in intestinal transit by 0.14 and 0.15% at 5 and 200 mg/kg of the extract was achieved as compared to an inhibition of 0.12% by 5 mg/kg loperamide. There was a dose-dependent decrease in the frequency of watery stool passed in castor oil-induced rats by 35.29% and 64.70% at 5 and 200 mg/kg, respectively. All the suspensions inhibited diarrhea, exhibiting a dose-dependent pattern and remained stable after 4 weeks. Their pH values ranged from 4.60±2.73 to 4.73±1.91, while viscosity ranged from 3.50±1.23 to 6.75±1.24 Pas at 60 rpm.
Conclusion: The results suggest that Pn possesses significant antidiarrheal activity. Suspensions of Pn were successfully formulated in structured vehicles and were effective in the control of diarrhea in Wistar rats.

Keywords: Parquetina nigrescens, acute toxicity, structured vehicle, antidiarrhea

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