1. Water in nigella oil microemulsion for enhanced oral bioavailability of linagliptin.
- Author
-
Eid RK, Arafa MF, and El Maghraby GM
- Subjects
- Animals, Administration, Oral, Male, Rats, Drug Liberation, Carum, Nigella sativa, Linagliptin pharmacokinetics, Linagliptin administration & dosage, Linagliptin chemistry, Emulsions, Biological Availability, Water chemistry, Diabetes Mellitus, Experimental drug therapy, Rats, Wistar, Plant Oils chemistry, Plant Oils administration & dosage, Plant Oils pharmacokinetics, Hypoglycemic Agents pharmacokinetics, Hypoglycemic Agents administration & dosage, Hypoglycemic Agents chemistry
- Abstract
Linagliptin is hydrophilic antidiabetic with poor oral bioavailability due to poor permeability and pre-systemic metabolism. The objective was to assess w/o microemulsion for enhanced oral bioavailability of linagliptin. Nigella oil was used as oily phase based on its reported antidiabetic effect. Isopropyl myristate (IPM) or capryol were combined with nigella oil to impart intestinal membrane permeabilizing abilities. Pseudoternary phase diagrams were constructed utilizing nigella oil in presence and absence of isopropyl myristate or capryol as oily phase using Tween 60 as surfactant. W/O microemulsion formulations were selected from the constructed phase diagrams and linagliptin was loaded in the internal aqueous phase at a concentration of 0.5 mg/ml. The prepared formulations were physically evaluated and linagliptin in vitro release was monitored. Eventually, the in vivo hypoglycemic effect was assessed using diabetic rats. The developed microemulsions were of w/o type and exhibited Newtonian flow behavior with nigella/capryol microemulsion recording the lowest viscosity. The recorded droplet size values were 104.9, 121.2 and 86.4 nm for nigella, nigella/IPM and nigella/capryol microemulsions, respectively. All microemulsion formulations showed slower drug release rate compared with aqueous suspension with nigella/capryol microemulsion showing the highest release rate compared to other microemulsions. Release data from microemulsion best fitted to Higuchi model. In vivo oral hypoglycemic activity measurement reflected a more intensified hypoglycemic effect with rapid onset after oral ingestion of microemulsion compared to linagliptin dispersion. Nigella oil/IPM-based microemulsion was ranked as the most effective. The investigation highlighted the feasibility of w/o microemulsion for enhanced oral bioavailability of hydrophilic drugs like linagliptin., Competing Interests: Declarations. Ethics approval and consent to participate: This investigation was conducted on male albino rats. Animal treatment and housing were based on the National Institute of Health guide for the care and manipulation of laboratory animals. The protocol of this investigation was initiated after approval from the ethical committee of Faculty of Pharmacy, Tanta University (approval number: TP/RE/8/23p-0044). Consent for publication: Not applicable. Competing interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024. The Author(s).)
- Published
- 2025
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