Formulation and Evalution of Microemulsion based Loratadine Gel

Abstract

Introduction: A second-generation H1-antihistamine is loratadine. that is frequently used to treat urticaria and Rhinitis caused by allergies. However, contrary to, topical delivery is being investigated because of its low oral pH and first-pass metabolism  bioavailability (~30%). The objective of this study is to create a loratadine-loaded microemulgel that will improve skin permeability and offer long-lasting medication release for efficient topical allergy treatment.

Objectives: This study's goal was to create and assess a loratadine-loaded microemulgel that would improve topical delivery for the treatment of allergic conditions by enhancing drug permeation, yielding prolonged release, and increasing bioavailability.

 Methods: According to solubility studies, the best ingredients are propylene glycol, Tween 20, and ethyl oleate. Using pseudoternary phase diagrams, the optimal microemulsion regions were created. tests of thermodynamic stability, involving Centrifugation, heating-cooling cycles, and freeze-thaw cycles were all carried out. on a selection of formulations. The Carbopol 934 gel at 1% w/v was mixed with the optimised microemulsion. The pH, viscosity, drug content, spreadability, in vitro permeation (utilising a Franz diffusion cell and Strat-M® membrane), and drug release kinetics of the microemulgel were assessed.

 Results: F2 had the best qualities of all the formulations a high drug content (97.26 ± 0.14%), good spreadability (6.5 ± 1.39 cm), and a pH that was skin-compatible (5.92 ± 0.28). A sustained drug release of 82.81% over a 24-hour period was found in  vitro permeation studies. This was much higher than the control gel's (35.09%) and closely matched the microemulsion's 91.71% release. Drug release was consistent with the Korsmeyer–Peppas model (R2 = 0.992), which suggests a Transport mechanism for Super Case-II  that includes polymer Relaxation and edoema  in addition to diffusion. The microemulgel's chemical and physical stability over a month was validated by stability tests carried out in an ICH setting.

Conclusions: The loratadine-loaded microemulgel showed sustained drug release, superior physicochemical stability, and improved skin penetration. It offers a promising non-invasive substitute for the topical management of allergic skin diseases like allergic rhinitis and urticaria.