Matrix tablets for extended-release orphenadrine citrate: a review on formulation approaches, polymer selection and RP-HPLC method development for quality control

Nihal Nagar*, Harshit Gautam

University Institute of Pharmaceutical Education & Research, University of Kota, Kota, Rajasthan, India

Refer this article

Nihal Nagar, Harshit Gautam, 2026. Matrix tablets for extended-release orphenadrine citrate: a review on formulation approaches, polymer selection and RP-HPLC method development for quality control. Journal of medical pharmaceutical and allied sciences, V 15, I 5, Pages 01 – 08. Doi: https://doi.org/10.55522/jmpas.V15I5.7113.

ABSTRACT

Orphenadrine citrate is a centrally acting skeletal muscle relaxant with anticholinergic properties and is frequently prescribed for painful musculoskeletal conditions. However, its conventional immediate-release formulation demands multiple dosing in a day due to short duration of action, which leads to poor patient compliance, plasma fluctuations, and side effects. This comprehensive review article explains the current knowledge on the formulation and optimisation of extended-release (ER) matrix tablets of Orphenadrine citrate with special emphasis on hydrophilic polymer systems, especially Hydroxypropyl Methylcellulose (HPMC). The review critically discusses formulation strategies, pre-compression and post-compression characterisation parameters and kinetics of drug release. Further, it offers a detailed study on analytical method development and validation by Reverse Phase High-Performance Liquid Chromatography (RP-HPLC) for assay determination and blend uniformity testing. The incorporation of Quality by Design (QbD) concepts, such as Design of Experiments (DoE) for systematic optimisation, is discussed. While much progress has been made, several research gaps remain, including limited systematic optimisation studies, incomplete mechanistic release modelling and a lack of bio-relevant dissolution methods. This review provides a roadmap for the development of robust, commercially viable ER formulations of Orphenadrine citrate and thereby contributing to better patient outcomes and progress in sustained drug delivery.

Keywords:

Orphenadrine citrate, Extended release, Hydrophilic matrix, Muscle relaxant, Quality by Design.

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