Department of Pharmaceutics, Delight College of Pharmacy, Koregaon Bhima, Pune, Maharashtra, India-412216
Sustained-release microencapsules have emerged as an advanced drug delivery approach designed to enhance therapeutic efficacy and reduce the side effects associated with anti-inflammatory medications. Diclofenac sodium (DS) microcapsules were developed using ethyl cellulose as the primary polymer in different ratios (1:1, 2:3, and 2:1), along with poly(lactic-co-glycolic acid) (PLGA) and chitosan. Various formulation techniques—including emulsion solvent evaporation, microfluidics, and spray drying—were employed to encapsulate the anti-inflammatory agent. In vitro release studies confirmed that all prepared batches exhibited controlled and sustained drug release over a period of 10 to 12 hours. The novel formulation method was assessed for its efficiency in producing microcapsules with uniform particle size, good flow characteristics, consistent drug loading, high entrapment efficiency, and no observable interaction between the drug, polymers, and processing parameters. Additionally, the release profiles indicated that a higher concentration of coating material led to a slower drug release. Kinetic analysis of the drug release data showed that the release mechanism follows a first-order kinetic model.
Diclofenac sodium chemically known as (2-[(2,6 dichlorophenyl)amino]benzene acetic acid) is a modern non-steroidal anti-inflammatory drug (NSAID) that falls under the category of aryl acetic acid derivatives [1,2]. It is commonly used to treat conditions such as rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis, particularly in long-term therapy for chronic musculoskeletal disorders, though it can notably affect the gastrointestinal tract. Due to its low oral bioavailability (around 60%), short plasma half-life (1–2 hours), and relatively low dosage requirement (25–75 mg three times daily), DFS — a potent non-steroidal anti-inflammatory and analgesic agent — is well-suited for development into a sustained-release drug delivery system for effective management of acute and chronic pain as well as traumatic conditions [5,6]. Microencapsulation is a highly promising drug delivery approach involving the coating or enclosing of minute liquid or solid particles with a continuous polymeric film. These microcapsules typically range in size from 1 to 5,000 microns. This technique is primarily employed for masking the unpleasant taste of bitter drugs, developing controlled or sustained release formulations, isolating incompatible substances, and protecting drugs that are sensitive to moisture or light. Overall, microencapsulation continues to be a valuable strategy in enhancing therapeutic efficacy and patient compliance in both oral and parenteral drug delivery systems [7,8]. The selection of a microencapsulation method depends on various factors, including the drug's physicochemical properties, polymer characteristics, desired release profile, and route of administration. Key considerations include drug stability, polymer compatibility, particle size requirements, encapsulation efficiency, and release kinetics. Additionally, factors like scalability, cost, and regulatory compliance influence the method's suitability for industrial application. The chosen technique should ensure optimal drug stability, efficacy, and overall product performance [3,4].
Microencapsulated diclofenac sodium works by inhibiting cyclooxygenase (COX) enzymes, reducing prostaglandin production responsible for pain and inflammation. The microencapsulation technique provides a controlled, sustained drug release, maintaining effective drug levels longer and enhancing therapeutic effects. This approach minimizes peak plasma concentrations, lowering the risk of side effects. It also protects the drug from premature degradation and reduces gastrointestinal irritation by limiting direct stomach contact. Overall, microencapsulation improves bioavailability, prolongs efficacy, and enhances patient compliance compared to standard diclofenac formulations.
Diclofenac sodium was generously supplied by Natco Pharmaceuticals, Hyderabad. Ethyl cellulose, sodium carboxymethyl cellulose, sodium alginate, chloroform, hydrochloric acid, methanol, cellulose acetate phthalate, sodium acetate, acacia, and sulfuric acid were obtained from SD Fine Chemicals Ltd., Mumbai. All reagents were of analytical grade, and double-distilled water was used in all experimental procedures.
Microencapsulation can be carried out using a variety of techniques, which are generally categorized into three main types: [8-12]
1. Physical methods
2. Physico-chemical methods
3. Chemical methods
Farhan Bilal Shaikh*, Pratiksha S. Gore, Formulation Approaches and Evaluation Parameters in Microencapsulation of Diclofenac Sodium for Sustained Drug Delivery, Int. J. Sci. R. Tech., 2026, 3 (1), 61-69. https://doi.org/10.5281/zenodo.18140419
10.5281/zenodo.18140419
