Department of Pharmacy, Samarth Rural Educational Institute, Pune, India
Nephrolithiasis remains a significant global health burden with a recurrence rate of approximately 50% within ten years [1]. Potassium citrate is the gold standard for urinary alkalinization and the management of hypocitraturia; however, conventional dosage forms, such as large extended-release tablets, often result in poor patient compliance due to their size and associated gastrointestinal (GI) side effects [2]. This review explores the formulation and evaluation of potassium citrate into a medicated gummy dosage form. By utilising a hydrocolloid gelling matrix, these gummies offer a palatable, chewable alternative that eliminates the need for water and improves the overall patient experience. Key evaluation parameters, including weight variation, texture profile analysis (TPA), and drug content uniformity, are discussed to ensure pharmaceutical quality and therapeutic efficacy.
Nephrolithiasis, or kidney stone disease, is a complex crystalline disorder affecting roughly 12% of the global population [3]. The most common stone compositions involve calcium oxalate and uric acid. Potassium citrate therapy is utilised to increase urinary pH and citrate levels, thereby inhibiting the nucleation and growth of these crystals [4].
Despite its efficacy, the "pill burden" associated with potassium citrate is a major hurdle. Patients are often required to take multiple large tablets several times a day. Furthermore, the high salt content can lead to "salty" aftertastes and gastric irritation [5]. Medicated gummies have emerged as a novel "Patient-Centric Drug Design" (PCDD) to address these issues. They provide a soft, chewable texture and allow for better taste-masking of saline active pharmaceutical ingredients (APIs) [6].
Mechanism of Calcium Oxalate Stone Formation
Supersaturation of Urine → Stone Formation (Short Explanation):
Urinary stone formation begins when the concentration of substances such as calcium and oxalate rises beyond their solubility threshold, creating a supersaturated environment. Under these conditions, initial crystal particles are generated through nucleation. These small crystals progressively enlarge as additional ions deposit onto their surfaces, a process known as crystal growth. Subsequently, individual crystals combine to form larger aggregates. When these aggregates are not effectively eliminated through urine flow, they remain within the kidney and gradually develop into detectable renal stones
Figure 1:
Figure 2: Role of Citrate in Prevention
Anti-Urolithiatic Mechanism of Citrate
Calcium ions (Ca²?) combine with oxalate ions to form insoluble calcium oxalate crystals, which are the primary components of kidney stones. Citrate acts as an inhibitor by binding with calcium ions to form a soluble calcium–citrate complex. This reduces the availability of free calcium, thereby preventing crystal formation and stone development.
Figure 3: Formulation of Citrate-Based Chewable Matrix
Development Process of Chewable Matrix
The chewable matrix is prepared by combining citrate salt with suitable polymers, sweeteners, and flavouring agents to ensure stability and palatability. The ingredients are first uniformly blended, followed by granulation to improve flow and compressibility. The granules are then shaped through compression or moulding to obtain the final chewable dosage form.
Figure 4: Physicochemical Characterisation Workflow
Evaluation of Chewable Matrix
The developed formulation is systematically evaluated to ensure its quality and performance. Initially, physical properties such as hardness, friability, and thickness are assessed to confirm mechanical strength. This is followed by chemical evaluation, including pH and drug content determination. Performance testing, such as disintegration and dissolution studies, is then conducted to understand the release behaviour. Finally, the data obtained are analysed using release kinetics models to characterise the drug release mechanism.
Figure 6: Mechanism of Drug Release from Matrix
Upon administration, saliva penetrates the chewable matrix, initiating hydration of the polymer. This leads to matrix swelling, which creates a gel-like structure. Citrate then gradually diffuses out of the swollen matrix, resulting in a controlled and sustained release of the active ingredient.
2. MATERIALS AND FORMULATION METHODOLOGY
2.1 Formulation Components
The success of a medicated gummy depends on the synergy between the API and the gelling matrix [7].
2.2 Manufacturing Process
The fabrication typically follows the "Moulding Method" [11]:
3. EVALUATION PARAMETERS
To ensure the gummy functions as a reliable drug delivery system, several pharmaceutical tests must be conducted:
4. DISCUSSION AND CLINICAL SIGNIFICANCE
The transition from tablets to gummies significantly lowers the threshold for patient adherence. Because the gummy is masticated, the API is pre-diluted with saliva before reaching the gastric mucosa, which may reduce the localized GI irritation often seen with concentrated potassium tablets [18]. However, challenges remain regarding the sugar content for diabetic patients and the stability of the gel matrix in humid climates like India [19].
5. CONCLUSION
The formulation of potassium citrate medicated gummies represents a viable and superior alternative to conventional oral dosage forms. Through careful selection of polymers and sweeteners, it is possible to create a product that is both therapeutically effective and highly palatable. This approach not only manages the physiological symptoms of nephrolithiasis but also addresses the psychological barriers to long-term medication [20].
REFERENCES
Waman Shraddha, Lamkhade Ganesh, Sarode Shreya, Sarode Athrav, Jamadar Saniya, Development and Physicochemical Characterisation of Citrate-Based Chewable Matrices for the Prophylaxis of Calcium-Urolithiasis, Int. J. of Pharm. Sci., 2026, Vol 4, Issue 5, 2573-2578. https://doi.org/10.5281/zenodo.20127557
10.5281/zenodo.20127557
