Preparation and Evaluation of Candesartan Fast Dissolving Tablets for Improved Dissolution Using Solid Dispersion Technique

The first alternative to conventional oral dosage forms emerged in the late 1970s with the introduction of quick-dissolving systems designed to improve drug delivery, especially for older people and children’s [1,2]. Water is not required to take mouth tablets that dissolve solid dosage forms that break down rapidly within saliva. After breaking down inside the oral cavity, a drug can enter the body through oral mucosa, pharynx, or esophagus, which makes it work faster and more effectively [2]. Solid oral formulations remain the most preferred dosage forms given that their ease of administration, precise dosing, and better patient adherence [3]. ODTs—also termed mouth-dissolving, fast-melting, or quick-disintegrating tablets— are especially helpful for people those with regular difficulty swallowing pills, such as children, the elderly, and people with mental illness [1].  There are a number of ways to make these formulations, such as mass extrusion, molding, sublimation, lyophilization, direct compression, and spray drying. [2,4]. The inclusion of superdisintegrants facilitates rapid tablet breakup into fine particles, enhancing dissolution and promoting faster drug absorption [3].

Angiotensin II receptor blockers (ARBs) like Candesartan are frequently used to treat type 2 diabetes patients' hypertension and diabetic nephropathy [4]. It acts by selectively antagonizing angiotensin II type 1 (AT₁) receptors, leading to vascular smooth muscle relaxation, reduced vasoconstriction, and enhanced blood circulation. The drug exhibits an absolute bioavailability of about 60–80%, demonstrates linear pharmacokinetic behavior within the therapeutic range, and possesses an elimination half-life ranging from 11 to 15 hours [5]. However, its low aqueous solubility restricts its dissolution rate and bioavailability. To overcome this limitation, solid dispersion techniques employing hydrophilic carriers have been widely investigated to enhance solubility and dissolving [6,7].

The current study's goal was to enhance the rate of dissolution and solubility for Candesartan through the formulation of solid dispersions utilizing carriers such as Poloxamer 407, PVP K30, and PEG 4000. These dispersions were subsequently incorporated into fast-dissolving tablet formulations employing super disintegrants including Crospovidone as well as Sodium Starch Glycolate (SSG).  To evaluate the efficacy of the devised system, the resultant physical-chemical properties and in-vitro dissolving performance of the tablets have been evaluated.

MATERIALS AND METHODS

Materials

Candesartan was given as a gift obtained from Hyderabad, India's Hetero Drugs Ltd.  Poloxamer 407PVP K30, PEG 4000 was obtained from Loba Chemie Pvt. Ltd. Crospovidone, SSG were commercially obtained from Ozone ® India, Loba Chemie Pvt. Ltd. MCC, talc and Mg Stearate obtained from Chemie Loba Pvt. Ltd.

Pre-formulation studies

Drug Saturation Solubility:

Candesartan's saturation solubility was assessed by mixing an excess of the medication with 25 milliliters, of various dissolving substances including- distilled water, 0.1 N HCl (PH-1.2) and phosphate buffer (pH 6.8), contained in individual conical flasks with a capacity of 50 mL. The flasks were sealed with aluminum foil and placed upside down on a rotary shaker operating at 50 rpm and 37 ± 1 °C for 24 hours. After equilibrium was reached, the Whatman paper filter used for filtering the solutions then appropriately diluted, and measured by using a visible-UV spectrophotometer at a peak wavelength (λ max) of 244 nm.

FTIR Spectroscopy:

Potential interactions among Candesartan and the selected analysis using FT-IR had been utilized in evaluating compounds. The spectra were recorded within 4000–500 cm⁻¹ wavelength region using the KBr pellet technique.   In order to find out whether there are any possible chemical interactions between drug and formulation components, then collected spectra were examined for the presence, absence, or shifting of distinctive peaks [6].

Method

Preparation of Solid Dispersions:

Candesartan was solvent-evaporated to create solid dispersions through hydrophilic carriers such as Poloxamer 407, PEG 4000, and PVP K30 in a 1:1 drug-to-polymer ratio. The drug and polymers were dissolved using methanol.  After that, a dry residue was created by evaporating the solvent at 60 °C. After that, the final mass was kept in a desiccator for a full day to guarantee that any remaining solvent had been completely removed and that it had solidified. Dried dispersions were subsequently pulverized, passed through a #60 mesh sieve, and preserved in airtight containers for further studies [5,7,8].

 Direct Compression Method:

The required quantities of excipients were carefully measured and combined with the drug–carrier dispersing with a pestle and motor, thorough and uniform blending. Pre-compression properties of the resultant powder combination, such as flowability and compressibility, were evaluated. The optimized powder became afterward pressed to tablets utilizing an 8 mm flat-faced punch and a rotating tablet compression apparatus. [9,10,11].

 

 

Figure. 1: FT-IR Spectra of Candesartan

 

 

Figure .2: FT-IR Spectra of Candesartan + Poloxamer 407+ PVPK30+ PEG4000+ Crospovidone+ SSG+ Mg Stearate+ Talc+ MCC

 

 

Figure. 9: Cumulative % drug release Candesartan FDTS F1-F6

 

 

 

Figure. 10: Cumulative % drug release Candesartan FDTS F8-F12

CONCLUSION

The study confirms that the solid dispersion approach significantly improves the solubility and dissolution performance of Candesartan. Among the developed formulations, F2 containing Crospovidone demonstrated superior performance, showing rapid disintegration, enhanced water uptake, and maximum drug release. All formulations met the acceptable limits for pre- and post-compression quality parameters, indicating formulation reliability. Therefore, Crospovidone-based Candesartan fast-dissolving tablets provide a promising strategy to enhance oral drug delivery and therapeutic efficacy.

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