Micromeritic properties and instrumental analysis of physical mixtures and solid dispersions with adsorbent containing losartan: Comparison of dissolution-differentiating factors

Formulation and Evaluation of Polymeric Spherical Agglomerates-Based Porous Orodispersible Tablets of Cilnidipine

Background/Objectives: Cilnidipine (CIL) is a calcium channel blocker that exhibits low bioavailability (~13%) due to poor aqueous solubility and extensive pre-systemic gut wall metabolism. The current study aimed to enhance the oral bioavailability of CIL by formulation of polymeric spherical agglomerates (CILSAs)-based orodispersible tablets (ODTs). Methods: Eight different batches of CILSAs were prepared by a crystallo-co-agglomeration technique using different proportions of hydrophilic polymers like hydroxy propyl methyl cellulose E50, polyvinyl pyrrolidone K30, or polyethylene glycol (PEG) 6000 as carriers. Fourier transform infrared spectroscopy (FTIR) of CILSAs proved the chemical integrity of CIL in SAs, while scanning electron microscopy revealed the spherical shape of CILSAs. Results: Differential scanning calorimetry and powder X-ray diffraction studies confirmed that CIL was rendered more amorphous in CILSAs. CILSAs displayed good flow behavior, high percentage yield, and high drug loads. The batch F4 composed of PEG 6000 emerged as the optimized batch as it displayed high percentage dissolution efficiency (57.01 ± 0.01%), which was significantly greater (p < 0.001) compared to CIL (26.27 ± 0.06%). The optimized formulation of CILSAs was directly compressed into ODTs that were rendered porous by vacuum drying. The optimized formulation of porous ODTs (T3) displayed low friability (0.28 ± 0.03%), short disintegration time (6.26 ± 0.29 s), and quicker dissolution (94.16 ± 1.41% in 60 min) as compared to marketed tablet Cildipin® 10 mg (85 ± 2.3%). Conclusions: Thus, porous ODTs of CILSAs can rapidly release the drug, bypass gut metabolism, enhance oral bioavailability, and improve CIL's therapeutic effectiveness for angina and hypertension.

Effect of pH adjustment and ratio of oppositely charged polymers on the mechanistic performance and sustained release of volatile perfume in interpolyelectrolyte complex microcapsules

In this study, volatile perfume was encapsulated in microcapsules (MCs) via interpolyelectrolyte complexes (IPECs) of oppositely charged polymers, with high encapsulation efficiency, to be delivered in a sustained manner. Positively charged chitosan (CTS) and negatively charged Eudragit® S100 (ES100) were used as eco-friendly biopolymers. Limonene (LMN) was selected as the model perfume. First, the solution of LMN in ethyl acetate and poloxamer 407 (POX407) in acidic solution was emulsified using ultrasonication. CTS and ES100 were added in that particular order to form o/w emulsion. LMN-loaded microcapsules (LMN-MCs) were prepared by adjusting the pH and freeze-drying for solidification. The electrostatic interactions of CTS and ES100 to form IPECs were highly dependent on pH, changing in the microscopic images of emulsion droplets and zeta potential. The NH₃⁺ group of CTS and the COO^- group of ES100 caused the electrostatic interactions at a specific pH. The formation mechanism of LMN-MCs was successfully validated using instrumental analysis, charge density, and energy dispersive X-ray spectrometer (EDS) mapping. Encapsulation efficiency, loading content, and release rates of LMN-MCs varied according to the ratios of CTS and ES100, demonstrating optimal performance at a 1:1 ratio. The current LMN-MCs could provide a simple manufacturing process with high performance in terms of encapsulation efficiency (>94%), drug loading, yield and sustained release of volatile perfume for 120 h.

Melt Dispersion Adsorbed onto Porous Carriers: An Effective Method to Enhance the Dissolution and Flow Properties of Raloxifene Hydrochloride

The objective of the present investigation is to enhance the dissolution and flow properties of raloxifene hydrochloride (RXH), a biopharmaceutical classification system class II drug. Melt dispersion of RXH with polyethylene glycol (PEG) 6000 was prepared by the fusion method. The melt dispersion was then adsorbed onto a porous adsorbent, Neusilin, by the melt adsorption method. Response surface methodology was employed to establish the design space for formulation variables such as the ratio of RXH to PEG 6000 in melt dispersion and amount of porous adsorbent to melt dispersion. Differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and accelerated stability techniques were utilized to characterize formulations. Negative Gibbs free energy values indicated spontaneous solubilization of RXH in PEG 6000. The time required for 80% of drug release from optimized formulation was <20 min compared with plain RXH. Accelerated stability studies confirmed the stabilization of amorphous melt dispersion in nanopores (nanoconfinement) of inorganic silicate Neusilin. Melt dispersion, adsorbed on porous carriers, is a promising technique to improve the dissolution characteristic as well as flow properties of drug molecules.

A 2D-g-C3N4 nanosheet as an eco-friendly adsorbent for various environmental pollutants in water

A novel graphitic carbon nitride (g-C₃N₄) nanosheet adsorbent with a large surface area, remarkable hydrophilicity and high adsorption capacity, was presented for the removal of cadmium ions (Cd²⁺) and methylene blue (MB) from aqueous solution. Adsorption measurements were conducted systematically to study the influences of the contact time, initial concentrations of Cd²⁺ and MB, temperature, and pH value. The maximum adsorption capacities of g-C₃N₄ towards Cd²⁺ and MB were 94.4 and 42.1 mg g^-1, respectively, at 318.5 K when the initial concentrations of Cd²⁺ and MB were 200 and 20 mg L^-1, respectively. The adsorption kinetics fit a pseudo-second-order model. The high adsorption performance of the g-C₃N₄ adsorbent can be attributed to the multiple adsorption sites on g-C₃N₄, including the π-π conjugate interactions and electrostatic attractions with pollutants in water. In addition, it is significant to achieve high adsorption performance of g-C₃N₄ nanosheets by efficiently exposing the adsorption sites by adjusting the microstructure surface properties and dispersity in solution.

Development and characterization of nifedipine-amino methacrylate copolymer solid dispersion powders with various adsorbents

Solid dispersions of nifedipine (NDP), a poorly water-soluble drug, and amino methacrylate copolymer (AMCP) with aid of adsorbent, that is, fumed silica, talcum, calcium carbonate, titanium dioxide, and mesoporous silica from rice husks (SRH), were prepared by solvent method. The physicochemical properties of solid dispersions, compared to their physical mixtures, were determined using powder X-ray diffractometry (PXRD) and differential scanning calorimetry (DSC). The surface morphology of the prepared solid dispersions was examined by scanning electron microscopy (SEM). The dissolution of NDP from solid dispersions was compared to NDP powders. The effect of adsorbent type on NDP dissolution was also examined. The dissolution of NDP increased with the ratio of NDP:AMCP:adsorbent of 1:4:1 when compared to the other formulations. As indicated from PXRD patterns, DSC thermograms and SEM images, NDP was molecularly dispersed within polymer carrier or in an amorphous form, which confirmed the better dissolution of solid dispersions. Solid dispersions containing SRH provided the highest NDP dissolution, due to a porous nature of SRH, allowing dissolved drug to fill in the pores and consequently dissolve in the medium. The results suggested that solid dispersions containing adsorbents (SRH in particular) demonstrated improved dissolution of poorly water-soluble drug when compared to NDP powder.