Pemilihan Jenis Koformer dan Metode Preparasi dalam Sistem Penghantaran Sediaan Ko-Amorf

Ko-amorf adalah suatu sistem multikomponen padat yang mengandung zat aktif dan molekul dengan berat molekul rendah lainnya (koformer) yang dapat berupa eksipien atau zat aktif yang relevan secara farmakologis. Formulasi ko-amorf yang dibuat dengan metode preparasi dan jenis koformer yang berbeda dapat menghasilkan perbedaan yang signifikan dalam stabilitas fisik dan profil disolusi suatu bentuk ko-amorf. Tujuan penulisan dari artikel review ini adalah untuk menggali informasi lebih dalam tentang sistem ko-amorf, klasifikasi ko-amorf, karakterisasi ko-amorf serta pengaruh jenis koformer dan metode preparasi ko-amorf terhadap pembentukan ko-amorf. Artikel review ini disusun dengan literature search melalui PubMed, MDPI dan Science Direct dengan memasukkan kata kunci co-amorphous, co-amorphous formulations, co-amorphous stabilizers, co-amorphous drug formulations. Dari review ini ditemukan terdapat beberapa jenis koformer yang dapat digunakan untuk pembentukan ko-amorf yaitu dapat berupa zat aktif yang relevan secara farmakologis dan eksipien seperti diantaranya yaitu asam amino, asam karboksilat, asam tanat, quercetin, sakarin dan nikotinamid. Dan untuk metode preparasi ko-amorf yang dapat digunakan diantaranya yaitu ball milling, cryomilling, melt quenching/ quench cooling, hot melt extrusion, solvent evaporation, spray drying, freeze drying hingga teknologi seperti supercritical antisolvent dan microwave technique. Keberhasilan pembentukan ko-amorf ditentukan diantaranya oleh pemilihan jenis koformer yang melibatkan berbagai sifat yang perlu dipertimbangkan, seperti Tg, potensial ikatan hidrogen, ketercampuran/ miscibility, atau perilaku kristalisasi. Sifat zat aktif dan eksipien seperti stabilitas termal, suhu leleh dan kecenderungan kristalisasi zat aktif dan eksipien, menjadi faktor yang perlu diperhatikan dalam pemilihan metode preparasi ko-amorf.

Optical and Electrical Properties of Nd3+doped Na2O-ZnO-TeO2 Material

Neodymium-doped Na2O-ZnO-TeO2 (NZT) glasses were prepared by the conventional melt quenching technique. DTA and TG were used to confirm glass preparation through the glass transition temperature at 447°C for the glass system. The analysis of FTIR spectra and X-ray diffraction described the samples' nature as ionic and amorphous, respectively. The optical band gap energy was estimated using absorption spectra and found to be decreased from 2.63eV to 1.32 eV due to the increase of doping concentration. The intensity of the emission spectra was enhanced for the higher concentration of Nd3+ ions. The dielectric constant of the glass samples was found to be constant for the large range of frequency (3 kHz to 1 MHz). The variation of conductivity with the temperature of the samples had shown the Arrhenius mechanism of conduction.

Structure and spectral properties of Fe:ZnAl2O4 transparent glass-ceramics and ceramic

Transparent glass-ceramics based on iron-doped ZnAl2O4 (gahnite) nanocrystals were prepared by melt-quenching (at 1580 °C) with subsequent heat-treatments (at 720 – 1050 °C). Polycrystalline transparent Fe:ZnAl2O4 ceramic was synthesized by hot pressing of powders (at 1600 °C, 50 MPa) using the sintering additive, ZnF2. A comparative study of the structure, Raman spectra and absorption properties of these materials was performed.

Correlation among the oxide ion polarizability, optical basicity and interaction parameter in Gd3+ ions doped oxyhalide borate glasses

A borate glasses doped with rare earth Gd3+ ion in the system [6OB2O3 + 30 L12O + x Gd2O3 + (10-x) BiCl3] is prepared by the conventional melt quenching method and their optical properties have been studied. The oxide ion polarizability parameter is calculating by using refractive index of glass materials, which is obtained from UV-Vis spectra. The borate glasses are known to possess high oxide ion polarizability, high refractive index, high basicity and low interaction parameter values. In this present study, theoretical calculation of basicity and interaction parameter, using oxide ion polarization, of the glass network has been addressed. A good linear correlation between the interaction parameter and basicity is observed.

Luminescent Properties of a Novel Mn2+ doped 3CaO-CaF2-2SiO2 Glasses

The transition metal Mn2+ ions doped materials have been widely reported for the luminescent properties for its broad emission band from green to red due to the spin-forbidden 4T1→6A1 transitions. To investigate the luminescent properties of Mn2+ ions in cuspidine glass, the 3CaO-CaF2-2SiO2 glasses doped with different Mn2+ concentration were prepared with traditional melt-quenching method. The luminescence emission spectra, excitation spectra and luminescence decay curves were recorded and analyzed. The tunable broadband emission from orange to red was obtained. The luminescence intensity and lifetime of Mn2+: 4T1 level showed different quenching points with the increasing of Mn2+ concentration. All these results indicate that Mn2+ doped 3CaO-CaF2-2SiO2 glass could be applied as light conversion material for solid-state lighting applications.

The ionic conductivity of alkali aluminum germanium phosphate glasses – comparison of Plasma CAIT with two electrode DC measurements

The ionic conductivity of alkali aluminum germanium phosphates (MAGP) has been investigated by two different techniques, i.) a fs-Plasma-Charge Attachment Induced Transport (CAIT) approach and ii.) a classical two electrode DC approach. Amorphous MAGP samples of the composition M1.5Al0.5Ge1.5(PO4)3 M=(Li–Cs) have been synthesized by the melt-quenching technique. Comparison of fs-Plasma-CAIT and DC data reveal that the ionic conductivities as well as the activation energies for ion transport agree within the error margins of the experiment. While conventional expectation suggests that a DC approach should fail because of spontaneous charge carrier blocking, this work demonstrates that DC measurements are a simple tool for quantifying ionic conductivities provided that only a small amount of charge has been transported in total.

A Significant Role of MoO3 on the Optical, Thermal, and Radiation Shielding Characteristics of B2O3-P2O5 -Li2O Glasses

Glasses based on borophosphate with the formula 42.5P2O5 – 42.5B2O3 – (15-x) Li2O – xMoO3 mol% where 𝑥 = (0 ≤ 𝑥 ≥ 15) were manufactured using the melt-quenching methodology. The status of prepared samples wasidentified by (XRD). The temperature of the glass transition Tg, the temperature of onset glass crystallisation Tc and the temperature of the crystallisation Tp were evaluated using a differential thermal analyser (DTA). The energy gap (𝐸𝑜𝑝𝑡), Urbach (𝐸𝑢), and parameters of dispersion were calculated through the data of optical spectra. Physical properties were determined and calculated, such as molar refractivity, metallization, electron polarizability, electronegativity, loss of reflection and dispersion parameters. Raising MoO3 at the expense of Li2O was used to assess the level of protection. For radiation protection applications, the glasses under investigation had superior characteristics.