In recent years, in situ gel delivery systems have received a great deal of attention among pharmacists. The in situ gelation mechanism has several advantages over ointments, the most notable being the ability to provide regular and continuous drug delivery with no impact on visual clarity. Bioavailability, penetration, duration, and maximum medication efficacy are all improved by this mechanism. Our review systematically synthesizes and discusses comparisons between three types of in situ gelling system according to their phase change performance based on the physicochemical aspect from publications indexed in the Pubmed, ResearchGate, Scopus, Elsevier, and Google Scholar databases. An optimal temperature-sensitive in situ gelling solution must have a phase change temperature greater than ambient temperature (25 °C) to be able to be readily delivered to the eye; hence, it was fabricated at 35 °C, which is the precorneal temperature. In a pH-sensitive gelling system, a gel develops immediately when the bio-stimuli come into contact with it. An in situ gelling system with ionic strength-triggered medication can also perhaps be used in optical drug-delivery mechanisms. In studies about the release behavior of drugs from in situ gels, different models have been used such as zero-order kinetics, first-order kinetics, the Higuchi model, and the Korsmeyer-Peppas, Peppas-Sahlin and Weibull models. In conclusion, the optimum triggering approach for forming gels in situ is determined by a certain therapeutic delivery application combined with the physico-chemical qualities sought.

Background/Objectives: The Self-Nanoemulsifying Drug Delivery System (SNEDDS) has been widely applied in oral drug delivery, particularly for poorly water-soluble compounds. The successful development of SNEDDS largely depends on the precise composition of its components. This narrative review provides an in-depth analysis of Quality by Design (QbD), Design of Experiment (DoE), and in silico approach applications in SNEDDS development. Methods: The review is based on publications from 2020 to 2025, sourced from reputable scientific databases (Pubmed, Science direct, Taylor and francis, and Scopus). Results: Quality by Design (QbD) is a systematic and scientific approach that enhances product quality while ensuring the robustness and reproducibility of SNEDDS, as outlined in the Quality Target Product Profile (QTPP). DoE was integrated into the QbD framework to systematically evaluate the effects of predefined factors, particularly Critical Material Attributes (CMAs) and Critical Process Parameters (CPP_S), on the desired responses (Critical Quality Attributes/CQA), ultimately leading to the identification of the optimal SNEDDS formulation. Various DoEs, including the mixture design, response surface methodology, and factorial design, have been widely applied to SNEDDS formulations. The experimental design facilitates the analysis of the relationship between CQA and CMA/CPP, enabling the identification of optimized formulations with enhanced biopharmaceutical, pharmacokinetic, and pharmacodynamic profiles. As an essential addition to this review, in silico approach emerges as a valuable tool in the development of SNEDDS, offering deep insights into self-assembly dynamics, molecular interactions, and emulsification behaviour. By integrating molecular simulations with machine learning, this approach enables rational and efficient optimization. Conclusions: The integration of QbD, DoE, and in silico approaches holds significant potential in the development of SNEDDS. These strategies enable a more efficient, rational, and predictive formulation process.

The physicochemical properties of κ-carrageenan gels and their ester forms derived from different fatty-acid saturations were characterized and compared with those of native κ-carrageenan. Furthermore, stearic and oleic acids were used as the saturated and unsaturated fatty acids, respectively. Fourier-transform infrared (FTIR) spectra confirmed the introduction of the ester into the κ-carrageenan backbone. The thermogravimetric analysis showed that thermal stability increased along with the level of unsaturation, but there was a decrease in viscosity, hardness, and syneresis, which caused the consistency of the product to become more elastic. The results also showed that the ester form still has a swelling ability that is almost the same as that of κ-carrageenan. After being formulated into a gel dosage form, the product was successfully produced from the ester with unsaturated fatty acids, and it was more elastic than native κ-carrageenan and had good physical properties with spreadability that meets the requirements for topical preparations.

Simvastatin-nicotinamide co-crystal: design, preparation and preliminary characterization

Gambir (Uncaria gambir, Roxb.) contains catechins that is often empirically used to treat various diseases. Catechins can reduce cholesterol levels by inhibiting coenzyme HMG-CoA reductase that plays a role in cholesterol metabolism. Research has been carried out covering the optimization of transethosomal catechins, the formulation of Transethosomal Catechin Gel (TCG) and Non-Transethosomal Catechin Gel (NTCG), which were then tested for catechin permeation from these gel preparations in vitro using Franz’s diffusion cell with PTFE membranes. The anti-hypercholesterol activity test was carried out with Simvastatin orally as a positive control using 25 male Wistar rats (Rattus norvegicus). The catechin transetosomes have a size of 176.1 ± 5.8 nm, Zeta potential −11.6 ± 5.28, and Entrapment Efficacy of 96.77% ± 0.05. The result of cumulative catechins that permeated from TCG and NTCG were and 172.454 ± 5.287 and 112.741 ± 2.241 μg respectively. Permeation test graphs showed similar permeation and flux profiles. TCG can reduce total cholesterol and LDL (Low Density Lipoprotein) values in rats by 39.77% and 51.52% respectively during 14 days of use.

Forced degradation study is the degradation of new drug substances and drug products in more severe conditions than accelerated conditions. Forced degradation study were conducted to demonstrate the specificity of stability-indicating methods, providing insight into degradation pathways and drug degradation products, assisting in the elucidation of degradation product structures, identifying degradation products that could be spontaneously generated during storage and use of drugs and to facilitate improvement in manufacturing process and formulation corresponding with accelerated stability studies. Statins, a class of lipid-lowering medications, are the most widely prescribed drugs and an example of an unstable drug. Statins are susceptible to hydrolysis in the presence of high temperatures and humidity. Therefore, the review discusses various studies of forced degradation studies in six statins drug (atorvastatin, fluvastatin, pitavastatin, pravastatin, rosuvastatin, and simvastatin) to describe the drug's intrinsic stability thus it can assist the selection of formulations and packaging as well as proper storage conditions.