Formulation Optimization of Estradiol Microemulsion Using Response Surface Methodology

Improving the clarity and sensitization of polysorbate 80 by ultrasonic-assisted ultrafiltration technology

The safety problem of injections caused by clarity has lately become a widely shared concern. Due to the synthesis process, polysorbate 80 had a wide molecular weight distribution, which is also related to the clinical anaphylaxis. In this paper, ultrasonic-assisted ultrafiltration (UAU) technology was firstly applied to regulate colloidal structure and remove macromolecules from polysorbate 80 to improve injection clarity. In the separation process, ultrafiltration molecular weight cut off (MWCO), ultrasonic power and polysorbate 80 concentraion were selected as variables to adjust the separation efficiency. The ultrasonic frequency and power were provided by KQ-700DE ultrasonic system, based on the data analysis by response surface methodology (RSM), the optimal UAU parameters were as follows: ultrafiltration MWCO of 50,000, ultrasonic power of 900 W and polysorbate 80 concentration of 15.00 mg/mL. The experimental transmittance of polysorbate 80 was 87.6% and the qualification rate of clarity was 94.5%, which solved the separation contradiction among yield, clarity and safety. As an innovation in colloidal separation fields, UAU had a vast range of prospects for making use in pharmaceutical area.

Design and Development of Repaglinide Microemulsion Gel for Transdermal Delivery

Microemulsion formulation of repaglinide, a BCS class II hypoglycemic agent with limited oral bioavailability, was developed considering its solubility in various oils, surfactants, and cosurfactants. The pseudo-ternary phase diagrams for microemulsion regions were constructed by water titration method at K _m 1:1 and characterized for optical birefringence, percentage transmittance, pH, refractive index, globule size, zeta potential, viscosity, drug content, and thermodynamic stability. To enhance the drug permeation and residence time, the optimized microemulsions having mean globule size of 36.15 ± 9.89 nm was gelled with xanthan gum. The developed microemulsion-based gel was characterized for globule size, zeta potential, pH, and drug content. All evaluation parameters upon gelling were found to be satisfactory. Ex vivo permeability study across rat skin demonstrated higher steady-state flux (P < 0.05) for microemulsion of repaglinide in comparison to the repaglinide microemulsion gel. At the end of 24 h, the cumulative drug permeation from microemulsion and microemulsion gel was found to be 229.19 ± 24.34 and 180.84 ± 17.40 μg/cm², respectively. The microemulsion formulation showed 12.30-fold increase in flux as compared to drug suspension with highest enhancement ratio (E _r ) of 12.36. Whereas microemulsion gel exhibited 10.97-fold increase in flux (with highest E _r , 11.78) as compared to repaglinide (RPG) suspension. In vivo efficacy study was performed in normal Sprague-Dawley rats by using oral glucose tolerance test. Results of RPG transdermal microemulsion gel demonstrated remarkable advantage over orally administered RPG by reducing the glucose level in controlled manner. Hence, it could be a new, alternative dosage form for effective therapy of type 2 diabetes mellitus.

An optimized two-step derivatization method for analyzing diethylene glycol ozonation products using gas chromatography and mass spectrometry

The ozonation of hydroxyl compounds (e.g., sugars and alcohols) gives a broad range of products such as alcohols, aldehydes, ketones, and carboxylic acids. This study developed and optimized a two-step derivatization procedure for analyzing polar products of aldehydes and carboxylic acids from the ozonation of diethylene glycol (DEG) in a non-aqueous environment using gas chromatography-mass spectrometry. Experiments based on Central Composite Design with response surface methodology were carried out to evaluate the effects of derivatization variables and their interactions on the analysis. The most desirable derivatization conditions were reported, i.e., oximation was performed at room temperature overnight with the o-(2,3,4,5,6-pentafluorobenzyl) hydroxyl amine to analyte molar ratio of 6, silylation reaction temperature of 70°C, reaction duration of 70min, and N,O-bis(trimethylsilyl)-trifluoroacetamide volume of 12.5μL. The applicability of this optimized procedure was verified by analyzing DEG ozonation products in an ultrafine condensation particle counter simulation system.

Formulation optimization of arecoline patches

The response surface methodology (RSM) including polynomial equations has been used to design an optimal patch formulation with appropriate adhesion and flux. The patch formulations were composed of different polymers, including Eudragit RS 100 (ERS), Eudragit RL 100 (ERL) and polyvinylpyrrolidone K30 (PVP), plasticizers (PEG 400), and drug. In addition, using terpenes as enhancers could increase the flux of the drug. Menthol showed the highest enhancement effect on the flux of arecoline.

Isotretinoin oil-based capsule formulation optimization

The purpose of this study was to develop and optimize an isotretinoin oil-based capsule with specific dissolution pattern. A three-factor-constrained mixture design was used to prepare the systemic model formulations. The independent factors were the components of oil-based capsule including beeswax (X₁), hydrogenated coconut oil (X₂), and soybean oil (X₃). The drug release percentages at 10, 30, 60, and 90 min were selected as responses. The effect of formulation factors including that on responses was inspected by using response surface methodology (RSM). Multiple-response optimization was performed to search for the appropriate formulation with specific release pattern. It was found that the interaction effect of these formulation factors (X₁X₂, X₁X₃, and X₂X₃) showed more potential influence than that of the main factors (X₁, X₂, and X₃). An optimal predicted formulation with Y_10 min, Y_30 min, Y_60 min, and Y_90 min release values of 12.3%, 36.7%, 73.6%, and 92.7% at X₁, X₂, and X₃ of 5.75, 15.37, and 78.88, respectively, was developed. The new formulation was prepared and performed by the dissolution test. The similarity factor f₂ was 54.8, indicating that the dissolution pattern of the new optimized formulation showed equivalence to the predicted profile.