“…It is worth noting that at body temperature the G ʹʹ value of GEL1 became obviously lower than that of GEL2. It is known that the gelation capability of poloxamer solutions depends closely on the polymer concentration22, 23, 24. Our result indicated that both the two formulations had adequate anti-dilution capacity, assuring that they could form hydrogels after administration in the vagina even after dilution by vaginal fluid.Figure 3Effect of dilution on the gelation process of the hydrogel formulations (5 mL) with 0.5 mL (A and B) or 0.75 mL (C and D) simulated vaginal fluid.…”
The purpose of this study is to evaluate the in vivo retention capabilities of poloxamer-based in situ hydrogels for vaginal application with nonoxinol-9 as the model drug. Two in situ hydrogel formulations, which contained 18% poloxamer 407 plus 1% poloxamer 188 (GEL1, relative hydrophobic) or 6% poloxamer 188 (GEL2, relative hydrophilic), were compared with respect to the rheological properties, in vitro hydrogel erosion and drug release. The vaginal retention capabilities of these hydrogel formulations were further determined in two small animal models, including drug quantitation of vaginal rinsing fluid in mice and isotope tracing with 99mTc in rats. The two formulations exhibited similar phase transition temperatures ranging from 27 to 32 °C. Increasing the content of poloxamer 188 resulted in higher rheological moduli under body temperature, but slightly accelerated hydrogel erosion and drug release. When compared in vivo, GEL1 was eliminated significantly slower in rat vagina than GEL2, while the vaginal retention of these two hydrogel formulations behaved similarly in mice. In conclusion, increases in the hydrophilic content of formulations led to faster hydrogel erosion, drug release and intravaginal elimination. Rats appear to be a better animal model than mice to evaluate the in situ hydrogel for vaginal application.
“…It is worth noting that at body temperature the G ʹʹ value of GEL1 became obviously lower than that of GEL2. It is known that the gelation capability of poloxamer solutions depends closely on the polymer concentration22, 23, 24. Our result indicated that both the two formulations had adequate anti-dilution capacity, assuring that they could form hydrogels after administration in the vagina even after dilution by vaginal fluid.Figure 3Effect of dilution on the gelation process of the hydrogel formulations (5 mL) with 0.5 mL (A and B) or 0.75 mL (C and D) simulated vaginal fluid.…”
The purpose of this study is to evaluate the in vivo retention capabilities of poloxamer-based in situ hydrogels for vaginal application with nonoxinol-9 as the model drug. Two in situ hydrogel formulations, which contained 18% poloxamer 407 plus 1% poloxamer 188 (GEL1, relative hydrophobic) or 6% poloxamer 188 (GEL2, relative hydrophilic), were compared with respect to the rheological properties, in vitro hydrogel erosion and drug release. The vaginal retention capabilities of these hydrogel formulations were further determined in two small animal models, including drug quantitation of vaginal rinsing fluid in mice and isotope tracing with 99mTc in rats. The two formulations exhibited similar phase transition temperatures ranging from 27 to 32 °C. Increasing the content of poloxamer 188 resulted in higher rheological moduli under body temperature, but slightly accelerated hydrogel erosion and drug release. When compared in vivo, GEL1 was eliminated significantly slower in rat vagina than GEL2, while the vaginal retention of these two hydrogel formulations behaved similarly in mice. In conclusion, increases in the hydrophilic content of formulations led to faster hydrogel erosion, drug release and intravaginal elimination. Rats appear to be a better animal model than mice to evaluate the in situ hydrogel for vaginal application.
“…Only a few studies have been carried out on developing non-oral sustained release SDF dosage forms using polymers, for example, lung-delivered, controlled release formulations of SDF with poloxamer-407 (P-407) [ 8 ] or a vaginal controlled release suppository of SDF containing EVAC 210 polymer [ 9 ]. In addition, some SDF formulations were prepared with polymers, such as SDF nano-dispersion inhalers incorporating poloxamer-188 (P-188) [ 10 ], SDF solid lipid nanoparticles formulated with gelucire 44/14 [ 11 ], SDF spray-dried microparticle inhalers formed by using sodium carboxymethylcellulose, sodium alginate, and sodium hyaluronate [ 12 ], SDF-loaded polymeric microparticles based on poly(lactide-co-glycolide) [ 13 ], and an SDF microemulsion-loaded hydrogel [ 14 ].…”
Sildenafil is the active substance in Viagra® tablets, which is approved by the FDA to treat sexual dysfunction in men. Poor solubility and short half-life, however, can limit the span of its effectiveness. Therefore, this study focused on an oral controlled release matrix system with the aim to improve solubility, control the drug release, and sustain the duration of drug activity. The controlled release matrices were prepared with poloxamer-188, hydroxypropyl methylcellulose, and magnesium stearate. Various formulations of different ratios were developed, evaluated in vitro, and assessed in silico. Poloxamer-188 appeared to have a remarkable influence on the release profile of sildenafil citrate. In general, the rate of drug release decreased as the amount of polymer was gradually increased in the matrix system, achieving a maximum release period over 12 h. The in silico assessment by using the GastroPlus™ PBPK modeling software predicted a significant variation in Cmax, tmax, t½, and AUC0-t among the formulations. In conclusion, the combination of polymers in matrix systems can have substantial impact on controlling and modifying the drug release pattern.
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