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Supersaturated drug delivery systems (SDDS) are defined as systems that are able to generate and maintain a sustained drug supersaturation in the gastrointestinal tract, facilitating the oral absorption of drugs with poor water solubility. Supersaturated drug solution is generated from a higher energy form of the drug or rapid dissolution through various formulation options. However, supersaturated solution is a thermodynamically unstable system that can easily lead to drug precipitation, missing the aim of improving the absorption. Therefore, maintenance of the supersaturated state is essential for the development of SDDS. Polymer-based SDDS take polymers as the precipitation inhibitor,which can effectively prevent the precipitation of drugs, generating an excellent effect on maintenance of the stability of supersaturated solution. However, different polymers have distinct anti-precipitation ability, and the mechanisms of such activity supported by the polymer remain unrevealed. In this review, we summarize the research advances in the absorption-enhancing mechanisms and in vitro evaluations of polymers-based SDDS. This review provides a reference for the design of rational SDDS.
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AIM To compare the effects of three preparation technologies on the oral bioavailability of HB (berberine α-hydroxy β-decanoylethyl sulfonate,houttuyn berberine).METHODS Solid dispersions,HP-β-CD inclusion complexes and nanosuspension freeze-dried powders were prepared.The suspensions of crude drug and these three preparations were intragastrically administered to SD rats,respectively.HPLC-MS/MS was adopted in the content determination of HB in plasma.then pharmacokinetics parameters were calculated.RESULTS Compared with the crude drug,three preparation technologies could significantly increase the Cmax value of this component (P ＜ 0.05),especially for HP-β-CD inclusion complexes (P ＜ 0.01).And HP-β-CD inclusion complexes demonstrated much higher AUC0-6h than the crude drug and the other two preparation technologies (P ＜ 0.05).CONCLUSION HP-β-CD inclusion complexes can effectively increase the oral bioavailability of HB.
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Poly(2-ethyl-2-oxazoline) (PEOz), a hydrophilic long-chain polymer synthesized by living cationic ring-opening isomerization polymerization of 2-ethyl-2-oxazoline, has the characteristics of low toxicity, biocompatibility, flexible chain, and modified expediently. PEOz is a potential substitute of polyethylene glycol (PEG) to render the ability of long-circulation, enhance cellular uptake and endosomal escape behaviors to PEOz modified drug delivery system. In this review, we summarized recent literature for the research progress of physicochemical properties, synthetic methods and the application of PEOz in drug delivery system.
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L-Glutamate is an important amino acid in protein. It has many physiological functions, such as nutrient metabolism, energy supply, immune response, oxidative stress, and signaling pathways regulation. Recent studies have found that glutamate prevents gastrointestinal damage induced by non-steroidal anti-inflammatory drugs (NSAIDs) and promotes the healing of the lesions. It can inhibit colonization of Helicobacter pylori and cell apoptosis caused by NH3. Hence, it has a potential value in protection of gastrointestinal from damage caused by NSAIDs and Helicobacter pylori. This article provides a review of the metabolism and physiological function of glutamate and its protective mechanisms of gastrointestinal injury caused by NSAIDs and Helicobacter pylori, which may serve as a reference in the study of glutamate in drug development.
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<p><b>AIM</b>To establish an HPLC-MS method for determination of octreotide in plasma and study the relative bioavailability of domestic and imported octreotide injections.</p><p><b>METHODS</b>Octreotide in plasma samples were extracted with a Waters solid-phase extraction mini column. HPLC-MS was carried out using a Waters Xetrra C18 column and a mobile phase consisting of CH3 OH-1% HAc (80 : 20), the flow rate was 0.2 mL x min(-1), and the internal standard was 6, 7, 4'-OH-isoflavone, the SIR ions for quantification were m/z 1 014.4 for octreotide and m/z 317.6 for internal standard. A single dose of 200 microg of domestic or imported preparations was intramuscularly given to 18 healthy volunteers in a randomized crossover study. Octreotide concentration in plasma was determined by LC-MS method. The pharmacokinetics and bioavailability were studied.</p><p><b>RESULTS</b>The regressive curve was linear (r = 0.9997) within the range of 0.5 - 40 microg x L(-1) for octreotide. The pharmacokinetics parameters of domestic and imported injection were reply to one compartment model. The mean C(max) were (19 +/- 10) microg x L(-1) and (19 +/- 11) microg x L(-1), T(max) were (0.50 +/- 0.15) h and (0.52 +/- 0.20) h, T1/2 were (1.5 +/- 0.8) h and (1.5 +/- 0.8) h, AUC(0-7 h) were (50 +/- 25) h x microg x L(-1) and (50 +/- 25) h x microg x L(-1), respectively. The relative bioavailability of domestic to imported injection was 101% +/- 10%.</p><p><b>CONCLUSION</b>The method is accurat and sensible for assay of plasma octreotide concentration. The results of statistics showed the two preparations were bioequivalent.</p>