Promoting effect of transdermal absorption of essential oils from Chinese materia medica and problem analysis in study of topical preparations / 中草药

In recent years, essential oils have drawn more and more attention of pharmaceutical workers due to its low toxicity and strong pharmacological activity. In addition to some pharmacological effects, some volatile oil also can be used as a good transdermal absorption enhancer, which has been widely used in topical preparation. The effect and mechanism of volatile oil as transdermal enhancers are different according to different kinds and active ingredients of essential oils. This paper summarizes the related researches on the promoting effect and mechanism of essential oil absorption by skin in recent years. The author analyzes the existing problems in the application of volatile oils in the topical preparations, so as to provide a reference for the later research.

Absorption characteristics of the total alkaloids from Mahonia bealei in an in situ single-pass intestinal perfusion assay / 中国天然药物

AIM@#To investigate the absorption characteristics of the total alkaloids from Mahoniae Caulis (TAMC) through the administration of monterpene absorption enhancers or protein inhibitors.@*METHOD@#The absorption behavior was investigated in an in situ single-pass intestinal perfusion (SPIP) assay in rats.@*RESULTS@#The intestinal absorption of TAMC was much more than that of a single compound or a mixture of compounds (jatrorrhizine, palmatine, and berberine). Promotion of absorption by the bicyclic monoterpenoids (borneol or camphor) was higher than by the monocyclic monoterpenes (menthol or menthone), and promotion by compounds with a hydroxyl group (borneol or menthol) was higher than those with a carbonyl group (camphor or menthone). The apparent permeability coefficient (Papp) of TAMC was increased to 1.8-fold by verapamil, while it was reduced to one half by thiamine. The absorption rate constant (Ka) and Papp of TAMC were unchanged by probenecid and pantoprazole.@*CONCLUSION@#The intestinal absorption characteristics of TAMC might be passive transport, and the intestinum tenue was the best absorptive site. In addition, TAMC might be likely a substrate of P-glycoprotein (P-gp) and organic cation transporters (OCT), rather than multidrug resistance protein (MRP) and breast cancer resistance protein (BCRP). Compared with a single compound and a mixture of compounds, TAMC was able to be absorbed in the blood circulation effectively.

Non invasive insulins: advanced insulin therapy over this decade.

Frederick Banting and Charles Best extracted insulin from bovine pancreas in 1922, who received the Nobel Prize for their contribution in Medical field with John McLeod. Conventional insulin treatment involves replacement therapy, which involves the administration of insulin exogenously via subcutaneous route to mimic the pancreatic insulin secretion. Many people with types 1 and 2 diabetes over the world have used subcutaneous injections daily in order to control blood glucose level and/or to eradicate ketoacidosis which is really life threatening. Although, these injections avoid many complications, they became a source of inconvenience and lack of comfort. currently many other techniques have been investigated which resulted in delivering insulin other than subcutaneous route. These formulations are designed in such a way that they will overcome the inherent barriers of insulin uptake across the skin, gastro intestinal tract and mucous membrane. Various routes other than sub cutaneous which are under investigation for insulin therapy include oral, pulmonary, transdermal; nasal, buccal, ocular, rectal etc. Many approaches have been pursued in order to deliver insulin orally which include the use of absorption enhancers,inhibitors of proteases,inclusion of mucoadhesive components,buffers,micro and nano particles,liposomes,niosomes,microspheres,hydrogels, smart polymers etc.Over last few decades research is going on several non invasive routes for the delivery of insulin and many of them have stepped into pre clinical and clinical trials. Even products like Exubera ® and Oral-lyn™ were marketed after passing phase 3 clinical trials. Non invasive insulin delivery will definitely prove to be a boon to several patients who are currently depending on daily subcutaneous multiple injections.

Percutaneous absorption enhancers: mechanisms and potential

Transdermal applications of drugs present many advantages in terms of absorption, however this is not easily obtained through the transdermal route. The principle barrier is the stratum corneum and one of the strategies that have been found to promote cutaneous drug penetration is through the use of absorption enhancers. Many substances have been identified as absorption enhancers. Although the list of substances that promote absorption is growing, in most cases, there is a direct correlation between the effects of absorption enhancers and their skin toxicity. The use of these substances depends therefore on studies which focus on local and systemic toxicity, as well as action mechanisms.

A via transdérmica para a absorção de fármacos apresenta várias vantagens, porém a absorção através desta via não é fácil de ser obtida. A principal barreira encontrada é o estrato córneo e uma das estratégias encontradas para promover a permeação cutânea de fármacos é o uso de promotores de absorção. Há uma variedade de substâncias identificadas como promotores de absorção. Enquanto a lista de substâncias de promotores de absorção percutânea vem aumentando, na maioria dos casos, há uma correlação entre o efeito promotor e a toxicidade para a pele. O emprego destas substâncias depende, portanto, de estudos enfocando a toxicidade local e sistêmica, bem como o mecanismo de ação.

Studies on ?-cobro-neurotoxin-loaded Poly(lactic-co-glycolic Acid) Nanoparticles: Preparation and Pharmacokinetics in vivo through Nasal Administration / 浙江中医药大学学报

[Objective] To investigate the possibility of [poly(lactic-co-glycolic acid) ,PLGA] nanoparticles (NP) as a new kind of protein drug carrier for nasal administration. [Method] CNT-PLGA-NP was prepared by double emulsification solvent evaporation. Its morphology was examined by transmission electronmicroscope (TEM). In the use of photon correlation spectroscopy(PCS) and laser Doppler anemometry(LDA),its Zeta potential and mean particle size were estimated .Also, the entrapment efficiency of CNT-PLGA-NP and its pharmacokinetics in rats through nasal administration were studied. [Result] The Zeta potential, mean particle size, entrapment efficiency of CNT-PLGA-NP were-13.4mV, 320.20nm and 45% respectively .Its vitro CNT release from CNT-PLGA-NP appeared to consisting of two components with initial rapid release followed by a exponential stage.The AUC and t1/2(?) of CNT, CNT-PLGA-Np and CNT-PLGA-NP(B+T)were 1.14, 8.37, 7.12?g?h/mL and 20.06, 44.14, 34.82h respectively. [Conclusion]PLGA-NP might be a potential new drug carrier for CNT.Polysorbate 80 and borneol might be good absorption enhancers.