Preparation of Levothyroxine Transdermal Absorption Gels and Preliminary Animal Studies

Author:Chai Jin Yan

Supervisor:tan jian


Degree Year:2016





Thyroxine(T4)was synthesized from thyroid,which was important to human body.Thyroid hormones was the only hormone replacement drug for the treatment of Hypothyroidism.Hypothyroidism was a frequently-occurring disease,including male,female,old and young can happen,which was a systemic and chronic disease.If not timely and reasonable treatment,Children can become cretinism and lifelong disability,adult severe cases may lose labor ability or even life ability,which seriously affect the quality of the population.But as long as the use of reasonable treatment can obtain ideal curative effect,the only way is thyroid hormones replacement therapy.The current domestic pills were thyroid tablet,L-T4 and L-T3.The current domestic medical field by German imports(L-T4)occupied almost the whole of the medical market which was always out of stock.Domestic manufacturer of dry thyroid tablets were also reduced.At home there was no other thyroid hormone dosage forms.Hypothyroidism patients were lifelong medication,including children particularly newborn infant feeding medicine everyday was inconvenient.Adult Hypothyroidism has not or would not oral people,such as patients with gastrointestinal diseases.This project intends to develop a new dosage form of percutaneous drug delivery.ObjectivePreparation Levothyroxine transdermal absorption gels;Screening,optimization of Levothyroxine gels formula and quality was studied for the thyroid hormone gels;Study the in vitro transdermal behavior of the gels and establish Levothyroxine gels in vitro release and in vitro transdermal performance measurement method,investigate Levothyroxine gels in vitro release behavior;Successful build a Hypothyroidism rat model;Daub by animal experiment,this paper observes the effect of preliminary treatment using Levothyroxine gels on Hypothyroidism rat model.MethodsLevothyroxine gels in vitro transdermal experiment was carried out by the vertical Franz diffusion pool.Use high performance liquid chromatography(HPLC)method to determine the content of thyroid hormone in accept liquid.conditions:Hypersil BDS C18 chromatographic column;Mobile phase of methanol:water:phosphate(700:300:1);detection wavelength of 225 nm;Flow rate:0.9 ml·min-1;Column temperature to room temperature;Sample quantity:20μl.For 24 h per unit area of the cumulative amount through examining indicators,through orthogonal design test screening of Levothyroxine formula of the gels.Intraperitoneal injection of500μCi131 I to prepare Hypothyroidism rat model.Using Fluorescent luminescence immunoassay method to detect the concentration of T4,FT3,FT4 and TSH in rat serum.Group:A:High dose group of Levothyroxine gels,5,every other day 0.2 g gels/100 g weight;B:Middle dose group of Levothyroxine gels,5,every other day 0.1 g gels/100 g weight;C:Low dose group of Levothyroxine gels,5,every other day 0.05 g gels/100 g weight;D:Oral group of L-T4,5,every day 5 ug L-T4/100 g weight;E:Blank gels group,5,every day 0.05 g blank gels/100 g weight;F:Normal group,5,no treatment.In 2 weeks,4 weeks,8 weeks after the angular vein blood,determine the content of serum T4,FT3,FT4,TSH(x±s).Comparison between groups using analysis of variance(ANOVA),with P<0.01 for the difference was statistically significant.Results1.Levothyroxine concentration within 0.1-10.0μg/ml had good linear relationship with the peak area and standard curve for:y=72688 x+2940.1 R2=0.9998,the average recovery was 99.48%,99.63%,99.85%,RSD was 1.39%,0.99%and 0.24%respectively.2.The gels accumulated through the drug release mechanism of the quantity conforms to zero order kinetic equation,y=0.2363 t+0.7235,R2=0.9978,the steady-state transdermal rate was 236 ng·cm-2·h-1.3.Optimum prescription of Levothyroxine gels was 20%PVA,5%glycerol,2%azone and 6%oleic acid.4.Concentrations of T4(nmol/L),FT3(pmol/L),FT4(pmol/L),TSH(uIU/mL)in Normal rats group were respectively(65.10±9.2、4.40±0.48、29.73±3.73、0.006±0.0008).Concentrations of T4,FT3,FT4,TSH in Hypothyroidism model rats group were respectively(3.51±1.2、0.54±0.29、2.63±1.52、0.016±0.003).Compare the concentrations of T4,FT3,FT4,TSH in Hypothyroidism model rats group to that of Normal rats group respectively,the difference is statistically significant(P<0.01).Succesefully made the Hypothyroidism rats model.5.Compare the concentrations of T4,FT3,FT4,TSH after 2 weeks of treatment.Compare A,B,C,D,Fgroup to E group,p<0.01;Compare A,B group to F group,p<0.01;Compare C group to F group,p>0.05;Compare D group to F group,p<0.01;Compare C group to D group,p<0.01.6.Compare the concentrations of T4,FT3,FT4,TSH after 4 and 8 weeks of treatment.Compare C,D group to F group,p>0.05;Compare C group to D group,p>0.05;Compare C,D,F group to E group,p<0.01.ConclusionThe successful preparation of Levothyroxine gels transdermal absorption,and successfully build Hypothyroidism animal model.Levothyroxine gels has obvious therapeutic effect on Hypothyroidism rats,Levothyroxine gels work fast,2 weeks can be up to the level of the normal rats,and smoothly until 8 weeks;Oral L-T4 group 4weeks to blood concentrations were relatively stable,to 8 weeks of low-dose Levothyroxine gels equre to oral L-T4 treatment effect.Indicate Levothyroxine gels superior to oral L-T4 on therapy Hypothyroidism.Levothyroxine gels has fast absorption,high bioavailability,good histocompatibility,easy to besmear exhibition and cleaning,etc.As a new dosage form of percutaneous drug treatment,can expand Hypothyroidism treatment method,in order to make sure the treatment of patients with unfavorable or inconvenience for oral administration.