Study Of Transdermal Drug Delivery System Of Naloxone

Naloxone,a potent opioid receptor antagonist,its affinity for morphine receptor is greater than that of morphine.It is widely used for the treatment of opioid abuse,for example,intoxication of anaesthetic and alcohol,shock,brain infarction and so on.It is not effective when administered perorally because of its high first pass metabolism,and it is currently administered either subcutaneous,intramuscular or intravenous injection.It has short biological half-life of 45-90 minutes;hence,repeated administration is necessary to obtain therapeutic efficacy.This results in unconvenience.Development of a transdermal drug delivery system would increase the bioavailability,reduce the administration times,elevate the compliance of patient's medication and decrease the adverse reaction.The purpose of this paper was to investigate the percutaneous absorption characteristics and aim to develop a transdermal drug delivery sysytem.The main five parts of the present study were:(1)The preformulation study for the development of transdermal preparation of naloxone;(2) Study of transdermal delivery of naloxone microemulsion that was prepared with the system contained of isopropyl myristate-water-lecithin-propanol;(3) Study on percutaneous permeation of naloxone which was carried by ethosomes;(4) Study on percutaneous permeation of naloxone ethosomes gel complex which was prepared with HPMC;(5) Study on pharmacokinetic characteristics of naloxone ethosomes gel in rabbits.In the preformulation study,the HPLC methods for the assay of naloxone was established firstly.Chromatography for separation and determination were carried out by applying the samples to a prepacked 5μtm(4.6mm×250mm,i.d.)Diamonsil C₁₈ column at 35℃.Mobile phase comprising of 0.1M phosphate buffer solution (pH=4.0),methanol and acetonitrile in the proportion of 75:15:10,v/v/v was pumped at a flow rate of 1ml/min.The mobile phase was filtered through 0.45μm nylon filters and degassed.Sample were injected at 20μl of injection volume and were analyzed at a wavelength of 240nm.The mean equation for the calibration curve was Y=4766.00X+528.06,r+0.9993(n=6).Recovery rate were 99.21～102.72%,intra-day and inter precision were 0.72～2.13%and 0.32～6.82%.Then,the possoblility of percutaneous transport of naloxone was investigated,while the effect of permeation enhancers,the concentration of enhancers and the concentration of naloxone on it was done.With the skin of SD male rate,the penetration eaperments in vitro were performed on modified Franz diffusion cells.The amount of drug penetration concentrations of naloxone was determined by HPLC.The steady state flux and total amount drug of naloxone were calculated.Though all permeation enhancers could enhanced the transdermal fulx of naloxone,the effect of Azone-Prophylene glycol was found to be the best one,and its steady rate was 10.34±1.61lμg·h^-1·cm^-2.The steady state flux and total amount drug of naloxone increased with increasing the concentration of naloxone.In the naloxone microemulsion study,W/O microemulsion formulation containing naloxone-lecithin,which was prepared with the system contained of isopropyl myristate(IPM)-water-lecithin-propanol,was investigated its transdermal delivery effect in vitro.For the microemulsion,lecithin was chosen as surfactant,IPM as oid phase,n-propanol as cosurfactant,the double-distilled water as water phase.The particle sizes and envelopment rates of microemulsion which was prepared with the optimal formulation were 45.10±21.13nm and 81.74±2.60%.The effect on percutaneous transport of naloxone by the content of lecithin,n-propanol and IPM as three factors were investigated.The relation of different weight ratios of elements and permeation rate of naloxone were:Y=-206.74+2654.18A-0.32B-166.07C+ 116.67AB + 558.33AC - 483.33BC - 9548.63A² + 987.75B² -- 235.25C² + I0385.42A³ - 1979.17B³ + 572.92C³ r = 0.9808,(P<0.0001 ).The optimal formulation contained lecithin(29%),propanol(25%) and IPM(35%)。The steady permeation rate of naloxone microemulsion was 4.33μg·h^-1·cm^-2,significantly higher than that of the aqueous solution(0.20μg·h^-1·cm^-2).Microemulsion enhanced the permeation of naloxone hydrochloride across the SD male rats skin. In the naloxone ethosomes study,naloxone ethosomes was prepared by injection method.The particle sizes and envelopment rates of naloxone ethosomes were determined.The possibility of percutaneous transport of naloxone which was carried by ethosomes ere investigated,while the concentrations of enhancers,;and ethanol had effect on the permeation rate were done.The effects of ethosomes,chemical enhancers and their binary combination on the in vitro permeability enhancement of naloxone through human skin were investigated.The obtained results indicated that the particle sizes and envelopment rates of ethosomes with 20%ethanol were 152.61±29.63nm and 82.50±1.84%.The particle sizes and envelopment rates of liposomes were 196.20±25.31nm and 84.00±2.23%.The steady state flux and accumulation of drug-penetration of naloxone increased with increasing the concentration of ethanol and naloxone.The steady state flux of naloxone ethosomes with 50%ethanol was 139.82±7.60μg·h^-1·cm^-2,and it was 5.17 higher than that of naloxone aqueous solution.The accumulation of drug-penetration of naloxone was 775.22±36.22μg.Propylene glycol(PG),N,N-dimethyl formamide(N,N-DMF),N,N-dimethyl acetamide(N,N-DMA),dimethyl sulfoxide(DMSO),polyethylene glycol 400(PEG400) and Azone(?)(3%)+PG(7%) were chosen as chemical enhancers.Permeation studies showed that the flux values of naloxoen in the presence of these chemical to that of control(P<0.05) and varied from 2.73 to 9.57 times.The most significant enhancement is obtained with Azone(?)(3%)+PG(7%).Yhe flux values of naloxone ehtosomes in the presence of these chemical enhancers were significantly indreased when compared to that of control(P<0.05) and varied from 14.17 to 54.97 times.The synergistic enhancerment of skin permeability to naloxone ethosomes and Azone(?)(3%)+PG(7%) were applied simultaneously was demonstrated.Application of the two enhancers resulted in enhancement ratio of～55,whereas for ethosomes and Azone(?)(3%)+PG(7%) applied separately.Hence,ethosomes carriers,combined with suitable enhancers may be good candidates to increase steady state flux and accumulation of drug-penetration.Ethosomes is a new,safe and effective naloxone carrier on percutaneous permeation and preparation is simple. In the naloxone ethosomes gel complex study,naloxone ethosomes gel complex was admixed with HPMC gel.The amount of drug penetration concentrations of naloxone was determined by HPLC.The accumulation of drug-penetration,the total amount drug released from ethosomes gel complex were calculated.To investigate the effect of HPMC on the flux values of naloxone ethosome gel complex.And the synergistic effect of naloxone ethosome gel complex and the chemical enhancers on enhancement of naloxone permeation.The obtained results indicated that ethosome gel complex is effective for transdermal delivery.Ethosome gel complex and the chemical enhancer show a synergestic effect on naloxone percutaneous drug permeation.DMSO pretreated in ethosomal form dramatically enhanced the skin permeation of naloxone in vitro compared with ethosomes.Keeping the concentrations of naloxone constantly 2mg/ml,3%HPMC and 30%ethanol,the steady-state flux of naloxone ethosomes gel complex were significantly increased when compared to that of ethosomes and varied from 1.33 to 1.82 times.In the study on pharmacokinetics for percutaneous permertion of naloxone ethosomes gel complex in rabbits,in a dual-test cycle of self-control is design wih naloxone injection for control.Using HPLC-MS determination different times of the plasma concentration values to obtain plasma-time curves,then get major all of the pharmacokinetic parameters.Study on pharmacokinetic characteristics of naloxone ethosomes gel.naloxone ethosomes gel after percutaneous administration pharmacokinetic characteristics for the role of a lag - absorption,and to eliminate a single compartment model,Lagtime was 3.33±1.20h,Ka 0.42±0.26h,Ke0.14±0.03h^-1,AUC = 103.71±24.54h·ng·mL^-1.Dose of naloxone for 20mg of alcohol in the naloxone ethosomes gel complex transdermal delivery about 10 h after the maximum plasma concentration,and an effective role for the 25 h time around.Compared with the injection,naloxone ethosomes gel complex have some forte:easy to use,reduction in the number of delivery,more lasting effect,increase compliance of patients,and its would have a good development prospects.