Study On Salmon Calcitonin Dry Powders For Inhalation

In this study,salmon calcitonin was used to be the model drug;the prescription of salmon calcitonin dry powder for inhalation was investigated systematically,the physicochemical properties of the powder were evaluated,and the pharmacodynamics of this preparation in rats was studied.1 Establishment of theophyiline and salmon calcitonin content determination methodThe theophylline was determined by UV-vis method.Good linear relationship was observed under the concentration range of 4.24μg/mL～15.26μg/mL.The theophylline solution was stable within 12.0 h.On the base of BP,an HPLC method to determine salmon calcitonin was established.This method was simple and specific.There was good linear relationship between the amount of salmon calcitonin and its peak areas between 2.12μg.mL^-1and 21.2μg.mL^-1 (A=40170c+1872,r=0.9993).The RSD of precision and reproducibility was 2.54%and 1.46%, respectively,and recovery was 100.4±3.3%.The salmon calcitonin solution was stable at least 4.0 h.2 Establishment of evaluation index on dry powder for inhalationsTwo types of evaluation index,including typical physicochemical properties of dry powders for inhalations(such as hygroscopicity,moisture content,morphology,particle size and distribution,density,and angle of repose),and evaluation index on in-vitro deposition(such as aerosolizing properties,and deposition property in-vitro and dumping ratio),were set to evaluate salmon calcitonin DPI.3 Preparation of salmon calcitonin dry powder for inhalationSpray-drying method was applied to prepare the salmon calcitonin dry powders,emphasizing the research on formulations and procedure.The influence of ingredients including lactose,mannitol, dextran and L-leucine on the physiochemical property of the salmon calcitonin dry powders was investigated.It was shown that the single cartier was not the optimum.So the mixed-carriers were investigated.After the studying the usage of mannitol and leucine,the formulation was set as follow:salmon calcitonin 2 mg,mannitol 500 mg,leucine 500 mg,F68 20 mg,HAC q.s.In the procedure study,based on the monofactorial investigation,the optimization of the preparation parameters was performed by using orthogonal design and Z-score method which employed four indices including powder yield,aerodynamic diameter,angle of repose and moisture content. The preparation condition was:inlet temperature 110℃;pump speed 7.0 mL.min^-1;atomization pressure;180 KPa;aspiration flow:0.60 L·min^-1;solution concentration:0.50%(w/v).The physicochemical property of salmon calcitonin dry powder(three batches)showed that the product owned hygroscopicity,little poor flowability,drug content and water content was 82.7±0.4%and 0.52±0.07%,respectively.Its aerodynamic diameter was about 2.7μm (span=1.49μm)that signified the product could reach the deep lung.The in-vitro deposition test showed that the powder was easily atomizated.The results of dumping ratio(97.0%)and effective deposition percentage(45.4%)further demonstrated that most of the powders could deposite in lung after being inhaled.Stability test showed that the product experienced no oblivious change under 4～8℃,RH＜25% for three months in respect of the external appearance,particle diameter and distribution,content and in-vitro deposition property.4 Potency of salmon caleitonin dry powder inhalationThe potency of salmon calcitionin dry powder determined by serum calcium OCPC method was 8.169 IU/mg,with confidence interval 38.1%,which met the requirement of ChP(2005). 5 Pharmaeodynamics study in vivoThe inhalation model of the normal rats for salmon calcitionin dry powder was established. The determination of serum calcium level of this powder(with/without salmon calcitionin)was assessed by intra-trachea administration,compared with control group by subcantaneouly administration.Serum calcium levels were examined by OCPC method,and the area above curve of calcium level was determined by trapezoidal rule to calculate the relative pharmacological bioavailability(PA%).General speaking,the bioavailability of the salmon calcitionin dry powder was considerable(76.3%in our experiment),and the powder could be used in clinical as a replacement of injection.