Determination of prednisolone in ointments

A method for the quantitative determination of prednisolone in ointment preparations is described. It uses TLC and UV spectrophotometry in combination. Solutions and ointments are chromatographed using silica gel GF 254 and various solvent systems, the layers containing the active ingredient are eluted and the substance determined at 240 nm.     

HPLC法测定他克莫司软膏剂含量及含量均匀度

目的建立他克莫司软膏剂含量测定方法。方法用四氢呋喃∶水∶无水乙醇(5∶2∶1)先、后在60℃水浴和冰浴中提取软膏,应用反相高效液相色谱法测定了两种规格共6批(30g,每支0.03%;30g,每支0.1%)他克莫司软膏剂的含量及含量均匀度。色谱条件:TSKgelODS-80TM柱(150mm×4.6mm,5μm);柱温(55±1)℃,流动相为水∶异丙醇∶四氢呋喃(5∶2∶2),流速0.6ml/min;紫外检测器,检测波长220nm。结果他克莫司的色谱峰与其它杂质峰能够较好的分离,柱理论塔板数按他克莫司峰计为5000,规格为30g,每支0.03%软膏的80%加样平均回收率为100.6%(RSD=0.5%,n=3),100%加样平均回收率为100.2%(RSD=1.6%,n=3),120%平均回收率为98.7%(RSD=2.3%,n=3);规格为30g,每支0.1%软膏的80%加样平均回收率为99.3%(RSD=0.5%,n=3),100%加标平均回收率为100.8%(RSD=1.6%,n=3),120%加标平均回收率为99.3%(RSD=0.7%,n=3);0.03%规格软膏的线性方程为y=6989786x+105.4(r=0.9999),浓度范围0.0075～0.0225mg/ml;0.1%规格的线性方程为y=6995488x-64.2(r=0.9999),浓度范围0.025～0.075mg/ml。他克莫司的检测限为0.002mg/ml,定量限为0.006mg/ml。结论方法简便,快速,回收率高,重现性好,可用于他克莫司软膏剂(0.03%,0.1%)含量测定,能够对药品质量进行控制。     

Evaluation of creams and ointments as suitable formulations for peldesine

In-vitro studies were conducted to study the efficacy of mixed and self-emulsifying creams and hydrophobic ointment formulations in delivering peldesine (BCX-34) into and across cryopreserved human cadaver skin (HCS). Oil-in-water cream formulations, containing 1% w/w of radiolabeled C(14) BCX-34 and propylene glycol (PG), glycerin (GLY), isopropyl myristate (IPM), oleic acid (OA) and capric-caprylic esters (CE) were prepared. Petrolatum and lanolin based ointments were also prepared with PG. Sections of the HCS, 250 microm thick, were fitted to vertical Franz diffusion chambers containing a receptor medium of pH 7.4 phosphate buffer solution maintained at 37 degrees C. Using the finite dose technique, 4-6 mg of a formulation sample was applied to the epidermal surface of each section and drug diffusion was permitted for 12 and 24 h periods. The distribution of drug into the HCS epidermis, dermis and into the receptor medium was measured by scintillation spectroscopy. The results show good correlation of the calculated in-vitro values for flux and skin-vehicle partition coefficients against the observed amounts of drug detected in the HCS. The mixed emulsion cream formulation containing PG delivered higher amounts of drug into the skin when compared to the same formulation containing GLY cream. The self-emulsifying cream formulation containing IPM had a higher skin-vehicle partition coefficient and delivered more drug into the dermis when compared to those formulations that contained OA and CE. The petrolatum ointment delivered six times more drug into the epidermis than the lanolin ointment, and had higher skin-vehicle partition values. In conclusion, creams containing PG and petrolatum-base formulations would be suitable for BCX-34 dermal delivery.     

Dilutions of corticosteroid creams and ointments - a stability study

A study was carried out on the stability of dilutions of creams and ointments of two corticosteroids, betamethasone valerate and beclomethasone dipropionate. A reversed-phase high-performance liquid chromatographic method was developed that is simple, efficient and stability-indicating in respect of the main decomposition products and has the advantage of being carried out at ambient temperature. The effect of water content of the sample solutions and the influence of large injection volumes (200-250 mul) on the resolution of the substances on the chromatogram was investigated. Use of the diluents, cetomacrogol cream (formula A) BP and white soft paraffin BP, resulted in satisfactory products in terms of chemical stability and efficacy of antimicrobial preservation.     

High-performance liquid chromatographic analysis of iodochlorhydroxyquin and hydrocortisone in ointments and creams

A simple isocratic, high-performance liquid chromatographic (HPLC) assay procedure was developed for the simultaneous determination of iodochlorhydroxyquin and hydrocortisone in ointments and creams using phenyl salicylate as an internal standard. Ointment samples were extracted by direct dissolution in ether. Homogeneous suspensions of the creams were prepared in the mobile phase. The samples were spiked by the addition of standard iodochlorhydroxyquin, standard hydrocortisone, and the internal standard and subsequently extracted with the mobile phase. HPLC was performed using a reverse-phase microparticulate C-18 column, a precolumn, and a UV detector set at 256 nm. A mobile phase containing methanol and 0.05 M phosphoric acid (70:30) was employed at a flow rate of 1 ml/min. The percent iodochlorhydroxyquin and hydrocortisone found to be present in eight commercial products is reported.