Mixed base of hydrophilic ointment and purified lanolin to improve the drug release rate and absorption of water of minocycline hydrochloride ointment for treatment of bedsores.

A desired ointment bases for better treatment of bedsores was developed to improve the release rate of minocycline hydrochloride (MH) and the water absorption capacity using various types of hydrophobic to hydrophilic ointment base. The influence of purified lanolin (PL) on the release behavior of MH from hydrophilic ointment (HO) base was primarily focused on. It was found that the release rate of drug increased with increase in the hydrophilicity of the base. A linear correlation between the apparent release rate constant of drug from the HO and PL mixed ointment base at various combination ratios and the elution of ointment base was noted. The HO ointment base containing 30% PL had the highest apparent release rate constant of MH. The mixed ointment base with the lowest viscosity showed the highest absorption of water and elution of ointment base. In conclusion, it was found that HO (70%) and PL (30%) mixed ointment base was a promising candidate for better treatment of bedsores.     

High-performance liquid chromatographic assay for prostaglandin E1 in various ointment vehicles. Separation and stability testing

A high-performance liquid chromatographic method for the determination of prostaglandin E1 (PGE1) incorporated in white petrolatum, white ointment, hydrophilic petrolatum and Plastibase was investigated. The prostaglandin was separated from the oleaginous vehicles with n-hexane-aqueous acetonitrile. Most of white petrolatum, which is a principal component in the vehicles, remained in the n-hexane layer, and the recovery of the drug from any vehicle attained 100%. The method was applied to stability studies of PGE1 in white petrolatum and macrogol ointment. In which pure PGE1 and PGE1-alpha-cyclodextrin complex (PGE1-CD) were incorporated. The drug remained intact for up to 6 months when stored at 5 degrees C. At 25 and 40 degrees C, pure PGE1 was more stable than PGE1-CD and both PGE1 species were more stable in white petrolatum than in macrogol ointment.     

Behaviour of silicon ointment for power-cable insulation under external heating

Journal of Thermal Analysis and Calorimetry - The burning process and typical fire parameters of power-cable silicon ointment were explored experimentally using a cone calorimeter, and the effects...     

External control of drug release and penetration. VI. Enhancing effect of ultrasound on the transdermal absorption of indomethacin from an ointment in rats.

The effect of an ultrasound (1 MHz) on transdermal absorption of indomethacin from an ointment was studied in rats. Ultrasound energy was supplied for between 5 and 20 min at a range of intensities (0.25, 0.5, 0.75, and 1 W cm-2), energy levels commonly used for therapeutic purposes. For evaluating skin penetration of indomethacin, the change of plasma concentration was measured. The pronounced effect of ultrasound on the transdermal absorption of indomethacin was observed at all ultrasound energy levels studied. The intensity and the time of application were found to play an important role in the transdermal phonophoretic delivery system of indomethacin; 0.75 W cm-2 appeared to be the most effective intensity in improving the transdermal absorption of indomethacin, while the 10 min ultrasound treatment was the most effective. Although the highest penetration was observed at an intensity of 0.75 W cm-2, 0.5 W cm-2 was preferred because intensities of less than 0.5 W cm-2 of ultrasound for 10 min did not result in any significant skin temperature rise nor did it have any destructive effect on rat skin. Progressively more skin damage was noted as the intensity and the time of application of ultrasound increased. When used at a proper intensity and time of application, ultrasound appears to be a safe technique for enhancing the passage of various drug molecules through human skin.     

Simultaneous determination of ingredients in an ointment by hydrophobic interaction electrokinetic chromatography

Hydrophobic interaction electrokinetic chromatography was used to simultaneously determine seven active ingredients (diphenhydramine hydrochloride, dibucaine hydrochloride, chlorhexidine hydrochloride, phenylephrine hydrochloride, hydrocortisone acetate, allantoin and tocopherol acetate) in an ointment. Not only hydrophobic but also ionic compounds were successfully separated by use of a separation solution composed of acetonitrile-water (80:20, v/v), tetradecylammonium salt and ammonium chloride. The migration behavior of the hydrophobic compound depended on tetradecylammonium concentration, while that of the ionic compounds depended on ammonium chloride concentration. An addition of triethylamine to the separation solution markedly improved the reproducibility of the peak areas of cations with a relative standard deviation (RSD) of less than 1.7% (n=6). The established method was validated and confirmed to be applicable to the determination of the active ingredients in a commercial ointment. Sample preparation was performed by liquid-liquid extraction and no interference from the formulation excipients was observed. Good linearities were obtained, with correlation coefficients above 0.999. Recoveries and precisions ranged from 98.0 to 100.8%, and from 0.4 to 2.9% RSD, respectively. These results suggest that hydrophobic interaction electrokinetic chromatography can be used for the determination of ionic compounds as well as hydrophobic compounds in ointment.     

Effect of γ-radiation on ointment cold cream

In this paper, Co-60γ ray was used to irradiate the ointment cold cream at room temperature (25°C). We also used FTIR, GC and thin film chromatogram to analyse various irradiated samples. It was found that the ointment cold cream can be irradiated at dose of 5–35 kGy and at dose rate from 0.2 to 0.6 kGy/h at room temperature (25°C) without evident decomposition. At dose of 5–15 kGy, the number of bacteria can be reduced to hygienic standard value. The radiation sterilization is a safe method for killing the bacteria in the ointment cold cream.     

Stability-indicating assay using capillary zone electrophoresis for an azaphenothiazine in an ointment formulation

A stability-indicating assay using a capillary zone electrophoresis method is reported for the determination of isothipendyl in an ointment formulation. Sample preparation consisted of a simple dissolution of the ointment in an internal standard (3-aminobenzoic acid hydrochloride) solution. Separation was carried out in a short fused silica capillary using a pH 2.5 phosphate buffer as electrolyte. After introduction of the sample solution into the capillary, the compounds were separated as cations and detected within 3 min. The procedure was validated following the guidelines of the International Conference on Harmonisation. The method was found to be specific in relation to potential degradation products and excipients. Linearity determined between 50 and 150% of the target concentration was satisfactory (r² = 0.999). Recovery studies from an analytical placebo spiked with the analyte at five concentration levels (50-150% of the target concentration) on each of 3 days ranged from 103.5 to 99.2%. The repeatability of the entire procedure (n = 7) was better than 1.0%. The detection limit was estimated to be approximately 0.5 mg l⁻¹.     

Identification and analysis of a degradation product of the glucocorticoid desonide in ointment

The major degradation product of desonide in a pharmaceutical ointment formulation has been shown to be identical with the C-17-carboxylic acid obtained on oxidative cleavage of the alpha-ketol group of desonide with alkaline hydrogen peroxide. The pKa value of this acid has been estimated from chromatographic data.     

Determination of madecassoside and asiaticoside contents of C. asiatica leaf and C. asiatica-containing ointment and dentifrice by HPLC-coupled pulsed amperometric detection

The present study reports the development and application of an HPLC-coupled pulsed amperometric detection method to determine the madecassoside and asiaticoside contents of Centella asiatica leaf and of commercial C. asiatica-containing ointment and dentifrice. C. asiatica, which was not pretreated, was extracted with 50% ethanol for 10 min. Madecassoside and asiaticoside were separated on a C18 column within 5 min using 25% (v/v) acetonitrile as the mobile phase. Both compounds were detected with high sensitivity when sodium hydroxide was used as a post-column eluent. Madecassoside and asiaticoside both displayed limits of detection of 0.005 μg/mL and linear regression coefficients of 0.9994 and 1.0000, respectively. The intra- and inter-day precisions were < 8.85% and average recovery was > 94.79%. The madecassoside and asiaticoside contents of ointment and dentifrice were successfully determined without sample purification or concentration owing to the high method sensitivity and selectivity.     

Formulation design of ointment base suitable for healing of lesions in treatment of bedsores

We intended to develop a desired ointment base suitable for treatment of bedsores including the proliferation of granulation and epidermis. The main bedsore bacteria detected in our hospital were S. aureus in gram-positive coccus and P. aeruginosa in gram-negative bacillus. As the macrogol ointment (MO) was found to have bactericidal effects on these bacteria, MO was adopted as the base for the objective ointment. To improve the properties of the ointment base such as regulating the humidity of the exudation and controlling the release of antibiotics formulated in the ointment, co-formulating effects of various additives to MO were evaluated. The sustained release function of the ointment base was obtained by adding hydrophilic petrolatum (HP) to MO. However, the resultant ointment was found to have a poor humidity regulating property. On the other hand, MO containing 5% of hydroxypropyl cellulose (HPC) showed both the humidity regulating and the controlled drug releasing properties. It was considered that HPC particles dispersed in the ointment could be swelled by absorbing water to form a gel network. The curd tension meter tests for the ointments prepared with the various polymers showed that the MO-HPC base, which showed the highest sustained drug releasing property, was found to have the highest hardness. This result means that HPC formulated into the base forms the most rigid gel structure to resist the erosion of the ointment and to control the drug release.     

Characterization of the gel structure in a nonionic ointment by small angle X-ray diffraction

The structure of systems containing equal weights of cetylalcohol, stearylalcohol and the nonionic surfactant poly(oxyethylene)₂₀-glycerolmonostearate is studied as a function of the water concentration. In this paper mainly results are presented obtained by small angle X-ray-diffraction. Up to ± 22% (w/w) water several coexisting phases were observed. From ± 22% to ± 55% water a lamellar structure is found. This structure consists of lipophilic bilayers formed by the hydrocarbon tails of cetylalcohol, stearylalcohol and the surfactant, alternated by hydrophilic layers formed by the polyoxyethylene glycerol chains, the hydroxyl groups of cetylalcohol and stearylalcohol and water. From the swelling behaviour the density of the gel structure (0.9 g/cm³) and the cross sectional area of the molecules in the bilayers (0.19 nm²) have been calculated. It is concluded that the hydrocarbon chains are in a crystalline, state and are placed perpendicular to the lattice plane. Upwards of ± 55% water the lamellar phase disperses in the excess of water.     

Modification of the physicochemical properties of minocycline hydrochloride ointment with cyclodextrines for optimum treatment of bedsore

Modification to find the best physicochemical properties of minocycline hydrochloride ointment for optimum treatment of bedsore was investigated by coformulating various types of cyclodextrins (CyD) in the ointment base. It was found that the drug release rate from the ointment base was modified according to the preparation method of ointment base and the type of CyD admixed. The physicochemical properties, such as viscosity, elution volume, water absorption of ointment base were also modified by those factors. The mechanism of physicochemical modification with CyD was explained by the structural change of ointment base and the change of surface tension of emulsifying agent solution with the CyD. The stability of ointment was investigated by confirming the reproducibility of drug release rate after storage at ambient and cooled temperature conditions. In conclusion, a fused mixed ointment with beta-CyD was found to be preferable for treatment of bedsore, because of the improved drug release rate, lowered viscosity and increased elution volume of the resultant ointment.