Diclofenac (2 (2,6 dichloro-anilino) phenyl] acetyl acid, CAS 15307-86-5) is a non-steroidal anti-inflammatory drug that is used for relief of different kinds of pain and the treatment of inflammatory processes of various localization (fig. 1) [1].
There are many pharmaceutical (herbal) forms of a drug, it can be used orally, rectally, intramuscularly or locally. On the market of drugs diclofenac presented in the form of free acid, sodium and potassium salt and potassium salt diclofenac much better dissolved in water [1,2].
The objective of this study was the comparative analysis of pharmacokinetic indicators and changes in the serum concentration of potassium salt of diclofenac, which volunteers received orally at a dose of 50 mg in the form of sachets or tablets, coated with sugar shell. In accordance with the design of the protocol (two forms of the drug, a cross-sectional study with two periods with a single injection of the drug) study group consisted of 24 clinically healthy men and women.
Materials and methods
Ethical aspects of
The study protocol was approved by the Ethical committee of the canton of Ticino (Switzerland). The selection of persons for phase I clinical trial was conducted in accordance with the standard criteria of inclusion / exclusion. Before the test begins, the International council on drugs (IKS) distributed investigational medicinal products under the encrypted rooms. At all stages of the research was conducted in accordance with the principles of the declaration of Helsinki and its amendments, as well as the resolutions of the government of Switzerland to conduct clinical trials [3].
A group of subjects
The study included 24 clinically healthy men and women of the european race in the age from 19 to 53 years (demographic characteristics indicated in table 1). The state of health of the subjects evaluated with the help of subjective and objective methods of examination, including the main indicators of the state of the organism, blood and urine tests. After the tests the same survey was repeated. The participants were informed in detail about the activity of the drug and its possible side-effects; if the subjects agreed to take part in the study, they signed the form of voluntary informed consent.
Treatment
Sasha: one sachet contains 50 mg of diclofenac potassium salt potassium for receiving a single party, IT 6502 (Voltfast z, manufacturer: Novartis Farma Spa, Italy).
Tablet: 1 tablet, covered with sugar-coated contains 50 mg of diclofenac potassium salt potassium for a single reception, party 96F25AB (Kataflam z, manufacturer: Novartis Farma Spa, Italy).
In accordance with the design of the test (two-period crossover study that examined the two sequences the introduction of drugs), sasha and tablet taken once, washout period was one week. Heparinized blood collected as follows: in front of the reception (time zero), in 5, 10, 15, 30 and 45 minutes, in 1, 1.5, 2, 3, 4, 6, 8, 10 and 12 hours after taking the drug. Blood was centrifuged collected plasma was stored at -20 C until analysis.
Analysis
The analysis was carried out using high performance liquid chromatography (HPLC), as detectors were used ultraviolet rays (275 nm), and as an internal standard (M) - flufenamic acid. Diclofenac and M extracted with the acidified plasma with a mixture of n-hexane and 2-propanol in volumetric ratio of 95:5. Organic component separated, concentrated to dryness, restored to 200 mm3 with a mixture of acetonitrile and water in volumetric ratio of 50:50 and they gathered in the automatic samplers. As the mobile phase used a mixture of acetonitrile and 0.4% orthophosphoric acid in volumetric ratio of 50:50 at a flow rate of 1 ml / min for the analytical column Hypersil BDS-C8 (150? 4.6 mm: ID 5 microns). The presence of linearity of the set of calibration curve in the range 10-3000 ng / ml. Retention time for diclofenac was equal to 7.2 min.for M - 10,7 min. (Fig. 2). Mezhseriynaya vnutriseriynaya and reproducibility was? 7,98% and an accuracy of? 5,27%. Specificity was very high. Returned extraction amounted to an average of 91,8%.
The analyzed substances remained stable when stored as plasma of blood, and in the automatic samplers at -4 C in 24 hours.
Prior to the trials and in the course of the study the calculations were made in accordance with the generally accepted international criteria [4].
Pharmacokinetic and statistical analysis
With the help of nekompartmentogo analysis of the curve for the dependence of the concentration of the drug in the blood plasma from time estimated the following indicators:
AUC0-t - empirical area under the curve from zero period of time until time "t" with the constant assessment of the concentration of the drug (Sposl.), calculated by the formula trapezoids;
AUC0-? - Empirical area under the curve extrapolated to? = (AUC0-t + Sposl ./?);
? - The slope of the last concentrations of the drug in plasma, converted by the log, on time;
Cmax - peak concentration (maximum concentration of the drug in plasma);
tmax - the time needed to reach peak concentration;
t1 / 2 - elimination half = 0,693 /?.
Bioavailability was assessed by the AUC0-t, AUC0-?, Cmax and tmax, these indicators logarithmically transformed and processed in the framework of the cross-analysis ANOVA with 90% confidence interval with two one-sided t-criteria [7-9] . The time needed to reach peak concentrations, calculated with the use of nonparametric criterion Wilcoxon, which allowed to identify a statistically reliable difference.
The Results Of The
Portability
It is proved that, and sasha, and the tablets were transferred subjects equally well, as evidenced by the subjective and objective observation. Side effects were absent, and in the laboratory analyses and indicators of vital functions were observed significant changes. The only side effect was slight headache, which complained to one of the subjects after taking the drug, in tablet form, but apparently, it was not directly connected to the reception.
The concentration of diclofenac in plasma
Figure 3 shows the curves of average concentrations of diclofenac in plasma of blood, depending on the time after the reception of the drug in two different forms. In both cases diclaufenaka concentration in plasma in all subjects began to grow quickly enough (already in 5 minutes after administration of the drug), reaches a maximum value and then monotonously decreased to undetectable within 4-12 hours. After receiving sasha diclaufenaka concentration in the plasma reaches a peak after 10 minutes at 7 out of 24 of the subjects and in 15 minutes - the remaining 17 persons. After 5 minutes of the concentration of the drug in plasma was in average 831,5 ng / ml (or 38% of the Cmax).
The pharmacokinetic parameters
Table 2 presents the mean values ​​of the measured farmakokineticeskih parameters them WITH, CV%, the minimum and maximum values, geometric mean and median. These data indicate that the rate of absorption of diclofenac after receiving sasha is much higher, than after the reception of tablets, the Cmax more (2213 ng / ml and 1071 ng / ml, respectively), but tmax short (0,228 h and 0,885 h , respectively).
Statistical processing of the results
The analysis ANOVA, adapted for cross-tests, statistically reliable difference between periods or sequences have been identified. In table 3 summarizes the data, allowing to compare the indicators for sasha and tablets at 90% confidence interval, as well as the results obtained in the analysis, with two one-sided t-criteria [9]. The values ​​of the AUC0-t and AUC0-? fit to adopted for bioequivalence range of 0.80-1,25. However, in the case of Cmax this did not happen due to a different rate of absorption of the drug.
When using nonparametric criterion Wilcoxon was revealed a statistically significant difference (p <0.01) the time required to achieve peak concentrations of diclofenac in plasma, that once again testifies to a more rapid return of the product after its acceptance, in the form of sasha.
Discussion and conclusion
According to the results of previous studies concentration of diclofenac sodium reached its peak after intramuscular injection in 15 minutes [10] and 25 minutes [11]. According to our data, the peak concentration of the drug intake of potassium salt of diclofenac in the form of sasha was noted earlier (in 10 minutes, seven volunteers and after 15 minutes the remaining 17 subjects), and already after 5 minutes of concentration of diclofenac amounted to 38% of Cmax. It is connected with very high solubility of potassium salt of diclofenac, which is much faster absorbed after administration of powder than tablet form [12]. From the point of view of the degree of suction sasha and pills were bioekvivalentna at 90% confidence interval in the range of 1.05-1,20 for AUC0-?.
According to recent data [13] diclofenac potassium salt in the form of tablets with the immediate-release formulation (50 mg, and 100 mg) has very good analgesic effect in the treatment of migraines, since the concentration of the drug in the blood plasma reached its maximum in an average of one hour after his reception (through the 0.33-2 hours), and analgesic effect has developed through 60-90 minutes. Comparing the rate of absorption, we can conclude that diclofenac potassium in the form of sasha will provide analgesic action is much faster.
In conclusion it should be noted that the high solubility of potassium salt of diclofenac and a very good absorbability (especially in the form of sasha) make this product an excellent analgesic, anesthetic effect at the reception which comes quickly enough.