796 Acta Chim. Slov. 2022, 69, 796–802 Mihovecet et al.: Evaluation of the Stability of Hydrocortisone Sodium ... DOI: 10.17344/acsi.2022.7539 Scientific paper Evaluation of the Stability of Hydrocortisone Sodium Succinate in Solutions for Parenteral Use by a Validated HPLC-UV Method Katja Mihovec,1 Žane Temova Rakuša,2 Enikő Éva Gaál2 and Robert Roškar2 1 University Medical Centre Ljubljana, Slovenia 2 University of Ljubljana, Faculty of Pharmacy, Ljubljana, Slovenia * Corresponding author: E-mail: robert.roskar@ffa.uni-lj.si Tel: +386 1 4769 655 Received: 06-30-2022 Abstract This study aimed to determine the in-use stability (t95%) of hydrocortisone sodium succinate (HSS) infusion solutions and provide evidence-based guidelines on their usability. HSS infusion solutions were prepared and stored as recommended by the manufacturer and under common conditions in our hospital. The effects of HSS concentration (1 and 4 mg/mL), solvent (isotonic saline and glucose), temperature (ambient and 30 °C), and light on its stability were evaluated using a validated stability-indicating HPLC-UV method. HSS degradation followed first-order kinetics. No significant difference in its stability was observed between the two evaluated concentrations, solvents and light exposure (t95% between 25 and 30 h). Elevated temperature (30 °C) affected HSS stability and significantly reduced the t95% (4.6–6.3 h). HSS infusion solutions are physically and chemically stable (<5% degradation) for at least 6 h if stored below 30 °C. The in-use stability may be extended up to 24 h if stored below 24 °C. Keywords: Forced degradation study; in-use stability; infusion; injection; Solu-Cortef. 1. Introduction Cortisone is a glucocorticoid hormone synthesized endogenously in the adrenal gland cortex, as a response to stress.1 Its synthetic form – hydrocortisone, mostly as hy- drocortisone sodium succinate (HSS), is used in medi- cines for various conditions, requiring rapid and intense corticosteroid effects, such as acute or chronic adrenal in- sufficiency, various autoimmune and allergic diseases, and septic shock, unresponsive to fluid resuscitation and treat- ment with vasopressors.2,3 Thus, the use of HSS as a con- tinuous infusion is associated with more stable cortisol plasma concentrations and reduced fluctuation in blood glucose levels compared to intermittent boluses.4 This is particularly important in patients with diabetes, as hyper- glycaemia is one of the most common glucocorticoid side effects.4,5 The application of continuous HSS infusion is also well-established practice for critically ill patients in hospital intensive care units (ICUs), also including the ICU of our hospital. For such purposes, commercially available medicinal products, in the form of vials contain- ing freeze-dried powder for solution for injection/infu- sion, are used. Thus, an intravenous infusion is prepared as recommended by the manufacturer – by reconstituting the powder with 2 mL of sterile water for injection and addi- tion of this solution to 100–1000 mL of 5% glucose in wa- ter or isotonic saline solution or 5% glucose in isotonic saline solution under aseptic conditions.2 While the man- ufacturer recommends immediate use after reconstitution with sterile water for injection and disposal of any remain- der, no information is provided on the in-use stability of the diluted HSS solution for infusion.2 HSS is an ester, sus- ceptible to hydrolysis and other degradation reactions (ox- idation and transesterification) in aqueous solutions.6–8 In a broader sense, data on HSS stability can be found in the literature, as HSS stability studies in oral solutions and sus- pensions,9,10 solutions for infusion,11,12 or as compatibility studies with other drugs.13–15 Focusing on stability studies of HSS individually in solutions for infusion, which are limited to isotonic saline solutions, we identified a need for 797Acta Chim. Slov. 2022, 69, 796–802 Mihovecet et al.: Evaluation of the Stability of Hydrocortisone Sodium ... a stability study under clinically relevant real-life condi- tions, since the type of media, temperature, and HSS con- centration may affect its stability.8–10 As medical personnel deal with these issues on daily basis, our primary objective within this study was to evaluate the stability of HSS under common real-life conditions and thus provide evi- dence-based guidelines. For such purpose, we investigated the stability of HSS in solutions for infusion, as commonly prepared in our hospital, by using a stability-indicating HPLC-UV method. We thus evaluated the effect of clini- cally relevant HSS concentration (1 mg/mL and 4 mg/mL), type of reconstitution solvent (isotonic saline and glucose solutions), temperature (24 °C and 30 °C), and light (pro- tected and exposed to daylight) on its stability in infusion solutions. 2. Experimental 2. 1. Chemicals and Preparations HPLC grade acetonitrile (ACN) was purchased from Sigma-Aldrich (Steinheim, Germany). Hydrochloric acid (HCl) and sodium hydroxide (NaOH) solutions (Titrisol®) as well as phosphoric acid (H3PO4) (85%) were purchased from Merck (Darmstadt, Germany). H2O2 solution (30%) was purchased from Honeywell FlukaTM (Seelze, Germa- ny). High purity water was obtained using a Milli-Q A10 Advantage water purification system (Millipore Corpo- ration, Bedford, MA, USA). Solu-Cortef 100 mg powder for solution for injection or infusion (Pfizer, Luxembourg, Luxembourg), and solutions for infusion: 0.9% sodium chloride (S) in 50 mL infusion bags (Baxter, Deerfield, Il- linois, USA), and 5% glucose (G) in 100 mL intravenous (IV) containers (B. Braun, Melsungen, Germany) were used. Due to the lack of an HSS reference standard, its calibration and quality control (QC) solutions, as well as samples for the forced degradation study, were prepared by dissolving a portion of the powder of the medicinal product Solu-Cortef in Milli-Q water. The total powder was initially weighted to calculate the share of HSS, ac- cording to the reported HSS content in the product. 2. 2. Instrumentation and Chromatographic Conditions The analysis was performed on an Agilent 1100/1200 series HPLC system (Agilent Technologies, Santa Clara, CA, USA) equipped with a UV–VIS detector and a Chem- Station data acquisition system. A reversed-phase Luna C18 250 × 4.6 mm, 5 μm particle size column (Phenomenex, Torrance, CA, USA) at 40 °C using 1% (v/v) H3PO4 (mo- bile phase A), and ACN (mobile phase B) in isocratic mode (33% A, 67% B), at a flow-rate of 1.5 mL/min was utilized for the analysis. Detection was performed at 254 nm. The injection volume was 2 µL. The retention time (tr) of HSS was 10.8 min and the total runtime was 13 min. 2. 3. Preparation of Samples for Forced Degradation Study The forced degradation study was performed accord- ing to the ICH guidelines Q1A (R2).16 A stock HSS solu- tion (5 mg/mL) was initially prepared and diluted 5-fold, to obtain samples containing 0.1 M HCl, 0.1 M NaOH, 3% H2O2, or Milli-Q water. Samples with Milli-Q water were used as controls (ambient temperature and protected from light) and to assess the effect of temperature (60 °C) and light (exposure to daylight). All samples, except those for thermal degradation, were stored at ambient tempera- ture (24 °C) and protected from light (except those for the photostability testing). The samples were exposed to stress conditions for 24  hours. The samples were neutralized with HCl or NaOH (when required) or cooled to ambient temperature (thermal stress samples) before analysis. 2. 4. Preparation of Calibration Standards and QC Solutions A stock solution containing 5 mg/mL HSS was initial- ly prepared and further diluted with Milli-Q water to ob- tain calibration standards with the following HSS concen- trations: 0.05 mg/mL, 0.5 mg/mL, 2.0 mg/mL, 3.0 mg/mL and 5.0 mg/mL. QC samples containing 0.1 mg/mL, 1.0 mg/mL, and 4.0 mg/mL HSS were prepared from the initially prepared HSS stock solution in triplicate in the same manner. The calibration and QC solutions were pre- pared and analysed on three consecutive days of the vali- dation. 2. 4. Method Validation The utilized HPLC–UV method was validated fol- lowing the ICH guidelines Q2(R1) in terms of specificity, linearity, precision, accuracy, quantitation limit (LOQ), detection limit (LOD), and sample stability.17 Specificity was evaluated in chromatograms of the used solvents (Milli-Q water, 0.9% sodium chloride solu- tion, 5% glucose solution, and the solvent in the vial of the medicinal product Solu-Cortef, which contains ben- zyl alcohol as a preservative), which were compared with the chromatogram of HSS solution. Specificity was also assessed in forced degradation HSS samples, which were evaluated for chromatographic interferences. Linearity was assessed by linear regression analysis of calibration standards, covering expected HSS concen- trations in solutions for infusion (0.05–5.0 mg/mL). The determination coefficient (R2) > 0.999 was considered ac- ceptable. The QC solutions, prepared at three concentration levels on each day of the validation, were used to evaluate the accuracy, precision, and injection repeatability. Intra- and inter-day accuracy was determined as the ratio be- tween the HSS concentration calculated from the regres- 798 Acta Chim. Slov. 2022, 69, 796–802 Mihovecet et al.: Evaluation of the Stability of Hydrocortisone Sodium ... sion line and its actual concentration. Intra- and inter-day precision was determined by calculating the relative stand- ard deviation (RSD) of the QC solutions in triplicate and injection repeatability was determined as the RSD of six consecutive injections of a QC solution. The acceptance criteria were 100 ± 5% for accuracy, ≤ 5% RSD for preci- sion, and ≤ 2% RSD for injection repeatability. The LOD and LOQ were calculated using the equa- tions LOD = (3.3 × σ)/S and LOQ = (10 × σ)/S, where σ is the standard deviation of the intercepts and S is the aver- age slope of the three regression lines. HSS stability was determined by storing the QC solu- tions at all three concentration levels in the autosampler (6 °C) and analysing them within 24 h. HSS stability, ex- pressed as a share of the initial response, was set at 100 ± 5%. 2. 6. Sample Preparation and HSS in-use Stability Study in Solutions for Infusion The stability of HSS was studied in solutions for in- fusion prepared according to the manufacturer’s instruc- tions, and as prepared in our hospital. A 50 mg/mL HSS solution was initially prepared by adding 2 mL of sterile water for injection to the content of a vial of Solu-Cor- tef, followed by manual shaking. Half of this solution (1 mL) was withdrawn and diluted up to 50 mL with S or G in the original IV containers to an HSS concentration of 1 mg/mL. The 4 mg/mL HSS solutions in S or G were pre- pared in the same way, using two vials of Solu-Cortef (2 × 2 mL diluted with 50 mL of S or G). The pH values of the prepared solutions were measured using a pH meter MP 220 (Mettler Toledo, Switzerland). The effects of different HSS concentrations (1 mg/mL and 4 mg/mL), solvent (S and G), temperature (controlled ambient (24 ± 1 °C) and elevated (30 ± 1 °C), and light exposure (protected (UV-prot) and unprotected (UV)) on HSS stability in solutions for infusion were studied (Table 1). All samples were prepared and stored in the original S and G IV containers in triplicate and analyzed at regular time points within 72 hours. All samples were also visually ex- amined for potential physical changes. 2. 7. In-use Stability Determination and Statistical Analysis The results are expressed as the mean of three par- allels of the samples along with the standard error of the mean. Zero (c = c0 – kt), first (lnc = lnc0 – kt), and sec- ond-order (1/c = 1/c0 + kt) kinetics, where t is time, c is the HSS concentration at time t, c0 is the initial HSS concentra- tion, and k is the reaction rate constant, were fitted to the HSS degradation using the least square regression func- tion. Among them, the model with the highest R-square was selected and applied for in-use stability determina- tion, which was defined as HSS content ≥ 95% of the initial content. The determined rate constants and in-use stabili- ty were compared by 95% confidence intervals. Statistical analyses using a two-sample t-test assuming variances, as previously determined by the F-test for two sets of data, which differ in only one parameter (e.g., different storage temperature, light, HSS concentration, or type of solvent) were performed using MS Excel 2019. Differences with p values < 0.05 were considered significant. 3. Results 3. 1. HSS Forced Degradation Study Among the conditions tested within the forced deg- radation study, HSS proved most susceptible to hydrolytic degradation with only 2% remaining in 0.1 M NaOH and 20% in 0.1 M HCl after 24 hours. HSS was also susceptible to oxidation (56% remaining after 24 hours in 3% H2O2), thermal degradation (63% remaining after 24 hours of storage at 60 °C), and photolytic degradation to a lesser extent (96% remaining after 24 hours). The HSS main deg- radation products (tr 4.0, 5.7, and 6.5 min) formed dur- ing the forced degradation study did not interfere with its chromatographic evaluation (tr 10.9 min) (Figures S1, S2, and S3). 3. 2. Method Validation The specificity of the method was confirmed as all solvents recommended by the manufacturer for dissolution and dilution of the medicinal product Solu-Cortef, did not contain interfering peaks at HSS retention time. Also, no interfering degradation product peaks were formed during the HSS forced degradation study (Figure S2). In addition, the linearity, intra- and inter-day accuracy and precision, Table 1. Conditions during hydrocortisone sodium succinate (HSS) stability study in isotonic saline (S) and 5% glucose (G) solutions for infusion. Sample HSS Solvent Storage Light concentration temperature exposure [mg/mL] [°C] 1 S 24 UV-prot 4 S 24 UV-prot 1 G 24 UV-prot 4 G 24 UV-prot 1 S 24 UV 4 S 24 UV 1 G 24 UV 4 G 24 UV 1 S 30 UV-prot 4 S 30 UV-prot 1 G 30 UV-prot 4 G 30 UV-prot S – isotonic saline (0.9% sodium chloride); G – 5% glucose solution; UV – exposed to daylight; UV-prot – light protected. 799Acta Chim. Slov. 2022, 69, 796–802 Mihovecet et al.: Evaluation of the Stability of Hydrocortisone Sodium ... and injection repeatability of the method were confirmed (Table 2), as all results were within the acceptance crite- ria. The method was found sufficiently sensitive for HSS evaluation within the stability study (LOQ ≤ 3.9% of the expected HSS content). HSS also proved proper stability in the QC solutions, with a < 1% change in its response after 24 hours (Table 2). 3. 3. HSS in-use Stability Study in Solutions for Infusion The determined pH values of the simulated solu- tions for infusion with different HSS concentrations were as follows: 7.04 in S containing 1 mg/mL HSS; 7.26 in S containing 4 mg/mL HSS; 7.42 in G containing 1 mg/mL HSS and 7.52 in G containing 4 mg/mL HSS and were within the pH range, specified by the manu- facturer.2 The obtained results on HSS stability in the simulated solutions for infusion are shown in Figure 1. The increase in temperature (from 24 °C to 30 °C) signif- icantly increased HSS degradation, while the other tested conditions – different HSS concentrations (1 mg/mL and 4  mg/mL), media (S or G), and light exposure only slightly affected HSS stability. No changes in colour, odour or precipitations were detected in the samples during the stability study. Table 2. Validation data of the analytical method for hydrocortisone sodium succinate (HSS) quantification. HSS Range [mg/mL] R2 LOD [mg/L] LOQ [mg/L] calibration 0.05-5.00 1.0000 12.6 39.2 samples QC samples Intra-day accuracy and precision Inter-day accuracy and precision HSS conc. Found conc. Accuracy RSD Found conc. Accuracy RSD Inj. Stability [mg/mL] [mg/mL] (%) (%) [mg/mL] (%) (%) rep. (%) 0.1 0.0981 98.1 1.29 0.0997 99.7 3.30 0.52 100.5 1.0 1.0054 100.5 0.02 1.0087 100.9 0.29 0.20 99.2 4.0 3.9901 99.8 0.46 3.9956 99.9 0.55 0.29 99.2 LOD – detection limit; LOQ – quantitation limit; QC – quality control; conc. – concentration; RSD – relative standard deviation; Inj. rep. – injection repeatability. Figure 1. Hydrocortisone sodium succinate (HSS) stability in the simulated solutions for infusion in isotonic saline (0.9% sodium chloride) (S) and 5% glucose solution (G) under different storage conditions. The results are presented as an average ± standard error of the mean, n = 3. 800 Acta Chim. Slov. 2022, 69, 796–802 Mihovecet et al.: Evaluation of the Stability of Hydrocortisone Sodium ... The fitting of zero, first, and second-order kinetic models showed that HSS degradation in aqueous solu- tions follows first-order kinetics, which was applied to its stability evaluation. First-order reaction rate constants were calculated for HSS degradation in each tested solu- tion and used for the determination of its in-use stabili- ty (Section In-use stability determination and statistical analysis) (Table 3). 4. Discussion The main objective of our study was to determine the chemical and physical stability of HSS at two concentra- tions (1 mg/ml and 4 mg/ml) at ambient temperature after reconstitution with the solvent in the vial of the medic- inal product and dilution with 0.9% sodium chloride or 5% glucose solution. Although the HSS concentration of 4 mg/ml exceeds the highest HSS concentration in in- fusions, prepared according to the manufacturer’s in- structions, it is a clinically relevant concentration in the treatment of ICU patients, for whom a reduction in the infusion volume is very desirable. These two HSS concen- trations represent the most common circumstances, when preparing an HSS infusion, in our hospital and were there- fore selected for the study. HSS stability evaluation was performed by utilizing a stability-indicating HPLC-UV method, based on the method proposed in the European pharmacopeia HSS monograph,18 which was further opti- mized and properly validated following the ICH Q2(R1) guidelines.17 The stability-indicating nature of the meth- od was confirmed by forced degradation studies, as the chromatographic peak of HSS was chromatographically separated from its degradation products, as can be seen in Figure S2, yet the peak purity was not assessed due to lim- itations of the analytical equipment (variable wavelength UV detector). Forced degradation studies also revealed the susceptibility of HSS to degradation under hydrolytic, ox- idative, and thermal conditions. However, these stability issues are not addressed by the manufacturer of the medic- inal product Solu-Cortef, who does not specify the in-use stability of the HSS solution for infusion. Specified in-use stability would be valuable information for the medical personnel with implications for the patients, as HSS is commonly applied as a continuous infusion. However, it is also unaccounted for in the accessible literature. There- fore, the in-use stability of HSS in solutions for infusion was determined within this study, together with the effects of real-life conditions and situations (use of different types and volumes of solution for dilution, temperature varia- tions, and exposure to light). The main conclusion from the performed in-use stability study is that HSS stability is mostly affected by temperature, as the increase in temperature (from 24 °C to 30 °C) significantly increased HSS degradation (reaction rate constants in Table 3) and resulted in significantly shorter in-use stability of ≤ 6.3 hours (in-use stability in Table 3) (t-test, p < 0.001). The destabilizing effect of high- er storage temperature on HSS in S was also demonstrat- ed by Gupta and Ling.16 The determined in-use stability, considering the 95% confidence interval was higher in the samples protected from light (Table 3). However, these dif- ferences were typically not statistically significant (t-test, p > 0.05), which is in line with the findings from the per- formed forced degradation study (Section HSS forced deg- radation study). Analogously, the differences between the stability of HSS at different concentrations in S were not significant (t-test, p > 0.05), whereas G containing a higher HSS concentration (4 mg/mL) was significantly less stable than the 1 mg/mL solution (t-test, p < 0.03) under all three evaluated conditions (24 °C, protected from light; 24 °C, exposed to daylight; and 30 °C, protected from light) (Ta- ble 3). Comparing the HSS stability in solution with the same concentration and stored under the same conditions Table 3. First-order rate constants (k1) and in-use stability (t95%) for hydrocortisone sodium succinate (HSS) at two concentrations (1 mg/mL and 4 mg/mL) in the simulated solutions for infusion under different storage conditions. Simulated k1 [h–1] (CI) In-use stability [h] (CI) solutions for 24 °C, 24 °C, 30 °C, 24 °C, 24 °C, 30 °C, infusion UV-prot UV UV-prot UV-prot UV UV-prot 1 mg/mL 1.84×10–3 1.92×10–3 8.79×10–3 28.0 26.7 5.9 HSS in S (1.86×10–3 – 2.01×10–3) (1.90×10–3 – 1.93×10–3) (7.84×10–3 – 9.74×10–3) (26.6 – 29.3) (26.5 – 27.0) (5.2 – 6.5) 4 mg/mL 1.94×10–3 1.99×10–3 1.03×10–2 26.5 25.8 5.0 HSS in S (1.86×10–3 – 2.01×10–3) (1.91×10–3 – 2.07×10–3) (9.46×10–3 – 1.10×10–2) (25.4 – 27.5) (24.7 – 26.8) (4.6 – 5.4) 1 mg/mL 1.64×10–3 1.76×10–3 7.81×10–3 31.2 29.1 6.6 HSS in G (1.55×10–3 – 1.73×10–3) (1.71×10–3 – 1.81×10–3) (7.46×10–3 – 8.17×10–3) (29.6 – 32.9) (28.2 – 29.9) (6.3 – 6.9) 4 mg/mL 1.98×10–3 2.00×10–3 1.10×10–2 25.9 25.4 5.0 HSS in G (1.91×10–3 – 2.05×10–3) (2.00×10–3 – 2.05×10–3) (9.88×10–3 – 1.05×10–2) (25.0 – 26.9) (25.0 – 25.7) (4.9 – 5.2) CI – 95% confidence interval; S – isotonic saline (0.9% sodium chloride); G – 5% glucose solution; UV – exposed to daylight; UV-prot – light pro- tected. 801Acta Chim. Slov. 2022, 69, 796–802 Mihovecet et al.: Evaluation of the Stability of Hydrocortisone Sodium ... (Table 3), we concluded that the use of different dilution solvents (S or G) does not significantly affect the HSS sta- bility (t-test, p > 0.05), which was expected as they are both recommended as dilution solvents by the manufacturer.2 The determined in-use stability of 24 hours under con- trolled room temperature provides the medical personnel reliable evidence on the usability of the infusion solution, during the application of the infusion. During this time period, all evaluated HSS solutions remained physically stable, as no changes in the organoleptic properties were observed. The microbiological stability was not evaluated within this study. The results of this stability study, per- formed in clinically relevant conditions on the medicinal product, represent a step forward in providing high-qual- ity patient care, which is primarily ensured by the quality of the medicinal product itself, guaranteed by its manufac- turer and the competent regulatory bodies. 5. Conclusion The chemical and physical stability of HSS in solu- tions for infusion under different conditions, which sim- ulate the conditions in hospitals, was assessed within this study. The results, obtained using a stability-indicating HPLC-UV method, revealed HSS degradation in these solutions, which followed first-order kinetics. Based on the stability data, in-use stability (t95%) of at least 24 hours was confirmed at ambient temperature and a significantly lower in-use stability (≤ 6 hours) at 30 °C. Other evaluated conditions (HSS concentration, light exposure, and use of different dilution solvents), did not significantly affect the stability of HSS in the examined solutions for infusion. All evaluated solutions were physically stable within the deter- mined in-use stability. The significant temperature effect on the stability of HSS in solutions for infusion should be considered in hospitals with uncontrolled temperatures and especially during summertime. Acknowledgements This research was financially supported by the Slove- nian Research Agency (ARRS) [P1-0189]. Competing interest: None declared. 6. References 1. M. Q. Almeida, B. B. Mendonca, Clinics (Sao Paulo) 2020, 75, e2022–e2022. DOI:10.6061/clinics/2020/e2022 2. ‘Solu-Cortef – Summary of Product Characteristics (SmPC) – https://www.medicines.org.uk/emc/medicine/7833#gref, (assessed: July 21, 2021). 3. R. H. Straub, M. Cutolo, Rheumatology 2016, 55, ii6–ii14. DOI:10.1093/rheumatology/kew348 4. H. Hoang, S. Wang, S. Islam, A. Hanna, A. Axelrad, C. Brath- waite, P T 2017, 42, 252–255. 5. H. E. Tamez-Pérez, D. L. Quintanilla-Flores, R. Rodríguez- Gutiérrez, J. G. González-González, A. L. Tamez-Peña, World J Diabetes 2015, 6, 1073–1081. DOI: 10.4239/wjd.v6.i8.1073 6. E. R. Garrett, J Pharm Sci 1962, 51, 445–450. DOI:10.1002/jps.2600510511 7. L. Solomun, S. Ibric, V. Pejanovic, J. Djuris, J. Jockovic, P. Stankovic, Z. Vujic, Hem Ind 2012, 66, 647–657. DOI:10.2298/HEMIND120207023S 8. V. Das Gupta, J Pharm Sci 1978, 67, 299–302. DOI:10.1002/jps.2600670305 9. J. Chappe, N. Osman, S. Cisternino, J.-E. Fontan, J. Schlatter, J Pediatr Pharmacol Ther 2015, 20, 197–202. DOI:10.5863/1551-6776-20.3.197 10. A. Manchanda, M. Laracy, T. Savji, R. H. Bogner, Int J Pharm Compd 2018, 22, 66–75. 11. V. D. Gupta, J. Ling, Int J Pharm Compd 2000, 4, 396–397. 12. D. C. Rigge, M. F. Jones, J Pharm and Biomed 2005, 38, 332– 336. DOI:10.1016/j.jpba.2004.12.026 13. J. C. Cradock, L. M. Kleinman, A. Rahman, Am J Hosp Pharm 1978, 35, 402–406. DOI:10.1093/ajhp/35.4.402 14. L. A. Trissel, K. M. King, Y. Zhang, A. M. Wood, J Oncol Pharm Pract 2002, 8, 27–32. DOI:10.1191/1078155202jp087oa 15. Y. W. Cheung, B. R. Vishnuvajjala, K. P. Flora, Am J Hosp Pharm 1984, 41, 1802–1806. DOI:10.1093/ajhp/41.9.1802 16. International Council for Harmonisation. ICH Harmonised Tripartite Guideline. Stability Testing of New Drug Substanc- es and Products Q1A(R2). Geneva, Switzerland, 2003. 17. International Council for Harmonisation. ICH Harmonised Tripartite Guideline. Validation of Analytical Procedures: Text and Methodology Q2(R1). Geneva, Switzerland, 2005. 18. Hydrocortisone Hydrogen Succinate. In: European Pharma- copoeia 10ed. Strasbourg: Council of Europe. 2020:2888-9. 802 Acta Chim. Slov. 2022, 69, 796–802 Mihovecet et al.: Evaluation of the Stability of Hydrocortisone Sodium ... Except when otherwise noted, articles in this journal are published under the terms and conditions of the  Creative Commons Attribution 4.0 International License Povzetek Namen te študije je opredelitev stabilnosti in določitev roka uporabnosti med uporabo (t95%) raztopin za infundiranje z natrijevim hidrokortizonsukcinatom (HSS) ter zagotovitev na dokazih podprtih priporočil o njihovi uporabnosti. Infuzijske raztopine HSS smo pripravili in shranjevali v skladu s priporočili proizvajalca in pri običajnih pogojih v naši bolnišnici. Z validirano stabilnostno indikativno HPLC-UV metodo smo ugotavljali vpliv koncentracije HSS (1 in 4 mg/mL), topila (izotonična fiziološka raztopina in raztopina glukoze), temperature (sobna in 30 °C) in svetlobe na njegovo stabilnost. Razgradnja HSS je sledila kinetiki prvega reda. Ugotovili smo, da različni preiskovani koncentraciji HSS, obe topili in izpostavljenost svetlobi niso značilno vplivali na stabilnost HSS (t95% med 25 in 30 urami), medtem ko je povišana tem- peratura (30 °C) značilno skrajšala t95% (4,6–6,3 ur). Infuzijske raztopine HSS so fizikalno in kemično stabilne (<5 % razgradnja) vsaj 6 ur pri temperaturi do 30 °C in najdlje 24 ur pri temperaturi do 24 °C.