Stability-indicating RP-HPLC method for determination of beclomethasone dipropionate in nanocapsule suspensions

Stability assessment and content determination test of oral liquid forms of beclomethasone dipropionate prepared in hospital pharmacy

OBJECTIVES

Oral beclomethasone dipropionate (BDP) is known for its use as a therapeutic medicine for gastrointestinal graft-versus-host disease (GI-GVHD). Despite growing demand for oral BDP formulation, no commercial forms have yet been marketed. Therefore, at the Tokyo Metropolitan Cancer and Infectious Disease Centre Komagome Hospital, pharmacists prepare oral liquid forms of BDP for patients with upper GI-GVHD. This study aims to develop a new high performance liquid chromatography (HPLC) method for measuring BDP in the prepared formulations and assessing its quality.

METHODS

We developed a new HPLC method for measuring BDP in prepared formulations validated according to international guidelines. Three types of formulations were prepared and analysed using the validated HPLC method. One contains 1 mg of BDP per 30 mL aqueous solution, and the others using ethanol for preparation contain 1 mg of BDP per 15 mL aqueous solution. For stability assessment, the BDP contents were assayed while formulations were stored in plastic bottles for 8 weeks under two different conditions of 25°C in bright light and 4°C in darkness. A content determination test was also conducted to assess the individual contents of BDP and lot-to-lot variation in dosage units.

RESULTS

A stability test demonstrated that the remaining BDP content after the storage period was greater than 90% of the initial content in almost all samples regardless of storage conditions. A content determination test showed thattwo new ethanol-containing formulations contained about 0.1 mg more BDP than the original ethanol-free formulation and it was close to the target BDP content of 1 mg. Furthermore, new formulations had less lot-to-lot BDP variation in dosage units than the original formulation.

CONCLUSIONS

A new HPLC method for measuring BDP in prepared formulations was developed and validated. The results of the stability test and content determination test indicated that the newly designed formulations were superior to the conventional formulation.

Identification and characterization of unknown degradation impurities in beclomethasone dipropionate cream formulation using HPLC, ESI-MS and NMR

The present study focuses on identifying the degradation profile and pathways of unknown impurities from beclomethasone dipropionate (BDP) topical cream formulation reported under accelerated stability conditions. Six degradation impurities were observed during the accelerated stability testing of BDP topical cream formulation, and these thermally labile degradation impurities were primarily identified using a simple, effective and mass compatible isocratic reversed-phase high-performance liquid chromatography with ultraviolet detection method. The degradation impurities found in this sample were of very low concentration levels, thus the concentration of these impurities in the sample was enriched by mimicking the thermal degradation conditions to structurally elucidate the unknown impurities. These BDP thermal degradation impurities were isolated using preparative liquid chromatography and followed by pre-concentration using rota-vapour. Further, the collected thermal degradation impurities were characterized using ESI-MS, and the major impurity was identified using ¹H and C¹³ NMR spectroscopy, and DEPT technique. Plausible degradation pathway and mechanism of each impurity from BDP has been proposed based on the obtained mass and NMR spectral data. Thus, the present method is simple and suitable to be applied towards BDP assay in various formulations, and also to investigate the thermal stability and degradation kinetics of the final drug product.

Long-lasting anti-platelet activity of cilostazol from poly(ε-caprolactone)-poly(ethylene glycol) blend nanocapsules

Cilostazol (CLZ) acts as a vasodilator and antiplatelet agent and is the main drug for the treatment of intermittent claudication (IC) related to peripheral arterial disease (PAD). The usual oral dose is 100 mg twice a day, which represents a disadvantage in treatment compliance. CLZ presents several side effects, such as headache, runny nose, and dizziness. This paper aimed to obtain novel polymeric nanocapsules prepared from poly(ε-caprolactone)-poly(ethylene glycol) (PCL-PEG) blend containing CLZ. Nanocapsules showed pH values between 6.1 and 6.3, average size lower than 137 nm, low polydispersity index (<0.22) and negative zeta potential. These nanoformulations demonstrated spherical shape with smooth surface. Results achieved by X-ray diffraction (XRD) and differential scanning calorimetry (DSC) indicated drug amorphization compared to pure CLZ. Fourier-transformed infrared spectroscopy (FTIR) showed no chemical bonds between drug and polymers. Formulations presented suitable stability for physical parameters. The in vitro drug release demonstrated prolonged release with no burst effect. Drug release was controlled by both mechanisms of polymer relaxation/degradation and Fickian diffusion. Moreover, chosen CLZ-loaded nanocapsules provided an in vivo prolonged antiplatelet effect for CLZ statistically similar to aspirin. These formulations can be further used as a feasible oral drug delivery carrier for controlled release of CLZ in order to treat PAD and IC events.