Vivapur 200

The model active ingredient of the tablets, drotaverine hydrochloride (DR) was purchased from Sigma Aldrich (Munich, Germany). The binder of the tablets was microcrystalline cellulose (MCC) with the brand name Vivapur 200, supplied by JRS Pharma (Rosenberg, Germany). As filler, α-lactose monohydrate was utilized; the supplier of type Granulac^® 70 was Meggle Pharma (Wasserburg, Germany). The component responsible for sustained release was hydroxypropyl methylcellulose (HPMC); specifically, its type was K100M DC2; this ingredient was a gift from Colorcon (Budapest, Hungary). Lastly, the lubricant of the tablets was magnesium stearate; this compound was obtained from Hungaropharma Ltd. (Budapest, Hungary). For the preparation of the dissolution medium, a 37% hydrochloric acid (HCl) solution was acquired from Merck (Darmstadt, Germany).

Acetylsalicylic acid (ASA) was used as a model API, and microcrystalline cellulose (MCC) was used as tableting excipient. Crystalline ASA (particle size: d₁₀ = 133.16 µm; d₅₀ = 532.86 µm; d₉₀ = 1223.77 µm) is marketed as Rhodine^® 3040 (Novacyl, Écully, France). MCC (particle size: d₁₀ = 113.88 µm, d₅₀ = 247.93 µm, and d₉₀ = 449.58 µm) is marketed as Vivapur^® 200 (JRS Pharma GmbH, Rosenberg, Germany).

Drotaverine (DR) was obtained from Sigma-Aldrich (Munich, Germany). Hydroxypropyl methylcellulose (HPMC) K4M DC2 was a kind gift of Colorcon (Budapest, Hungary). Microcrystalline cellulose (MCC, Vivapur 200) was purchased from JRS Pharma (Rosenberg, Germany). Magnesium stearate (MgSt) obtained from Hungaropharma Ltd. (Budapest, Hungary) was used as a lubricant. Concentrated hydrochloric acid solution was purchased from Merck Ltd. (Darmstadt, Germany).