[Model analysis of tulobuterol patch formulations to explain the influence of drug release rate and transdermal transfer rate on the plasma concentration profile]

Generic selection criteria for safety and patient benefit [Ⅻ]: Comparing the physicochemical and pharmaceutical properties of brand-name and generic tulobuterol tape

Physicochemical properties (drug release, peel strength, adhesion, and stiffness) of Hokunalin® Tape (Hokunalin) and 13 generic transdermal bronchodilator patches containing tulobuterol were characterized and evaluated for comparison. Drug-release studies evaluating sustained release behavior demonstrated better performance by the drug Hokunalin, than the generics MED, YP, Sawai, and Teikoku. Hokunalin yield a 16.2% release 1 hour after initiation, 30.1% at 3 hours, 50.0% at 8 hours. In comparison, the generics MED, YP, Sawai, and Teikoku showed an intermediate release behavior to that of Hokunalin, with more than 80% release after 8 hours. A 90-degree peel adhesion test for tape peel strength demonstrated that the generic MED (4.99 N), YP (3.26 N), Sawai (4.17 N), and Teikoku (4.37 N) tapes yielded significantly higher values compared to Hokunalin (2.66 N). Probe tack tests, evaluating adhesive strength, yielded significantly higher values for the generics HMT (4.89 N)and Towa (4.25 N) compared to Hokunalin (3.66 N). Furthermore, for the stiffness-softness test, a significantly higher value was obtained for each generic yielded compared to Hokunalin (3.7-degree). These factors are important components of product qualities that affect treatment efficacy, including "ease of application" and other usability factors.

[Effect of Storage of Tulobuterol Tapes after Package Opening and Liner Peeling on Their Formulation Properties]

Although tulobuterol tape is provided to patients in an inner package, information regarding the stability of the tape after opening the packaging may be requested by patients. This study was performed to generate underlying data on the storage stability after package opening or liner peeling with package opening. Tulobuterol tapes were stored at 25℃, 60% relative humidity (RH); 40℃, 75%RH; or in a refrigerator (2-4℃, 10-30%RH) for 1 day or 3 days. In a peel adhesive strength test after package opening, storage at 25℃, 60%RH had a low effect on the adhesive strength of the tape. Storage after liner peeling with package opening resulted in variable adhesive strength of the tape. Regarding drug release properties, for storage after package opening, the f2 values of tapes stored in the three different conditions were over 50, except for tapes stored at 25℃, 60%RH for 3 days. For the tapes stored at 25℃, 60%RH or 40℃, 75%RH after liner peeling with package opening, the release rate and the ratio of drug released at 24 h may be decreased because the drug content decreased due to drug sublimation. This study suggested that tulobuterol tapes can be stored after package opening at 25℃, 60%RH for 1 d.

Evaluation of the pharmaceutical characteristics of various enteric-coated aspirin tablets under different storage conditions

The formulation characteristics of 6 brands of enteric-coated aspirin tablets under unpackaged conditions at 40°C and 60°C for 4 weeks were analyzed. Appearance, salicylic acid content, dissolution rates, and surface properties (by Raman microscopy) were evaluated to determine stability data, taking into account the clinical use of generic drugs. No change in appearance, decomposition, or dissolution rates was observed in unpackaged aspirin tablets stored at 40°C for 4 weeks. However, when stored at 60°C, tablets of 5 of the 6 brands showed whiskers on their surfaces along with an increase in salicylic acid content and a decrease in dissolution rate. Results of Raman mapping on the surface and cross sectional surface of the tablets with whiskers showed a salicylic acid peak associated with storage at 60°C for 4 weeks. However, for tablets from 1 of the 6 brands, no salicylic acid peaks were observed. For this tablet, Raman microscopy revealed 2 layers of film coating, and talc, which greatly affected the stability of the acetylsalicylic acid, was found only in the outer layer film. These results indicated that the protection of compatibility with talc is one of the important factors in enhancement of aspirin tablet stability in this tablet. We concluded that certification of the characteristics associated with stability and formulation is essential for generic drugs, which are not required to undergo stability testing under extreme storage conditions.

[Questionnaire survey on the change of asthmatic response, adverse events and product usability due to drug switching between name-brand and generic tulobuterol tapes]

Aggravation of asthmatic response (asthmatic attack, 2 cases) and adverse events (tremor, 1 case) due to a switch from a brand-name tulobuterol tape to a generic tape were recently reported. These changes disappeared after reformulation from generic to the brand-name tape. To investigate this issue, we conducted a questionnaire survey on changes of asthmatic response, adverse events and product usability due to a switch between tulobuterol tapes. We identified 44 cases (18 from doctors, 26 from pharmacists) in which changes of asthmatic response or adverse events had occurred due to a switch between tulobuterol tapes. Aggravation of asthmatic response had occurred in 30 cases and adverse events in 21 cases due to switch from brand-name tulobuterol tape to generic tape. As regards change of product usability, we obtained 96 relevant responses (18 from doctors, 78 cases pharmacists), and the major response was that generic tulobuterol tape peeled off the skin more easily than did the brand-name tape (60 cases). These results suggest that changes of asthmatic response, adverse events and product usability should be carefully monitored when switching tulobuterol tapes.