Study of reaction mechanism between piroxicam and tenoxicam drugs with iodate and N-bromosuccinamide oxidants and their microdetermination by spectrophotometric and potentiometric measurements

Piroxicam [Pir] and tenoxicam [Ten] are specified as nonsteriodal anti-inflammatory drugs. They are used in the symptomatic management of osteoarthritis, rheumatoid arthritis and in short term management of soft-tissue injury. Therefore, their reactions with oxidants, Iodate and N-bromosuccinamide [NBS] are suggested, discussed and used for microdeterminations of these essential biomedical drugs. A sensitive Spectrophotometric method has been suggested and used in comparison with a potentiometric one to follow these reactions mechanisms aiming to apply them in microdetermination of piroxicam [Pir] and tenoxicam [Ten]. No interference from excipients was observed in both techniques. The Spectrophotometric procedure was better than the potentiometric one, because of the sensitivity of the former to detect lower concentration ranges [50 to 1100 micro g ml[-1]] of the pure standard drugs and the detection of high concentration range [300 to 3980 micro g ml[-1]] by the latter. The high molar absorptivity [e = 0.25-0.29 x 10[3] L.mol[-1] cm[-1]] and Sandell sensitivity [1.2 - 13 micro g cm[-2]] refer to the high selectivity of the Spectrophotometric method. The between -day precision of the potentiometric procedure refers to the greater stability and good reliability of this procedure in high concentration [% recovery = 99 to 102%]. These procedures were applied for successful microdetermination of Pir and Ten in many pharmaceutical preparations, such as tablets and capsules. The values of SD [0.03 to 0.6 for five replicates] and RSD [0.6 to 1.2%] refer to reproducibility and precision of the applied procedures. The results of analyses of these drugs were compared with those obtained by the application of the official method using Ringbom, t-test and f-test. These results gave t- value of 2.776 and f-value of 6.31 at 95% confidence level. The obtained results also refer to the robustness of the proposed procedures

Two colorimetric methods for the assay of six nonsteroidal anti-inflammatory drugs in their pure and dosage forms

This paper described two new colorimetric methods for estimation of six nonsteroidal anti-inflammatory drugs; namely, piroxicam, tenoxicam, mefenamic acid, flufenamic acid, ibuprofen and ketoprofen in their pure forms and pharmaceutical preparations. The first method depends on scanning the azodyes resulting from the reaction of piroxicam and tenoxicam with diazonium salts of benzocaine, p-amino-N- methylbenzamide and sulfadiazine. The second procedure is based on colorimetric determination of the blue colored complexes yielded from the reaction of methylene blue with drugs under investigation. The different conditions for the proposed methods were studied. The methods have been applied for the analysis of pharmaceutical preparations containing these drugs and the results obtained were compared with those of pharmacopoeial or published methods. The methods are simple, precise and reproducible

Avaliacao da dissolucao de formas farmaceuticas solidas contendo piroxicam e piroxicam-beta-ciclodextrina / Evaluation of dissolution of solid dosage forms containing piroxicam and piroxicam-beta-cyclodextrim

No presente estudo avaliaram-se nove lotes de capsulas de piroxicam-20mg, provenientes de seis fabricantes, e um lote de comprimidos contendo o complexo de inclusao piroxicam-beta-ciclodextrina. Determinaram-se o peso medio e o teor de piroxicam, efetuando-se o teste e o perfil de dissolucao. Os produtos analisados, comercializados como similares no mercado nacional, apresentaram comportamentos distintos. Setenta e oito por cento das amostras foram reprovadas em relacao ao teste de dissolucao. o perfil de dissolucao foi util para discriminar os produtos e, como era esperado, o comprimido contendo o complexo de inclusao demonstrou disssolucao superior aos demais

Anestesia regional intravenosa com associaçåo de lidocaína - tenoxicam em cirurgia ortopédica de membro superior / Intravenous regional anesthesia with lidocaine - tenoxicam in orthopedic surgery on upper limbs

Background and Objectives - Intravenous regional anesthesia is an easy, safe, and reliable technique for surgery on the limbs, although it does not provide good post operative analgesia. Tenoxican is a non steroidal antiinflamatory drug which was developed for intravenous use. The purpose of this study was to evaluate if the asociation of tenoxicam to the lidocaine used as the local anesthetic for intravenous regional anesthesia further enhances the quality and duration of post operative analgesia in orthopedic surgery on the upper limbs. Methods - Seventy-five patients, allocated into 3 groups of 25, were studied. Group A received 2 ml of saline associated with the local anesthetic and 2 ml of saline intravenously in the contra-lateral lim. Group B receveid 20 mg de tenoxican intravenously in the contra-lateral limb. Group C received tenoxican 20 mg asociated with the local anesthetic. The following parameters were evaluated: duration of postoperative analgesia, pain intensity, analgesic requirements and side effects. Results - Duration of postoperative analgesia was significantly longer and opioid requirements significantly less in the groups which received tenoxicam. The painless intervals were 23 +- 10 minutes in Group A, 89 +- 44 minutes in Group B (p< 0.01 as compared to A) and 417 +- 190 minutes in Group C (p<0.01 as compared to A and B). Side effects were similar in all groups. Conclusions - Data collected in this study demonstrate that the asociation of lidocaine and tenoxicam induces good quality of analgesia in the post operative period of orthopedic surgery, The duration of the analgesic effect of the asociation is significantly longer as compared to that of the local anesthetic alone. The administration of the two drugs in the same solution produces better results