Development and evaluation of nifedipine controlled release tablets prepared using mucoadhesive swellable polymer

Nifedipine is embedded in Gelcarin GP-379 to develop a prolonged release matrix. The effect of polymers levels (15, 20, 30 and 50% w/w), diluent type (lactose Fast Flo, DiTab, and Avicel PH-101), and drug levels (13, 20 and 30% w/w) on in vitro release rate of the drug were investigated. The formulation containing 13% nifedipine, 20% Gelcarin GP-379, and lactose Fast Flo controlled the dissolution rate of nifedipine and released approximately 51% drug at 8?h of testing dissolution. The use of different types of diluents, different drug levels, and different rotational speeds during dissolution testing did affect the drug release rate from the swellable matrices. The dissolution data were analyzed according to Higuchi model, zero order, first order, and Peppas kinetic model. Drug release was found to follow the anomalous diffusion model for swellable matrix.     

Development and evaluation of nifedipine controlled release tablets prepared using mucoadhesive swellable polymer

Nifedipine is embedded in Gelcarin GP-379 to develop a prolonged release matrix. The effect of polymers levels (15, 20, 30 and 50% w/w), diluent type (lactose Fast Flo, DiTab, and Avicel PH-101), and drug levels (13, 20 and 30% w/w) on in vitro release rate of the drug were investigated. The formulation containing 13% nifedipine, 20% Gelcarin GP-379, and lactose Fast Flo controlled the dissolution rate of nifedipine and released approximately 51% drug at 8?h of testing dissolution. The use of different types of diluents, different drug levels, and different rotational speeds during dissolution testing did affect the drug release rate from the swellable matrices. The dissolution data were analyzed according to Higuchi model, zero order, first order, and Peppas kinetic model. Drug release was found to follow the anomalous diffusion model for swellable matrix.     

硝苯地平控释片与氢氯噻嗪治疗老年高血压的研究

目的 探讨盐酸贝那普利联合硝苯地平控释片或氢氯噻嗪治疗老年高血压的临床疗效比较.方法 选取140例3级老年高血压患者,随机分为观察组（70例）和对照组（70例）,观察组给予贝那普利10 mg,早上1次,硝苯地平控释片30 mg,早上1次;对照组贝那普利10 mg,早上1次,氢氯噻嗪25 mg,早上1次,观察入选时和治疗4周后,收缩压和舒张压的变化.结果 治疗前,观察组平均血压为：（187.3±5.2）/（115.5±2.4） mmHg,对照组平均血压为：（186.2±5.5）/（116.2±2.2） mmHg,差异均无统计学意义（P＞0.05）;治疗后,观察组平均血压为：（135.1±1.5）/（83.3±2.2） mmHg,对照组平均血压为：（142.2±2.1）/（89.1±2.5）mmHg,差异有统计学意义（P＜0.05）;观察组的总有效率为90％,对照组的总有效率为80％,差异有统计学意义（P＜0.05）.结论 观察组和对照组均能降低3级老年高血压,观察组疗效优于对照组,具有起效快、作用强、易于达标特点.     

Availability of NSAIDH beta-cyclodextrin inclusion complexes

The diffusion of a series of non steroidal antiinflammatory drugs through a silicone rubber membrane has been studied from suspensions both of the free and beta-cyclodextrin complexes forms at different pH values of the medium. Higher diffusion rates of the complexed forms as compared with the free ones and a rate-limiting effect of the apparent stability constant in the diffusion of the complexes were observed.     

硝苯地平缓释片与普通片在健康人体内药动学的比较

目的比较硝苯地平缓释片与硝苯地平普通片在健康人体内药动学。方法 12名男性健康志愿者平均分为2组,分别单剂量口服硝苯地平缓释片与硝苯地平普通片20 mg,用高效液相色谱法检测硝苯地平的血药浓度,并用DAS 2.1软件进行数据处理。结果硝苯地平缓释片与硝苯地平普通片主要药动学参数ρmax分别为(1 247.8±78.4)μg.L-1和(1 896.7±109.2)μg.L-1,tmax分别为(4.6±0.7)h和(2.6±0.9)h,t1/2分别为(8.6±2.8)h和(4.8±1.5)h,AUC0-∞分别为(5 879.3±176.2)μg.h.L-1和(3 724.9±121.3)μg.h.L-1,AUC0-t分别为(4 427.8±131.7)μg.h.L-1和(2 936.5±75.4)μg.h.L-1。结论硝苯地平缓释片的tmax、t1/2长于普通片,AUC0-t、AUC0-∞高于普通片,而ρmax低于普通片,说明硝苯地平缓释片具有良好的缓释效果。     

Insulin availability from mucoadhesive tablets

The widespread implementation of peptides as drugs encounters numerous obstacles, the main being invasive and inconvenient parenteral administration. Oral transmucosal administration is one of the possible alternatives, valuable for its noninvasiveness and easy accessibility. The aim of our study was to determine the implementation possibilities of mucoadhesive tablets prepared on a methylcellulose and sodium alginate basis with an addition of absorption-modifying hyaluronic acid, as carriers for peptides destined for oral transmucosal administration. Two series of 50 mg tablets containing 5mg of insulin were prepared for the study. The first series contained methylcellulose, hyaluronic acid and mannitol, while the second series' formulation included sodium alginate, hyaluronic acid and mannitol. Carried out study confirmed that insulin administration in the form of mucoadhesive tablets lowers blood glucose levels in rabbits. Better effects were reached in vivo in the case of MC-based tablets, for which stronger and longer glycemia lowering was achieved.     

Effect of low-molecular-weight beta-cyclodextrin polymer on release of drugs from mucoadhesive buccal film dosage forms

We investigated the effect of low-molecular-weight beta-cyclodextrin (beta-CyD) polymer on in vitro release of two drugs with different lipophilicities (i.e., lidocaine and ketoprofen) from mucoadhesive buccal film dosage forms. When beta-CyD polymer was added to hydroxypropylcellulose (HPC) or polyvinylalcohol (PVA) film dosage forms, the release of lidocaine into artificial saliva (pH 5.7) was reduced by 40% of the control. In contrast, the release of ketoprofen from the polymer film was enhanced by addition of beta-CyD polymer to the vehicle. When lidocaine and ketoprofen was incubated with beta-CyD polymer in the artificial saliva, concentration of free lidocaine molecules decreased in a beta-CyD polymer concentration-dependent manner. The association constant with beta-CyD polymer was 6.9+/-0.6 and 520+/-90 M(-1) for lidocaine and ketoprofen, respectively. Retarded release of the hydrophilic lidocaine by beta-CyD polymer might be due to the decrease in thermodynamic activity by inclusion complex formation, whereas enhanced release of the lipophilic ketoprofen by the beta-CyD polymer might be due to prevention of recrystallization occurring after contacting the film with aqueous solution. Thus, effects of low-molecular-weight beta-CyD polymer to the drug release rate from film dosage forms would vary according to the strength of interaction with and the solubility of active ingredient.     

使用亲水性聚合物调节硝苯地平从缓释骨架片中的释放(英文)

目的根据体外释放曲线调节硝苯地平缓释片(20 mg)的药物释放特性同时评价不同羟丙甲纤维素(HPMC)作为骨架材料的作用。方法硝苯地平HPMC骨架片使用不同粘度的HPMC和其他辅料由湿法制粒后压片制得。自制制剂和参比制剂的释放曲线采用美国药典中桨法进行评价,硝苯地平药物含量采用高效液相色谱法进行测定。结果使用不同的骨架材料药物的释放具有显著性差异,通过改变HPMC的种类调节和控制硝苯地平的释放。聚合度相同,与低粘度的HPMC(K4M,K100LV,E5)相比高粘度的HPMC(K15M)会使硝苯地平释放变慢。最终的处方用10 mg K4M作为主要的骨架材料,10 mg PVP K30作为释药调节剂。结论制备硝苯地平缓释片使用骨架材料HPMC K4M和释药调节剂PVP K30;口服缓释剂型可以改善慢性治疗顺应性并且可维持有效血药浓度。     

Controlled release of saccharides from matrix tablets.

The aim of this study was to design site specific, controlled release tablets of N-acetyl-d-glucosamine (NAG), maltose monohydrate and maltopentaose by using hydrophobic matrix formers starch acetate (SA) and ethyl cellulose (EC). The optimized matrices, which had either low porosity and high drug load or high porosity and low drug load, released the saccharides within the desired 2-4 h. In general, it was possible to control the release rate of saccharides by altering the relative amount of hydrophobic matrix former in the tablet and tablet porosity. The release type of saccharides from these formulations varied from immediate release to sustained release. In the case of sustained release formulations, it was found that the release of maltose monohydrate and maltopentaose was biphasic and slower than the release rate of NAG from similar tablets. NAG release kinetics followed square root of time kinetics, while in the case of maltose monohydrate and maltopentaose, the release kinetics were zero order in both phases. The biphasic dissolution profile was proposed to be caused by water mediated recrystallisation of the disordered material formed during the dissolution. Both SA and EC matrices were found to represent suitable controlled oral delivery vehicles for saccharides.     

Influence of beta-cyclodextrin complexation on glipizide release from hydroxypropyl methylcellulose matrix tablets

Glipizide was complexed with beta-cyclodextrin in an attempt to enhance the drug solubility. The phase solubility diagram was classified as A(L) type, which was characterized by an apparent 1:1 stability constant that had a value of 413.82 M(-1). Fourier transform infrared spectrophotometry, differential scanning calorimetry, powder x-ray diffractometry and proton nuclear magnetic resonance spectral analysis indicated considerable interaction between the drug and beta-cyclodextrin. A 2(3) factorial design was employed to prepare hydroxypropyl methylcellulose (HPMC) matrix tablets containing the drug or its complex. The effect of the total polymer loads (X1), levels of HPMC K100LV (X9), and complexation (X3) on release at first hour (Y1), 24 h (Y2), time taken for 50% release (Y3), and diffusion exponent (Y4) was systematically analyzed using the F test. Mathematical models containing only the significant terms (P < 0.05) were generated for each parameter by multiple linear regression analysis and analysis of variance. Complexation was found to exert a significant effect on Y1, Y2, and Y3, whereas total polymer loads significantly influenced all the responses. The models generated were validated by developing two new formulations with a combination of factors within the experimental domain. The experimental values of the response parameters were in close agreement with the predicted values, thereby proving-the validity of the generated mathematical models.     

Solubility enhancement of celecoxib using beta-cyclodextrin inclusion complexes.

Celecoxib has very low water solubility. It forms a complex with beta-cyclodextrin (betaCD) both in aqueous and in solid state. It was observed that due to formation of the inclusion complex, the solubility and dissolution rate of celecoxib were enhanced. The formation of 1:1 complex with betaCD in solution was confirmed by phase solubility and spectral shift studies. The apparent stability constants calculated by these techniques were 881.5 and 341.5 M(-1), respectively. The solid inclusion complexes of celecoxib and betaCD were prepared by the kneading method using different molar proportions of betaCD, and formation of solid inclusion complexes of celecoxib and betaCD at different molar ratios were confirmed by differential scanning calorimetry. Enhancement of dissolution rates with increasing quantity of betaCD in the complex was observed. It was also observed that the complexes exhibit higher dissolution rates than the pure drug and physical mixture.     

In-vitro evaluation of cinnarizine as a competing agent to beta-cyclodextrin inclusion complexes: effect of cinnarizine on the membrane permeation rate of progesterone from its beta-cyclodextrin inclusion complex

The use of competing agents is considered a powerful tool for the development of a drug-delivery system with drug/cyclodextrin inclusion complexes. However, there are very few studies examining this issue. To explain this phenomenon, it was thought that a competing agent with a sufficiently high stability constant had not yet been reported. In this study, cinnarizine (CN), which has a high stability constant with beta-cyclodextrin (beta-CD) and unique solubility characteristics, was selected, and its ability as a competing agent was examined in a membrane permeability study. The permeability study showed that the permeation rates of the drugs flurbiprofen, progesterone, and spironolactone decreased with their stability constants with the addition of beta-CD. In one of the drugs, progesterone (Pro), the decrease was restored by the addition of CN. The amount of CN added was a 1:1 molar ratio to the amount of Pro. However, no similar action was induced with the addition of DL-phenylalanine (Phe) in the permeation study at the 1:5 (Pro:Phe) molar ratio. These finding indicate that CN acts as a competing agent, and its action is much stronger than that of Phe.     

Controlled indomethacin release from mucoadhesive film: in vitro and clinical evaluations

To develop a film formulation allowing controlled release for long-term analgesia, we selected ethyl cellulose (EC) as a novel additive, prepared a film formulation using indomethacin (IM film), and evaluated it in vitro and clinically. In the in vitro experiments, the effects of the EC concentration on the release rate of IM and on the adhesion force to the mucous membrane were investigated. The addition of 10% EC resulted in more sustained slow release compared with no EC, and the adhesion of the film with 10% EC added was similar to that of films containing carboxyvinyl polymer, which we reported previously showed significantly increased adhesion. A two-layered film consisting of an adhesive layer with 2% or 1% IM and 10% EC and a nonadhesive layer with 2% polyethylene glycol as a softening agent, was investigated for clinical use. Film consisting of an adhesive layer with 2% IM and 10% EC exhibited rapid onset of potent analgesia and was expected to prolong the duration of analgesia. These results suggest that IM film with EC added may be useful clinically, since it shows both immediate analgesic effects and prolonged duration of release.     

Influence of beta-cyclodextrin complexation on carbamazepine release from hydroxypropyl methylcellulose matrix tablets.

The in vitro release profiles of carbamazepine and beta-cyclodextrin either complexed or simply mixed and subsequently incorporated in hydrophilic matrix tablets containing 15 or 30% hydroxypropyl methylcellulose were evaluated. Solubility studies revealed a linear relationship between the increase in carbamazepine solubility and the increase in beta-cyclodextrin concentration. Drying methods (spray-drying and freeze-drying) were used to obtain carbamazepine/beta-cyclodextrin solid complexes in order to prepare tablets. The results demonstrated that matrix tablets containing carbamazepine/beta-cyclodextrin solid complexes displayed faster carbamazepine and beta-cyclodextrin release compared to that containing simple physical mixture. Gelling and matrix formation was impaired in formulation containing 15% hydroxypropyl methylcellulose and spray-dried complex. The comparison of spray-drying and freeze-drying revealed no significant influence of both drying methods on carbamazepine and beta-cyclodextrin dissolution rate when carbamazepine/beta-cyclodextrin complexes were incorporated in 30% hydroxypropyl methylcellulose matrix tablets. The results point to the possibility of modulating carbamazepine release using a hydroxypropyl methylcellulose matrix associated to the drug complexed with beta-cyclodextrin.     

Preparation and characterization of inclusion complexes of prazosin hydrochloride with beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin

The slightly water-soluble drug prazosin hydrochloride (PRH) and its inclusion with either beta-cyclodextrin (betaCD) or hydroxypropyl-beta-cyclodextrin (HPbetaCD) were investigated. The phase solubility profiles of PRH with betaCD and HPbetaCD were classified as B(s)- and A(L)-types, respectively. Stability constants with 1:1 molar ratio were calculated from the phase solubility diagrams and the solubility of PRH could be enhanced by 27.6% for betaCD and 226.4% for HPbetaCD, respectively. Binary systems of PRH with betaCD or HPbetaCD prepared by various methods were characterized by differential scanning calorimetry and Fourier transformation-infrared spectroscopy. It could be concluded that PRH could form inclusion complex with either betaCD or HPbetaCD. The dissolution profiles of inclusion complexes were determined and compared with those of PRH alone and their physical mixtures. The dissolution rate of PRH was increased by betaCD and HPbetaCD inclusion complexation remarkably. Both the preparation technique and nature of the carriers played important roles in the dissolution performance of the systems. All the systems with HPbetaCD showed better performance than the corresponding ones with betaCD.     

硝苯地平缓释片在中国健康人体的生物等效性

目的评价硝苯地平缓释片在健康人体的生物等效性。方法 20名男性健康志愿者进行随机双交叉试验,分别单次和多次口服硝苯地平受试药物和参比药物,用液相色谱-串联质谱法测定血浆中硝苯地平的血药浓度,DAS2.1软件计算药代动力学参数。结果单次口服2种硝苯地平缓释片,受试药物和参比药物的主要药动学参数分别如下:Cmax为(92.68±34.98),(112.39±47.98)ng.mL-1,tmax为(2.68±0.69),(2.70±0.57)h;t1/2为(5.01±1.65),(4.83±2.16)h;AUC0-36 h为(648.09±332.98),(659.62±376.95)ng.h.mL-1;F为(104.1±25.6)%。AUC0-36 h,AUC0-∞,Cmax的[1-2α]置信区间分别为94.6%～108.29%,93.9%～106.9%,72.8%～100.6%。多次口服2种硝苯地平缓释片,达稳态时受试药物和参比药物的体内药代动力学参数分别如下:Cmax为(122.85±45.46),(141.29±53.51)ng.mL-1;tmax为(2.55±0.65),(2.70±0.66)h;t1/2为(5.57±1.91),(3.83±1.25)h;Cav为(57.36±26.31),(59.26±25.25)ng.mL-1;AUCss为(688.26±315.67),(711.10±303.01)ng.h.mL-1;F为(99.8±29.9)%。AUCss,Cmax的[1-2α]置信区间分别为85.8%～107.3%,73.5%～103.2%。结论受试药物与参比药物具有生物等效性。     

硝苯地平缓释片的制备及体外释放研究

目的制备具有良好释放性能的硝苯地平（NF）缓释片。方法将NF制备成固体分散体后,再以羟丙甲纤维素（HPMC）为骨架材料制备成缓释片,对固体分散体载体及骨架材料用量进行考察。结果随着聚乙烯吡咯烷酮用量的增加NF固体分散体溶出速率加快,所制备的缓释片体外释放缓慢、完全。结论固体分散技术可用于难溶性药物NF缓释片的制备。     

Effect of slow release nifedipine tablets in patients with essential hypertension.

The antihypertensive effect of slow release nifedipine (CAS 21829-25-4) tablets (20 mg, Adalat) administered once or twice daily was studied in patients with essential hypertension of WHO stage I or II. Ambulatory blood pressure was monitored by a finger volume oscillometric device every 5 min for 24 h before and during the treatment with nifedipine. Whether administered once or twice daily, nifedipine tablets dit not change the pattern of circadian blood pressure variation; i.e. diurnal rise and nocturnal fall. Twice daily administration induced a significant downward shift in the blood pressure pattern. In other words, further hypotensive effect was observed during the night when the blood pressure was already low. On the other hand, administration once daily in the morning lowered daytime blood pressure without affecting blood pressure during the night. The duration of action of nifedipine tablets administered once daily was 12 h or more. In the acute experiment using 20 mg tablets of nifedipine, plasma concentration of nifedipine was well correlated with the percentage change in mean blood pressure. The minimal effective plasma concentration of nifedipine was estimated to be 13.4 ng/ml. However, in chronic treatment, nifedipine lowered blood pressure at the plasma concentration of 10 ng/ml. The results indicate that nifedipine tablets administered once daily provide an effective antihypertensive regimen for controlling daytime hypertension with minimal antihypertensive effect during the night.