The formulation and stability of erythromycin-benzoyl peroxide in a topical gel

The combination of benzoyl peroxide and erythromycin is used for the local treatment of acne and available as a commercial preparation. Because of the stability problems of erythromycin an extempore preparation is required. The influence of storage temperature and non active ingredients on the stability of benzoyl peroxide and erythromycin in topical gel preparations for extempore compounding is described. A microbiological and an HPLC method were used to determine the erythromycin and the benzoyl peroxide concentrations, respectively. For a formulation compounded with hydroxyethylcellulose no stability problems were observed. For the formulation containing Carbopol 940, the levels of erythromycin varied over a wide range due to precipitation and aggregation of the drug during compounding.     

异维A酸红霉素凝胶联合过氧苯甲酰凝胶治疗中、重度痤疮

目的观察异维A酸红霉素凝胶联合过氧苯甲酰凝胶治疗中、重度痤疮的疗效。方法将201例Ⅱ～Ⅳ度寻常痤疮患者随机分为2组,治疗组106例,对照组95例。治疗组予异维A酸红霉素凝胶联合过氧苯甲酰凝胶,对照组给予异维A酸红霉素凝胶治疗。每2周随访1次,观察疗效及不良反应,8周后进行治疗评定。结果治疗组痊愈率和有效率(58.49%、96.23%)高于对照组(36.84%、88.42%)。结论异维A酸红霉素凝胶联合过氧苯甲酰凝胶治疗中、重度痤疮较单纯外用异维A酸红霉素凝胶疗效好。     

A multicenter efficacy and tolerability evaluation of benzoyl peroxide in a 10% urea vehicle for the treatment of acne vulgaris

BACKGROUND: Acne vulgaris is a common skin disease that affects 70 to 96% of individuals. Topical benzoyl peroxide has been used successfully for acne treatment; however, it may be accompanied by drying and or flaking skin. The addition of a 10% urea to the product excipient is theorized to moisturize the skin due to its humectant properties, aid in the efficacy of benzoyl peroxide due to its keratolytic properties, and effectively combat Propionibacterium acnes due to its antibacterial properties. OBJECTIVE: To assess the efficacy and tolerability of the treatment of acne vulgaris with multiple strengths of benzoyl peroxide in a 10% urea vehicle gel or cream and cleanser. Methods: A multicenter, non-randomized, open-label study in which 1,089 patients with acne vulgaris were enrolled at 133 participating physician office sites. Qualifying and consenting patients were prescribed either 4.5% or 8.5% benzoyl peroxide in a 10% urea vehicle cream or gel and cleanser. Additional medications were permitted during the study with the exception of those containing benzoyl peroxide. The physician assessed lesion counts, both inflammatory and non-inflammatory, at baseline and Week 4. Dryness and erythema were rated by the physician on a scale from 0 (none) to 8 (severe or deep) at baseline and Week 4. RESULTS: Nine hundred sixty-three patients completed the study. The following significant treatment arms were analyzed: patients treated with 4.5%/8.5% benzoyl peroxide in a 10% urea vehicle product only, patients treated with 4.5%/8.5% benzoyl peroxide in a 10% urea vehicle products along with oral doxycycline, and patients treated with 4.5%/8.5% benzoyl peroxide in a 10% urea vehicle products along with oral minocycline. A 44% (n=567) mean reduction in total lesion count was observed after 4 weeks of treatment with 4.5%/8.5% benzoyl peroxide in a 10% urea vehicle products only. Dual therapy using oral doxycycline (n=17) proved to be even more effective with a significant mean reduction in lesion count of 52% after only 4 weeks of treatment. Dual therapy using oral minocycline (n=21) yielded a significant mean reduction in lesion count of 34% after 14 weeks of treatment. The overall tolerability of the treatment illustrated the utility of urea as a moisturizing agent. CONCLUSION: Benzoyl peroxide in a 10% urea vehicle gel or cream and cleanser, used once daily for 4 weeks was found to be both effective and well tolerated for the treatment of symptoms related to acne vulgaris.     

Topical antibacterial therapy for acne vulgaris

Topical antibiotics and benzoyl peroxide, are the two main topical antibacterial treatments indicated for mild-to-moderate acne vulgaris. Topical antibiotics act both as antibacterial agents suppressing Propionibacterium acnes in the sebaceous follicle and as anti-inflammatory agents. Benzoyl peroxide is a powerful antimicrobial agent that rapidly destroys both bacterial organisms and yeasts. Topical clindamycin and erythromycin have been proven to be effective against inflammatory acne vulgaris in concentrations of 1-4% with or without the addition of zinc. However, none of the antibacterials tested was more effective than benzoyl peroxide, which also has the advantage of not being associated with antimicrobial resistance.Topical antibacterial therapy should be discontinued once improvement is observed. If no improvement is observed within 6-8 weeks, the agent should be discontinued and a therapeutic switch considered. The primary limitation of benzoyl peroxide for some acne vulgaris patients is cutaneous irritation or dryness.Antibacterial therapy can be used in combination with other agents. Combining topical antibiotics and topical retinoids may enhance the efficacy, since the retinoid will improve the penetration of the antibiotic. Combining a topical antibiotic with benzoyl peroxide may increase the bactericidal effect of the antibiotic and reduce the potential for bacterial resistance. Topical and oral antibacterials should not be used in combination for the treatment of acne vulgaris, since this association may increase the risk of bacterial resistance.     

The utility of benzoyl peroxide in hydrophase base (Brevoxyl) in the treatment of acne vulgaris

Available for more than 5 decades, benzoyl peroxide has been a "workhorse" of acne therapy. The benefits of this agent include reduction in Propionibacterium acnes (P. acnes) with decrease in inflammatory lesions, efficacy as both "leave on" and cleanser formulations and reduced emergence of antibiotic-resistant P. acnes strains. As the effect of benzoyl peroxide on P. acnes is a direct toxic effect rather than as a "true" antibiotic, resistance to benzoyl peroxide does not occur and has never been reported. Benzoyl peroxide in hydrophase base (Brevoxyl Creamy Washes and Gels) has shown significant efficacy in the treatment of acne, with lower irritancy than other benzoyl peroxide preparations. It is felt that the low irritancy of this product is related to a unique delivery vehicle containing dimethyl isosorbide, which dissolves benzoyl peroxide crystals on the skin. Clinical studies demonstrating the efficacy and safety of benzoyl peroxide in hydrophase base will be reviewed.     

The absorption of benzoyl peroxide from leg ulcers.

Absorption and clinical efficacy of a preparation containing 20% benzoyl peroxide were studied in 20 patients with leg ulcers of varying etiology. Benzoic acid formed from benzoyl peroxide on penetration through the skin cannot be demonstrated in the plasma until three days after commencing application at the earliest. This indicates a building up of deposits of benzoyl peroxide in the skin. The plasma benzoic acid levels in all patients amounted to less than 5 mumol/l and is therefore toxicologically inoffensive. Clinically, the known therapeutic effects of benzoyl peroxide were confirmed. Neither sensitization nor allergic reactions were found in the 20 patients taking part in this study.     

Allergic contact dermatitis caused by topical antiacne drugs

Acne is a chronic inflammatory disease for which a long-lasting therapy, very often with topical drugs, is necessary. Despite the fact that several topical antiacne drugs (in particular, tretinoin, benzoyl peroxide, clindamycin and erythromycin) are used for many years, often on broad skin surfaces and for long periods of time, their potential for contact sensitization is low. Their potential for phototoxic and photoallergic reactions is also low. Much more frequent is irritant contact dermatitis caused by some of these drugs, in particular, retinoids and benzoyl peroxide, for which the short contact therapy has been recently suggested.     

Efficacy and safety of a ceramide containing moisturizer followed by fixed-dose clindamycin phosphate 1.2%/benzoyl peroxide 2.5% gel in the morning in combination with a ceramide containing moisturizer followed by tretinoin 0.05% gel in the evening for the treatment of facial acne vulgaris

Combination therapy addressing multiple pathogenic factors should be used to achieve optimal outcomes in treating acne. The following study demonstrated both safety and efficacy of fixed-dose clindamycin phosphate 1.2%/benzoyl peroxide 2.5% in the morning with micronized tretinoin 0.05% gel in the evening. Both products were applied to the skin following the use of a ceramide containing moisturizing lotion.     

Tazarotene versus tazarotene plus clindamycin/benzoyl peroxide in the treatment of acne vulgaris: a multicenter, double-blind, randomized parallel-group trial

Topical retinoids offer highly effective treatment for both inflammatory and non-inflammatory acne, with tazarotene demonstrating greater efficacy than other topical retinoids. A multicenter, double-blind, randomized, parallel-group trial has been performed to evaluate whether the adjunctive use of clindamycin/benzoyl peroxide could enhance the efficacy of tazarotene still further. Patients with moderate to severe inflammatory acne applied tazarotene 0.1% cream each evening and were randomly assigned to morning applications of vehicle gel or a ready-to-dispense formulation of clindamycin 1%/benzoyl peroxide 5 % gel containing 2 emollients. Tazarotene/clindamycin/benzoyl peroxide achieved a significantly greater reduction in comedo count than tazarotene monotherapy and, among patients with a baseline papule plus pustule count of > or =25 (the median value), a significantly greater reduction in inflammatory lesion count. The combination therapy was also at least as well-tolerated as tazarotene monotherapy. The adjunctive use of clindamycin/benzoyl peroxide gel with tazarotene cream promotes greater efficacy and may also enhance tolerability. Any improvements in tolerability could be due to the emollients in the clindamycin/benzoyl peroxide gel formulation.     

Evidence-based review: fixed-combination therapy and topical retinoids in the treatment of acne

Topical fixed-combination products and topical retinoid monotherapy are established first-line treatments for mild-to-moderate acne vulgaris, yet adequate comparative data are lacking. The following evidence-based review addresses the question: "In patients with mild-to-moderate acne, are topical fixed-combination products or topical retinoids a more efficacious choice in reducing noninflammatory, inflammatory and total lesions after 12 weeks of treatment?" To identify relevant studies, a PubMed search was performed using "acne" and search terms for adapalene, tretinoin, tazarotene, benzoyl peroxide, clindamycin, or erythromycin. Forty-two studies from January 1991 to November 2009 were included. The studies were evaluated using the Strength of Recommendation Taxonomy, and all but seven received the highest level of evidence grade. To evaluate efficacy, a side-by-side comparison was made using reduction in acne lesion counts at week 12 for study groups treated with fixed-combination therapy or retinoid monotherapy. Twenty-nine studies containing relevant efficacy data for fixed-combination therapy and retinoid monotherapy are summarized here. Nine studies compared fixed-combination therapy with retinoid monotherapy; in eight of these studies, fixed-combination therapy was significantly more efficacious in reducing acne lesion counts. This evidence-based review analyzes clinical evidence to date for these therapies to provide guidance in determining appropriate treatment for patients with mild-to-moderate acne.     

Benzoyl Peroxide Solubility and Stability in Hydric Solvents

Saturated solubility and reaction rate constants for the decomposition of benzoyl peroxide in solution and suspension were determined for use in formulation development. The solvents studied included ethanol, propylene glycol, and cosolvent mixtures of PEG 400 and water. The solubility of benzoyl peroxide was inversely related to the solvent polarity, with greater solubility occurring with semipolar solvents. The stability of benzoyl peroxide in solution was dependent on the solvent, concentration of benzoyl peroxide, and temperature. The compound was least stable in PEG 400. Stability was improved when water was added to PEG 400. Similar solvent effects were observed in suspension. In benzoyl peroxide suspensions of PEG 400 and PEG 400/water blends, benzoyl peroxide stability was dependent on solubility, with improved stability occurring in blends where the benzoyl peroxide was least soluble. Thus, solution formulations of benzoyl peroxide in pharmaceutically acceptable solvents are unlikely to show good stability; however, suspension formulations should be reasonably stable if the vehicle is selected to provide low benzoyl peroxide solubility.     

HPLC法测定祛痘类化妆品中的过氧化苯甲酰

目的建立高效液相色谱法测定祛痘除螨类化妆品中的过氧化苯甲酰的方法。方法采用ZORBAX C18柱,4．6×250mm．5μm;以甲醇-0．02mol·L^-1的醋酸铵溶液（80：20）为流动相;检测波长为230nm。结果过氧化苯甲酰在0．224μg·mL^-1～44．8μg·mL^-1范围内呈良好线性关系,r=0．9996．过氧化苯甲酰的平均回收率为95．94％．RSD％为2．5％。结论上述建立的方法简便易行、准确、重现性好,可用于祛痘类化妆品中禁用物质过氧化苯甲酰的检测。     

Topical clindamycin in the management of acne vulgaris

A small cadre of antimicrobials are commonly used and regarded as effective and safe, as systemic and topical treatments of acne vulgaris. These include oral tetracycline, doxycycline, minocycline and topical clindamycin and erythromycin. Topical antimicrobials work via both antimicrobial and non-antimicrobial mechanisms: the former due to suppression of the growth of propionibacterial species (especially Propionibacterium acnes and P. granulosum). Clindamycin appears to be superior in efficacy compared with erythromycin and tetracycline. However, the emergence and spread of resistance among propionibacteria to both erythromycin and clindamycin calls into question their long-term viability as topical anti-acne therapies. Only through judicious use of combination topical therapies (e.g., topical retinoid, benzoyl peroxide or azelaic acid plus clindamycin or erythromycin) and the practice of effective infection control (i.e., handwashing between seeing patients in the clinic) can both clindamycin's and erythromycin's widespread utility be preserved in this disorder.     

Topical clindamycin in the management of acne vulgaris

A small cadre of antimicrobials are commonly used and regarded as effective and safe, as systemic and topical treatments of acne vulgaris. These include oral tetracycline, doxycycline, minocycline and topical clindamycin and erythromycin. Topical antimicrobials work via both antimicrobial and non-antimicrobial mechanisms: the former due to suppression of the growth of propionibacterial species (especially Propionibacterium acnes and P. granulosum). Clindamycin appears to be superior in efficacy compared with erythromycin and tetracycline. However, the emergence and spread of resistance among propionibacteria to both erythromycin and clindamycin calls into question their long-term viability as topical anti-acne therapies. Only through judicious use of combination topical therapies (e.g., topical retinoid, benzoyl peroxide or azelaic acid plus clindamycin or erythromycin) and the practice of effective infection control (i.e., handwashing between seeing patients in the clinic) can both clindamycin's and erythromycin's widespread utility be preserved in this disorder.     

Comparison of clindamycin/benzoyl peroxide, tretinoin plus clindamycin, and the combination of clindamycin/benzoyl peroxide and tretinoin plus clindamycin in the treatment of acne vulgaris: a randomized, blinded study

In the treatment of mild to moderate acne vulgaris, the combination of an antibiotic and benzoyl peroxide provides enhanced efficacy over the individual agents, with the potential to decrease the emergence of resistant strains of P. acnes. To evaluate treatment regimens combining the daily use of a clindamycin/benzoyl peroxide gel, a tretinoin gel, and a clindamycin gel, the current randomized, evaluator-blind study was conducted. Results demonstrate that once-daily administration of clindamycin/benzoyl peroxide gel (combination formulation) was as effective as clindamycin/benzoyl peroxide gel + tretinoin gel + clindamycin gel. Both of these regimens provided greater efficacy than tretinoin + clindamycin. Treatment with clindamycin/benzoyl peroxide demonstrated a significant benefit over other treatments at Week 2, highlighting its rapid onset of action. All regimens were safe and generally well tolerated, with less severe peeling seen in patients who received clindamycin/benzoyl peroxide. In conclusion, the regimens that included clindamycin/benzoyl peroxide were more effective than tretinoin + clindamycin in the treatment of acne vulgaris, with no clinical advantage of adding tretinoin + clindamycin to once-daily clindamycin/benzoyl peroxide treatment.     

进口10%过氧化苯甲酰乳膏(欧可喜)与国产5%过氧化苯甲酰凝胶治疗寻常痤疮临床疗效比较

研究进口10%过氧化苯甲酰乳膏治疗寻常痤疮的疗效和安全性,以国产5%过氧化苯甲酰凝胶作阳性对照,进行了随机对照平行试验.两药分别外用患处,每日2次,连续6周.结果:10%过氧化苯甲酰与5%过氧化苯甲酰比较治疗寻常痤疮的治愈率和有效率分别为30.2%,85.7%和14%,62.8% (P〈0.05).两药的药物不良反应发生率分别为17.2%和33.0%( P>0.05).结果提示进口10%过氧化苯甲酰治疗寻常痤疮、的疗效和安全性优于国产5%过氧化苯甲酰,也是一种安全有效治疗痤疮的外用药.     

Benzoyl peroxide in the treatment of acne vulgaris: a double-blind, multi-centre comparative study of 'Quinoderm' cream and 'Quinoderm' cream with hydrocortisone versus their base vehicle alone and a benzoyl peroxide only gel preparation

A double-blind, multi-centre general practice study was carried out to compare the effectiveness of benzoyl peroxide/potassium hydroxyquinoline sulphate cream, with or without hydrocortisone, its aqueous astringent cream base alone, and a benzoyl peroxide alcoholic gel in the treatment of 107 patients with acne vulgaris. Patients on entry were allocated at random to one of four treatment groups and instructed to apply the medication twice daily to all affected areas for 12 weeks. Assessments of the severity of acne on the face, chest and back, and response to treatment were made at 2, 4, 8 and 12 weeks. Acceptability of the treatment, i.e. 'greasiness', was also assessed by patients. The results showed that the combination cream preparation produced a greater reduction in acne scores than did the base or benzoyl peroxide alone. The addition of 1% hydrocortisone eliminated the flare reaction to benzoyl peroxide seen in patients in the other two active treatment groups. The majority of patients found the preparations cosmetically acceptable.     

The stability of benzoyl peroxide by isothermal microcalorimetry

Isothermal microcalorimetry may be used to determine kinetic and thermodynamic parameters for chemical reactions. This paper reports rate constants, determined as a function of temperature, and the activation enthalpy for the degradation of solid benzoyl peroxide as determined by isothermal microcalorimetry. Studies were conducted on aqueous suspension phase, solid benzoyl peroxide. In addition, supporting evidence is cited from work carried out in this laboratory on the solution phase degradation of benzoyl peroxide using UV-visible spectrophotometry. The activation energy obtained by microcalorimetry was E(a)=137.8+/-6.6 kJ mol(-1) and the activation energy obtained from UV-visible spectrophotometry was E(a)=112.7+/-4.2 kJ mol(-1).     

High-pressure liquid chromatographic assay of benzoyl peroxide in dermatological gels and lotions.

A high-pressure liquid chromatographic method for the assay of benzoyl peroxide in dermatological preparations is described. Degradation products such as benzoic acid and perbenzoic acid do not interfere. The method is simple, precise, accurate, and stability indicating.     

Quantitative determination of benzoyl peroxide by high-performance liquid chromatography and comparison to the iodometric method

A selective high-performance liquid chromatographic (HPLC) procedure for the quantitative determination of benzoyl peroxide in pharmaceutical dosage forms is described. Benzoyl peroxide was dissolved or extracted in the presence of an internal standard, acenaphthylene. The specificity of the stability-indicating HPLC and iodometric procedures are presented for benzoyl peroxide.