Biochemistry. 1995 Feb 28;34(8):2504-10.
Acyclic guanosine analogs inhibit DNA polymerases alpha, delta, and epsilon with very different potencies and have unique mechanisms of action.

Ilsley DD, Lee SH, Miller WH, Kuchta RD.

Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309.

Acyclovir triphosphate, ganciclovir triphosphate and penciclovir triphosphate inhibited DNA polymerases alpha, delta, and epsilon. Each triphosphate preferentially inhibited pol delta, although ganciclovir triphosphate was the most impressive of the three; the Ki for inhibition of pol delta was 2 microM (competitive with dGTP), while the Kis for inhibition of pol alpha and epsilon were 80 and 140 microM, respectively. Each of the compounds was polymerized by pol alpha, delta, and epsilon. Incorporation of acyclovir triphosphate resulted in immediate chain termination, whereas incorporation of ganciclovir triphosphate often allowed polymerization of additional dNTPs. Interestingly, chain termination most often occurred after polymerization of just one additional dNTP onto the ganciclovir monophosphate. All three compounds were very weak inhibitors of DNA primase. Acyclovir triphosphate, however, was a unique inhibitor of the pol alpha-catalyzed elongation of primase-synthesized primers. Immediately after DNA primase synthesized a primer, pol alpha frequently incorporated acyclovir triphosphate with consequent chain termination. If, however, pol alpha did not immediately polymerize acyclovir triphosphate onto the primase-synthesized primer, further dNTPs were readily added and acyclovir triphosphate was incorporated much less frequently.

Online pharmacy ref source - acyclovir: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7873530&dopt=Abstract acyclovir Zovirax




Ther Drug Monit. 1999 Feb;21(1):129-33.
Determination of acyclovir in plasma by solid-phase extraction and column liquid chromatography.

Poirier JM, Radembino N, Jaillon P.

Department of Pharmacology, Saint-Antoine University Hospital, Paris, France.

After oral administration, valacyclovir, the L-valyl ester of acyclovir, converts to the antiherpes virus drug, acyclovir. The bioavailability of acyclovir after valacyclovir administration is between 3- to 4.5-fold higher than that achieved after oral acyclovir administration. Therefore, despite the drug's short terminal half-life (3 hours), acyclovir plasma concentrations obtained after oral administration of the prodrug offer a more convenient dosage regimen in patients with herpes zoster than that required after acyclovir administration. Acyclovir is also used for viral infection prophylaxis in patients with hematologic disorders and in those who have undergone solid organ transplantation. We have described a simple and selective liquid chromatographic method for the determination of acyclovir in plasma using a new polymeric reversed-phase sorbent for solid-phase extraction. A mean acyclovir absolute recovery of 90% was found after elution of the drug from the cartridge with the mobile phase. This procedure allowed us to measure 62.5 ng/mL of acyclovir with an acceptable precision using a plasma volume of 250 microL, and no drug was found to interfere with the assay. This method is suitable for the therapeutic monitoring of acyclovir in patients who have been given a wide variety of coadministered drugs.

Online pharmacy ref source - acyclovir: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10051066&dopt=Abstract acyclovir Zovirax




J Ocul Pharmacol. 1994 Summer;10(2):439-51.
Ganciclovir ophthalmic gel in herpes simplex virus rabbit keratitis: intraocular penetration and efficacy.

Castela N, Vermerie N, Chast F, Sauvageon-Martre H, Denis J, Godard V, Goldschmidt P, Pouliquen Y.

Service de Pharmacie et de Pharmacologie, Paris, France.

A chronic administration of three ganciclovir gels (0.2%, 0.05%, 0.0125%) was compared with a placebo gel and a 3% acyclovir ophthalmic ointment in the treatment of HSV-1 rabbit keratitis. All the ganciclovir gels showed a clinical efficacy: a significant reduction of the corneal ulcer area, clouding and vascularization (p < 0.05) and a fast inhibition of HSV isolates into tear film with the 0.2% and 0.05% ganciclovir gels. However the efficacy was slower than using acyclovir ointment. No significant difference could be shown between the 0.2% and 0.05% ganciclovir gels or the 0.05% ganciclovir gel and the acyclovir treatment on viral isolation, when it was performed on pooled samples. The distribution of ganciclovir and acyclovir into the rabbit eyes (HPLC methods), were similar but markedly higher in solid tissues than ocular fluids. It might explain the recovery from tissue damages. The mean corneal ganciclovir concentrations were largely higher than ED 50 of ganciclovir for HSV-1. No toxicity was expected, due to very limited systemic availability. This study suggests a comparable activity on HSV-1 superficial keratitis between 0.05%, 0.2% ganciclovir gels and 3% acyclovir ointment. Higher concentration of ganciclovir gels are probably necessary in order to treat the HSV-1 kerato-uveitis.

Online pharmacy ref source - acyclovir: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8083563&dopt=Abstract acyclovir Zovirax

smh.toronto.on.ca

Acyclovir or similar agents with activity against Epstein-Barr virus (EBV) theoretically may prevent non-Hodgkin's lymphoma (NHL) in AIDS. A case-control study of 29 patients with AIDS-related NHL and 58 matched control subjects assessed the frequency with which daily acyclovir (>/=800 mg/d) or similar agents were used for > or =1 year. In a historical cohort of 304 patients with AIDS for > or =2 years, the prevalence of NHL was assessed among 3 groups of patients: those who received long-term treatment with high-dose acyclovir (or similar agents) or low-dose or intermittent acyclovir; those treated with ganciclovir/foscarnet for <1 year; and those who had not previously been treated with acyclovir, ganciclovir, or foscarnet. In the case-control study, 22 patients (72.4%) with NHL never received acyclovir or similar drugs versus 19 control subjects (32.8%; P=. 002); 2 patients (6.9%) with NHL received acyclovir (> or =800 mg/d) for > or =1 year versus 27 (46.6%) of control subjects (P=.0001). In the cohort study, 6 (6.8%) of 88 patients who received acyclovir (> or =800 mg/d) for > or =1 year developed NHL versus 15 (15.5%) of 97 patients who received intermittent or lower-dose acyclovir and 30 (25.2%) of 119 patients who never received these agents (P=.002). Long-term administration (>1 year) of high-dose acyclovir or similar agents with anti-EBV activity may prevent NHL in patients with AIDS. A prospective, randomized study is warranted to confirm these results.

Online pharmacy ref source - acyclovir: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10816144&dopt=Abstract acyclovir Zovirax




Transpl Int. 1995;8(2):152-6.
High-dose acyclovir and intravenous immune globulin reduce the incidence of CMV disease after liver transplantation.

Mor E, Meyers BR, Yagmur O, Kishikawa K, Sheiner PA, Emre S, Schwartz ME, Miller CM.

Department of Surgery, Mount Sinai Medical Center, New York, NY 10029, USA.

We attempted to prevent cytomegalovirus (CMV) disease in liver transplant (LTx) recipients by means of a combined prophylaxis regimen consisting of high-dose acyclovir (HDA) and immune globulin (IVIG). In 259 consecutive patients, HDA was given for 3 months post-LTx; recipients seronegative for CMV also received IVIG. The previous 94 patients comprised our control group; in this group, low dose acyclovir was given to prevent herpes, and prophylaxis of CMV consisted of IVIG given only to seronegative recipients of seropositive donors. The overall incidence of CMV disease was lower in the HDA group (10.8%) than in the control group (27.6%); (P < 0.001). The CMV disease rate associated with primary exposure was 26.3% in the HDA group and 83.3% in the control group (P < 0.001). The incidence of CMV disease occurring after acute rejection was 9.5% in HDA patients and 24.6% in controls (P < 0.005) The HDA protocol was associated with a trend toward a lower incidence of CMV in patients requiring OKT3 therapy (16.7% vs 29%). High-dose acyclovir/IVIG thus reduces the incidence of CMV disease in seronegative recipients after LTx and lowers the risk of CMV disease associated with therapy for rejection.

Online pharmacy ref source - acyclovir: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7766298&dopt=Abstract acyclovir Zovirax